A review of commercially important African medicinal plants

A review of commercially important African medicinal plants

Author’s Accepted Manuscript A review of commercially important African medicinal plants B.-E. Van Wyk www.elsevier.com/locate/jep PII: DOI: Referen...

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Author’s Accepted Manuscript A review of commercially important African medicinal plants B.-E. Van Wyk

www.elsevier.com/locate/jep

PII: DOI: Reference:

S0378-8741(15)30189-6 http://dx.doi.org/10.1016/j.jep.2015.10.031 JEP9788

To appear in: Journal of Ethnopharmacology Received date: 21 September 2015 Revised date: 11 October 2015 Accepted date: 19 October 2015 Cite this article as: B.-E. Van Wyk, A review of commercially important African medicinal plants, Journal of Ethnopharmacology, http://dx.doi.org/10.1016/j.jep.2015.10.031 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

A review of commercially important African medicinal plants B.-E. Van Wyk Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa.

ABSTRACT Ethnopharmacological relevance: Data on the relative importance and research status of commercially relevant African medicinal plants are needed for developing new research strategies in order to stimulate much-needed ethnopharmacological research and to promote the commercialization of African plants. Aim of the study: To present an illustrated bird’s eye view and comparative analysis of the relative popularity and importance of commercialised African medicinal plants. A comparison is made between the general popularity and commercial importance of the species (as indicated by their footprint on the World Wide Web) and their scientific popularity and importance (as indicated by the number of research publications). The inventory and review is strongly focussed to cover all or most of the medicinal plant raw materials in the international trade that are exported from African countries, with less emphasis on those that are regularly traded on local and regional markets within Africa. Materials and methods: The review is based on literature data, Scopus and Google searches, commercial information and the author’s own experience and observations. Results: More than 5400 plant species are used in traditional medicine in Africa, of which less than 10% have been commercially developed to some extent. Africa is home to more than 80 valuable commercial species that are regularly traded on

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international markets, including phytomedicines (e.g. Harpagophytum procumbens and Pelargonium sidoides), functional foods (e.g. Adansonia digitata and Hibiscus sabdariffa) and sources of pure chemical entities (e.g. caffeine from Coffea arabica and yohimbine from Pausinystalia johimbe). According to the Scopus results, about 60% of all recent publications on African medicinal plants appeared in the last decade, with an average of 280 papers (28 per year) for 85 prominent species of international trade. The most popular African species for research (number of publications in brackets) were: Ricinus communis (5187), Aloe vera (2832), Catharanthus roseus (2653), Sesamum indicum (2534), Strophanthus gratus (2514), Coffea arabica (2431), Citrullus lanatus (2215), Momordica charantia (2047), Withania somnifera (1767), Trigonella foenum-graecum (1687), Acacia senegal (1373), Centella asiatica (1355), Griffonia simplicifolia (1010), Hibiscus sabdariffa (987), Tamarindus indica (973) and Catha edulis (947). The top species in terms of recent research interest (% of publications in last decade) were: Hoodia gordonii (95%), Cyclopia genistoides (93%), Sceletium tortuosum (90%), Agathosma betulina (89%), Pelargonium sidoides (86%), Boswellia papyrifera (85%), Lessertia (Sutherlandia) frutescens (84%), Boswellia sacra (83%), Mondia whitei (81%), Hibiscus sabdariffa (80%), Hypoxis hemerocallidea (80%) and Tylosema esculentum (80%). Both lists reflect the recent interest in functional foods and dietary supplements. Conclusion: Despite a marked recent increase in the number of publications on indigenous medicinal plants and dietary supplements, Africa lags behind Europe and Asia in terms of the number of products that have been commercialised and the percentage of the flora that is utilised for international trade. There is a tremendous potential for developing new crops and new products but much work remains to be

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done to generate more focussed and relevant pre-clinical data and convincing proof of concept through clinical studies. Keywords: Africa; Continental comparisons; Functional foods; Inventory; Phytomedicines; Pure chemical compounds; Traditional Medicine E-mail address: [email protected] (B.-E. Van Wyk); Telephone number: +27-11559-2412; Fax number: +27-11-559-2411

1. Introduction

Africa is home to a remarkable diversity of medicinal plants and is also a focal point of human cultural diversity. De Smet (1999) provided an excellent ethnopharmacological introduction to the healing practises of African Traditional Medicine and to several iconic African medicinal plants and their modes of action. The combination of botanical and cultural diversity, together with local endemism, results in a complex geographical mosaic of indigenous plant use that remains only partially explored from a scientific and commercial perspective. It is the aim of this paper to provide a bird’s eye view of African medicinal plants and other natural products. The main trends towards commercialization and associated scientific exploration and documentation are highlighted.

2. Materials and Methods

2.1 Search strategy

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This review differs from traditional scientific reviews in the sense that the international popularity of a carefully selected list of medicinal plant species (Table 1) were evaluated, using the search engine Google (as an indication of general and commercial prominence) and not Google Scholar (to reflect scientific prominence, the search engine Scopus was used instead).

Personal experience (e.g. with Sutherlandia) has shown that Google can be effectively used to trace the international popularity of a new medicinal product by noting changes in the number of hits over time. The result should be used and interpreted with caution, as some poorly known or commercially unimportant medicinal plants may have a higher than expected footprint due to their key ecological or social functions or other specialized points of interest. Some medicinal plants, for example, are also important sources of commercial timber. Using the default setting of Google, the Latin binomial of each plant was entered (in quotation marks, as a phrase). Any species that is widely traded on international markets is likely to have a much larger web footprint (presence in a large number of websites) than one which is simply traded on local markets in Africa, however popular it may be. Google Scholar will obviously give a much better reflection of the scientific and research status of the species than Google, but for this purpose the search engine Scopus was chosen. Once again, the search terms were the Latin binomial of the plant but in some cases also prominent synonyms, as shown in Table 1. Scopus default settings were used, with the name search within the title, abstract and keywords of scientific publications, and with no limitations on the publication date or type of paper.

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2.2 Choice of species, classification and nomenclature

Critical to the success of the approach followed in this review, was the correct choice of species. An attempt was made to list (from general literature, scientific literature and own experience) all or most of the medicinal plants species that have in one way or another gained international prominence, mostly as items of trade (medicinal raw materials, phytomedicines, dietary supplements, functional foods and sources of valuable chemical entities. The choice was focused on African plants in the international trade, some of which are featured in international books and publications, including well-known pharmacopoeias.

The classification, nomenclature and author citations of the species follow The Plant List (2003).

2.3 Choice of subregion classification

The subregions of Africa as used here (Table 1 and Figure 1) follow the United Nations geoscheme for Africa (United Nations Statistics Division, 2015) but with the exception that Madagascar and associated Indian Ocean Islands are not included in East Africa but are regarded as a separate subregion (as shown in Fig. 1 and Table 1). This classification system is also similar to the climatic classification used by the Food and Agricultural Organization of the World (FAO, 2003), except that their Sudano-Sahelian and Gulf of Guinea are combined into one (West Africa) and that Mozambique, Malawi, Zambia and Zimbabwe are included in East Africa and not Southern Africa.

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3. Results

3.1 Botanical diversity and the documentation of medicinal plant use

Medicinal plants and their uses in sub-Saharan Africa are part of an ancient oraltraditional system of knowledge that remains incompletely documented. During the colonial era, much effort went into the production of local and regional Floras, which not only recorded and classified the plants but also served as plant use catalogues for the development of trade. An early example of an ethnobotanical survey was that of Simon van der Stel, the Dutch governor at the Cape of Good Hope, who undertook an exploratory journey to Namaqualand in 1685 (De Wet and Pheiffer, 1979). During the 19th and 20th centuries, colonial Floras were produced for the majority of African countries, which are now often outdated but still serve as important historical reference points. Major contributions to the current knowledge of African medicinal plants were the monumental compilations by Watt and BreyerBrandwijk (1962) for southern and eastern Africa, Burkill (originally published in 1937, revised edition 1985–2004) for West Africa and Neuwinger (2000) for Africa as a whole. The first African pharmacopoeia was published in two volumes (African Pharmacopoeia 1981, 1986). Iwu (1993) summarized available data, while Vasisht and Kumar (2004) gave a useful review of traditional medicine in the various regions of Africa.

A special milestone was the publication of a first comprehensive plant checklist for sub-Saharan Africa (Klopper et al., 2006), which provided new perspectives on the

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species diversity of the flora. An African herbal pharmacopoeia, providing detailed monographs for 51 species, was published in 2010 (Brendler et al., 2010). Pioneering work by Ermias Dagne at Addis Ababa University resulted in a comprehensive database of African medicinal plants, their chemistry and biological activity (Natural Database for Africa, 2011). The most extensive and valuable recent contribution to the documentation of the useful plants of tropical Africa is the PROTA programme, which was initiated in 2000 (see http://www.prota4u.org). PROTA stands for the Plant Resources of Tropical Africa and aims to treat more than 7000 species and publish them according to their commodity groups. An updated species list (PROTA, 2010a) increased the number of useful plants to 8681. Two volumes (out of a planned total of four) on medicinal plants have been published as volumes 11(1) and 11(2) of the PROTA series of publications. Volume 1 (Schmelzer and Gurib-Fakim, 2008) includes 894 primary use species, while Volume 2 treats 409 species in the form of 146 review articles (Gurib-Fakim and Schmelzer, 2013).

At a regional and local level, many review publications exist with data on medicinal plants and their uses. These include the results of ethnobotanical surveys, published as scientific papers in journals or as books, as well as published or unpublished reports. Neuwinger (2000) provides a comprehensive reference list, including the extensive literature for French-speaking Africa. For West Africa, there are, in addition to Burkill (1985–2004), also Ayensu (1978), Oliver-Bever (1986), the Ghana Herbal Pharmacopoeia (1992) and the compilations by the Nigerian Natural Medicine Development Agency (2004, 2006). For East Africa, there are reviews by Watt and Breyer-Brandwijk (1962), Kokwaro (1993), Abebe and Ayehu (1993) and Hedberg et al. (2009). A valuable recent contribution for Central Africa is that of Latham and

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Kondu ku Mbuta (2014), which includes colour photographs of many poorly known tropical species, together with notes on their uses, not only in the Democratic Republic of the Congo but also in other tropical parts of Africa. Monographs for 350 medicinal and aromatic plants of Madagascar and the Indian Ocean Islands were compiled by Gurib-Fakim and Brendler (2004), based on earlier publications by the first author. For southern Africa there are several publications, including Watt and Breyer-Brandwijk (1962), Gelfand et al. (1985), Hedberg and Staugård (1989), Hutchings et al. (1996), Von Koenen (2001), Van Wyk et al. (1997, 2009), Van Wyk and Gericke (2000) and Arnold et al. (2002).

Plants sold on local medicinal markets reflect local customs and traditions and often do not have any relation to international markets. Local markets are usually informal and unregulated, with the bulk of materials supplied through wild-harvesting or at best wild-crafting. These plants have been classified as “primary use medicinal plants” (PROTA 2010a). Of special value at local and regional level are the market surveys done by Cunningham (1988), Mander (1998) and Von Ahlefeldt et al. (2003) on traditional markets in KwaZulu-Natal, South Africa and similar work done by Williams et al. (2000) on the Witwatersrand. More recently, such studies were done in other parts of Africa, and a comprehensive review of the emerging pattern of local and trans-border trade would be most worthwhile (but is beyond the scope of the present study). Examples of recent market surveys include Van Andel et al. (2012) for Ghana, Quiroz et al. (2014) for Benin, Towns et al. (2014) for Gabon, Jusu and Sanchez (2014) for Sierra Leone, Otiena et al. (2015) for Tanzania and Randriamiharisoa et al. (2015) for Madagascar. These studies generally revealed exceptionally large volumes of trade and a massive annual turnover in what are still

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informal and unregulated markets. The formal, highly regulated market for over-thecounter products therefore exists in parallel to the informal traditional markets, with little or no evidence of integration.

