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Traditional Chinese medicine and the search for new antineoplastic drugs
Journal of Ethnopharmacology, 24 (198811- 17 Elsevier Scientific Publishers Ireland Ltd.
Review Paper
TRADITIONAL CHINESE MEDICINE ANTINEOPLASTIC DRUGS*
AND THE SEARCH
FOR NEW
JUI HAN Department of Pharmacology, Institute of Mateti 1 Xiun Nong Tan Street, Beijing /Chid
Medica, Chinese Academy of Medical Sciences,
(Accepted May 12,19881
Summary The experience of traditional Chinese medicine affords a valuable approach in the search for new antineoplastic drugs as illustrated by indirubin from Dang Gui Lu Hui Wan, irisquinone from Iris Zuctea pallasii and Zhuling polysaccharide from Polyporus umbelluta The application of chemotaxonomic principles to related species of those plants used in folk medicine has also provided an approach which can be used successfully for the development of new drugs. The studies of Cephalotaxus hainanesis and Camptotheca accuminuta provide two typical examples in this regard. One must be aware that the experience of traditional Chinese medicine cannot be used without elaborate efforts in many cases. For example, the ancient Chinese ideograph for spleen does not mean spleen in the modern sense, instead it refers to the entire gastrointestinal system. Similarly, the ancient ideograph for kidney does not mean kidney in the modern sense, and can mean the entire endocrine system. Therefore, for the reasonable utilization of traditional Chinese medicine, one must be familiar with its basic concepts and terminology. In addition, one must bear in mind that the term “tumor” in folk medicine is applied to a very wide range of pathological manifestations which sometimes have no relation to the various forms of neoplasia. It is important for drugs and treatments to be analyzed carefully in modern terms to eliminate the false and to utilize the true information. Only in such a way can the experience of traditional medicine be integrated into modern medicine and make its contribution in the advancement of health care in the world.
*This paper was presented at the First Beijing International Symposium on Immunology: Impact of Traditional Medicine, June lo- 12,1984. 0378-8’741/88/$06.30 0 1988 Elsevier Scientific Publishers Ireland Ltd. Published and Printed in Ireland
2
Introduction Shen Nong Ben Cao Jing (Anon., 22 - 250 A.D.) and Ben Cao Gang Mu (Li, 1590 - 1596 A.D.)are the two most famous classics on Chinese materia medica. The description of the pharmacologic actions of the majority of the drugs included in these books are precise and useful in the treatment of diseases even today. For example, Ephedra sinica relieves asthma, Rheum palmatum improves constipation, Angelica sine&a ameliorates menstruation disorders. Dichroa febr& fuga and Artemisia apiacea are active against malaria and Omphaliu lupialia is effective for helminth infestations. All these therapeutic effects have been confirmed by contemporary scientific research. Chemical and pharmacologic studies conducted in the last 30 years have proven that Chinese materia medica and Chinese medicine represent a great treasure house of knowledge. Many clinical and experimental studies indicate that the development of cancer is related to the functional status of the host’s immune system. By manipulating the immune system, it is possible to eradicate residual tumor cells when the tumor load is minimal. Panax ginseng, Astragalus membranaceus, PO& cocos, Polyporus umbellata, Tremmella fuciformis and Cordyceps sine&s are widely used tonics from ancient times. Recent studies have demonstrated that certain of these drugs are immunomodulators and active against rodent tumors. Their clinical evaluation is now in progress. Historical perspective Traditional Chinese Medicine (TCM) has an ancient history and a unique system of practice which includes Theory, Methodology, Prescription Formulation and Drugs. It is highly treasured as a precious cultural heritage. Since the majority of Chinese Traditional drugs are of plant origin, this system was once called “herbal” (Ben Caol. Now it is called Chinese materia medica (Zhong Yao Xuel and represents the accumulation of the extensive daily experiences of medical practice by the Chinese people since prehistoric times. In the famous book Huui Nan Zi from the Han dynasty of the 10th century A.D.(Nanjing Traditional Chinese Medical College, 19591, there is a quote that “Shen Nong tried hundreds of herbs and met with seventy poisons in a day”. This illustrates the difficulties of the “trial-and-error” accumulation of clinical experience in the treatment of disease. The broad stretches of Chinese territory lying in the subtropic and temperate zones provide favorable conditions for the growth of diverse plants. A recent survey (Xiao, 1983) of these plants has identifed 4877 species with potential therapeutic value of which about 500 are in common usage. Descriptions of cancer have been found in many of the classics of TCM, but due to the limited exposition of historical background, their use in the diagnosis of cancer and as a basis for prescribing treatments for cancer has not been very useful, especially for malignancies of the viscera. Nevertheless, the experience of traditional medicine can provide clues for new antineoplastic drugs. For
example, the discovery of the antitumor effect of indirubin illustrates the value of this approach. Plants providing drugs have received much attention, not only due to their enormous potential for the development of new and useful therapeutic agents but also because they can provide fascinating novel chemical structures which may be used as rational leads for the design of more nearly ideal drugs. Special efforts have been made to use the experience of folk medicine and TCM in the research and development of new antineoplastic drugs in China. In contrast to random screening, a rational approach guided by the experience of TCM is economical and can increase the probability of success. The chemotaxonomic interrelationships of medicinal plants provide another useful tool for the discovery of new drugs. This paper will provide examples which illustrate how TCM has helped in the search for new antineoplastic drugs and biological response modifiers, and how modern science and technology have been used in China to study the chemistry and pharmacology of traditional Chinese drugs and plant-derived pharmaceuticals. Guidanceof traditional
Chinesemedicine
Indirabin Guided by the therapeutic principle of “purge the hepatic substantial fire” of TCM, a group of scientists from the Institute of Hematology, Chinese Academy of Medical Sciences (1979a1, has discovered the efficacy of a famous Chinese prescription, Dang Gui Lu Hui Wan, for the treatment of chronic myelocytic leukemia @ML). Dang Gui Lu Hui Wan are pills which contain 11 Chinese traditional drugs, i.e. Angelica sine&s (Oliv.1 Diels, Aloe vera L., Elephantopus scaber L., Saussurea lappe Clarke, Scutellaria baicalensis Georgi, Phillodendron chinensis Schneid., Coptis chine&s Franch, Gardenia jasminoides Ellis, Rheum palmatum L., ind& gofera tinctoria L., Moschus moschiferus L. Clinical studies demonstrated that the withdrawal of Moschus moschiferus from these pills did not affect the efficacy of Dang Gui Lu Hui Wan, nor did the withdrawal of Coptis chine&s. However, the withdrawal of Moschus moschiferus, Aloe veTa and Indigofera tinctoria made them inactive. The prescription lacking Moschus moschiferus and Coptis chinensis could be divided into two parts, according to the pharmacological characteristics of the remaining drugs, i.e., purgatives (Aloe Vera, Rheum palmatum, Elephantopus scaber, Saussurea lappa) and non-purgatives (Scutellaria baicalensis, Phillodendron chinensis, Gardenia jasminoides, Angelica sine&s, Indigofera tinctoria). Clinical studies showed that pills made of the non-purgatives showed definite efficacy (Institute of Hematology, Chinese Academy of Medical Sciences, 1979131.Pills consisting of only two drugs, Indigofera tinctoria and Aloe Vera showed a clearly significant therapeutic effect. Experimental therapeutic studies with transplantable tumors demonstrated
Patient response w) Complete remission Partial remission Improved No effect Total cases 4 5 7 6 22
+ + + + + + + + + +
Dry juice Whole herb Root Root Bark Root Fruit Root Leaf Musk
0 2 6 2 10
+ + + + + + + + +
+
+
Root
Angelica sine&s Aloe vem Elephantopw scabes Saussurea lappa Scutellaria baicalensis Phillodendron chinen..+ Coptis chine&s Gardenia jaaminoides Rheum palmatum Indigofera tinctoria Moschua moschiferzls
2
Pill no. 1
Part
Pill Composition
EFFICACY OF DANG GUI LU HUI WAN (PILL NO. 1) AND SIMPLIFIED
TABLE 1
0 0 5 0 5
-
+ + + + + + + +
+
3
0 0 0 3 3
-
+
+ + +
4
PILLS (NOS. 2-8)
0 0 3 3 6
-
+
+ + +
+
5
IN CML
0 0 0 4 4
+ -
+ + + + + +
+
6
0 4 3 0 7
+
+
7
1 4 10 0 15
+
8
Fig. 1. Chemical structure of indirubin.
