Medicinal and Poisonous Plants of the Tropics
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Medicinalan d poisonous plants of the tropics Proceedings of Symposium 5-35 of the 14th International Botanical Congress, Berlin, 24July- I August 1987 A.J.M. Leeuwenberg (compiler) 5 7PO ; \\' ^ '* ,7^ Pudoc Wageningen •tciï CIP-gegevensKoninklijk e Bibliotheek, Den Haag ISBN90-220-0921- 1 NUGI824 ©Centre for Agricultural Publishingan dDocumentation , Wageningen, 1987 No part of thispublication ,apar t from bibliographic dataan dbrie f quotations embodiedi n critical reviews, may bereproduced , re-recorded or published inan yfor m including print, photocopy, microform, electronic or electromagnetic record without written permission from the publisher Pudoc, P.O.Bo x 4,670 0A A Wageningen, Netherlands. Printed inth e Netherlands L. CONTENTS Preface 7 Research onmedicina l and poisonous plants of the tropics -past , present and future - I.Hedber g 9 Medicinal plants in tropical areas of China -Pei Sheng-ji 16 Tropical plants used in Chinesemedicine :potentia l leads for pharmaceutical development -Pau l Pui-Hay But 24 Medicinal plants of wide use in Zimbabwe -N.Z .Nyazem a 36 Some common African herbal remedies for skin diseases: with special reference to Kenya -J.0 .Kokwar o 44 Plants as sources of antimalarial and amoebicidal compounds - J.D. Phillipson, M.J. O'Neill, C.W. Wright,D.H . Bray and D.C.Warhurs t 70 Plants in thehealt h care delivery system of Africa -Dawi t Abebe 79 The investigation and research onHseny i -natura l resources of Henan -Ga o Zengyi,Zho u Changshan, CuiBo ,A n Zhuojun and / Tang Shian 88 Introduction to the ethnobotanical pharmacopeia of the Amazonian Jivaro of Peru -W.H . Lewis,M . Elvin-Lewis and M.C. Gnerre 96 Analysis of the volatile constituents of Piper betle L. cultivars - a chemosystematic approach -A.K.S . Rawat,Ush a Shome and V.R. Balasubrahmanyam 104 Medicinal and poisonous plants in the West Indies -C.E . Seaforth 109 Some Malvaceae of Mozambique with medicinal properties - Angelina L. Maite 116 Medicinal use of some Philippine plants -Ma .Agne s Abad Flores 119 Recent efforts ofpreservatio n and exploitation of medicinal and aromatic plants -J . Bernäth 121 Drumstick {Moringa oleifera Lam.) -A multipurpos e perennial Indian vegetable tree of considerable medicinal value -K.V . Peter 124 Glycoside formation in Digitalis lanata Ehrh leaves with special reference togrowt h hormones and mineral nutrients treatments - S.K. Chatterjee and R.P.Nand i 128 Plant remedies used against 'fevers' ina Mixe lowland community,Oaxaca ,Mexic o -Michae l Heinrich and Horst Rimpler 134 Indigenous medicinal plants of Garhwal Himalaya (India): an ethnobotanical study -R.D . Gaur and J.K. Tiwari 139 Index of chemical compounds 143 Index of scientific names 146 PREFACE The presentpublicatio n contains theproceeding s of Symposium 5-35 "Medicinal and poisonousplant s of the tropics"hel d on 30Jul y 1987 during the 14th International Botanical Congress atBerlin . The contributions areb y experts from all over the world. The great diversity of their papers onplant s from differentpart s of the world makes itver y attractive. The compiler wishes to thank Professor Dr U. Jensen and Professor DrN.G . Bisset for their advice;th e Central Congress Committee, especially Professor Dr W. Greuter and Dr B. Zimmer for their efficient organization and invaluable assistance with the symposium; Dr I.Hedberg , whokindl y replaced Professor Dr E.L.Ayensu ,wh o washindered , and chaired the symposium as symposium organizer. A.J.M. Leeuwenberg RESEARCH ONMEDICINA L ANDPOISONOU S PLANTS OFTH ETROPIC S -PAST , PRESENTAN D FUTURE IngaHedber g Department of Systematic Botany,Uppsal aUniversity , Uppsala, Sweden Summary Plants have fed the world and cured its ills since timeimmemorial . Avas t knowledgeo f medicinal andpoisonou s plants musttherefor e have accumulated, especially in thetropics , where the large majority of allhighe rplan t species are found. But most of this knowledge onlyexist s asverba l tradition andonl y afractio n isye tavailabl et o science. Lesstha n 10% of all species have been subjected to investigations of secondary metabolites and their effects. Furthermore, the present trend is to concentrate the screening on relatively few species or groups of special interest. Sincepeopl e in the tropics willremai n dependent on herbal medicines for many years tocome ,th e growing interest in thoseregion s to savean d utilize the knowledge found in traditional medicine is of utmost importance. In this connection it is alarming that it has become increasingly difficult to find young people willingt otrai na straditiona lpractitioners ,an dtha tman yo fth eplant suse d arethreatene db y extinction through exploitation of natural vegetation. The most urgent tasks for the future musttherefor e bedocumentatio n of theknowledg e heldb ytraditiona lpractitioners , training of taxonomie botanists, development of tropical herbaria and conservation of ecosystems andmedicina lplants . Introduction Theus eo f plants in curing andhealin