3.2 Commercially relevant African plants and their relative importance

A total of 175 of the most prominent and well-known African medicinal plants are listed in Table 1. Names of 85 species prominent in international trade are given in bold and are listed with a relatively small selection of some of the most popular species that are commonly encountered on local African markets (names in normal script). The former have been subjected to further analyses, as shown in Table 2. The choice of species has partly been informed by Neuwinger (2000), Wichtl and Bisset (2001), Vasisht and Kumar (2004), Wichtl (2009), Brendler et al. (2010), Van Wyk et al. (2015) and Van Wyk and Wink (2015). Author citations for scientific names are given in the table and are not repeated elsewhere in the text. This data, incomplete as it may be, provide basic information for qualitative and semiquantitative assessments of the status of African plants, as presented in this paper. A selection of 71 commercially relevant African medicinal plants and plant products are shown in Figure 2.

Using the Google and Scopus search engines, the general (international) popularity and commercial/social relevance of the species (Google) and their popularity as research topics (Scopus) can be evaluated (Table 2). The steep increase in publications in recent years is noteworthy, showing that 60% of the total number of research publications appeared in the last decade (2006 to 2015). Medicinal plants,

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functional foods, dietary supplements, chemical entities and biodiesel have become popular in research programs. Pure chemical entities of commercial importance are also reflected in Tables 1 and 2, where they are included under the plant species from which they are extracted (or from which they were first extracted, before methods of synthesis or semi-synthesis were developed). It is evident from Tables 1 and 2 that only some of these source plants are still popular topics for publications (e.g. Catharanthus roseus, Strophanthus gratus and Coffea arabica) while for others the emphasis has shifted to the compounds themselves and the plant sources have gradually become less important (e.g. Ammi majus, Visnaga daucoides (=A. visnaga), Tabernanthe iboga, Synsepalum dulcificum, Voacanga africana, Rauvolfia vomitoria, Thaumatococcus daniellii, Physostigma venenosum, Pausinystalia johimbe and Sclerochiton ilicifolius. The popular interest in some of these compounds, as reflected in the number of Google hits, is noteworthy. Sclerochiton ilicifolius, the original source of the non-carbohydrate sweetener monatin, is conspicuous by its virtual absence from the scientific literature. The same is true for Namibian myrrh (Commiphora myrrha).

3.3 African species with the highest number of research publications

Tables 1 and 2 also show that species with (old or recent) cosmopolitan distributions (some of which have become popular crops) have the highest total number of research publications. The top species are Ricinus communis (5187), Aloe vera (2832), Catharanthus roseus (2653), Sesamum indicum (2534), Strophanthus gratus (2514), Coffea arabica (2431), Citrullus lanatus (2215), Momordica charantia (2047), Withania somnifera (1767), Trigonella foenum-graecum (1687), Acacia senegal

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(1373), Centella asiatica (1355), Griffonia simplicifolia (1010), Hibiscus sabdariffa (987), Tamarindus indica (973) and Catha edulis (947). Ricinus communis, of current interest as oilseed, is almost certainly of Ethiopian origin, given the extreme morphological diversity in that country (personal observations – see Figure 2, 53a and 53b). Aloe vera, of North African and Arabian origin, remains an important research subject. African species such as Citrullus lanatus, Hibiscus sabdariffa and Tamarindus indica (all originally endemic to Africa) are of current interest as sources of functional food, together with Adansonia digitata, Balanites aegyptiaca, Irvingia gabonensis, Sesamum indicum, Tamarindus indica, Trigonella foenum-graecum, Vitellaria paradoxa and others.

3.4 African species of recent scientific interest

In recent years, several African medicinal plants have become the subjects of intense commercial and scientific interest, as reflected in the percentage of research publications that have appeared during the last decade (in relation to preceding years). The 85 species listed in Table 2 had an average of 280 papers, i.e. 28 per year. Species with 80% or more of the total number of publications appearing in the last decade (shown in bold in Table 2) are Hoodia gordonii (95%), Cyclopia genistoides (93%), Sceletium tortuosum (90%), Agathosma betulina (89%), Pelargonium sidoides (86%), Boswellia papyrifera (85%), Lessertia (Sutherlandia) frutescens (84%), Boswellia sacra (83%), Mondia whitei (81%), Hibiscus sabdariffa (80%), Hypoxis hemerocallidea (80%) and Tylosema esculentum (80%). This list also reflects the recent interest in functional foods and dietary supplements. Excellent reviews on several of the listed species can be found in this and other

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issues of the Journal of Ethnopharmacology, the South African Journal of Botany and other journals.

3.5 International importance of African plants and continental comparisons

In the four volumes of the WHO Selected Monographs of Medicinal Plants (WHO 1999, 2003, 2007, 2009) only four African traditional medicines from sub-Saharan Africa are included, namely Aloe ferox (vol. 1, p.33), Commiphora myrrha (as C. molmol) (vol. 3, p. 247), Harpagophytum procumbens (vol. 3, p. 182) and Prunus africana (vol. 2, p. 246). To these may be added another four African plants that are shared with Ayurvedic and other systems of medicine: Centella asiatica (vol. 1, p. 77), Momordica charantia (vol. 4, p. 192), Ricinus communis (vol. 4, p. 271 and Withania somnifera (vol. 4, p. 373. If four North African plants are also counted in [Aloe vera (vol. 1, pp.. 33, 43), Ammi majus (vol. 3, p. 9), Senna alexandrina (as Cassia senna) (vol. 1, 241, 250) and Visnaga daucoides (as Ammi visnaga) (vol. 3, p. 23)] then the selection of African species for the monographs series comes to a total of only 12 species out of a total of 118 monographs, just over 10%. [Aloe vera is an ancient cultigen believed to be of North African or possibly Arabian origin].

In their most recent review entitled Medicinal Plants of the World, Van Wyk et al. (2015) included 36 African plants out of a total of 350 monographs, i.e. ca. 11%. Of the total of 43 species considered by Van Wyk and Wink (2015) to meet the criteria of phytomedicine (i.e. those with at least some clinical evidence of efficacy for a particular health condition), four are African endemics (nearly 10%). These are Griffonia simplicifolia, Harpagophytum procumbens, Pelargonium sidoides and

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Prunus africana. To these could be added three cosmopolitan species, namely Centella asiatica, Trigonella foenum-graecum and Withania somnifera). A fifth species that may soon qualify as a truly African phytomedicine is Sceletium tortuosum (kanna or kougoed), with a range of potential uses in neurology and psychiatry (it is a hypnotic and sedative) (Nell et al., 2013; Chiu et al., 2014). In the case of functional foods and nutraceuticals, at least 10 out of a total of 56 species are African in origin (nearly 18%). These are Adansonia digitata, Aloe ferox, Aspalathus linearis, Lepidium sativum, Hibiscus sabdariffa, Hoodia gordonii, Hypoxis hemerocallidea, Sesamum indicum, Synsepalum dulcificum and Tamarindus indica (see Table 1).

African plants also feature prominently amongst ca. 135 plants that are sources of commercially important chemical compounds, either used directly for therapeutic purposes or as starting materials for the semi-synthesis of valuable constituents. These include 13 species (nearly 10%): Catharanthus roseus (vincristine, vinblastine and several others – antitumour), Centella asiatica (asiaticoside – vulnerary), Coffea arabica (caffeine – CNS stimulant), Cissampelos pareira (cissampeline – skeletal muscle relaxant), Cyclopia genistoides (mangiferine – antioxidant), Pausinystalia johimbe (yohimbine – aphrodisiac), Synsepalum dulcificum (miraculin – sweetener), Sclerochiton illicifolius (monatin – sweetener), Strophanthus gratus (ouabain – cardiotonic), Physostigma venenosum (physostigmine – cholinesterase inhibitor, Alzheimer’s), Thaumatococcus daniellii (thaumatin – sweetener), Voacanga africana and V. thouarsii (tabersonine – used in the synthesis of vincamine, a cerebral stimulant).

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In their global review, Van Wyk et al. (2015) listed 911 of the most popular and best known medicinal plant species. A breakdown of these species according to their (sometimes overlapping) continental origin shows the following pattern: Asia – 432 spp. (47.4%), Europe – 339 spp. (37.2%), North America (including Central America) – 174 spp. (19.1%), Africa (including North Africa) – 111 spp. (12.2%), South America – 65 spp. (7.1%) and Australia (including the Pacific) – 10 spp. (1.1%). If North Africa is excluded, then the total for sub-Saharan Africa becomes 83 species (9.1%). It is noteworthy that the genetically rich southern hemisphere (sub-Saharan Africa, together with South America and Australia) are markedly under-represented, with only 158 species (collectively 17.3%).

The numbers of google hits also give some indication of the relative commercial importance of African plants in a global context. “Aloe vera” had by far the largest number of hits but this is somewhat misleading, because the common name for the plant agrees with the scientific name. “Coffea arabica” produced only 508 000 hits but the word “coffee” gave over a billion hits (1 030 000 000). Monatin gave 28 600 hits, while the name of the original African source plant (“Sclerochiton ilicifolius”) for this non-carbohydrate sweetener gave a mere 978 hits. It is interesting to note that Africa has contributed some of the most valuable of natural products on the international market, namely coffee (the most popular of all stimulant beverages, second only to petroleum as the most valuable natural product in international trade) and aloe vera (with an annual global retail value exceeding 110 billion US dollars, making it the most valuable of all medicinal plants (Geldenhuys and Van Wyk, 2002).

4. Discussion

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4.1 Gaps in the scientific knowledge

The data presented show that there is limited information available (or accessible) for Central Africa. It also shows several species for which hardly any recent scientific publications are available, despite commercial interests in the plants. Examples are Acanthosicyos horridus, Boswellia species, Bulbine frutescens, Commiphora guidottii, C. wildii, Drosera madagascariensis, Pausinystalia johimbe, Sclerochiton ilicifolius, Siphonochilus aethiopicus and Xysmalobium undulatum. Do we really need more scientific papers on Ricinus communis and Aloe vera when so many African plants have remained practically unstudied? Madagascar, given its rich species diversity and high levels of endemism, contributed a surprisingly small number of species to Table 1 (only 12) and Table 2 (only two). Apart from the well-known endemic Catharanthus roseus, the cosmopolitan Centella asiatica and the endangered Drosera madagascariensis, few if any local species have been commercialised for international markets. The rapidly developing medicinal and aromatic plants industry is mainly based on introduced species such as Vanilla planifolia and Cananga odorata. The same can be said for West and Central Africa (e.g. Ageratum conyzoides, Senna alata) and East Africa (e.g. Azadirachta indica, Cajanus cajan, Chenopodium ambrosioides, Jatropha curcas, Moringa oleifera, Tanacetum cinerariifolia). Several European and Asian species (not listed in Table 1) are grown on a commercial scale for the international market.

4.2 General trends

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The statistics given above demonstrate three general trends: (1) a steep increase, in the last decade, of the number of research outputs based on African plants, with 60% of the total number published since 2006; (2) commercial herbal medicine has been dominated by northern hemisphere plants, mainly from the traditional medicine systems of Europe and Asia (especially Ayurveda and Chinese Traditional Medicine); (3) the incorporation of southern hemisphere plants into the often formalised and highly regulated markets of the northern hemisphere has been a slow process. Although most of the African products on European markets have been there for a very long time, a few examples exist of recent introductions, such as Hoodia gordonii and Adansonia digitata. The statistics given above about the relatively small contribution of African plants to world health when compared to European, Asian and North American plants is noteworthy, as is the very modest contribution from South America and Australia. These regions seem poised to make a greater international impact in the future. The introduction of functional foods and so-called nutraceuticals from African and South American countries appears to be a new trend, probably aimed at breaking the barriers to market entry that are caused by the strict regulations that apply to products with explicit medical claims. Functional foods also featured prominent among the 25 African plants highlighted in a publication by PROTA (2010b). Roselle (Hibiscus sabdariffa) and sorghum (Sorghum bicolor) were singled out as plants with considerable commercial potential. It is likely that African products with some pharmacological activity, in addition to their nutritional value, will gain popularity in international markets and provide new research and development opportunities along the entire plant-to-product pipeline.