that Indigofera timto& alone prolonged the life span of L-1210 leukemia-bearing mice significantly while Aloe vera alone did not. These results indicated that Indigofera tinctoria (Legumino Seael was the major effective drug in Dang Gui Lu Hui Wan. Phase I and phase II clinical studies (Cooperative Group of Clinical Therapy of Indirubin, 19801of Indigofera timto& showed very encouraging therapeutic effects (Table 11. Phytochemi~al studies demonstrated that hzdigofera tinctoria contains several components, e.g. indigo blue, indigo brown, kaempferol and inorganic salts. Among these ingredients, the content of indigo blue is most abundant but inactive in experimental chemotherapy. Further studies showed that a minor component, indirubin (Fig. 11,exhibited pronounced therapeutic effects on animal tumors as well as in clinical studies for the treatment of CML fWu et al., 1978; Zeng et al., 1979a,b; Wu et al., 19801. Furthermore, it was reported that indirubin can increase the cellular immunity and cyclic AMP content of leukocytes of CML patients (Table 2). In view of the fact that the content of indirubin in Indigofera tinctoriu is minute (O.ll%l, chemists at our Institute &hen et al., 19791have succeeded in the total synthesis of indirubin from indigo blue (Fig. 21.On the basis of toxieologieal studies (Li and Ji, 19831, synthetic indirubin was approved for clinical trial and was found to be effective against CML with less side effects than Indigofera tinctoriu (Ji and Chang, 19811.Table 3 indicates that complete remission was attained in 26% of 314 cases while the partial remission rate was 33%. Clinical pharmacological studies indicated that the major side effects of indirubin are abdominal pain and diarrhea. A decrease of platelet count was also
TABLE 2 EFFECT OF INDIFWBIN LEUKEM~ PATIENTS
ON CELLULAR
IMMUNITY
OF CHRONIC MYELOCYTIC
Group
SK-SD skin delayed hypersensitivity (mm*)
E rosette (%I
Phagoeytosis (%I
Z $-rosette (%I
Normal volunteers CML patients before treatment CML patients after treatment (in remission)
44.3 14.8
33.3 40.1
2.6 33.7
9.3 10.7
36.2
60.4
67.0
15.8
Fig. 2. Chemical synthesis of indiibin (IV).
found in some patients. A comparison of the efficacy of indirubin and busulfan (Myleran) showed that the effective rates were similar but the complete remission rate was slightly higher for busulfan. No cross-resistance between these two drugs was observed. In a preliminary study, some new derivatives of indirubin have shown more promising and more interesting results than their progenitor. Further work is in progress. The process of transfer from Dang Gui Lu Hui Wan to ~~~gof~~ tractor to indirubin and to new derivatives of indirubin for the treatment of CML furnishes a typical example of our approach to the study and development of new antineoplastic agents. This example also illustrates how modern medicinal chemistry and pharmacology can help traditional medicine develop to a new level.
Iris latea pallusi Fischer var. chinelasis and Rabdda
rubescence
TABLE 9 CLINICAL EFFICACY OF INDIBUBIN IN CHRONIC MYELOCYTIC LEUKEMIA
Total easea Complete remission ParW remkkm Beneficial No response
No.
%
514 82 106 87 40
100.0 26.1 23.4 27.7 2.7
(Hemsl.1
CH30
(cll& WCH-(cH&-CHs 0
Fig. 3. Chemical structure of iriequinone.
may serve as additional examples of the guidance of TCM in the search for antineoplastic drugs. The former plant belongs to the Iridaceae family and its seeds have been used for the treatment of malignancies in folk medicine. The chemists of Tientsin Institute of Materia Medica have isolated an active principle (irisquinone) from the seeds of Iris &eapaZlasi(Fig. 31.Chemically it is 6-methoxy 2-A10&-heptadecenyl-l,4phenylquinone. Experimental chemotherapeutic studies have shown that irisquinone is effective against transplantable tumors, such as cervical carcinoma U14, lymphosarcoma, hepatoma and Ehrlich ascites carcinoma in mice. It is in phase I studies at present (Li et al., 1981). Rabdosiu rubescence from the Labiatae family has been used for the treatment of esophageal cancer in folk medicine in Henan province, China (Cheng et al., 1986). Several diterpine compounds, for example oridonine, ponicidine, rabdoserrin A, amethystoidin A and rabdophyllin have been isolated from this plant and some related plants which belong to the same species. Experimental therapeutic studies have demonstrated that oridonine and ponicidine show significant antitumor effects on rodent tumors such as L-1210, P-388 and Ehrlich ascites carcinoma. Clinical studies are in progress in the teaching hospital of Henan Medical College (Zhang, 19861. Zhuling polysaccharide From ancient times, many species of the polyporaceae have been used for the treatment of disease. Zhuling (Polyporus umbelkztu) was originally described in Shen Nong Ben Cao Jing as having diuretic action and was used mainly for the
TABLE 4 EFFECT OF ORALLY ADMINISTERED POLYPORUS ON S-180 IN MICE
UMBELLATA
POLYSACCHAIUDE
Group kimage)
N
Tumor weight (g)
Inhibition (%I
Control 125 mg/kg ( x 14) loo0 mg/kg ( x 14)
33 19 20
l&l f 0.19 1.34 f 0.24 0.92 f 0.17
28.0 so.6
P
< 0.06 < 0.01
3 TABLE
5
CHANGES TREATED
Phagocytosis Phagocytosis
IN PHAGOCYTOSIS FOR 67 PATIENTS WITH PRIMARY LUNG WITH THE POLYSACCHARIDE OF POLYPORUS UMBELLAZ’A
(%I index
CANCER
Before treatment
After treatment
P
35.3 0.45
44.0 0.55
< 0.01 < 0.01
teatment of edema and dysuria (Wang et al., 19641. Clinical studies have demonstrated that Polyporus umbellata is an effective diuretic, without side effects, for the treatment of pyelonephritis, nephritis and urologic calculi (Wang et al., 19641. Maeda et al. (19761 have published that a polysaccharide from Poriu cocos was able to exert a significant antitumor effect on sarcoma 180 in mice. Since then, much attention has been directed to the anticancer and immune potentiation effect of related fungi. Scientists of the Institute of Chinese Materia Medica, Academy of Traditional Chinese Medicine (1981) have found that the related herbal diuretic, Polyporus umbellata is also effective against sarcoma 180 (Table 41. Miyasaki (19831 reported similar results in a Japanese journal. In addition, Chinese scientists claimed that the polysaccharide of Polyporus umbellata increased both cellular and humoral immunities in experimental animals. The medical doctors of Dong Zhi Men Hospital, Beijing Traditional Chinese Medical College, noted that the polysaccharide of Polyporus umbellata decreased the side effects of chemotherapy and increased the phagocytic activity of macrophages in patients with advanced primary lung cancer (Table 5). A group of scientists from Guan An Men Hospital, Academy of Traditional Chinese Medicine reported similar results on similar patients with advanced lung cancer (Dong Zhi Men Hospital and Guan An Men Hospital, 19’79). TCM also has a resource of nourishing tonics, also called the Fu Zheng drugs (Tang et al., 19861; for example, Panux ginseng C.A. Meyer, Cordycepes sinensis (Berk) Sacc. and Tremmellu fuciformis Berk. Recent studies have shown that certain of these drugs can increase the number of leukocytes in patients with depressed hematopoietic function and improve the immune competence of patients receiving chemotherapy and/or radiotherapy (Chang, 1985). Thus it is apparent that the search for new biological response modifiers from these herbal drugs may be a fruitful one for the development of new drugs. Chemotaxonomic principles applied to folk medicine Harringtonine
and homoharringtonine
An alternative approach for seeking new antineoplastic drugs is to use the chemotaxonomic principle of chemical relatedness among taxonomically close plant species, especially if one or more are used in folk medicine. The basic
9
Compound
R2
4 OH
OH
I
I
CH,-C-(CH,k,-C-CH,-COOCH,
Harringtonine
I CH,
I coo-
OH
OH
I
I
CH,-C-(CH,),-C-Cl+,-COOCH,
Homoharringtonine
I CH,
H-
H-
1 cooOH
I
CH,-CH-(CH,),-C-CH,-COOH,
Deoxyharringtonine
I CH,
lsoharringtonine
c60OH
OH
I
I
CH,-CH-(CH,),-C-CH-COOCH,
I %
H-
1
H-
I coo-
Cephalotaxine
HO-
H-
Acetylcephalotaxine
CH,OCO-
H-
Epicephalotaxine
H-
HOOH
Deoxyharringtonic
acid
I
CH,-CH-(CHJ,-C-CH,-COOH
I C%
OH lsoharringtonic acid
I
Fig. 4.Alkaloids foundin Cep~a~~
OH
CH,-CH-(CH,),--C-CHCOOH
I CH, kainanensis.
