Media reviews: Trease and evans pharmacognosy

Media Reviews SPIRITUAL HEALING: SCIENTIFIC VALIDATION OF A HEALING REVOLUTION Professional Supplement – Healing Research Volume 1 Daniel J. Benor Vision Publications, 2002 ISBN 1-886785-12-0 Paperback, $28-00 600 pp For the growing number of people who recognise that anecdotes represent poor evidence for the efficacy of healing, any book which purports to present scientific and medical evidence on the matter is welcome. So much the better if the book is from Dan Benor, an indefatigable proponent of healing who nevertheless accepts the possibility that its effects on clients can be measured despite the (apparent) ineffable mystery at the core of the healing encounter. As the title suggests, this book is marketed as a supplement to the popular edition of Healing Research Volume 1. It is a “professional supplement” for healthcare workers, such as medical professionals and nurses, focusing on research and “scientific proof”. In fact the book consists of only two parts: the bulk, which purports to describe scientific studies of healing grouped by target organism (plants, yeasts, human subjective experiences), and another section – “Further clues to the mystery of healing” – which contains information on Shamanism, Healing at shrines, etc. provided as background for discerning professionals. The usefulness of the book is that it contains information not readily available elsewhere. There are brief descriptions of healing trials reported in obscure PhD theses, comments which Benor has obtained directly from study authors themselves, and references galore. It all adds up to an enormous amount of work over many years: a labour of love, actually, and probably worth the price for this alone. However, the book claims to report on the “scientific validation” of healing. Indeed, the cover speaks of “proof that spiritual healing works”. Essentially, the basis of this claim is that Benor has found 191 “controlled” studies (across a broad range of conditions and organisms) and that 43.4% are positive at the p < 0.01 level and 21.5% at the p < 0.05 level, resulting in a greater number of positive than negative outcomes. As we know from the work of the movement for evidence-based medicine, however, this tally is not as impressive as it might seem to the layman. Benor’s own notes point out that a significant number of studies are of poor quality, badly reported, not blinded and non-randomised, yet the summary and the overall “spin” of the book appear to say something Complementary Therapies in Medicine (2002) 10, 123–125

else. Given the great variability in trial quality, reporting and type of publication, the usual course of action would have been to classify each trial on a validated quality scale – with blinding and randomisation at its core – and then consider seriously both the negative and positive high-quality trials. Instead, Benor has devised his own rating system, banded together the trials self-classified as “grade 1”, extracted the ones with a positive outcome for healing and presented proudly to the reader these 39 studies to indicate that healing works. Interestingly, at least one trial1 in this list would be classed as “negative” by most researchers, and at least two good quality “negative” trials are not considered in the book. This book is probably a useful overview of the studies of healing, yet its interpretation of the evidence is unconventional and its conclusions eccentric: most independent researches would conclude that no firm conclusions about the efficacy or inefficacy of healing can be drawn from the 191 “trials”.2 It probably does no service to the subject in the long term to over-egg the pudding, though it does sell books. N. C. Abbot REFERENCES 1. O’Laoire S. An experimental study of the effects of distant, intercessory prayer on self-esteem, anxiety, and depression. Altern Ther Health Med 1997; 3: 38–53. 2. Abbot NC. Healing as a therapy for human disease: a systematic review. J Altern Complement Med 2000; 6(2): 159–69. doi:10.1054/ctim.2002.0518, available online http://www.idealibrary.com on

MEDICINAL NATURAL PRODUCTS – A BIOSYNTHETIC APPROACH Paul M Dewick Wiley, Second Edition, 2002 Paperback, 507 pp, Price £34–95 ISBN 0 471 49641 Natural products comprise a wide range of different chemical substances obtained from plant, animal and microbial sources. Practitioners of herbal medicine might think it more appropriate to clarify medicinal natural products within clinical or pharmacological categories, but for those interested in understanding the underlying relationships in the chemistry of such substances, it does make good sense to arrange them in families of biosynthetically related compounds. This book is not for the faint-hearted, because it abounds in chemical structures, but to people such as myself it is a joy to read. I do believe that anyone with even a passing interest in medicinal