4.3 The commercialization of African medicinal plants

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This paper gives some new perspectives on the current status of African medicinal plants in a global context and the enormous future potential for new crop and new product development, especially in nutritional products and functional foods. It will hopefully help to motivate and inspire scientists and entrepreneurs from all over the world but from Africa in particular, to make a contribution to the African Renaissance (Baijnath and Singh, 2002) and to ensure that African plants are developed into innovative and sustainable new products for local and international markets. It is interesting to note the vision of a famous African intellectual and statesman, Jan Christiaan Smuts (amongst others, the founder of the concept of holism) that was published as a signed foreword on a new Pan-African map (Cape Times, 1944): “Our common task in Africa today is to develop the heritage handed down to us by many men and many nations. This continent, rich in untapped wealth, must be used for the common good if real progress is to be achieved. We can thus make Africa the continent of the future.”

The commercialization process is currently informed and regulated within the framework of the Convention on Biological Diversity (CBD) and the Nagoya Protocol. The CBD was opened for signature at the Earth Summit in Rio de Janeiro, Brazil, in June 1992 and has been signed by 168 countries. It has three main objectives, aimed at ensuring sustainable development: the conservation of biological diversity, the sustainable use of natural resources and the fair and equitable sharing of the benefits arising from the commercial use of indigenous plants and animals. Sustainable use, conservation concerns and the need to develop cultivation protocols are discussed by Ojewole (this issue) and are not repeated here. The

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equitable sharing of benefits is now regulated by the adoption (on 29 October 2010, in Nagoya, Japan) of the Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilisation. Although the Nagoya Protocol provides a sound framework for achieving a fair and equitable sharing of benefits, the implementation and associated regulations at national level have many unintended consequences that threaten to hinder rather than promote new product development. Phillips (2009) provides a balanced and informative review of African perspectives on Access and Benefit Sharing and what this means in practice.

International treaties and associated regulations are highly relevant in the context of product development and commercialization because they tend to create additional barriers to market entry in a field of commercial endeavour where “tapping the untapped wealth” and “developing the heritage handed down to us” will depend on entrepreneurial enthusiasm and an increase in commercial activity. A reversal of the recent trend towards more and more regulations and unproductive official interference seems desperately needed in order to allow dedicated and inspired scientists (botanists, ethnobotanists, ethnopharmacologists, organic chemists), entrepreneurs, administrators and government officials the freedom to work towards “the common good” and “real progress”.

Although a detailed exploration of the taxonomy, morphology, anatomy, chemistry, genetics and pharmacology of African plants is a pre-requisite for new innovations, a shift from a product-driven to a market-driven research approach may lead to a more efficient use of scientific resources and research funding. Access to international

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markets is important, but much can be done to focus on proof-of-concept studies and the development of cost-effective phytomedicines, functional foods and other natural products for local markets. These should conform to the highest possible quality standards in terms of ethics, efficacy and economics. Local capacity and local success stories will ultimately contribute towards African Traditional Medicine gaining its rightful place alongside the other great healing traditions of the world.

5. Conclusions

African species represent ca. 10% of the medicinal plants traded in international markets, as well as ca. 10% of plant-derived pure chemical entities. African plants such as Coffea arabica and Aloe vera are amongst the most valuable of all natural products on international markets. Beaurocracy and regulations may have a negative impact on innovation and the commercialization of African medicinal plants. There is a tremendous potential for the commercialization of under-utilised African plants, especially in functional foods and nutraceuticals, where Africa is already making a substantial contribution, with at least 10 species of major economic importance. Many medicinal plants remain scientifically poorly known, especially those from Central Africa and Madagascar. There has been a recent strong surge in research publications on African medicinal plants – ca. 60% of all scientific papers were published in the last decade. Research strategies should focus on obvious gaps in the literature, including proof-of-concept studies to further stimulate commercial interest.

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Acknowledgements Funding from the University of Johannesburg and the National Research Foundation of South Africa (to the National Research Chair in Indigenous Plant Use) is gratefully acknowledged.

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study of cognition effects of the proprietary extract Sceletium tortuosum (Zembrin) targeting phosphodiesterase-4 in cognitively healthy subjects: Implications for Alzheimer's dementia. Evidence-based Complementary and Alternative Medicine, 2014, art. no. 682014. DOI: 10.1155/2014/682014 Cunningham, A.B., 1988. An investigation of the herbal medicine trade in Natal/KwaZulu. Investigational Report No. 29. Institute for Natural Resources, University of KwaZulu-Natal, Pietermaritzburg. De Smet, P.A.G.M., 1999. Herbs, health, healers – Africa as ethnopharmacological treasury. Afrika Museum, Berg en Dal. De Wet, G.C., Pheiffer, R.H. (eds), 1979. Simon van der Stel’s journey to Namaqualand in 1685. Human and Rossouw, Cape Town. FAO, 2003. Review of world water resources by country. Food and Agriculture Organization of the United Nations. http://www.fao.org/docrep/005/y4473e/y4473e09.htm (accessed 25 September 2015) Geldenhuys, C.J., Van Wyk, B.-E., 2002. Indigenous biological resources of Africa. In: Baijnath, H., Singh, Y. (eds), Rebirth of Science in Africa. Umdaus Press, Hatfield. Gelfand, M., Mavi, S., Drummond, R.B., Ndemera, B., 1985. The Traditional Medicinal Practitioner in Zimbabwe. Mambo Press, Gweru, Zimbabwe. Ghana Herbal Pharmacopoeia, 1992. Policy Research and Strategic Planning Institute, Accra. Gurib-Fakim, A., Brendler, T., 2004. Medicinal and aromatic plants of Indian Ocean islands: Madagascar, Comores, Seychelles and Mascarenes. Medpharm Scientific Publishers, Stuttgart.

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Gurib-Fakim, A., Schmelzer, G.H. (eds), 2008. The Plant Resources of Tropical Africa 11(2). Medicinal Plants 2. CTA PROTA, Wageningen. Hedberg, I., Staugård, F., 1989. Traditional medicinal plants: Traditional medicine in Botswana. Ipeleng, Gaborone. Hedberg, I., Friis, I., Persson, E., 2009. Flora of Ethiopia and Eritrea, Vol. 8. The National Herbarium, Addis Ababa University, Addis Ababa and the Department of Systematic Botany, Uppsala University, Uppsala. Hutchings, A., Scott, A.H., Lewis, G., Cunningham, A. 1996. Zulu Medicinal Plants. Natal University Press, Pietermaritzburg. Iwu, M.M., 1993. Handbook of African Medicinal Plants. CRC Press, Boca Raton. Jusu, A., Sanchez, A.C., 2014. Medicinal plant trade in Sierra Leone: threats and opportunities for conservation. Economic Botany 68, 16–29. Klopper, R.R., Chatelain, C., Bänninger, V., Habashi, C., Steyn, H.M., De Wet, B.C., Arnold, T.H., Gautier, L., Smith, G.F., Spichiger, R., 2006. Checklist of the flowering plants of Sub-Saharan Africa. An index of accepted names and synonyms. South African Botanical Diversity Network Report No. 42. SABONET, Pretoria. Kokwaro, J.O., 1993. Medicinal Plants of East Africa, 2nd ed.. East Africa Literature Bureau, Nairobi. Latham, P., Konda ku Mbuta, A., 2014. Useful plants of Bas-Congo province, Democratic Republic of Congo, 2nd ed., 2 vols. Published by the authors. Mander, M., 1998. Marketing of Indigenous Medicinal Plants in South Africa: A Case Study in KwaZulu-Natal. Food and Agricultural Organization of the United Nations, Rome.

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Natural Database for Africa, 2011. Version 2.0. NDA is a species based versatile database developed by Ermias Dagne, Ethiopia ([email protected]). Nell, H., Siebert, M., Chellan, P., Gericke, N., 2013. A randomized, double-blind, parallel-group, placebo-controlled trial of extract Sceletium tortuosum (Zembrin) in healthy adults. Journal of Alternative and Complementary Medicine, 19 (11), 898– 904. Neuwinger, H.D., 2000. African Traditional Medicine – A Dictionary of Plant Use and Applications. Medpharm Scientific Publishers, Stuttgart. Nigerian Natural Medicine Development Agency, 2004. Medicinal plants of Nigeria: South-West Nigeria. Nigerian Natural Medicine Development Agency, Lagos. Nigerian Natural Medicine Development Agency, 2006. Medicinal plants of Nigeria: North Central Zone. Nigerian Natural Medicine Development Agency, Lagos. Oliver-Bever, B. (ed.), 1986. Medicinal Plants of Tropical West Africa. Cambridge University Press, Cambridge. Otieno, J., Abihudi, S., Veldman, S., Nahashon, M., Van Andel, T., De Boer, H.J., 2015. Vernacular dominance in folk taxonomy: a case study of ethnospecies in medicinal plant trade in Tanzania. Journal of Ethnobiology and Ethnomedicine 2015, 11: 10 doi:10.1186/1746-4269-11-10 Phillips, D. (ed.), 2009. Plants, people and nature. Benefit sharing in practice. AAMPS Publishing, Mauritius. PROTA, 2010a. The Plant Resources of Tropical Africa. Updated list of species and commodity groupings. Backhuys Publishers and CTA PROTA, Wageningen. PROTA, 2010b. Review of 25 African plants with special potential. Backhuys Publishers and CTA PROTA, Wageningen.

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Quiroz, D., Towns, A., Legba, S.I., Swier, J., Brière, S., Sosef, M., Van Andel, T., 2014. Quantifying the domestic market in herbal medicine in Benin, West Africa. Journal of Ethnopharmacology 151, 1100–1108. Randriamiharisoa, M.N., Kuhlman, A.R., Jeannoda, V., Harison Rabarison, H., Rakotoarivelo, N., Randrianarivony, T., Raktoarivony, F., Randrianasolo, A., Bussmann, R.W., 2015. Medicinal plants sold in the markets of Antananarivo, Madagascar. Journal of Ethnobiology and Ethnomedicine 2015, 11: 60. doi:10.1186/s13002-015-0046-y Schmelzer, G.H., Gurib-Fakim, A. (eds), 2008. The Plant Resources of Tropical Africa 11(1). Medicinal Plants 1. Backhuys Publishers and CTA PROTA, Wageningen. The Plant List, 2013. The Plant List. A working list of all plant species, version 1.1. Royal Botanic Gardens, Kew and Missouri Botanical Garden. http://www.theplantlist.org/ Towns, A.M., Quiroz, D., Guinee, L., De Boer, H., Van Andel, T., 2014. Volume, value and floristic diversity of Gabon‫׳‬s medicinal plant markets. Journal of Ethnopharmacology 155, 1184–1193. United Nations Statistics Division, 2015. Standard Country and Area Codes Classifications. http://millenniumindicators.un.org/unsd/methods/m49/m49regin.htm (accessed 25 September 2015) Van Andel, T., Myren, B., Van Onselen, S., 2012. Ghana’s herbal market. Journal of Ethnopharmacology 140, 369–378. Van Wyk, B.-E., Gericke, N., 2000. People’s Plants – A Guide to Useful Plants of Southern Africa. Briza Publications, Pretoria.

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Van Wyk, B.-E., Wink, M., 2015. Phytomedicines, herbal drugs and poisons. Kew Publishers, Kew and University of Chicago Press, Chicago. Van Wyk, B.-E., Van Oudtshoorn, B., Gericke, N., 1997. Medicinal Plants of South Africa. Briza Publications, Pretoria. Van Wyk, B.-E., Van Oudtshoorn, B., Gericke, N., 2009. Medicinal Plants of South Africa, 2 nd edn. Briza Publications, Pretoria. Van Wyk, B.-E., Wink, C., Wink, M., 2015. Handbuch der Arzneipflanzen. Wissenschaftliche Verlagsgesellschaft, Stuttgart. Vasisht, K., Kumar, V., 2004. Compendium of Medicinal and Aromatic Plants. Vol. 1. Africa. ICS-UNIDO, Trieste. Von Ahlefeldt, D., Crouch, N.R., Nichols, G., Symmonds, R., McKean, S., Sibiya, H., Cele, M.P., 2003. Medicinal plants traded on South Africa’s eastern seaboard. Ethekwini Parks Department and University of Natal, Durban. Von Koenen, E., 2001. Medicinal, poisonous and edible plants in Namibia. Klaus Hess Publishers, Windhoek and Göttingen. Watt, J.M., Breyer-Brandwijk, M.G., 1962. The Medicinal and Poisonous Plants of Southern and Eastern Africa. 2nd edn. Livingstone, London. WHO Monographs on selected medicinal plants, 1999, 2003, 2007, 2009 (Vols 1–4). World Health Organisation, Geneva. Wichtl, M., 2009. Teedrogen und Phytopharmaka. Wissenschaftliche Verlagsgesellschaft, Stuttgart. Wichtl, M., Bisset, N.G. (eds), 2000. Herbal Drugs and Phytopharmaceuticals. CRC Press, Boca Raton.