H-
I coo-
I coo-
I
H-
10 TABLE
6
EFFECTS MICE
OF
HARRINGTONINE
AND
HOMOHARRINGTONINE
Dose
Group
N
0.7 0.55 2.4 2.7
x x x x
L-1210-BEARING
Average
survival time
(days)
(m&g) Control Harringtonine Homoharringtonine Isoharringtonine Deoxyharringtonine
ON
10 10 10 10 10
8 8 8 8
9.8 17.8 17.8 16.2 18.2
strategies of this approach are illustrated by the studies of a tree called CephaG otazus hainanensis Li (Cephalotaxaceael from which harringtonine and homoharringtonine were isolated. This study was inspired by two factors. One was the beneficial effect obtained by folk medical practitioners in Fukien Province for the treatment of neoplastic diseases with CephoZotams fortuni Hook F. (Cephalotaxus Research Coordinating Group, 1976; Institute of Materia Medica, Chinese Academy of Medical Sciences, 1977; Han and Roboz, 1982; Han, 1984,1987a,bl. The other was the antitumor activity exhibited by the alkaloids isolated from Cephabtams harringtoniu (Forbes) Koch as reported by Powell et al. (1972). Since then a systematic investigation including chemical, pharmacological and botanical studies, has been carried out for Cephalotaxw hainanensis in our institution (Ji et al., 1979; 1982; Roboz et al., 1982; Li and Han, 19861. Colleagues at the Institute of Materia Medica, Chinese Academy of Medical Sciences (19761 have isolated more than 16 alkaloids and two lactones from a related plant, Cephalotams hainunensis, indigenous to Hainan Island, Kwangdong Province, China. These alkaloids include cephalotaxine, harringtonine, homoharringtonine, isoharringtonine and deoxyharringtonine. Hainanolide and hainanolidol are two lactones (Huang and Xue, 19841. All these compounds were identified by infrared and mass spectroscopy, nuclear magnetic resonance and X-ray diffraction analysis. Their chemical structures are shown in Fig. 4.
TABLE
7
LDa, IN MICE
( f S.D.) OF HARRINGTONINE
AND HOMOLOGUES LDso (m&kg) i.p.
Harringtonine Homoharringtonine Isoharringtonlne Daoxyharringtonine
4.3 3.3 14.6 16.0
i.v. f f f f
0.5 0.4 0.7 2.4
4.5 2.4 13.2 8.8
f f f f
0.2 0.2 0.1 0.5
11 TABLE 8 SUBACUTE TOXICITY OF HARRINGTONINE AND HOMOHARRINGTONINE IN DOGS Drug
Dosage (i.v. mgllrg)
Toxic effects
Harringtonine
0.1 x 12 0.2 x 9 0.076 x 9
Bone marrow depression Severe bone marrow depression Bone marrow depression and gastrointestinal disturbances Severe bone marrow depression and severe gatrointestinal disturbances
Homoharringtonine
0.16 x 8
Pharmacological studies (Han, 1987al indicate that cephalotaxine, the most constituent of the bark of this tree is inactive. However the esters of this alkaloid, i.e. harringtonine, homoharringtonine, isoharringtonine and deoxyharringtonine, all exhibit remarkable antileukemic action on L-1210 and P-338 bearing mice (Table 61. A significant antitumor action was also demonstrated in some solid transplantable tumors (melanoma B16, sarcoma 180 and Walker carcinosarcoma 2861. The acute LD, values for these alkaloids are shown in Table 7. In subacute toxicological experiments on dogs, harringtonine at a dosage of 0.1 mg/kg per day for 14 days showed no serious side effects but only a mild bone marrow depression. At a higher dosage (0.2 mg/kgl, it caused bone marrow depression and gastrointestinal disturbances (anorexia, nausea, vomiting) (Han and Ji, 19’791.At a similar dosage schedule, homoharringtonine showed more pronounced side effects than harringtonine, especially in regard to the gastrointestinal system (Table 81. abundant
Lsu -protein ‘_a____b___~-__-_--____~ 01
1
,
I
I
20
40
60
80
1
100
Minutes Fig. 5. Inhibition of precursor incorporation into protein, DNA and RNA by harringtonine.
12
To explore the mechanism of action of harringtonine, we have studied the effect of this drug on the incorporation of radioactive precursors of DNA, RNA and protein (Chou et al., 19831. Experiments have demonstrated that the incorporation of THfleucine into protein of L-1210 cells was inhibited very quickly, followed by the inhibition of incorporation of ~H~hymidine into DNA of L-1210 cells (Fig. 51.Harringtonine showed no effect on the incorporation of rH]uridine into RNA of L-1210 cells. These results seem to indicate that the primary effect of harringtonine relies on an inhibition of protein synthesis. It is interesting that harringtonine has no cross-resistance with the majority of known anticancer drugs except vincristine. The uptake of PHJharringtonine by a vincristine-resistant cell line of L-1210 was also decreased significantly. This means that the occurrence of drug resistance can be related to the membrane transport of antineoplastic drugs. After intravenous injection of ~HJharrin~onine to rats, the blood radioactivity level decreased rapidly and after 15 min the decrement rate was slowed (Fig. 61.Its distribution pattern is shown in Fig. 7. The biological half life of ~H]homoharrin~onine in rats is similar to [3H]harringtonine except that the content of homoharringtonine in bone marrow was higher than that of harringtonine (Ji et al., 1979.19821. Considering the fact that the content of harringtonine and homoharringtonine in the plant is very low, a group of chemists at our institute have succeeded in the partial synthesis of certain desired diastereoisomers of harringtonine and homoharringtonine which consist of epiharringtonine plus harringtonine and homoharringtonine plus epihomoharringtonine separately (Fig. 81(Institute of Materia Medica, Chinese Academy of Medical Sciences, 19751.The partially synthetic harrin~onine and homoharrin~onine exhibited sign~icant inhibition
i
Fast
phase
t y* = 3’30”
I
Slow
phase
t y2 =
50’
x
i
7-i
--r-m I:1
x--_
I
x-X 1
x
5 IO 20 30
60
Minut8s Fig. 6. Pkarma~kineti~
after
of ~~]har~n~onine
120
IV in rats after intravenous injection.
13
Kidney *. Liver
Bone marrow
Heart Lung
0
15 mins
@
2 hrs
m
24
after
hrs
Muscle
IV iV
after
Testis
Spleen GI
after
IV
Brain Blood
Fig. 7. The distribution of [~H]harringtonine in rats after intravenous injection.
of experimental tumors (Ji e al., 19833.On the basis of toxicological studies, all of these compounds were recommended for clinical trials. Phase I and phase II studies have shown that the partial synthetic compounds are as active as the natural products @hang, 19881.The clinical effects of harringtonine are shown in Table 9 (187th Hospital of Peoples Liberation Army, 1978; Chang and Ho, 1981; Ohnuma and Holland, 1985; Chang, 1988; Shan et al., 19881. Camptothecin and lo-Hydroxy camptothecin The studies of camptothecin and IO-hydroxy camptothecin afford additional examples of exploiting the chemotaxonomic principles of botany. Wall et al. Harringtonine PH
R,=(CH3)iC R2=CH2*
* (CH,
I2
9
C - 0 * CHS
Epiharringtonine fl
R, = CH2* C * 0 * CH3
R2 =(CHJ)2-
1”.
(CH&
Fig. 8. Chemical structures of harringtonine and epiharringtonine.
14 TABLE 9 SINGLE AGENT TREATMENT WITH HARRINGTONINE CHEMOTHERAPY WITH HOMOHARRINGTONINE Types of leukemia
Harringtonine
AND
COMBINATION
Combination’
Cases
CR
PR
NR
Cases
CR
PR
NR
Acute myelocytic leukemia Acute monoeytic leukemia Erythroleukemia Chronic myelocytic leukemia crisis Acute promyelocytic leukemia Chronic myelocytic leukemia
93
22
22
49
59
36
10
13
8
2
4
2
6
3
2
1
3 10
2 0
0 4
1 6
3 17
1 3
1 7
1 7
4
3
0
1
97
46
48
4
Total uv)
215
74
73
63
a5
37
26
22
‘Combination: homoharringtonine + oncovine + Ara C + prednisone. Key: CR, complete remission; PR, partial remission: NR, no response.