g is asol d asma n himself.Bu twhils t industrialized countries during the last hundred years have gradually reduced the use of plant remedies these stillpla y anenormou srol ei nth etropics . In tropical developing countries about 80%o f therura lpopulatio n dependfo r their health careo ntraditiona lpractitioners ,whic hals omean stha tth epeopl ei nth emai nhav et orel yo n medicinal plants for treatment. This fact, together with the WHO programme launched in 1976fo r the "Promotion andDevelopmen t ofTraditiona l Medicine"should ,i n myopinion , provide strong reasons for devoting considerable resources toresearc h on medicinal plants in the tropics. In the developed world the use of such plants in medicine in developing countries is, however, often looked upon as obselete and largely based on superstition. Scientists inth ewester n world workingi n so-called modern biology,lik emolecula r biology and biotechnology, as well as those concerned only with the study of the compounds or with medicine as such, seem tohav e littleunderstandin g of theresearc h need in this field. There are also strong antagonists toresearc h programmes on medicinal plants among the decision-makers andfundin g agencies. Thepas t In order to evaluate theprospect s of medicinalplant sresearc h we must know something aboutth eresult s already obtained.Histor y isimportan t sinceth epas t givesu sth eke y toth e present and should help planning for the future. Already many hundred years ago a vast knowledge had accumulated onplan t species used for medicinalpurposes . Iti s amatte r of definition to stateth e timewhe n the scientific research started onplant s usedi n traditional medicine. But it would probably be safe to date it back to the late 18th century when investigations werecarrie d outo n theeffec t of, e.g., Digitalis (Withering, 1785). Up toearl y 1800th edrug swer euse dra w ora s simple extracts.A ne w epoch wasinitiate d when for the first time morphine was isolated from opium and from then on the interest seems to have gradually diverged from research on medicinal plants toresearc h on plant medicines.I nothe r words,th eresearc h becameincreasingl y oriented towards the chemical aspects and the manufacturing of pure compounds (like strychnine, caffeine and quinine, etc.) and substancesfro m tropical plantscam et opla y amajo rrole . Theimprovin g possibilities to synthesize desirable substancesmean t that the searchingo f theplan t kingdom for remedies diminished, moreresearc h instead beingdirecte d towards the synthesizing of newproducts . This downward trend is seen in the continuous decrease in theimportanc eo f medicinaldrug so fplan torigin ,a fac t thati n 1941mad eth eDirecto ro f Harvard Botanical Museum, Dr. P. Mangelsdorf, predict that in another 25 years such drugs would beo f littlemor e thanhistorica l interest.I n the new era the scientists obviously often forgot that the starting material for their research was nearly always natural compounds from plants known tob e usedi n traditional medicine, and that their successi n creatingne wmedicine s thus shouldlargel yb eattribute d tosuc hsubstances . Iti spossibl etha t Dr. Mangeldorfs prediction mighthav ecom etru e -a tleas t asfa r asth e most sophisticated developed countriesar econcerne d -wer ei tno tfo r awidesprea d tropical plant,extensivel y usedi n traditional medicine butunti labou t 1950ignore d byth escientists . Thediscover y ofpoten t substances in Catharanthusroseu si n 1957 (Bernard,1967 ) turned thewheel .Althoug h notexplicitl y stated,thi sdiscover y wasprobabl y amajo r reasonfo r the changes in attitude towards research on plants used in traditional medicine, so eminently illustrated by the above-mentioned Dr. Mangelsdorf, who at a symposium in 1968 on "Plantsi n thedevelopmen t of modem medicine" madeth efollowin g comment tohi s 1941 statemento n thedeclinin g interestfo r suchplants : "Twenty-seven yearshav eno welapse d sinceI mad e thisbol dpredictio n andi tturn sou ttha tI coul dhardl y havebee n morewrong " (Mangelsdorf, 1972). The discovery of oncolytic properties of the alkaloids in Catharanthus roseus hasi n 30 years resulted in hundreds of scientific reports and stimulated the search for other antitumour agents ofplan torigin . In this context it is of considerable interest to note that the first report on Catharanthus roseus dates back to more than three hundred years. The first printed information on the speciesi sgive n in 1658i nD eFlacourt' s "Histoired el a GrandIl ed eMadagascar " (Boiteau, 1972). The description runs asfollows : "Herbe ressemblante au Saponaria.qu i al a fleure comme celle du Jassemine, l'unees t blanche, l'autre est le coleur de pourpre, la racine est fort amère,d elaquell eil s se servent contrel ema ld ecoeu r &es t bonnecontr ele spoisons ; elle approche du Vincetoxicon ou Asclepias...." The comparison to the Asclepias is interesting sincethoug hi ti sobviousl y basedmor eo nmedicina lpropertie s ofth eplan ttha n on morphology, it nevertheless indicates a relationship that has later been confirmed by systematists.