25

Williams, V.L., Balkwill, K., Witkowski, E.T.F., 2000. Unravelling the commercial market for medicinal plants and plant parts on the Witwatersrand, South Africa. Economic Botany 54, 310–327.

Captions for figures Figure 1. Map of sub-Saharan Africa showing the countries that are included in each of the five major regions as listed in Table 1.

Figure 2a. African medicinal plants of traditional and/or commercial importance. 1, Abrus precatorius (1a, leaves and flowers; 1b, seed); 2, Acacia drepanolobium (2a, twigs showing swollen thorn bases; 2b, gum); 3, Acacia senegal (3a, leaves and fruits; 3b, gum); 4, Acacia seyal (4a, leaves and flowers; 4b, gum); 5, Acanthosicyos horridus (5a, female – fruiting – plant; 5b, male and female flowers; 5c, fruit and edible seeds); 6, Adansonia digitata (6a, tree; 6b, fruit with seeds and edible dry fruit pulp); 7, Aframomum melegueta (seeds); 8, Agathosma betulina (8a, leaves and flowers; 8b, dried leaves); 9, Aloe ferox [9a, flowering plant; 9b, aloe lump (bottom), powdered aloe lump (middle), spray-dried leaf juice (top)]; 10, Aloe vera [10a, plants; 10b, fresh gel (left), spray-dried gel (right)]; 11, Artemisia afra (11a, leaves and flower heads; 11b, dried leaves); 12, Aspalathus linearis [12a, leaves, flowers and fruits; 12b, rooibos tea (fermented left, green rooibos on the right)]; 13, Azadirachta indica leaves and flowers; 14, Balanites aegyptiaca (14a, tree; 14b, leaves and thorns; 14c, fruits).

26

Figure 2b: 15, Boswellia neglecta (15a, leaves and fruits; 15b, gum-resin); 16, Boswellia papyrifera (16a, tree; 16b, leaf and flowers; 16c, gum-resin); 17, Boswellia rivae gum-resin; 18, Boswellia sacra (18a, leaves; 18b, gum-resin); 19, Bulbine frutescens (19a, flowering plant; 19b, leaves showing gel); 20, Cajanus cajan (20a, leaves, flowers and fruit; 20b, seeds); 21, Carissa edulis (21a, flowers; 21b, fruits); 22, Catha edulis fresh leaves; 23, Catharathus roseus flowers; 24, Centella asiatica leaves; 25, Coffea arabica flower and fruits; 26, Cola acuminata leaves and fruit.

Figure 2c: 27, Combretum micranthum (dried leaves and cut leaves – kinkeliba tea); 28, Commiphora guidottii (gum-resin – scented myrrh); 29, Commiphora myrrha (29a, leaves and fruits; 29b, gum-resin – myrrh); 30, Commiphora wildii (gum-resin – Namibian myrrh); 31, Cyclopia genistoides (31a, leaves and flowers; 31b, cut and processed herb – honeybush tea); 32, Griffonia simplicifolia seeds; 33, Hagenia abyssinica (33a, female tree in flower; 33b, leaf and female flowers – kosso); 34, Harpagophytum procumbens (34a, leaves and flowers; 34b, fruit; 34c, sliced and dried secondary roots); 35, Harungana madagascariensis (leaves and fruits); 36, Hibiscus sabdariffa (36a, flower; 36b, dried calyces – roselle); 37, Hoodia gordonii (flowering plant); 38, Hypoxis hemerocallidea (38a, flowering plant; 38b, corms); 39, Kigelia africana fruits; 40, Lepidium sativum (40a, flowers and fruits; 40b, seeds); 41, Lessertia (Sutherlandia) frutescens (41a, flowers and fruits; 41b, dried leaves); 42, Lippia javanica leaves and flower heads; 43, Mondia whitei (43a, flowers; 43b, dried roots and powdered root).

27

Figure 2d: 44, Moringa oleifera (44a, leaf and flower; 44b, seeds); 45 Moringa stenopetala (45a, tree; 45b, flowers; 45c, bundle of fresh leaves as sold on local markets); 46, Pausinystalia johimbe (46a, leaves; 46b, bark – source of yohimbine); Myriothamnus flabellifolius (47a, flowering plant; 47b, leaves and flowers); 48, Pelargonium sidoides (48a, flowering plant; 48b, flowers, 48c, fresh roots); 49, Physostigma venenosum (48a, leaves; 48b, seeds – source of physostigmine); 50, Phytolacca dodecandra (50a, leaves and flowers; 50b, fruits); 51, Prunus africana (51a, leaves and fruits; 51b, bark); 52, Rauvolfia vomitoria (leaves and fruits); 53, Ricinus communis (53a, leaves and flowers; 53b, seeds – Ethiopian provenances); 54, Salvadora persica (54a, leaves and fruits; 54b, stems – toothbrush sticks); 55, Sceletium tortuosum (55a, flowering plant; 55b, traditional dried product); 56, Securidaca longepedunculata (56a, leaves and flowers; 56b, root bark – inner and outer surfaces).

Figure 2e: 57, Sclerochiton ilicifolia – the original source of monatin; 58, Senna alexandrina (58a, leaves and flowers; 58b, dried leaves and pods – senna products); 59, Sesamum indicum (59a, leaves and flower; 59b, seeds – white and black cultivars); 60, Siphonochilus aethiopicus (60a, flowering plant; 60b, rhizome with fleshy roots; 60c, dormant rhizomes as sold on markets); 61, Solanum incanum (flowers and green fruits); 62, Strophanthus gratus – source of ouabain; 63, Tamarindus indica (63a, fruits; 63b, flower); 64, Trigonella foenum-graecum (64a, plant; 64b, leaves, flower and fruit; 64c, seeds – modern cultivar on the left); 65, Vernonia amygdalina (leaves and flowers); 66, Vitellaria paradoxa – seed oil (shea butter); 67, Voacanga africana seeds – source of tabersonine); 68, Warburgia salutaris (68a, leaves and fruits; 68b, mature bark; leaves and bark from cultivated

28

trees); 69, Withania somnifera (69a, leaves, flowers and fruits; 69b, roots); 70, Xylopia aethiopica (dried fruits – Guinea pepper); 71, Xysmalobium undulatum (71a, leaves and flowers; 71b, dried roots – uzara, ishonghwe).

Table 1. A selection of 175 of the most popular and important medicinal plants of subSaharan Africa. Species of commercial interest in the international pharmaceutical and nutraceutical industries are shown in bold type. The list is incomplete for species that are traded mainly within Africa (shown in normal type). Main uses: PH = phytomedicine (at least some clinical evidence of efficacy; DS = dietary supplement and/or functional food; CH = source of a useful chemical compound(s); ES = source of essential oil; TM = traditional medicine (i.e., as yet no convincing clinical data to support efficacy for any particular application). Origin (see Figure 1 for included countries): WA = West Africa; EA = East Africa; SA = Southern Africa; PA = Pan-African; Ma = Madagascar and Indian Ocean Islands; Co = Cosmopolitan; Cu = cultigen of unknown/uncertain origin. General references (1–6): 1 = Neuwinger (2000); 2 = Vasisht and Kumar (2004); 3 = Wichtl (2009), but see also Wichtl and Bisset (2001); 4 = African Herbal Pharmacopoeia (Brendler et al., 2010); 5 = Van Wyk et al. (2015); 6 = Van Wyk and Wink (2015). Species, author citation and family (nonindigenous species)*

Trade name and/or Vernacula r name

Part(s ) used

Main uses (see caption)

Origi n (see capti on)

Abrus precatorius L. (Fabaceae) Fig. 2

crab’s eye vine, coral pea

leaves (seeds are extrem ely toxic)

PA, Ma

Acacia drepanolobiu m Sjöstedt (Fabaceae) Fig. 2 Acacia karroo Hayne (Fabaceae)

whistling thorn

gum

sweet thorn

gum

Acacia

Egyptian

gum

TM (asthma, bronchitis, coughs, stomach cramps, malaria, physical and sexual asthenia; wounds) TM (root: diuretic; bark: pharyngitis); gum as for gum arabic TM (bark: diarrhea; root: colic); gum as for gum arabic TM (all

29

SubSaharan African countries involved in local, regional or internati onal trade many countries

Refere n-ces (see caption )

No. of Scopus hits

No. of Google hits on 24 June 2015

1, 2, 6

472

190 000

EA

Ethiopia (gum)

1, 2

96

21 700

SA, EA

South Africa, Zimbabw e

1, 2

183

59 600

EA

Mozambi

1, 2

1046

372 000

nilotica (L.) Willd. ex Delile (Fabaceae) Acacia senegal (L.) Willd. Fabaceae) Fig. 2

thorn

gum arabic

gum (exuda te)

TM (bark, root); gum: emollient, wound healing); pharmaceutic al aid (emulsifier, stabilizer, additive)

WA, EA

Acacia seyal Delile (Fabaceae) Fig. 2 Acanthosicyos horridus Welw. ex Hook.f. (Cucurbitacea e) Fig. 2 Adansonia digitata L. Malvaceae) Fig. 2

red acacia

gum

EA

!nara

seeds

TM (bark, root, leaf); gum as for gum Arabic TM (root); seed oil (edible, cosmetics)

SA

baobab

dry fruit pulp

TM (all parts); DS (fruit pulp: anti-oxidant)

PA

Aframomum melegueta K.Schum. (Zingiberacea e) Fig. 2

melegueta pepper

seeds

TM (leaf, fruit, seed); DS (spice)

WA, CA

Agathosma betulina (Berg.) Pillans (Rutaceae) Fig. 2

round leaf buchu

leaves

TM (urinary antiseptic); DS (bitter tonic); ES (food

SA

parts); gum as for gum arabic

30

que, South Sudan, Tanzania Central African Republic, Chad, Eritrea, Ethiopia, Ghana, Madagas car, Mali, Nigeria, Rwanda, South Sudan, Tanzania Ethiopia, South Sudan

1, 2, 4, 5, 6

1373

430 000 (gum arabic: 553 000)

1, 2

219

86 500

Namibia

1

4

5 500

Burkina Faso, Madagas car, Malawi, Nigeria, South Africa, South Sudan, Tanzania, Zimbabw e Cameroo n, Democrat ic Republic of the Congo (hereafter D.R. Congo), Equatoria l Guinea, Gabon, Ghana South Africa

1, 2, 4, 6

358

313 000 (baobab: 11 100 000 )

1, 2, 3, 5, 6

115

51 600

1, 2, 3, 4, 5, 6

47

25 900 (buchu: 414 000)

flavourant) TM (wound healing, diarrhea, dyspepsia, as febrifuge; many uses) TM (diversity of ailments)

Ageratum conyzoides L. (Asteraceae)*

goat weed, billy-goat weed

leaves

Albizia adianthifolia (Schumach.) W.Wight (Fabaceae) Alepidea amatymbica Eckl. & Zeyh., A. cordifolia B.-E. van Wyk and other spp. (Apiaceae) Allanblackia floribunda Oliv.

flat crown, umgadank awu

bark

ikhathazo

rhizom e and roots

TM (respiratory ailments – colds and influenza)

tallow tree

seeds

Aloe ferox Mill. and other species (Asphodelacea e) Fig. 2 Aloe vera L. (Asphodelacea e) Fig. 2

Cape aloe

exudat e, leaf gel

aloe vera

leaf gel

Ammi majus L., Visnaga daucoides Gaertn. [=Ammi visnaga (L.) Lam.] Apiaceae Antidesma madagascarie nse Lam. (Euphorbiacea e) Aphloia theiformis Benn. (Flacourtiacea e) Artemisia afra Jacq. ex Willd. (Asteraceae) Fig. 2

bishop’s weed

fruits

bois bigaignon

Artemisia rehan Chiov.