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drugs should have at least an idea of their chemical nature. For new drug development, a knowledge of natural product chemistry leads to synthetic modifications or to totally synthetic molecules based on natural products. This second edition is similar to the first edition, but it has been extended and updated. The building blocks and construction of secondary metabolism are succinctly covered in some 20 pages and the B vitamins are used as examples of the way these molecules are made in nature. The majority of the book deals with acetate, mevalonate and shikimate pathways, alkaloids, peptides and proteins, and carbohydrates. There are frequent illustrations of compounds that are important constituents of major herbal drugs (e.g. echinacea, feverfew, garlic, ginkgo, St John’s wort), and these appear in clearly presented boxed areas of text. The sections on ginkgo, opium and cannabis can be used to illustrate how this book is informative to individuals interested in herbal medicines. The boxed section of text on ginkgo appears in the section on diterpenes because of the ginkgolides, but the flavonoid constituents and bilobalide are also included. The medicinal uses of ginkgo are briefly summarized, and the percentage composition of individual constituents and their percentage in standardized extracts are also given. The boxed text section for opium covers some eight pages and in addition to the naturally occurring alkaloids, it also covers semisynthetic (e.g. heroin, nalorphine) and synthetic analogues (e.g. dextromethorphan, pentazocine, naloxone). The major constituents of cannabis are the cannabinoids (there are more than 60) and the structures of the major ones are clearly given. Discussion includes the treatment of multiple sclerosis, chronic pain, glaucoma, asthma, migraine and epilepsy. The potential for new drug development utilizing our knowledge of the pharmacology of cannabinoids, and of the two cannabinoid receptors currently known, is briefly summarized. Products of animal metabolism of medicinal interest are included (e.g. corticosteroids, oestrogens, androgens, peptide hormones) and a knowledge of these is useful in understanding the action of a number of medicinal herbs. The major products of lower organisms covered in the book are the antibiotics. The layout of the book is excellent. The biosynthetic schemes and chemical structures are clearly presented, there are numerous references to current literature, cross references occur throughout the text, and the index is comprehensive. This book will be useful to undergraduate students, but it is an excellent resource for natural product chemists, pharmacists, pharmacologists, pharmacognosists, toxicologists, and botanists who are interested in the way in which drugs interact with living organisms. What about doctors, nurses, and complementary practitioners? Do not be put off by the

chemical structures because there is a wealth of valuable, accurate and up-to-date information on the therapeutic role of plants, animals, microbes, and their constituents. J David Phillipson doi:10.1054/ctim.2002.0515, available online http://www.idealibrary.com on

TREASE AND EVANS PHARMACOGNOSY W. C. Evans Published by W. B. Saunders, 2002, 15th edition Hardback, price: £59.95 ISBN 0-7020-2617-4 585 pp The demand for medicinal plants continues to increase in both the developed and developing world, and this is well illustrated in the 15th edition of the UK textbook of Pharmacognosy. Of the topselling pharmaceutical drugs in 1999, 13 (with combined sales of more than US $29 billion) have a chemical structure based on a compound originally found in Nature. The 15th edition of Trease and Evans Pharmacognosy is more attractively presented than previous editions and is published in a larger page format. It continues to be encyclopaedic in its coverage of the subject matter. Increasing use has been made of specialist contributors for some chapters, including those on plant sources for pure medicinal drugs and for herbal uses. The text is divided into nine sections and includes plant and animal sources of drugs, commercial production, current trends in the development of new drugs, phytochemistry, pharmacopoeial and related drugs of biological origin (15 chapters dealing with chemical constituents, clinical uses, and potential drug use, e.g. antitumour, antiprotozoal), complementary and traditional systems of medicine, toxic plants and pesticides, morphological and microscopical examination of drugs. Of particular interest to the readers of this journal are the five chapters dealing with plants used in complementary and traditional systems of medicine covering herbal medicine in Britain and Europe, homoeopathy and aromatherapy, Asian medicine and its practice in the West, Chinese herbs in the West, and plants in African traditional medicine. Four-year BSc degree programmes on herbal medicine have been introduced in the UK, and in 2000 there were nearly 1000 professional and practising herbalists. Although homoeopathy and aromatheraphy are mainly not accepted from scientific and medical viewpoints, there is no doubt that they are popular in the UK. Many Asian and Chinese people have settled in Western countries and they continue to use their systems of

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medicine. Hundreds of plants are used in Asian medicine and the most important ones are listed together with their uses. Although attention is drawn to the adverse effects of heavy metals and of some medicinal plants (e.g. their ability to interact with conventional medicines used concurrently), no mention is made of the toxicity and legal ban imposed on Aristolochia species, apart from queried mutagenic activity. Chinese herbal medicine is rapidly growing in popularity in the Western world and in the UK the Register of Traditional Chinese Medicine has some 400 members. Concern has been expressed about the quality and safety of some Chinese herbs, and in this chapter the ability of Aristolochia species to cause terminal renal failure and renal cancer is included. The chapter on African traditional medicine differs

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from the other chapters in that it deals with the use of medicinal plants within African countries. There is a good overview of African medicinal plants, including the chemical structures of some of their active ingredients and a useful list of more than 45 references to the original scientific publications. I have always been impressed by the way in which this textbook has continuied to adapt to meet the changing role of natural medicines and am more than happy to recommend it as a useful reference source to individuals and institutions having an interest in medicinal drugs obtained and developed from natural sources. J. David Phillipson doi:10.1054/ctim.2002.0517, available online http://www.idealibrary.com on