(19661 reported that camptothecin and several other alkaloids isolated from the tree Camptotheca accuminata Decsne. (Myssaceael from the family Nyssaceae showed significant growth inhibition for transplantable tumors. The medical practitioners in China also have been using this plant for the treatment of leukemias. Camptotheca accuminata is a plant native to China. Scientists of the Shanghai Institute of Materia Medica, Academia Sinica, have made great strides in chemical and pharmacological studies of this plant using some of the alkaloids isolated and characterized (Shanghai Instiute of Materia Medica, Academia Sinca, 1978). Two of them, camptothecin and lo-hydroxy camptothetin, exhibit a wide antitumor spectrum (Table 101.
TABLE 10 EFFECT OF 19HYDROXY CAMPTOTHECIN ON EXPERIMENTAL Tumor (animal host)
Ehrlich ascites carcinoma bite) Hepatoma (mice) Yoshida sarcoma (rat.91 Leukmnia616 fmice)
Dowe (mg/kg)
TUMORS Increase of life span (%I)
Life span (days) Control
Treated
1x26
10.7
36.0
+ 236.4
1x26 1 x 10 2x 5
17.0 11.7 6.7
37.3 39.8 7.1
+ 119.4 + 246.2 + 6.0
15
These scientists claimed that lo-hydroxy camptotheein is more active and less toxic than camptothecin. On the basis of toxicity studies, these two compounds were recommended for clinical trials. Preliminary studies demonstrated that lo-hydroxy camptothecin is more effective than camptothecin for head and neck cancer and stomach cancer. It was reported that lo-hydroxy camptothecin inhibited the clonogenicity of KB cells and exhibited DNA damage in L-1210 cells (Wang et al., 19861.At a concentration of 50 - 200 pm, lo-hydroxy camptothecin revealed a pronounced inhibition on protein synthesis of chromatin in mouse hepatoma cells. Yang et al. (19301studied the pharmaco~etics of lo-hydroxy camptothecin and indicated that PHt labelled IO-hydroxy ~mptothecin is widely distributed t~ougho~t the body in mice. The half-life of this compound was 4.5 min for the Q phase and 29 min for the 6 phase. They also demonstrated that at a dosage of IO mg/kg per day for 3 days intraperitoneal injection of lo-hydroxy camptothecin exhibited significant inhibition of tumor growth and elevated the CAMP level in tumor cells but not in normal cells. It had no effect on the content of cGMP in both normal cells and cancer cells (Leng and Xu, 1982). Conclusions
Increasing emphasis has been laid on medicinal plants for the development of new anticancer drugs recently. The main reason for this is as follows: first, the plant kingdom has been man’s earliest source for useful drugs and several powerful anticancer drugs e.g. vinblastine, vincristine and etoposide (VP-161 have been found in plants already. Second, traditional medicine, especially TCM, has a very ancient history and vast amounts of experience have been accumulated. Some of the therapeutic applications of medicinal herbs used in TCM have already been confirmed by contemporary scientific research. Thirdly, the plant-originated drugs can provide some fascinating novel chemical structures which could be used as rational leads for designing more ideal synthetic or semisynthetic new drugs (Wang and Han, 1987).
Anon. (22-2S0 a.~.) Shen iVong Ber Cao J&g, Current edition &%5), People’s Health Sciences Publishers, Beijing. Cephalotaxus Research Coordinating Group (19781 Cephaiotaxine esters in the treatment of acute leukemias. A preliminary clinical assessment. Chineee Medical Jow42,283272 (English edition). Chang, D.-Z. (1936) Progress on the prevention and treatment of the side effects of radiotherapy and chemotherapy by traditional Chinese medicine. Chinese Joumal of Cancer 4(4), 240- 242. Chang, Z.-I. (1938) Analysis of 304 cases of nonlymphocytic leukemia treated with harringtonine, partially synthetic harringtonine and HOAP protocol. Chinese Medical Jow& in press. Chnng, Z.-I. and Ho, C.-H. (1931) Efficacy analysis of 55 cases of nonlymphocyte leukemia with partiaIIy synthetic harringtonine. Chinese Jomnalof internal Medicine zo(llf, 887-889. Chen. D.-W., Li, Y.-F. and Ye, H.-P. (1979) AntiIeukemic principles of Zadigo natfLmlis - synthesis of indiibin. G~rn~n~~ of Chinsre Herbal Medicine 10(3), 7 - 9.
16 Cheng. P.-Y.. Xu, M.-J., Lin, Y.-L. and Jin, R.-L. (19861 The chemical constituents and antitumor activities of ENT-kaurene diterpenaids from several species of ~abdos~ Abstra&s, First Bei& ing Inte~tio~l Symposium on Cancer Treatment and New Trends of Cancer Chemothe~~, September 7-9, p. 83. Choa, T.-C., Schmid, F.A., Feinberg, A., Philips, F.S. and Han, J. (1983) Uptake, initial effects and chemotherapeutic efficacy of harringtonine in murine leukemic cells sensitive and resistant to vincristine and other chemotherapeutic agents. CancerResearch 43,3074- 3079. Cooperative Group of Clinical Therapy of Indirubin (19801 Clinical studies of 314 cases of CML treated with indirubin. Chinese Journal of IntenullMedicine l(3), 132- 135. Dong Zhi Men Hospital and Guan An Men Hospital (19793 Clinical studies on the effect of polysaccharide from Polyps umbel~ta on advanced patients with lung cancer. Jou~l of Hew Medi tine and hgs 9(2111- 14. Han, J. and Ji. X.-J. (19791 Chemical, pharmacological and clinical studies on the antitumor active principles of Cephalotaxus hainonensti Li. Chinese Journal of Oncology l(3), 176- 181. Han, J. (19841Recent progress on the study of experimental chemotherapy of cancer. Chinese Yeurbook of Medicinal Sciences, Peoples Health Publishers, Beijing, pp. 199-206. Han, J. (1987al Pharmacological studies and clinical application of harringtonine and homoharring tonine in China. Current Medicine in China (in press). Han, R. [Han, J.] (1987bl Highlight on the progress of anticancer drug studies in China. Proceedings of ~hi~e&e Academy of ~ed~aZ Sciences and Peking anon Medical College 2W,l-6. Han, J. and Roboz, R. (19821~uantitation of harringtonine and homoharrin~onine in serum by high performance liquid chromatography. Journal of Chromatography 273,203 - 211. Huang, L. and Xue, Z. (19841 Cephalotaxus alkaloids. In: Brossi, A. and Manske, R.H.F. teds.), The Alkaloids, Vol. 23. Academic Press, New York, pp. 157-226. Institute of Chinese Materia Medica, Academy of Traditional Chinese Medicine (19811Experimental studies of antitumor effect of an extract derived from Zhuling u3olyporu.s umbellata). Chinese Journal of Oncology 3(2), 106 - 109. Institute of Hematology, Chinese Academy of Medical Sciences (1979al Clinical studies of Dang Gui Lu Hui Wan in the treatment of CML. Chinese Journal of Intel Med~ine X%21,86-88. Institute of Hematology, Chinese Academy of Medical Sciences 0979bl Experimental and clinical studies of indirubin in the treatment of CML. Chinese Journal of Internal iMedicine 18(21,83- 88. Institute of Materia Medica, Chinese Academy of Medical Sciences (19751 Partial synthesis of harringtonine. Kexei Tongbao 20,437. Institute of Materia Medica, Chinese Academy of Medical Sciences (19761Studies on the antitumor constituents of Cephalotaxus hainunensis Li. Acta Chimica Sinica 34(41,283-293. Institute of Materia Medica, Chinese Academy of Medical Sciences (19771The antitumor effects and pharmacological actions of harringtonine. Ch&ese Me&d Journal 3(21,f32- 136. Ji, X.-J., Lui, J.-S. and Liu, Z.-M. (19793Metabolism of harrin~onine. ActaPha~acent~a Sinica 14, 234 - 240. Ji, X.-J. and Chang, F.-R. (19811Studies on the antineoplastic action and toxicity of synthetic indirubin. Acta Pharmaceutics Sinica 16(21,146- 148. Ji, X.-J., Liu, Y.. Liu, H. and Liu, Z.-M. (19821 Metabolism of homoharringtonine in rats and mice. Acta Pharmaceutics Sinica 17,881- 888. Ji, X.-J., Zhang, F.-R. and Dong, X.-L. (19831Studies on the antineoplastic action and toxicity of partial synthetic harringtonine. Acta Phannaceutdea Sinica 18(4), 299 - 302. Leng, Y.-H. and Xu, B. 11982) Effect of lO-hydroxy eamptothecin on the activity of adenylate eyclase in mouse hepatoma cells. Acta P~~~o~g~a Sinica 3,264 - 268. Li, C-L. and Ji, X.-J. (19831A comparative study on the physiolo~e~ ~s~ition of sH-indi~bin and its derivatives H-79002 and H-79003 on animals. Acta Pharmaceutics Sinica 18[5], 332- 338. Li, D.-X., Hao, X.-G. and Zhang, S.-K. (19811toxicity and anticancer effect of irisquinone. Acta Pharmocologica Sin&a 2(21,131- 134. Li, S.-Z. (1696-1696)Ben Coo Gang Mu (Current edition 19751.Peoples Health Sciences Publishers, Beijing. Li, Z.-R. and Han, J. [Han, R.] (1986) Progress on the study of new antitumor drugs - harringtonine and homoharringtonine. Chinese Herbal Drugs 17(3),39 - 43.