Burundi, D.R. Congo, Ethiopia, Ghana, Nigeria Kenya, South Africa

1, 2

567

177 000

1

32

12 100

SA, EA

South Africa, Zimbabw e

1, 2

31, 2

3580, 227

TM (bark, fruit, leaves); seed oil (edible, cosmetics) TM (laxative); DS (gel drinks, bitter tonic, flavourant) DS (tonic drinks); leaf gel (cosmetic, wounds) TM (many uses); CH (xanthotoxin: psoriasis, leukoderma, vitiligo)

CA, WA

Cameroo n, Côte d’Ivoire

1,2

23

9 350

SA, EA

South Africa, Kenya

1, 3, 4

150

370 000

Cu

South Africa

1, 3, 5, 6

2832

25 900 000

EA

South Sudan, Ethiopia, Somalia (India)

3, 5, 6

186, 335

143 000 (A. visnaga: 130 000)

leaves, bark

TM (dysentery, fever, diabetes)

Ma

Madagas car

4

11

1 530

fandamane

leaves, roots

TM (leaves: malaria, fever; root: worms)

Ma

Madagas car

1, 4

19

6 550

African wormwood

herb

TM (digestive and respiratory ailments); ES (fragrance)

SA, EA

1, 4

108

18 700

ariti

herb

ritual incense; ES

EA

Ethiopia, South Africa, Tanzania, Zimbabw e Ethiopia

5

4 150

31

WA, CA, EA

PA

(=A. absinthium L.?) (Asteraceae) Aspalathus linearis (Burm.f.) R. Dahlgren (Fabaceae) Fig. 2 Athrixia phylicoides DC. (Asteraceae) Aucoumea klaineana Pierre (Burseraceae) Azadirachta indica A.Juss.* (Meliaceae) Fig. 2

(fragrance)

rooibos tea

herb

TM (antispasmodi c); DS (health tea); cosmetics

SA

South Africa

bush tea

herb (tea)

DS (health tea)

SA

South Africa

oukoumé

resin

TM (general health)

WA

Gabon

neem

all parts

TM (malaria and many other ailments); seed oil (antifertility agent)

Asia

African pearwood tree, moabi tree desert date

bark, seeds

TM (bark); seed oil (cosmetics)

CA

all parts, fruits, seeds

DS (fruits); seed oil (food, cosmetics)

CA, EA

Bersama abyssinica Fresen. (Melianthacea e)

winged bersama, umukaka

bark, leaves, roots

WA, EA, SA

Boophone disticha (L.f.) Herb. (Amaryllidace ae) Boswellia frereana Birdw. (Burseraceae) Boswellia neglecta S.Moore (Burseraceae) Fig. 2 Boswellia papyrifera (Del. ex Caill.) Hochst.

poison bulb

bulb

maydi frankincen se

resin

olibanum

gumresin

TM (anthelmintic, dysentery, roundworm, hemorrhoids, aphrodisiac) TM (analgesic, wound healing; hallucinogen) TM (topical); traditional incense; ES (fragrance) TM (topical); traditional incense

Ethiopian frankincen se

gumresin

TM (topical); traditional incense; ES (fragrance)

Baillonella toxisperma Pierre Balanites aegyptiaca (L.) Delile (Zygophyllace ae) Fig. 2

32

260

148 000 (rooibos tea: 517 000)

28

4 100

1

39

23 100

Chad, Kenya, Madagas car, Niger, South Sudan, Tanzania Cameroo n

1,2

4 861

545 000

1,2

24

10 100

Chad, Ethiopia, Madagas car, South Sudan Ethiopia and many other countries

1,2,4

312

86 400

1

33

7 450

Lesotho, South Africa, Swazilan d Somalia only

1

17

14 500

2

10

18 200

EA

Ethiopia, Kenya

1

6

8 750

EA

Ethiopia, Eritrea, South Sudan

1

66

20 600 (frankincen se: 1 220 000)

SA

EA

1,2,3,4, 5,6

(Burseraceae) (Fig. 2) Boswellia rivae Engl. (Burseraceae) Fig. 2 Boswellia sacra Flueck. (=B. carteri Birdw.) (Burseraceae) Fig. 2 Bowiea volubilis Harv. ex Hook.f. (Hyacinthacea e)

frankincen se

gumresin

TM (topical); traditional incense; ES (fragrance)

EA

Ethiopia

Arabian frankincen se

gumresin

TM (topical); traditional incense; ES (fragrance)

EA

Somalia

climbing potato, igibisila

bulb

TM (headache, constipation, oedema, infertility, cystitis) TM (diarrhea, indigestion, skin problems, leprosy)

SA

abalo, Brucea antidysenter waginos ica J.F.Mill. (Simarouba ceae)

leaves, roots

4

4 150

1, 4

152

103 000

South Africa

1

16

30 100

EA

Ethiopia, Kenya

1

27

10 500

Bulbine frutescens (L.) Willd. (Asphodelacea e) Fig. 2 Cajanus cajan (L.) Millsp.* (Fabaceae) Fig. 2

bulbine, burn jelly plant

leaf gel

TM (topical); cosmetics

SA

South Africa

1, 4

29

48 100 (bulbine: 203 000)

pigeon pea

leaves, seeds, roots

India

Kenya, Malawi, Nigeria, Uganda, Tanzania

1, 4

2691

372 000 (pigeon pea: 386 000)

Calotropis procera (Aiton) W.T. Aiton (Apocynaceae )

giant milkweed, arka (Ayurveda )

roots, leaves

TM (leaves: sickle-cell anaemia, numerous ailments); DS (seeds) TM (root: diarrhea, dysentery, dyspepsia; leaves or latex: ulcers, leprosy)

WA, EA

1

827

174 00

Cananga odorata (Lam.) Hook.f.* (Annonaceae) Cannabis sativa L.* (Cannabaceae)

ylangylang

fresh flower

ES (fragrance))

Asia

Benin, Ethiopia, Ghana, Kenya, Somalia, Sierra Leone, South Sudan, Togo Madagas car

1,2

105

394 000

marijuana

herb

TM (analgesic, anti-emetic, asthma); intoxicant

Asia

1, 3, 5, 6

3569

915 000

Carapa procera DC.

African crabwood

seeds

seed oil: cosmetic

CA, WA

Ethiopia, South Africa and other countries (usually illegal) Cameroo n, Congo,

1

56

17 600

33

(Meliaceae)

uses; TM (bark, leaves, seed oil: fever, respiratory and digestive ailments) TM (numerous ailments); DS (fruits: appetizer for invalids)

Gabon, Ivory Coast, Mali, Senegal

Carissa edulis (Forssk.) Vahl. (Apocynaceae ) Fig. 2

simple spined carissa

roots, leaves, fruits

Cameroo n, Ethiopia, Kenya, Madagas car, Namibia, South Africa, Tanzania, Zimbabw e Ethiopia, Somalia

1, 4

71

18 500

Catha edulis (Vahl.) Forssk. (Celastraceae) Fig. 2 Catharanthus roseus (L.) G.Don (Apocynaceae ) Fig. 2

khat

roots, bark, leaves

TM (roots, bark); DS (fresh leaves: stimulant)

SA, EA

1, 5, 6

947

131 000 (khat: 3 240 000)

Madagasca r periwinkle

herb

Cedrelopsis grevei Baill. (Rutaceae) Centella asiatica (L.) Urb. (Apiaceae) Fig. 2

katrafay

bark

CH (vinca alkaloids vinblastine, vincristine and others: leukemia and Hodgkin’s lymphoma) TM (fever, back pain)

Ma

Burundi, Madagas car, Rwanda and other countries

1, 4, 5, 6

2653

411 000

Ma

Madagas car

1

22

12 600

Indian pennywort

herb

PH (topical: prevention of scar tissue formation); CH (asiaticoside: vulnerary) TM (anthelmintic, fever); ES (anthelmintic)

Co

Madagas car, Tanzania

1, 3, 4, 5, 6

1355

583 000 (gotu kola: 631 000)

Chenopodium ambrosioides L.* (Amaranthace ae)

wormseed

seeds

SAm, CAm

Burundi, Rwanda, Zimbabw e

1, 2, 5, 6

384

130 000

Chironia baccifera L. (Gentianaceae ) Cinchona ledgeriana (How.) Bern.Moens. and other spp.* (Rubiaceae)

Christmas berry

herb

TM (hemorrhoids, ulcers, acne)

SA

South Africa

1

7

4530

quinine tree

bark

TM (malaria, appetite stimulant)

SAm

Burundi, D.R. Congo, Guinea, Kenya, Madagas car, Rwanda,

1, 5, 6

63 (Cinch ona: 4167)

25 800 (Cinchona: 482 000)

34

PA

Cissampelos pareira L., C. mucronata A.Rich. (Menispermac eae) Citrullus lanatus (Thunb.) Matsum. & Nakai (Cucurbitacea e) Clausena anisata (Willd.) Hook.f. (Rutaceae) Clivia miniata (Lindl.) Regel (Amaryllidace ae) Coffea arabica L. (Rubiaceae) Fig. 2

velvetleaf

all parts

TM (gout, syphilis and numerous other ailments)

PA

Tanzania almost all countries

1, 2

117

41 400

Kalahari melon

seeds

seed oil (edible, cosmetics); also TM

SA

Botswana

1

2215

381 000

horsewood

root, leaves

PA

many countries

1

94

15 900

bush lily

whole plant

TM (numerous ailments; chewing sticks) TM (uterotonic)

SA

South Africa

1

82

176 000

coffee

seeds

CH (caffeine: CNS stimulant)

EA

1, 2,

2431

509 000 (coffee: 1 030 000 00)

Cola nitida (Vent.) Schott. & Endl., C. acuminata (P.Beauv.) Schott. & Endl. (Malvaceae) Fig. 2 Colophosper mum mopane (J.Kirk ex Benth.) J.Léonard (Fabaceae) Combretum micranthum G.Don (Combretacea e) Fig. 2 Combretum nigricans Lepr. ex Guill. & Perr. (Combretacea e) Commiphora africana (A.Rich) Engl. (Burseraceae) Commiphora erythraea

cola nuts

seeds

CH (caffeine, theobromine: stimulant)

WA, CA

Ethiopia, Kenya, South Africa, Tanzania Cameroo n, D.R. Congo, Gabon, Ghana, Nigeria, Senegal

1, 2, 3, 5, 6

113, 134

110 000

mopane

seeds

ES (frangrance); TM (bark: diarrhoea; many uses)

SA, EA

Namibia

1

218

33 700

kinkeliba

leaves

DS (tonic tea); also TM (bark, leaves: many uses)

WA

Côte d’Ivoire, Mali, Senegal

1, 4

21

18 800 (kinkeliba: 54 600)

gum combretum

gum

TM (root, leaves); edible gum, similar to gum Arabic

WA

Burkina Faso, Nigeria

1, 2

45

4 700

African myrrh, bdellium

gumresin

PA

Chad

1

45

16 100

opopanax tree

gumresin

incense; TM (all parts: numerous ailments) incense, TM, ES

EA

Somalia

13

6 630

35

Engl. (Burseraceae) Commiphora guidottii Chiov. (Burseraceae) Fig. 2 Commiphora myrrha (Nees) Engl. (Burseraceae) Fig. 2 Commiphora wildii Merxm. (Burseraceae) Fig. 2 Cryptolepis sanguinolenta (Lindl.) Schltr. (Apocynaceae ) Curtisia dentata (Burm.f.) C.A.Sm. (Curtisiaceae) Cyclopia genistoides (L.) R.Br. and other spp. (Fabaceae) Fig. 2 Dacryodes edulis (G.Don) H.J.Lam (Burseraceae) Danais fragrans C.F.Gaertn. (Rubiaceae) Dichrostachys cinerea (L.) Wight & Arn. (Fabaceae)

(fragrance) scented myrrh, bisabol

gumresin

incense, TM, ES (frangrance)

EA

Ethiopia, Somalia

1

7

1 900

myrrh tree

gumresin

TM (antiseptic); incense; ES (fragrance)

