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Ironically, thalidomide has been approved recently by the US Food and Drug Administration, for use in treating erythema nodosum leprosum, a severe complication in leprosy. Thalidomide is also under consideration for use in AIDS-related ulcers and wasting. This instance indicates the complexity of drug action and the inherent dangers, that justify rigorous drug testing.
Now systems have been developed with which it is possible to conduct a battery of simultaneous testing of the potential and possible therapeutic and deleterious effects of a single drug. Through a series of simultaneous procedures, one would be evaluating the antibacterial, antiviral, analgesic, anti-inflammatory (or several other) effects, along with the cytotoxic, mitostatic, mutagenic, or carcinogenic potential of the drug. An expensive, time consuming and complicated procedure but essentially needed for our safety.
Pharmacological testing of indigenous plant based drugs will help in proving (or disproving) the claims made for them and places their local uses on a firm scientific footing. Drugs should be used only if they are safe and effective and not merely because they are traditional.
Ethnopharmacology is a subdivision of ethnobotany (or ethnoecology). It is the study of aboriginal knowledge of the physical properties of plants or their products and the accompanying familiarity with those components of the vegetal environment that permit indigenous peoples to use various plants for their presumed medicinal value. Ethnopharmacology is one of the most active and modern fields of ethnobotanical research. Its importance in human welfare is well recognised and an exclusive research journal, Ethnopharmacology, was started almost 20 years ago.
The origins, development and current status of different aspects of ethnopharmacology have been reviewed (Bruhn and Helmstedt, 1981; several authors in Schultes and Reis, 1995).
The first successful multidisciplinary study on an ethnopharmacological problem is that of an arrow poison from Strychnos nux-vomica, Loganiaceae, which is well recorded (Holmstedt, 1995; Holmstedt and Bruhn, 1995). In 1803, the French botanist Leschenault de la Tour collected in Java, samples of an arrow poison along with the detailed information of ingredients and preparation. A.L. de Jussieu, another French botanist, identified the major plant ingredient as belonging to the genus Strychnos and related it to the species nux-vomica. Leschenault gave samples of the poison to Magendie and Delile, who studied its effects on hens, rabbits, dogs and a horse. In 1809, they reported violent convulsions, asphyxia and death of the test animals in five minutes and discovered that its chief action was on the spinal cord. This is a very significant finding as, for the first time the action of a drug is associated with a particular organ. In 1824, strychinine, the alkaloid responsible for the physiological effects, was isolated and characterised by Pelletier and Caventou. Later, strychnine was introduced into clinical medicine. In 1963, Woodward et al., succeeded in the total synthesis of the alkaloid. Such complete successes of collaborative research programmes are rare but they are pointers to the need for, and the potential of, such studies.A complete scientific ethnopharmacological study involves
a) field studies on the source plant species, the crude drug obtained from it and its traditional
use;b) collection and the botanical authentication of the source plant material;
c) maintenance of complete records of the botany and distribution of the species, preparation
of the crude drug and its traditional uses;d) preparation and preservation of voucher specimens of the plant and the crude drug;
e) experimental study of the physiological effects of the drug on animal models to understand
the drug target organs and the mode of action; andf) clinical studies on human subjects to evaluate the potential of the drug, its toxicity and side
effects, contra-indications, effective dosage, supplementary and complementary additives, etc. Any or all of these criteria constitute ethnopharmacological research, whether conducted by individual or collaborating scientists. But the emphasis of essentiality is on the first four criteria.A large number of pharmacological and clinical investigations do not qualify to be considered as ethnopharmacology as they missed on the first four criteria mentioned above. The often cited case of anti-leukaemic studies on Catharanthus roseus is not considered as an example of ethnopharmacology, as the drug’s traditional use was as an anti-diabetic and not as an anti-leukaemiac agent. But it is an instance where a new drug, other than what was being looked for, was discovered.
A large number of traditional plant based drugs from China, Africa, South America and India have been subjected to pharmacological studies.
Baphicacanthus cusia, Aucklandia lappa, Pueraria lobata, Agrimonia pilosa, Scopoloa tanguitica, Curcuma aromatica, Mylabris phalarata, Ilex pubescens, Uncaria rhynchophylla, Andrographis paniculata, are among the Chinese species in traditional medicine subjected to pharmacological confirmation (Xiao, 1981).Tubocurarine, the muscle relaxant compound in the traditional arrow poison from Chondrodendron tomentosum (Menispermaceae) from South America, is an indispensable aid in modern surgery. The studies on this species are hailed as an example of success of ethnopharmacology (Bisset, 1995). A number of arrow poisons that were investigated were discussed by Bisset (1995).
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