17 Maeda, Y.Y.. Ishimura, K. and Chihara, G. (19761 Antitumor polysaccharides and host defence against cancer: A new way for cancer immunochemotherapy. Protein, Nucleic Acids and Enzymes 2U61.425 - 435. Miyasaki, T. (1983) Antitumor activity of fungal crude drugs. Journal of Traditional &no-Japanese Medicine 4(l), 61- 65. Nanjing Traditional Chinese Medical College (19591An outline of Chinese Materia Medica. Peoples Health Sciences Publishers, Beijing, pp. 1- 3. Ohnuma, T. and Holland, J.F. (19851 Homoharringtonine as a new antileukemic agent. Journal of Clinical Oncology 3(51,604 - 606. Powell, R.G., Weisleder, D. and Smith, Jr., CR. (1972) Antitumor alkaloids from Cephalotoxus harringtonti structure and activity. Journal of Pharmaceutical Sciences 61(81,1227- 1230. Roboz, J., Greves, J. and Han, J. (19821 Quantification of homoharringtonine and harringtonine in serum by chemical ionization mass spectrometry. Biomedical Mass Spectrometry 9(121, 510514. Shan, Y.-D., Liu, E.-K., Chang, Z.-N. and Chang, A. (19881Clinical analysis of acute non-lymphocytic leukemias (6s cases) treated with HOAPHOACP protocol. Chinese Medical Journal 65(10) 590-592. Shanghai Institute of Materia Medica, Academia Sinica (1978) Studies on the anticancer action of lo-hydroxy camptothecin. Chinese Medical Journal 58(10), 598-602. Tang, M.-X., Yu, G.-Q. and Duan, F.-W. (19861 Experimental studies on the antitumor effect of Fu Zheng prescription and drugs used in traditional Chinese medicine. Chinese Journal of Cancer 5(11,65-68. Wall, M.E., Wani, M.C., Cook, C.E. and Palmer, K.H. (1966) Plant antitumor agents. I: the isolation and structure of camptothecin, a novel alkaloidal leukemia and tumor inhibitor from Camptotheta acuminuta Journal of the American Chemical Society 88.3888-3890. Wang, L.-W., Su, C. Liu, K.-S. and Chang, I. (19641 A preliminary report on the diuretic action of Polyporus umbellata. Acta Pharmaceutics Sinica 11(12), 815- 818. Wang, X.-W., Shen, Z.-M., Yang, J.-L. and Xu, B. (1986) Inhibitory effect of hydroxy-camptothecin on colony formation of KB cells and DNA damage. Acta Pharmaceutics Sinica 21(71,492-497. Wang, Z.-Y. and Han, J. (1987lDrug Treatment of Cancer, Peoples Health Sciences Publisher, Beijing, China, pp. 7- 14. Wu, L.-M., Yang, Y.-P. and Zhu, Z.-H. (19781Studies on the active principles of Zndigofera tinctoria in the treatment of CML. Communications of Chinese Herbal Medicine 9(4), 6-8. Wu, G.-Y., Fang, F.-D., Liu, J.-Z., Chang, A. and Ho, Y.-H. (19801Studies on the mechanism of action of indirubin in the treatment of chronic granulocytic leukemia: I: Effects on neucleic acid and protein synthesis in human leukemic cells. Chinese Medical Journal 60(8), 451- 454. Xiao, P.-G. (19831Recent developments on medicinal plants in China. Journal of Ethnopharmacology 7.95 - 105. Yang, J.-L., Han, J.-X. and Xu, B. (19801Distribution, excretion of lo-hydroxy camptothecin in mice and its effect on immune function. Acta Pharmacologica Sinica l(l), 44- 48. Zhang, T.-M. (19861Recent status of the study of oridonine. In: Abstracts of the First Beijing Znternational Symposium on Cancer Treatment and New Trends of Cancer Chemotherapy, September 7 - 9, Beijing, pp. 85. Zheng, Q.-T., Lu, D.-J. and Yang, S.L. (1979al Pharmacological studies of indirubin. I: Antitumor effect. Communications of Chinese Herbal Medicine 10(111,35-39. Zheng, Q.-T., Qi, S.-B. and Cheng, Z.-Y. (1979133Pharmacological studies of indirubin. II: absorption, distribution and excretion of 3-H-indirubin. Communications of Chinese Herbal Medicine 10(12), 19-21. 187th Hospital of Peoples Liberation Army (19781Efficacy analysis of 72 cases of leukemias treated by harringtonine and related drugs. Chinese Medical Journal 58(3), 163- 166.
Review Paper
TRADITIONAL CHINESE MEDICINE ANTINEOPLASTIC DRUGS*
AND THE SEARCH
FOR NEW
JUI HAN Department of Pharmacology, Institute of Mateti 1 Xiun Nong Tan Street, Beijing /Chid
Medica, Chinese Academy of Medical Sciences,
(Accepted May 12,19881
Summary The experience of traditional Chinese medicine affords a valuable approach in the search for new antineoplastic drugs as illustrated by indirubin from Dang Gui Lu Hui Wan, irisquinone from Iris Zuctea pallasii and Zhuling polysaccharide from Polyporus umbelluta The application of chemotaxonomic principles to related species of those plants used in folk medicine has also provided an approach which can be used successfully for the development of new drugs. The studies of Cephalotaxus hainanesis and Camptotheca accuminuta provide two typical examples in this regard. One must be aware that the experience of traditional Chinese medicine cannot be used without elaborate efforts in many cases. For example, the ancient Chinese ideograph for spleen does not mean spleen in the modern sense, instead it refers to the entire gastrointestinal system. Similarly, the ancient ideograph for kidney does not mean kidney in the modern sense, and can mean the entire endocrine system. Therefore, for the reasonable utilization of traditional Chinese medicine, one must be familiar with its basic concepts and terminology. In addition, one must bear in mind that the term “tumor” in folk medicine is applied to a very wide range of pathological manifestations which sometimes have no relation to the various forms of neoplasia. It is important for drugs and treatments to be analyzed carefully in modern terms to eliminate the false and to utilize the true information. Only in such a way can the experience of traditional medicine be integrated into modern medicine and make its contribution in the advancement of health care in the world.