EA

Ethiopia, Somalia

1, 2, 3, 4, 5, 6

95

183 000 (myrrh: 1 080 000)

Namibian myrrh tree, omumbiri

gum resin

ES (fragrance)

SA

Namibia

0

2600

Ghana quinine

roots

TM (malaria)

WA

Ghana, Madagas car

1, 4

105

11 200

assegai, umlahleni

bark

TM (tonic, aphrodisiac, diarrhea)

SA

South Africa

1

14

6 100

honeybush

herb

TM (health tea); CH (mangiferin)

SA

South Africa

4

44

6 200 (honeybus h tea: 62 500)

safou, safu, butterfruit

seed

DS (seed oil); also TM (all parts: many ailments)

CA

Cameroo n, Gabon

1

132

25 900

liane jaune

roots, bark

Ma

Madagas car

1, 4

4

1 330

sickle bush

roots

TM (analgesic, skin infections) TM (numerous ailments)

SA, EA

South Africa, Mozambi que, Zimbabw e

1

179

43 500

Dicoma anomala Sond. (Asteraceae)

hloenya

root (leaves )

TM (numerous ailments)

SA, EA

1

23

3 390

Dicoma capensis Less. (Asteraceae) Dodonaea viscosa Jacq. (Sapindaceae) Drosera

koorsbossi e

leaves

TM (fever, diuretic)

SA

Lesotho, South Africa, Zimbabw e South Africa

1

6

1 220

sand olive, umusasa

leaves, roots

TM (many ailments)

many countries

1

226

95 400

sundew

herb

TM

EA, CA, SA Ma

Madagas

3, 5, 6

7

18 500

36

madagascarie nsis DC. (Droseraceae) Echinops kebericho Mesfin (Asteraceae) Embelia schimperi Vatke (Primulaceae) Eucomis autumnalis (Mill.) Chitt. (Hyacinthacea e) Euphorbia hirta L. [=Chamaesyce hirta (L.) Millsp.]

(respiratory ailments)

car

kebericho

roots

TM (diarrhea, stomach ache, fever, typhus)

EA

Ethiopia

inkoko

seeds

TM (anthelmintic)

EA

Ethiopia, Tanzania

pineapple flower, amathunga

bulb

TM (bone fractures, numerous ailments)

SA

asthma herb

leaves

TM (amebic dysentery and numerous other ailments)

Co

Fadogia agrestis Schweinf. ex Hiern (= Vangueria agrestis) Rubiaceae Faidherbia albida (Delile) A. Chev. (Fabaceae)

baraboro

bark

TM (aphrodisiac, erectile dysfunction)

WA

ana tree

bark

Garcinia afzelii Engl., G. mannii Oliv. and other spp. (Clusiaceae)

garcinia

stems, roots

TM (toothache, cough, diarrhea and other ailments) oral hygiene (toothbrush sticks)

Garcinia kola Heckel (Clusiaceae)

bitter kola

seeds

TM (numerous ailments); DS (antioxidant, aphrodisiac, immunostimu lant)

WA, CA

Glinus lotoides Loefl. (Molluginacea e) Gnetum africanum Welw. (Gnetaceae)

damascisa, lotus sweetjuice, metera eru

fruits

TM (tapeworm)

EA

leaves

DS (leaves); TM (numerous uses)

CA

37

9

1 530

1

20

3 960

South Africa

1

41

23 300

Madagas car, Mauritius and many other African countries Nigeria

1, 4

396

108 000

1

15

23 500

WA, EA, SA

Mali, South Sudan, Ethiopia

1

158

47 200

WA, CA

Cameroo n, Côte d’Ivoire, Equatoria l Guinea, Gabon, Ghana, Nigeria Cameroo n, D.R. Congo, Equatoria l Guinea, Nigeria, Sierra Leone Ethiopia

1, 2

7, 5

15 800, 1 320

1, 4

326

435 000

1

42

11 700

Cameroo n, D.R. Congo, Gabon

1

47

14 600

Griffonia simplicifolia (Vahl ex DC.) Baill. (Fabaceae) Fig. 2

griffonia

seeds

CH (5hydroxytrypt ophan: neurological and psychiatric disorders) TM (impotence, infertility and many other uses) TM (anthelmintic)

WA

Côte d’Ivoire, Ghana

1, 4

1010

357 000 (griffonia: 431 000)

Gunnera perpensa L. (Gunneraceae)

river pumpkin, ugobho

rhizom e

SA

South Africa

1

29

5 650

Hagenia abyssinica (Bruce) J.F.Gmel. (Rosaceae) Fig. 2 Harpagophyt um procumbens DC. ex Meisn. , H. zeyheri Decne (Pedaliaceae) Fig. 2 Harungana madagascarie nsis Lam. ex Poir. (Hypericaceae ) Fig. 2 Helichrysum odoratissimum (L.) Sweet (Asteraceae) Heteromorpha arborescens (Spreng.) Cham. & Schltdl. Apiaceae) Hibiscus sabdariffa L. (Malvaceae) Fig. 2

kosso

female flower s

EA

Ethiopia

1

58

18 600

devil’s claw

second ary roots

TM (antiinflammatory ; bitter tonic); PH (low back pain)

SA

Botswana , Namibia, South Africa

1, 2, 3, 4, 5, 6

331

212 000

haronga

bark, leaves

TM (digestive ailments, topical uses)

PA

Madagas car

1, 4, 5, 6

73

17 000 (haronga: 29 900)

imphepho

leaves

TM; ritual incense

SA

South Africa

1

22

5 390

parsley tree, mkatlala

stems

TM (aphrodisiac, hypertension, headache)

SA, EA

Lesotho, South Africa, Zimbabw e

1

6

3 720

hibiscus, red sorrel

calyx and epicaly x

CA

Mali, Senegal, South Sudan

1, 2, 3, 4, 5, 6

987

410 000

hoodia, ghaap, ghôba

stem

DS (antioxidant); TM (numerous uses; also topical) DS (functional food, to suppress hunger and thirst)

Hoodia gordonii (Masson) Sweet ex Decne (Apocynaceae ) Fig. 2 Hypoxis hemerocallide a Fisch. & C.A.Mey.

SA

Botswana , Namibia, South Africa

4, 5, 6

98

494 000 (hoodia: 1 100 000)

hypoxis, African potato

corm

DS (general tonic; prostate hyperplasia)

EA, SA

Mozambi que, South Africa

1, 4, 5, 6

90

12 000 (Harzol: 18 900)

38

(Hypoxidacea e) Fig. 2 Ipomoea pescaprae L. (Convolvulace ae)

goat’s foot

leaves, roots

Irvingia gabonensis Baill. (Irvingiaceae)

dika nut tree

seed oil

Jateorhiza palmata (Lam.) Miers (Menispermac eae)

calumba

root

Jatropha curcas L.* (Euphorbiacea e) Juniperus procera Hochst. ex Endl. (Cupressaceae )

purging nut

seeds, leaves

African cedar

twigs and leaves

Kigelia africana (Lam.) Benth. (Bignoniaceae ) Fig. 2

sausage tree

fruit (bark, roots)

Leonotis leonurus (L.) R.Br. (Lamiaceae)

wild dagga

herb

Lepidium sativum L. (Brassicaceae) Fig. 2

garden cress

seeds

Lessertia frutescens (L.) P.Boldblatt & J.C.Manning [=Sutherlandi a frutescens

sutherlandi a, cancer bush

leaves

TM (antihistamini c, antimicrobial, antiinflammatory ) DS (edible nut, oil); also TM (bark, leaves: numerous ailments, weight loss) TM (diarrhoea, dysentery and other uses); DS (bitter tonic, anorexia nervosa) TM (purgative; numerous other uses) TM (antifertility, expectorant, rheumatism) ES (fragrance, medicinal) TM (antimicrobial , antineoplastic ; numerous traditional uses) TM (respiratory ailments, numerous other uses) DS (colic, dysentery, headache, asthenia, measles, rheumatism) DS (bitter tonic; diabetes, numerous ailments)

39

Co

all coastal countries

1, 4

127

74 200

CA, WA

Cameroo n, Equatoria l Guinea, Gabon

1

161

353 000

EA

Malawi, Mozambi que

1

1

7 500

SAm

Many countries

1

2801

440 000

EA

Kenya

1

114

26 700

PA

Ethiopia, South Africa and many other countries

1, 4

139

160 000

SA

South Africa

1

66

81 600

EA

South Sudan, Ethiopia

1

1084

195 000

SA

Lesotho, Namibia, South Africa,

1,4

99, 16

6 470 (Sutherlan dia frutescens: 31 800)

(L.) R.Br.] (Fabaceae) Fig. 2 Lippia javanica (Burm.f.) Spreng. (Verbenaceae) Fig. 2

fever tea

herb

TM (coughs, colds, headache, numerous other ailments); ES (mosquito repellent) DS (stomachic, tonic, health tea) TM (chewing sticks, aphrodisiac)

SA, EA

Mozambi que, South Africa, Zimbabw e

1

77

12 300

Lippia scaberrima Sond. (Verbenaceae) Massularia acuminata (G.Don) Bullock ex Hoyle (Rubiaceae) Merwilla plumbea (Lindl.) Speta (=Scilla natalensis Planch.) (Hyacinthacea e)

mosukujan e

herb

SA

Botswana

1

27

1 720

massularia

bark, roots

CA, WA

Cameroo n, Sierra Leone

1

18

25 000

inguduza

bulb

TM (fertility, purgative, wound healing)

SA

South Africa

1

15, 12

21, 4 290

Momordica charantia L. (Cucurbitacea e) Mondia whitei (Hook.f.) Skeels (Apocynaceae ) Fig. 2

bitter melon

leaves

TM (numerous ailments)

PA

Many countries

1, 3, 5, 6

2047

428 000

White’s ginger

root

TM (aphrodisiac; numerous ailments)

PA

1, 4

43

43 200

Monodora myristica (Gaertn.) Dunal (Annonaceae)

calabash nutmeg, African nutmeg

fruit, seeds

PA

1

83

25 700

Morinda lucida Benth. (Rubiaceae)

brimstone tree

leaves, roots, bark

135

16 100

drumstick tree, horseradis h tree

all parts

Madagas car, Nigeria, D.R. Congo Madagas car, South Sudan and most tropical parts

1

Moringa oleifera Lam.* (Moringaceae) Fig. 2

fruit: essential oil, spice; ES (flavourant); TM (stimulant, stomachic, many ailments) TM (fever, diabetes and numerous other ailments) DS (health food); TM (many and diverse ailments)

Benin, Kenya, South Africa, Zimbabw e Benin, Cameroo n, Equatoria l Guinea, Gabon

1, 4

1638

583 000

40

CA, WA

India

Moringa stenopetala (Baker f.) Cufod. (Moringaceae) Fig. 2 Myrianthus arboreus P. Beauv. (Urticaceae)

Ethiopian horseradis h tree, African moringa

leaves

DS (health food)

EA

Ethiopia, Kenya

giant yellow mulberry, bush pineapple

leaves, bark, roots

DS (fruits, leaves); TM (headache, pains, numerous ailments)

WA, EA

Myrothamnus flabellifolius (Sond.) Welw. (Myrothamnac eae) Fig. 2

resurrectio n plant

herb

TM (respiratory ailments); ES (antimicrobial )

SA

Cameroo n, Congo, Ghana, Ivory Coast, Nigeria, Sierra Leone, Tanzania Angola, Mozambi que, Namibia, South Africa, Zimbabw e

andy

bark

Ma

Ocimum gratissimum L. (Lamiaceae)

African basil, romba

herb

Ocotea bullata (Burch.) Baill. (Lauraceae)

stinkwood, unukani

bark

Olea europaea L. subsp. africana (Mill.) P.S.Greene (Oleaceae) Parinari excelsa Sabine (Chrysobalana ceae)

wild olive

leaves, bark, roots

TM (rheumatism, asthenia, erectile dysfunction) TM, ES (colds, respiratory ailments, headache, fever and diversity of other uses) TM (headache, stomach complaints, nervous disorders, infantile diarrhoea) TM (urinary tract, colic, ophthalmia, tapeworm)