*This paper was presented at the First Beijing International Symposium on Immunology: Impact of Traditional Medicine, June lo- 12,1984. 0378-8’741/88/$06.30 0 1988 Elsevier Scientific Publishers Ireland Ltd. Published and Printed in Ireland
2
Introduction Shen Nong Ben Cao Jing (Anon., 22 - 250 A.D.) and Ben Cao Gang Mu (Li, 1590 - 1596 A.D.)are the two most famous classics on Chinese materia medica. The description of the pharmacologic actions of the majority of the drugs included in these books are precise and useful in the treatment of diseases even today. For example, Ephedra sinica relieves asthma, Rheum palmatum improves constipation, Angelica sine&a ameliorates menstruation disorders. Dichroa febr& fuga and Artemisia apiacea are active against malaria and Omphaliu lupialia is effective for helminth infestations. All these therapeutic effects have been confirmed by contemporary scientific research. Chemical and pharmacologic studies conducted in the last 30 years have proven that Chinese materia medica and Chinese medicine represent a great treasure house of knowledge. Many clinical and experimental studies indicate that the development of cancer is related to the functional status of the host’s immune system. By manipulating the immune system, it is possible to eradicate residual tumor cells when the tumor load is minimal. Panax ginseng, Astragalus membranaceus, PO& cocos, Polyporus umbellata, Tremmella fuciformis and Cordyceps sine&s are widely used tonics from ancient times. Recent studies have demonstrated that certain of these drugs are immunomodulators and active against rodent tumors. Their clinical evaluation is now in progress. Historical perspective Traditional Chinese Medicine (TCM) has an ancient history and a unique system of practice which includes Theory, Methodology, Prescription Formulation and Drugs. It is highly treasured as a precious cultural heritage. Since the majority of Chinese Traditional drugs are of plant origin, this system was once called “herbal” (Ben Caol. Now it is called Chinese materia medica (Zhong Yao Xuel and represents the accumulation of the extensive daily experiences of medical practice by the Chinese people since prehistoric times. In the famous book Huui Nan Zi from the Han dynasty of the 10th century A.D.(Nanjing Traditional Chinese Medical College, 19591, there is a quote that “Shen Nong tried hundreds of herbs and met with seventy poisons in a day”. This illustrates the difficulties of the “trial-and-error” accumulation of clinical experience in the treatment of disease. The broad stretches of Chinese territory lying in the subtropic and temperate zones provide favorable conditions for the growth of diverse plants. A recent survey (Xiao, 1983) of these plants has identifed 4877 species with potential therapeutic value of which about 500 are in common usage. Descriptions of cancer have been found in many of the classics of TCM, but due to the limited exposition of historical background, their use in the diagnosis of cancer and as a basis for prescribing treatments for cancer has not been very useful, especially for malignancies of the viscera. Nevertheless, the experience of traditional medicine can provide clues for new antineoplastic drugs. For
example, the discovery of the antitumor effect of indirubin illustrates the value of this approach. Plants providing drugs have received much attention, not only due to their enormous potential for the development of new and useful therapeutic agents but also because they can provide fascinating novel chemical structures which may be used as rational leads for the design of more nearly ideal drugs. Special efforts have been made to use the experience of folk medicine and TCM in the research and development of new antineoplastic drugs in China. In contrast to random screening, a rational approach guided by the experience of TCM is economical and can increase the probability of success. The chemotaxonomic interrelationships of medicinal plants provide another useful tool for the discovery of new drugs. This paper will provide examples which illustrate how TCM has helped in the search for new antineoplastic drugs and biological response modifiers, and how modern science and technology have been used in China to study the chemistry and pharmacology of traditional Chinese drugs and plant-derived pharmaceuticals. Guidanceof traditional
Chinesemedicine
Indirabin Guided by the therapeutic principle of “purge the hepatic substantial fire” of TCM, a group of scientists from the Institute of Hematology, Chinese Academy of Medical Sciences (1979a1, has discovered the efficacy of a famous Chinese prescription, Dang Gui Lu Hui Wan, for the treatment of chronic myelocytic leukemia @ML). Dang Gui Lu Hui Wan are pills which contain 11 Chinese traditional drugs, i.e. Angelica sine&s (Oliv.1 Diels, Aloe vera L., Elephantopus scaber L., Saussurea lappe Clarke, Scutellaria baicalensis Georgi, Phillodendron chinensis Schneid., Coptis chine&s Franch, Gardenia jasminoides Ellis, Rheum palmatum L., ind& gofera tinctoria L., Moschus moschiferus L. Clinical studies demonstrated that the withdrawal of Moschus moschiferus from these pills did not affect the efficacy of Dang Gui Lu Hui Wan, nor did the withdrawal of Coptis chine&s. However, the withdrawal of Moschus moschiferus, Aloe veTa and Indigofera tinctoria made them inactive. The prescription lacking Moschus moschiferus and Coptis chinensis could be divided into two parts, according to the pharmacological characteristics of the remaining drugs, i.e., purgatives (Aloe Vera, Rheum palmatum, Elephantopus scaber, Saussurea lappa) and non-purgatives (Scutellaria baicalensis, Phillodendron chinensis, Gardenia jasminoides, Angelica sine&s, Indigofera tinctoria). Clinical studies showed that pills made of the non-purgatives showed definite efficacy (Institute of Hematology, Chinese Academy of Medical Sciences, 1979131.Pills consisting of only two drugs, Indigofera tinctoria and Aloe Vera showed a clearly significant therapeutic effect. Experimental therapeutic studies with transplantable tumors demonstrated
Patient response w) Complete remission Partial remission Improved No effect Total cases 4 5 7 6 22
+ + + + + + + + + +
Dry juice Whole herb Root Root Bark Root Fruit Root Leaf Musk
0 2 6 2 10
+ + + + + + + + +
+
+
Root
Angelica sine&s Aloe vem Elephantopw scabes Saussurea lappa Scutellaria baicalensis Phillodendron chinen..+ Coptis chine&s Gardenia jaaminoides Rheum palmatum Indigofera tinctoria Moschua moschiferzls
2
Pill no. 1
Part
Pill Composition
EFFICACY OF DANG GUI LU HUI WAN (PILL NO. 1) AND SIMPLIFIED
TABLE 1
0 0 5 0 5
-
+ + + + + + + +
+
3
0 0 0 3 3
-
+
+ + +
4
PILLS (NOS. 2-8)
0 0 3 3 6
-
+
+ + +
+
5
IN CML
0 0 0 4 4
+ -
+ + + + + +
+
6
0 4 3 0 7
+
+
7
1 4 10 0 15
+
8
Fig. 1. Chemical structure of indirubin.
that Indigofera timto& alone prolonged the life span of L-1210 leukemia-bearing mice significantly while Aloe vera alone did not. These results indicated that Indigofera tinctoria (Legumino Seael was the major effective drug in Dang Gui Lu Hui Wan. Phase I and phase II clinical studies (Cooperative Group of Clinical Therapy of Indirubin, 19801of Indigofera timto& showed very encouraging therapeutic effects (Table 11. Phytochemi~al studies demonstrated that hzdigofera tinctoria contains several components, e.g. indigo blue, indigo brown, kaempferol and inorganic salts. Among these ingredients, the content of indigo blue is most abundant but inactive in experimental chemotherapy. Further studies showed that a minor component, indirubin (Fig. 11,exhibited pronounced therapeutic effects on animal tumors as well as in clinical studies for the treatment of CML fWu et al., 1978; Zeng et al., 1979a,b; Wu et al., 19801. Furthermore, it was reported that indirubin can increase the cellular immunity and cyclic AMP content of leukocytes of CML patients (Table 2). In view of the fact that the content of indirubin in Indigofera tinctoriu is minute (O.ll%l, chemists at our Institute &hen et al., 19791have succeeded in the total synthesis of indirubin from indigo blue (Fig. 21.On the basis of toxieologieal studies (Li and Ji, 19831, synthetic indirubin was approved for clinical trial and was found to be effective against CML with less side effects than Indigofera tinctoriu (Ji and Chang, 19811.Table 3 indicates that complete remission was attained in 26% of 314 cases while the partial remission rate was 33%. Clinical pharmacological studies indicated that the major side effects of indirubin are abdominal pain and diarrhea. A decrease of platelet count was also
TABLE 2 EFFECT OF INDIFWBIN LEUKEM~ PATIENTS
ON CELLULAR
IMMUNITY
OF CHRONIC MYELOCYTIC
Group
SK-SD skin delayed hypersensitivity (mm*)
E rosette (%I
Phagoeytosis (%I
Z $-rosette (%I
Normal volunteers CML patients before treatment CML patients after treatment (in remission)
44.3 14.8
33.3 40.1
2.6 33.7
9.3 10.7
36.2
60.4
67.0
15.8
Fig. 2. Chemical synthesis of indiibin (IV).
found in some patients. A comparison of the efficacy of indirubin and busulfan (Myleran) showed that the effective rates were similar but the complete remission rate was slightly higher for busulfan. No cross-resistance between these two drugs was observed. In a preliminary study, some new derivatives of indirubin have shown more promising and more interesting results than their progenitor. Further work is in progress. The process of transfer from Dang Gui Lu Hui Wan to ~~~gof~~ tractor to indirubin and to new derivatives of indirubin for the treatment of CML furnishes a typical example of our approach to the study and development of new antineoplastic agents. This example also illustrates how modern medicinal chemistry and pharmacology can help traditional medicine develop to a new level.
Iris latea pallusi Fischer var. chinelasis and Rabdda
rubescence
TABLE 9 CLINICAL EFFICACY OF INDIBUBIN IN CHRONIC MYELOCYTIC LEUKEMIA
Total easea Complete remission ParW remkkm Beneficial No response
No.
%
514 82 106 87 40
100.0 26.1 23.4 27.7 2.7
(Hemsl.1
CH30
(cll& WCH-(cH&-CHs 0
Fig. 3. Chemical structure of iriequinone.
may serve as additional examples of the guidance of TCM in the search for antineoplastic drugs. The former plant belongs to the Iridaceae family and its seeds have been used for the treatment of malignancies in folk medicine. The chemists of Tientsin Institute of Materia Medica have isolated an active principle (irisquinone) from the seeds of Iris &eapaZlasi(Fig. 31.Chemically it is 6-methoxy 2-A10&-heptadecenyl-l,4phenylquinone. Experimental chemotherapeutic studies have shown that irisquinone is effective against transplantable tumors, such as cervical carcinoma U14, lymphosarcoma, hepatoma and Ehrlich ascites carcinoma in mice. It is in phase I studies at present (Li et al., 1981). Rabdosiu rubescence from the Labiatae family has been used for the treatment of esophageal cancer in folk medicine in Henan province, China (Cheng et al., 1986). Several diterpine compounds, for example oridonine, ponicidine, rabdoserrin A, amethystoidin A and rabdophyllin have been isolated from this plant and some related plants which belong to the same species. Experimental therapeutic studies have demonstrated that oridonine and ponicidine show significant antitumor effects on rodent tumors such as L-1210, P-388 and Ehrlich ascites carcinoma. Clinical studies are in progress in the teaching hospital of Henan Medical College (Zhang, 19861. Zhuling polysaccharide From ancient times, many species of the polyporaceae have been used for the treatment of disease. Zhuling (Polyporus umbelkztu) was originally described in Shen Nong Ben Cao Jing as having diuretic action and was used mainly for the
TABLE 4 EFFECT OF ORALLY ADMINISTERED POLYPORUS ON S-180 IN MICE
UMBELLATA
POLYSACCHAIUDE
Group kimage)
N
Tumor weight (g)
Inhibition (%I
Control 125 mg/kg ( x 14) loo0 mg/kg ( x 14)
33 19 20
l&l f 0.19 1.34 f 0.24 0.92 f 0.17
28.0 so.6
P
< 0.06 < 0.01
3 TABLE
5
CHANGES TREATED
Phagocytosis Phagocytosis
IN PHAGOCYTOSIS FOR 67 PATIENTS WITH PRIMARY LUNG WITH THE POLYSACCHARIDE OF POLYPORUS UMBELLAZ’A
(%I index
CANCER
Before treatment
After treatment
P
35.3 0.45
44.0 0.55
< 0.01 < 0.01
teatment of edema and dysuria (Wang et al., 19641. Clinical studies have demonstrated that Polyporus umbellata is an effective diuretic, without side effects, for the treatment of pyelonephritis, nephritis and urologic calculi (Wang et al., 19641. Maeda et al. (19761 have published that a polysaccharide from Poriu cocos was able to exert a significant antitumor effect on sarcoma 180 in mice. Since then, much attention has been directed to the anticancer and immune potentiation effect of related fungi. Scientists of the Institute of Chinese Materia Medica, Academy of Traditional Chinese Medicine (1981) have found that the related herbal diuretic, Polyporus umbellata is also effective against sarcoma 180 (Table 41. Miyasaki (19831 reported similar results in a Japanese journal. In addition, Chinese scientists claimed that the polysaccharide of Polyporus umbellata increased both cellular and humoral immunities in experimental animals. The medical doctors of Dong Zhi Men Hospital, Beijing Traditional Chinese Medical College, noted that the polysaccharide of Polyporus umbellata decreased the side effects of chemotherapy and increased the phagocytic activity of macrophages in patients with advanced primary lung cancer (Table 5). A group of scientists from Guan An Men Hospital, Academy of Traditional Chinese Medicine reported similar results on similar patients with advanced lung cancer (Dong Zhi Men Hospital and Guan An Men Hospital, 19’79). TCM also has a resource of nourishing tonics, also called the Fu Zheng drugs (Tang et al., 19861; for example, Panux ginseng C.A. Meyer, Cordycepes sinensis (Berk) Sacc. and Tremmellu fuciformis Berk. Recent studies have shown that certain of these drugs can increase the number of leukocytes in patients with depressed hematopoietic function and improve the immune competence of patients receiving chemotherapy and/or radiotherapy (Chang, 1985). Thus it is apparent that the search for new biological response modifiers from these herbal drugs may be a fruitful one for the development of new drugs. Chemotaxonomic principles applied to folk medicine Harringtonine
and homoharringtonine
An alternative approach for seeking new antineoplastic drugs is to use the chemotaxonomic principle of chemical relatedness among taxonomically close plant species, especially if one or more are used in folk medicine. The basic
9
Compound
R2
4 OH
OH
I
I
CH,-C-(CH,k,-C-CH,-COOCH,
Harringtonine
I CH,
I coo-
OH
OH
I
I
CH,-C-(CH,),-C-Cl+,-COOCH,
Homoharringtonine
I CH,
H-
H-
1 cooOH
I
CH,-CH-(CH,),-C-CH,-COOH,
Deoxyharringtonine
I CH,
lsoharringtonine
c60OH
OH
I
I
CH,-CH-(CH,),-C-CH-COOCH,
I %
H-
1
H-
I coo-
Cephalotaxine
HO-
H-
Acetylcephalotaxine
CH,OCO-
H-
Epicephalotaxine
H-
HOOH
Deoxyharringtonic
acid
I
CH,-CH-(CHJ,-C-CH,-COOH
I C%
OH lsoharringtonic acid
I
Fig. 4.Alkaloids foundin Cep~a~~
OH
CH,-CH-(CH,),--C-CHCOOH
I CH, kainanensis.
H-
I coo-
I coo-
I
H-
10 TABLE
6
EFFECTS MICE
OF
HARRINGTONINE
AND
HOMOHARRINGTONINE
Dose
Group
N
0.7 0.55 2.4 2.7
x x x x
L-1210-BEARING
Average
survival time
(days)
(m&g) Control Harringtonine Homoharringtonine Isoharringtonine Deoxyharringtonine
ON
10 10 10 10 10
8 8 8 8
9.8 17.8 17.8 16.2 18.2
strategies of this approach are illustrated by the studies of a tree called CephaG otazus hainanensis Li (Cephalotaxaceael from which harringtonine and homoharringtonine were isolated. This study was inspired by two factors. One was the beneficial effect obtained by folk medical practitioners in Fukien Province for the treatment of neoplastic diseases with CephoZotams fortuni Hook F. (Cephalotaxus Research Coordinating Group, 1976; Institute of Materia Medica, Chinese Academy of Medical Sciences, 1977; Han and Roboz, 1982; Han, 1984,1987a,bl. The other was the antitumor activity exhibited by the alkaloids isolated from Cephabtams harringtoniu (Forbes) Koch as reported by Powell et al. (1972). Since then a systematic investigation including chemical, pharmacological and botanical studies, has been carried out for Cephalotaxw hainanensis in our institution (Ji et al., 1979; 1982; Roboz et al., 1982; Li and Han, 19861. Colleagues at the Institute of Materia Medica, Chinese Academy of Medical Sciences (19761 have isolated more than 16 alkaloids and two lactones from a related plant, Cephalotams hainunensis, indigenous to Hainan Island, Kwangdong Province, China. These alkaloids include cephalotaxine, harringtonine, homoharringtonine, isoharringtonine and deoxyharringtonine. Hainanolide and hainanolidol are two lactones (Huang and Xue, 19841. All these compounds were identified by infrared and mass spectroscopy, nuclear magnetic resonance and X-ray diffraction analysis. Their chemical structures are shown in Fig. 4.
TABLE
7
LDa, IN MICE
( f S.D.) OF HARRINGTONINE
AND HOMOLOGUES LDso (m&kg) i.p.