Guinea plum

roots, bark

TM (stomach complaints, headache, wounds)

Nauclea – see Sarcocephalus Neobeguea mahafaliensis J.-F.Leroy (Meliaceae)

41

57

24 200

1

21

5 500

1

31

22 200

Madagas car

1

0

685

PA

Burundi, Madagas car, Nigeria

1

631

138 000

SA

South Africa

1

21

10 400

EA, CA, SA

Many countries

1

23

2 060

WA, CA

Central African Republic, Ghana, Ivory Coast, Mali, Senegal,

1

22

8 860

Parkia biglobosa (Jacq.) R.Br. ex Don (Fabaceae) Pauridiantha paucinervis (Hiern) Bremek. (Rubiaceae) Pausinystalia johimbe (K.Schum.) Pierre (Rubiaceae) Fig. 2 Pelargonium cv. Rosé [“P. graveolens” = P. capitatum (L.) L’Hérit. x P. radens H. Moore) (Geraniaceae) Pelargonium sidoides DC. (Geraniaceae) Fig. 2

African locust bean

seeds (all parts)

TM (wide diversity of uses)

WA

Chad, Nigeria

1

257

48 300

tamirova

roots, leaves

TM (headache, purgative, wounds)

Ma

Madagas car

1

1

537

yohimbe tree

bark

CH: yohimbine (aphrodisiac)

WA, CA

Cameroo n

1, 2, 3, 4, 5, 6

10 (yohim -bine: 14 428)

78 700 (yohimbe: 747 000)

rose geranium

leaves

ES (fragrance)

SA

Kenya, Reunion, South Africa

19 (rose geraniu m: 186)

254 (rose geranium: 421 000)

rooirabas, umckaloab o

roots

SA

Lesotho, South Africa

1, 2, 3, 4, 5, 6

220

92 300 (umckaloa bo: 240 000

Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. (Rubiaceae) Physostigma venenosum Balf. (Fabaceae) Fig. 2

icimamlilo

roots (leaves )

PH (bronchitis, immune stimulant); TM (dysentery; general tonic) TM (headache, pain, purgative, wounds)

SA

South Africa

1

19

2 630

calabar bean

seeds

WA

Cameroo n

1

34 (physostigmin e: 13 065)

40 500 (physostig mine: 388 000)

Phytolacca dodecandra L’Hérit. (Phytolaccace ae) Fig. 2

endod

all parts

EA

Burundi, Ethiopia, Madagas car

1

124

14 500

Piper guineense Schumach. & Thonn. (Piperaceae)

West African pepper

fruit; roots, leaves

CH (physostigmi ne: cholinesterase inhibitor; Alzheimer’s) TM (numerous ailments; control of snails and bilharzia) spice (fruit, essential oil); ES (flavourant); TM (numerous ailments)

WA, CA

1

168

28 800

Prosopis africana

African mesquite

seeds

DS (fermented

WA

Cameroo n, Central African Republic, Congo, D.R. Congo, Equatoria l Guinea Mali, Nigeria

1

105

19 900

42

(Guill. & Perr.) Taub. (Fabaceae)

seeds); TM (bark, roots, leaves: numerous uses) PH (benign prostate hyperplasia); TM (pain, fever, inflammation and other uses)

Prunus africana (Hook.f.) Kalkman (Rosaceae) Fig. 2

red stinkwood, pygeum

bark

Rauvolfia vomitoria Afzel. (Apocynaceae ) Fig. 2

African serpentwood

roots

TM (mild essential hypertension) ; CH: isolation of ajmaline

CA, WA

Ravenala madagascarie nsis Sonn. Strelitziaceae Rhamnus prinoides L’Hérit. (Rhamnaceae)

traveller’s palm

leaves

TM (antiseptic, fever)

Ma

geisho, umunanira

roots, bark, leaves

Ricinodendron heudelotii (Baill.) Pierre (Euphorbiacea e) Ricinus communis L. (Euphorbiacea e) Fig. 2

erimado, ground nut tree, musodo

seeds

castor oil plant

coldpresse d seed oil

TM (colic, fever, pneumonia, headache and other uses) DS (seeds: nuts); TM (roots, bark, leaves: many uses) TM (seed oil: purgative; leaves, roots: many other uses) [biodiesel]

Salvadora persica L. (Salvadoracea e) Fig. 2 Sarcocephalu s latifolius (Sm.) Bruce (= Nauclea latifolia Sm.) (Rubiaceae)

mustard tree, toothbrush tree African peach, African quinine, opepe

roots, stems

TM (toothbrush sticks, oral hygiene) TM (fever, malaria and many other uses)

PA

roots, bark and leaves

PA

Cameroo n, D.R. Congo, Equatoria l Guinea (& Bioko), Ethiopia, Kenya, Madagas car, Tanzania, Uganda Cameroo n, Central African Republic, Guinea, Kenia, Madagas car, South Sudan Madagas car

1, 2, 3, 4, 5, 6

130

87 500

1, 2, 4, 5, 6

52

10 800

1, 4

24

122 000

EA

Ethiopia, Rwanda

1

17

9 540

WA, CA, EA

Cameroo n, Equatoria l Guinea

1

51

14 000

PA

Burundi, Ethiopia, Mozambi que, Nigeria, Rwanda, South Africa Chad, Ethiopia, Tanzania

1

5 187

616 000 (castor oil: 4 610 000)

1, 2, 4, 5

273

160 000

Benin, Burkina Faso, Cameroo n, D.R. Congo,

1, 4

29

22 200

WA, CA

43

Sceletium tortuosum (L.) N.E.Br. (= Mesembryanth emum tortuosum L.) (Aizoaceae) Fig. 2 Sclerocarya birrea (A.Rich) Hochst. (Anacardiacea e)

sceletium, kanna

whole plant

TM/PH (sedative; neurological and psychiatric disorders)

SA

marula, umganu

seeds; bark, fruits

seed oil (edible, cosmetic); TM (bark: diarrhoea, dysentery, malaria and many other uses)

SA, EA

Sclerochiton ilicifolius A.Meeuse (Acanthaceae) Fig. 2 Securidaca longepeduncul ata Fresen. (Polygalaceae) Fig. 2.

molomo monate

root bark

SA

violet tree

root bark (leaves , stem bark)

CH (monatin/arru va: sweetener, now synthesized) TM (a wide diversity of ailments in most parts of Africa)

Senna alata (L.) Roxb.* (Fabaceae)

ringworm cassia

leaf

TM (purgative, antifungal)

Trop. Am.

Senna alexandrina Mill. (Fabaceae) Fig. 2 Senna

senna

leaf, fruit

TM (purgative)

EA

coffeewee

roots,

TM (many

PA

44

PA

Gabon, Gambia, Ghana, Ivory Coast, Mali, Nigeria, Sierra Leone South Africa

4, 5, 6

29

97 000 (Sceletium: 145 000)

Botswana , Mozambi que, Namibia, South Africa, Swazilan d, Zimbabw e, Tanzania South Africa

1

248

107 000

3 (monati n: 24)

978 (monatin: 28 600)

Ethiopia, Madagas car, Malawi, Mali, Mozambi que, Tanzania, Zimbabw e Benin, Congo, Ghana, Ivory Coast, Nigeria, Sierra Leone, Uganda Ethiopia, South Sudan

1

90

12 600

1

262

61 900

1, 3, 5, 6

100

72 200

Madagas

1

306

49 400

occidentalis (L.) Link (Fabaceae)

d, tsotsorinan gatra

leaves

ailments)

Sesamum indicum L. (= S. orientale L.) (Pedaliaceae) Fig. 2

sesame

seeds, seed oil

EA

Siphonochilus aethiopicus (Schweinf.) B.L.Burtt (Zingiberacea e) Fig. 2 Solanum incanum L. (Solanaceae) Fig. 2

African ginger

rhizom e and roots

DS (functional food: reduction of cholesterol and blood sugar levels) TM (antiinflammatory, anti-malarial); ES (flavourant)

bitter apple

fruit, leaves, roots

TM (wounds, pain, toothache, venereal diseases and numerous other ailments)

EA, CA, SA

Sterculia setigera Delile (Malvaceae)

karaya

exudat e; roots, bark

exudate (gum, gum karaya); TM (roots, bark: diversity of uses)

EA

Strophanthus gratus (Wall. & Hook.) Baill. (Apocynaceae ) Fig. 2

strophanth us

seeds; root, stem leaf

WA, CA

Strophanthus kombe Oliv. (Apocynaceae ) Sutherlandia – see Lessertia Synsepalum dulcificum (Schumach & Thonn.) Daniell (Sapotaceae) Syzygium cordatum Hochst. (Myrtaceae)

strophanth us

seeds

CH (seeds: ouabain, a cardiotonic); TM (gonorrhea and numerous other uses) CH (kstrophanthin: cardiotonic)

CA, SA, EA

Madagas car

miracle fruit, miraculous berry

fruit

CH (miraculin: sweetener; taste modifier)

WA

Congo, Ghana

water berry, umdoni

bark

TM (diarrhea, stomach ailments and other uses)

SA, EA

Kenya, South Africa, Zimbabw

45

PA

car and many other countries Ethiopia, South Sudan,

South Africa, Mozambi que, Swazilan d Botswana , Djibouti, Ethiopia, Namibia, Rwanda, South Africa, Tanzania and other countries South Sudan (gum); Benin, Cameroo n, Central African Republic, Senegal Cameroo n

1, 2, 6

2534

438 000

4

23

4 490

1

141

25 000

1

30

8 370

4

2574 (ouabai n: 28 824)

27 100 (ouabain: 456 000)

23

11 900

1

66 (miracu lin: 144)

117 000 (miraculin: 74 200)

1

53

14 800

Tabernanthe iboga Stapf (Apocynaceae )

iboga

root

Tamarindus indica L. (Fabaceae) Fig. 2

tamarind

fruit pulp

Tanacetum cinerariifolia (Trevir.) Sch.Bip. (=Chrysanthe mum cinerariifoliu m (Trevir.) Vis.* (Asteraceae) Taverniera abyssinica Rich. (Fabaceae)

pyrethrum

flower heads

taverniera, dingetegna

root

Terminalia sericea Burch. ex DC. (Combretacea e)

silver clusterleaf, mususu

roots, leaves, bark

Tetradenia riparia (Hochst.) Codd (Lamiaceae)

iboza, umuravum ba

leaves

Tetrapleura tetraptera (Schumach. & Thonn.) Taub. (Fabaceae)

aridan

fruits, bark

CH (ibogaine, a stimulant used for the treatment of drug addiction); TM (hallucinogen , aphrodisiac, asthenia; conjunctivitis and other ailments) DS (fruit pulp: mild laxative, general tonic); TM (roots, bark, leaves: diverse uses) CH (source of pyrethrins, natural insecticides)

CA, WA

e Cameroo n, Central African Republic, Congo, D.R. Congo, Equatoria l Guinea, Gabon

1

86 (ibogai ne: 610)

173 000 (ibogaine: 396 000)

1

973

398 000

EA

Chad, Ethiopia, South Sudan

Balka ns

Cultivate d: Kenya, Tanzania

0, 362

29 600, 17 500

TM (headache, stomach ache, fever – root chewed) TM (general tonic, diarrhea, many other ailments)

EA

Ethiopia

8

1 150

SA, EA

1, 4

94

83 800

TM (coughs, colds, bronchitis, respiratory ailments, diarrhea, angina, venereal diseases) DS (fruit: spice, tonic); TM (fruit, bark: numerous ailments)

CA, SA, EA

Botswana , Mozambi que, South Africa, Zimbabw e Burundi, D.R. Congo, Rwanda, South Africa, Zimbabw e

1

44

22 000

Cameroo n, Congo, D.R. Congo, Equatoria l Guinea,

1

110

15 600

CA, WA, EA

46

Thaumatococ cus daniellii (Bennett) Benth. (Marantaceae) Toddalia asiatica (L.) Lam. (Rutaceae)

miraculous fruit, ewe eran

seed aril

CH (source of thaumatin, a protein sweetener)

WA, CA

orange climber, Lopez root

leaves, roots

TM (antimalarial, antiinflammatory, spasmolytic)