Harringtonine Homoharringtonine Isoharringtonlne Daoxyharringtonine
4.3 3.3 14.6 16.0
i.v. f f f f
0.5 0.4 0.7 2.4
4.5 2.4 13.2 8.8
f f f f
0.2 0.2 0.1 0.5
11 TABLE 8 SUBACUTE TOXICITY OF HARRINGTONINE AND HOMOHARRINGTONINE IN DOGS Drug
Dosage (i.v. mgllrg)
Toxic effects
Harringtonine
0.1 x 12 0.2 x 9 0.076 x 9
Bone marrow depression Severe bone marrow depression Bone marrow depression and gastrointestinal disturbances Severe bone marrow depression and severe gatrointestinal disturbances
Homoharringtonine
0.16 x 8
Pharmacological studies (Han, 1987al indicate that cephalotaxine, the most constituent of the bark of this tree is inactive. However the esters of this alkaloid, i.e. harringtonine, homoharringtonine, isoharringtonine and deoxyharringtonine, all exhibit remarkable antileukemic action on L-1210 and P-338 bearing mice (Table 61. A significant antitumor action was also demonstrated in some solid transplantable tumors (melanoma B16, sarcoma 180 and Walker carcinosarcoma 2861. The acute LD, values for these alkaloids are shown in Table 7. In subacute toxicological experiments on dogs, harringtonine at a dosage of 0.1 mg/kg per day for 14 days showed no serious side effects but only a mild bone marrow depression. At a higher dosage (0.2 mg/kgl, it caused bone marrow depression and gastrointestinal disturbances (anorexia, nausea, vomiting) (Han and Ji, 19’791.At a similar dosage schedule, homoharringtonine showed more pronounced side effects than harringtonine, especially in regard to the gastrointestinal system (Table 81. abundant
Lsu -protein ‘_a____b___~-__-_--____~ 01
1
,
I
I
20
40
60
80
1
100
Minutes Fig. 5. Inhibition of precursor incorporation into protein, DNA and RNA by harringtonine.
12
To explore the mechanism of action of harringtonine, we have studied the effect of this drug on the incorporation of radioactive precursors of DNA, RNA and protein (Chou et al., 19831. Experiments have demonstrated that the incorporation of THfleucine into protein of L-1210 cells was inhibited very quickly, followed by the inhibition of incorporation of ~H~hymidine into DNA of L-1210 cells (Fig. 51.Harringtonine showed no effect on the incorporation of rH]uridine into RNA of L-1210 cells. These results seem to indicate that the primary effect of harringtonine relies on an inhibition of protein synthesis. It is interesting that harringtonine has no cross-resistance with the majority of known anticancer drugs except vincristine. The uptake of PHJharringtonine by a vincristine-resistant cell line of L-1210 was also decreased significantly. This means that the occurrence of drug resistance can be related to the membrane transport of antineoplastic drugs. After intravenous injection of ~HJharrin~onine to rats, the blood radioactivity level decreased rapidly and after 15 min the decrement rate was slowed (Fig. 61.Its distribution pattern is shown in Fig. 7. The biological half life of ~H]homoharrin~onine in rats is similar to [3H]harringtonine except that the content of homoharringtonine in bone marrow was higher than that of harringtonine (Ji et al., 1979.19821. Considering the fact that the content of harringtonine and homoharringtonine in the plant is very low, a group of chemists at our institute have succeeded in the partial synthesis of certain desired diastereoisomers of harringtonine and homoharringtonine which consist of epiharringtonine plus harringtonine and homoharringtonine plus epihomoharringtonine separately (Fig. 81(Institute of Materia Medica, Chinese Academy of Medical Sciences, 19751.The partially synthetic harrin~onine and homoharrin~onine exhibited sign~icant inhibition
i
Fast
phase
t y* = 3’30”
I
Slow
phase
t y2 =
50’
x
i
7-i
--r-m I:1
x--_
I
x-X 1
x
5 IO 20 30
60
Minut8s Fig. 6. Pkarma~kineti~
after
of ~~]har~n~onine
120
IV in rats after intravenous injection.
13
Kidney *. Liver
Bone marrow
Heart Lung
0
15 mins
@
2 hrs
m
24
after
hrs
Muscle
IV iV
after
Testis
Spleen GI
after
IV
Brain Blood
Fig. 7. The distribution of [~H]harringtonine in rats after intravenous injection.
of experimental tumors (Ji e al., 19833.On the basis of toxicological studies, all of these compounds were recommended for clinical trials. Phase I and phase II studies have shown that the partial synthetic compounds are as active as the natural products @hang, 19881.The clinical effects of harringtonine are shown in Table 9 (187th Hospital of Peoples Liberation Army, 1978; Chang and Ho, 1981; Ohnuma and Holland, 1985; Chang, 1988; Shan et al., 19881. Camptothecin and lo-Hydroxy camptothecin The studies of camptothecin and IO-hydroxy camptothecin afford additional examples of exploiting the chemotaxonomic principles of botany. Wall et al. Harringtonine PH
R,=(CH3)iC R2=CH2*
* (CH,
I2
9
C - 0 * CHS
Epiharringtonine fl
R, = CH2* C * 0 * CH3
R2 =(CHJ)2-
1”.
(CH&
Fig. 8. Chemical structures of harringtonine and epiharringtonine.
14 TABLE 9 SINGLE AGENT TREATMENT WITH HARRINGTONINE CHEMOTHERAPY WITH HOMOHARRINGTONINE Types of leukemia
Harringtonine
AND
COMBINATION
Combination’
Cases
CR
PR
NR
Cases
CR
PR
NR
Acute myelocytic leukemia Acute monoeytic leukemia Erythroleukemia Chronic myelocytic leukemia crisis Acute promyelocytic leukemia Chronic myelocytic leukemia
93
22
22
49
59
36
10
13
8
2
4
2
6
3
2
1
3 10
2 0
0 4
1 6
3 17
1 3
1 7
1 7
4
3
0
1
97
46
48
4
Total uv)
215
74
73
63
a5
37
26
22
‘Combination: homoharringtonine + oncovine + Ara C + prednisone. Key: CR, complete remission; PR, partial remission: NR, no response.
(19661 reported that camptothecin and several other alkaloids isolated from the tree Camptotheca accuminata Decsne. (Myssaceael from the family Nyssaceae showed significant growth inhibition for transplantable tumors. The medical practitioners in China also have been using this plant for the treatment of leukemias. Camptotheca accuminata is a plant native to China. Scientists of the Shanghai Institute of Materia Medica, Academia Sinica, have made great strides in chemical and pharmacological studies of this plant using some of the alkaloids isolated and characterized (Shanghai Instiute of Materia Medica, Academia Sinca, 1978). Two of them, camptothecin and lo-hydroxy camptothetin, exhibit a wide antitumor spectrum (Table 101.
TABLE 10 EFFECT OF 19HYDROXY CAMPTOTHECIN ON EXPERIMENTAL Tumor (animal host)
Ehrlich ascites carcinoma bite) Hepatoma (mice) Yoshida sarcoma (rat.91 Leukmnia616 fmice)
Dowe (mg/kg)
TUMORS Increase of life span (%I)
Life span (days) Control
Treated
1x26
10.7
36.0
+ 236.4
1x26 1 x 10 2x 5
17.0 11.7 6.7
37.3 39.8 7.1
+ 119.4 + 246.2 + 6.0
15
These scientists claimed that lo-hydroxy camptotheein is more active and less toxic than camptothecin. On the basis of toxicity studies, these two compounds were recommended for clinical trials. Preliminary studies demonstrated that lo-hydroxy camptothecin is more effective than camptothecin for head and neck cancer and stomach cancer. It was reported that lo-hydroxy camptothecin inhibited the clonogenicity of KB cells and exhibited DNA damage in L-1210 cells (Wang et al., 19861.At a concentration of 50 - 200 pm, lo-hydroxy camptothecin revealed a pronounced inhibition on protein synthesis of chromatin in mouse hepatoma cells. Yang et al. (19301studied the pharmaco~etics of lo-hydroxy camptothecin and indicated that PHt labelled IO-hydroxy ~mptothecin is widely distributed t~ougho~t the body in mice. The half-life of this compound was 4.5 min for the Q phase and 29 min for the 6 phase. They also demonstrated that at a dosage of IO mg/kg per day for 3 days intraperitoneal injection of lo-hydroxy camptothecin exhibited significant inhibition of tumor growth and elevated the CAMP level in tumor cells but not in normal cells. It had no effect on the content of cGMP in both normal cells and cancer cells (Leng and Xu, 1982). Conclusions
Increasing emphasis has been laid on medicinal plants for the development of new anticancer drugs recently. The main reason for this is as follows: first, the plant kingdom has been man’s earliest source for useful drugs and several powerful anticancer drugs e.g. vinblastine, vincristine and etoposide (VP-161 have been found in plants already. Second, traditional medicine, especially TCM, has a very ancient history and vast amounts of experience have been accumulated. Some of the therapeutic applications of medicinal herbs used in TCM have already been confirmed by contemporary scientific research. Thirdly, the plant-originated drugs can provide some fascinating novel chemical structures which could be used as rational leads for designing more ideal synthetic or semisynthetic new drugs (Wang and Han, 1987).
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