EA, CA, SA, Ma

Trichilia emetica Vahl (Meliaceae)

Cape/Natal mahogany

bark; seeds

PA

Trigonella foenumgraecum L. (Fabaceae) Fig. 2

fenugreek

seeds

Tylosema esculentum (Burch.) Schreib. (Fabaceae) Urera acuminata Gaudichaux (Urticaceae) Vernonia amygdalina Delile, V. colorata (Willd.) Drake (Asteraceae) Fig. 2

marama bean

seeds

TM (bark: many uses); seeds: cosmetic oil (mafura butter, mafoureira tallow) DS, PH (hypoglycae mic, cholesterollowering); TM (convulsions, stomach disorders; topical for ulcers) DS (seeds); seed oil (edible, cosmetics)

sampivato

root

bitter leaf

Vitellaria

karate,

Gabon, Ivory Coast, Senegal, Togo, Uganda Côte d’Ivoire, D.R. Congo, Nigeria Uganda, Gabon, Kenya, Madagas car, South Africa, Tanzania Ethiopia, Mozambi que, South Africa, Zimbabw e

1

52 (thaumatin: 1 143

17 100 (thaumatin: 213 000)

1, 4

127

22500

1, 4

61

17 300

1

1 687

380 000

EA

Ethiopia, South Sudan

SA

Namibia

49

9 610

TM (gynecologica l use)

Ma

Madagas car

2

683

leaves, roots,

TM (general tonic, numerous uses)

PA

1, 4

359

56 300

seeds

DS (seed oil:

WA,

D.R. Congo, Ethiopia, Kenya, Mozambi que, Nigeria, Rwanda, Tanzania, Uganda, Zimbabw e Burkina

1

261, 39

76 000

47

paradoxa Gaertn.f. (=Butyrosper mum parkii Kotschy) (Sapotaceae) Fig. 2 Voacanga africana Stapf (Rubiaceae) Fig. 2

shea tree, shea butter tree

edible shea butter, cosmetics); TM (leaf, bark: several uses)

CA

Faso, Cameroo n, Chad, Mali, Nigeria

voacanga

Warburgia salutaris (G. Bertol) Chiov. (=W. ugandensis Sprague) (Canellaceae) Fig. 2 Withania somnifera (L.) Dunal (Solanaceae) Fig. 2

seeds

CH (isolation of tabersonine; synthesis of vincamine); TM (bark, roots: many uses)

PA

1, 4

58 (tabersonine: 197)

156 000 (tabersonin e: 22 000)

pepperbark tree

bark, leaves

TM (bark: antibiotic, many uses; leaves: tablets, spice)

EA, SA

1, 4, 5, 6

51

8 510 (Warburgia : 32 300)

Indian ginseng, ashwagand ha

roots

Co, PA

1, 4, 5, 6

1 767 (ashwaganda: 10)

437 000 (ashwagan da: 859 000

Ximenia americana L. (Olacaceae)

small sourplum

seeds

PH (physical and psychological stress); TM (roots, leaves: many uses, also topical for sores) seed oil: cosmetic; TM (roots, leaves: many uses)

Cameroo n, Côte d’Ivoire, Madagas car, Sao Tome and Principe, Tanzania South Africa, Kenya, Madagas car, Mozambi que, Tanzania Almost all countries

1

114

52 600

Xylopia aethiopica (Dunal) A.Rich. (Annonaceae) Fig. 2

Guinea pepper

fruits

fruits: essential oil, spice; ES (flavourant) TM (fruits, leaves, bark: diverse uses)

CA, WA

1, 4

168

50 000

Xysmalobium undulatum (L.) Aiton f. (Apocynaceae ) Fig. 2

uzara, ishongwe

roots

SA, EA

1, 3, 4, 5, 6

23 (uzara: 31)

7 930 (uzara: 95 900)

Ziziphus mucronata Willd. (Rhamnaceae)

buffalo thorn, mokgalo

bark (roots, leaves, fruits)

TM/PH (diarrhea, dysentery, dysmenorrhea , colic; root powder: headache) TM (numerous ailments, including stomach and

Ethiopia, Madagas car, Mozambi que, Namibia Benin, Cameroo n, Central African Republic, Congo, Equatoria l Guinea, Sierra Leone Namibia, South Africa, Zimbabw e

Many African countries

1

71

38 000

48

PA

WA, EA, SA

(shea butter: 9 430 000)

urinary tract; topically for ulcers)

Table 2. A selection of 85 species indigenous to sub-Saharan Africa that are of international commercial interest in the pharmaceutical and nutraceutical industries (those indicated in bold in Table 1), ranked by the number of Scopus hits. Species names in bold indicate that 60% or more of the publications appeared in the last decade. Species

Number of Scopus hits

Number of Google hits

before 2000

2001 – 2005

2006 – 2010

2011 – 2015

Acacia drepanolobium Acacia senegal Acacia seyal Acanthosicyos horridus Adansonia digitata Aframomum melegueta Agathosma betulina Allanblackia floribunda Aloe ferox Aloe vera

17

19

30

30

256 75 3

233 39 0

423 43 1

461 62 0

1373 219

68 20

47 10

91 38

152 47

358

2 2

3 3

24 7

18 11

47

24 313

22 424

44 800

60 1295

150

Ammi majus Artemisia afra Aspalathus linearis Balanites aegyptiaca Boswellia frereana Boswellia neglecta Boswellia papyrifera Boswellia rivae Boswellia sacra Bulbine frutescens Carapa procera Carissa edulis Catha edulis Catharanthus roseus Centella asiatica Citrullus lanatus Coffea arabica Cola nitida Colophospermum mopane Combretum

123 17 35 78 4 0 4 0 3 2 22 11 309 953 189 296 421 31 60

20 17 35 34 2 4 6 1 23 7 9 12 112 390 172 392 368 17 54

21 35 76 92 2 0 15 2 45 8 6 26 252 602 375 731 727 37 53

22 39 114 108 2 2 41 1 81 12 19 22 274 708 619 796 915 28 51

186 108 260 312 10 6 66 4 152 29 56 71 947 2653 1355 2215 2431 113

16

8

14

14

52

49

Total number of hits 96

4

115

23

2832

218

Percentage of publications in last decade (since 2006) 63

21 700

64 50 25

430 000 86 500 5 500

68 74

313 000 51 600

89 78

25 900 9 350

69 74 23 69 73 64 40 30 85 75 83 69 45 68 56 49 73 69 68 58 48

370 000 25 900 000 143 000 18 700 148 000 86 400 18 200 8 750 20 600 4 150 103 000 48 100 17 600 18 500 131 000 411 000 583 000 381 000 509 000 110 000 33 700

54

18 800

micranthum Combretum nigricans Commiphora erythraea Commiphora guidottii Commiphora myrrha Commiphora wildii Cryptolepis sanguinolenta Cyclopia genistoides Drosera madagascariensis Garcinia kola Griffonia simplicifolia Harpagophytum procumbens Harungana madagascariensis Hibiscus sabdariffa Hoodia gordonii Hypoxis hemerocallidea Irvingia gabonensis Kigelia africana Lessertia frutescens Lippia javanica Lippia scaberrima Momordica charantia Mondia whitei Pausinystalia johimbe Pelargonium cv. Rosé Pelargonium sidoides Physostigma venenosum Piper guineense Prunus africana Rauvolfia vomitoria Ricinus communis Salvadora persica Sarcocephalus latifolius Sceletium tortuosum Sclerocarya birrea Sclerochiton ilicifolius Senna alexandrina Sesamum indicum Siphonochilus aethiopicus

8

4

6

3

21

4

1

1

7

13

3

1

1

2

7

8

18

22

47

95

0 45

0 17

0 16

0 27

0

1 0

2 5

21 0

20 2

44

61 620

41 165

100 135

124 90

326

73

68

115

75

331

16

12

28

17

73

120 0 3

79 3 15

312 50 39

476 45 33

987 98

37 14 1 11 2 343

19 19 18 12 4 289

40 50 39 22 13 602

65 56 57 32 8 813

161 139 115 77 27

3 4

5 2

15 1

20 3

43

4

8

5

2

19

10

20

107

83

220

16

8

8

2

34

48 25 6 2578 49 2

28 32 5 486 47 5

47 30 23 834 65 9

45 43 18 1289 112 13

168 130 52 5187 273

3 21 0

0 42 0

4 82 0

22 103 3

29 248

10 421 4

22 410 8

31 880 3

37 823 8

100 2534

50

105

7

1010

90

2047

10

29

3

23

43

4 700

62

6 630

43

1 900

73

183 000

0 41

2600 11 200

93 29

6 200 18 500

69 22

435 000 357 000

57

212 000

62

17 000

80 95 80

410 000 494 000 12 000

65 76 84 70 78 69

353 000 160 000 31 800 12 300 1 720 428 000

81 40

43 200 78 700

37

254

86

92 300

29

40 500

55 56 79 41 65 76

28 800 87 500 10 800 616 000 160 000 22 200

90 75 -

97 000 107 000 978

68 67 48

72 200 438 000 4 490

Sterculia setigera Strophanthus gratus Synsepalum dulcificum Tabernanthe iboga Tamarindus indica Thaumatococcus daniellii Trichilia emetica Trigonella foenumgraecum Tylosema esculentum Vernonia amygdalina Vitellaria paradoxa Voacanga africana Warburgia salutaris Withania somnifera Ximenia americana Xylopia aethiopica Xysmalobium undulatum TOTAL % of TOTAL

8 1355 16

8 481 2

6 416 19

8 262 29

30 2514

40 143 28

10 140 5

18 295 10

18 395 9

86 973

10 297

12 267

18 495

21 628

61

7

3

17

22

49

46

41

124

148

359

23 28 7 209 15 35 2

55 2 12 201 16 21 6

107 7 20 491 36 50 8

115 21 12 866 47 62 7

300 58 51 1767 114 168

10 197 26

5 685 14

10 513 26

13 299 34

37 983

40

60

51

66

52

1687

23

100

47 27 73

8 370 27 100 117 000

42 71 37

173 000 398 000 17 100

64 67

17 300 380 000

80

9 610

76

56 300

74 48 63 78 73 67 65

76 000 156 000 8 510 437 000 52 600 50 000 7 930

Graphical Abstract

PERCENTAGE IN LAST DECADE 1. Hoodia gordonii – 95% 2. Cyclopia genistoides – 93% 3. Sceletium tortuosum – 90% 4. Agathosma betulina – 89% 5. Pelargonium sidoides – 86% 6. Boswellia papyrifera – 85% 7. Lessertia frutescens – 84% 8. Boswellia sacra – 83% 9. Mondia whitei – 81% 10. Hibiscus sabdariffa – 80% 11. Hypoxis hemerocallidea – 80% 12. Tylosema esculentum – 80%

TOTAL NUMBER OF PUBLICATIONS 1. Ricinus communis – 5187 2. Aloe vera – 2832 3. Catharanthus roseus – 2653 4. Sesamum indicum – 2534 5. Strophanthus gratus – 2514 6. Coffea arabica – 2431 7. Citrullus lanatus – 2215 8. Momordica charantia – 2047 9. Withania somnifera – 1767 10. Trigonella foenum!graecum – 1687 11. Acacia senegal – 1373 12. Centella asiatica – 1355

MOST POPULAR AFRICAN MEDICINAL PLANTS IN SCIENTIFIC LITERATURE

Figure 1

Central Africa CA

Mauritania Mali

Niger

Chad

Senegal The Gambia Guinea Bissau Burkina Guinea Sierra Leone Liberia

West Africa WA

Ivory Coast Ghana

Eritrea

Nigeria Cameroon

Togo Benin Equatorial Guinea

Gabon

South Sudan

Central African Republic

Somalia

Democratic Republic of the Congo (Zaire)

Congo

Ethiopia

Rwanda

Uganda Kenya

East Africa EA

Tanzania

Burundi

Angola

Malawi Zambia

Zimbabwe Namibia

Mauritius

Mozambique

Botswana Madagascar

Southern Africa SA

Swaziland South Africa

Lesotho

Reunion

Madagascar and Indian Ocean Islands Ma

Figure 2a

Figure 2b

Figure 2c

33a

Figure 2d

Figure 2e