Investigating medicinal herbs


By Dr. Rohan H. Wickramasinghe

It is commonly known that many substances (e.g vitamin C, quinine, artemisinin, reserpine), which have been included in various pharmacopeias, are present in plants or are produced by microorganisms. To these are attributed the effectiveness of the herbal medicines used traditionally in countries such as Sri Lanka, China, India etc. This also accounts for the quest by biomedical research organisations and drug companies to identify new products which may have advantages, for instance, commercially or with less adverse side effects than currently used drugs or when resistance builds up against existing preparations.

In this context, the (US) Committee on Scholarly Communication with the People’s Republic of China (CSCPRC) sponsored the visit of a twelve-member Herbal Pharmacology Study Group to the People’s Republic of China (PRC) from June 1 to 26, 1974. CSCPRC was, in turn, sponsored jointly by the American Council of Learned Societies, the National Academy of Sciences of the US and the Social Science Research Council. In China, the Group was hosted by the Chinese Medical Association and visited Beijing, Tientsin, Shanghai, Nanking, Hangchow and Kwangchow. Institutes and some botanical/ medicinal plant gardens were visited. The 500 acre botanical garden at Kwangtung was noted to include some 3000 species, while 1500 species of medicinal plants were under cultivation in the 64 acre experimental plantation of the Institute of Materia Medica, Beijing.

The Herbal Pharmacology Study Group was composed of nine leading scientists (led by Professor Louis Lasagna of the University of Rochester, New York ) whose fields of interest included chemistry, medicine, pharmacology, pharmacognosy and pharmacy and three specialists (including Patricia Jones Tsuchitani of the National Academy of Sciences) in Chinese culture. This visit of the American team to China in June 1974 was followed in November of the same year by a Chinese delegation to the US, whose main interest was in neuropharmacology and cancer chemotherapy. A ten-member Chinese delegation came subsequently to the US for a follow-up US-China Pharmacology Symposium, which was chaired by Dr. J.J.Burns of Hoffman-LaRoche Inc. and Professor Song Zhenyu of the Chinese Academy of Medical Sciences, Beijing and took place from October 29 to 31, 1979.

The report ‘Herbal Pharmacology in the People’s Republic of China’, which resulted out of the visit of the US delegation to the PRC makes fascinating reading. While one needs to take into account the fact that China has changed vastly since 1974, some extracts merit highlighting:

a) page 4/5 – " Great emphasis is placed on the need for technological self-reliance and scientists are taught that they must combine what is useful from the West with native devices and discoveries in order to meet the needs of the nation. In pharmacological work, this effort is expressed in Mao Tse-tung’s formula calling for the union of Western and Chinese medicine."

b) page 80 – "Placebo-controlled trials are out, since the Chinese object to such ‘deception’."

c) page 89 – " As the Chinese may benefit from whatever we can offer in the way of techniques and ideas, so may we profit from their advances and perhaps even absorb the extraordinary sense of social responsibility displayed by so many of the scientists we encountered in the course of our journey in the PRC".

d) Professor Norman Farnsworth’s view (page 81) that "If peoples geographically distinct use a given plant for the same purpose, does that not constitute impressive prima facie evidence that the putative use is valid? Is not the likelihood of such a phenomenon being due to chance statistically remote?" merited following up. The programme attempted to study this hypothesis, which suggested that the same plant or closely related species in the same genus may have constituents (phytochemicals) with similar medicinal properties.

In the course of a visit to the Institute of Materia Medica of the Chinese Academy of Medical Sciences in Beijing, the delegation had been presented with a formulary-type book. This had been prepared by the Institute as a guide to barefoot doctors and other medical practitioners in rural areas a) to help them to identify local plants (n.b. in the Beijing area) that could be used as drugs and b) to give them the medical uses of each plant or animal (page 81). Some 248 plant and animal drugs used in the PRC and listed in ‘The Atlas of Commonly used Chinese Traditional Drugs’ were considered in relation to this hypothesis. Comparisons were made of the claimed medicinal properties of herbs used in the Beijing area (or of preparations containing them) with reference literature in the files of the Department of Pharmacognosy and Pharmacology at the University of Chicago. Interestingly, some encouraging results were obtained. In the opinion of Dr. Farnsworth, the percentage of known or predictably known useful pharmacologic effects for traditional Chinese medicines was considerably higher than would result from analysis of medicinal plants used in the West (page 83).

These encouraging results prompted an enquiry by the present writer as to whether herbs used in traditional medicinal preparations in Sri Lanka bear relationships to plant species used in other countries/ cultures for similar health problems. Available information on medicinal herbs used in Sri Lankan ayurvedic preparations was compared with that presented in the report referred to above. While the writer was resident in the US in 1977/78 and did not have many sources of information relating to Sri Lankan ayurvedic preparations/ medicinal herbs, such as were available were made use of and gave some leads. These leads are presented in abstracts in the journal CLINICAL RESEARCH, as follows: volume 25(1977) Abstract 278A (fevers); 25(1977) 451A (urinary disorders); 25(1977)575A (gastroenterology); 25(1977)589A (dermatology); 26(1978)14A (dysentery, microbial infections and antipyretic action); 26(1978)87A (pulmonary affections); 26(1978)101A (worm infestations) and 26(1978)269A (ophthalmia). A further note relating to medications for the treatment of menstrual disorders appears as abstract no. 577 of the Proceedings of the 59th meeting of the Endocrine Society on 8-10 June 1977 at Chicago, Illinois.

This information is presented in the hope that it will further encourage research on Sri Lankan medicinal herbs (n.b. This writer is well aware of the researches on Sri Lankan medicinal herbs by our own giants in the various relevant fields.). However, it must be noted that in recent years information, which may be relevant to this subject, has been presented regarding the voyages and travels of the Chinese in earlier times. Examples which come to mind are those of Fa-Hsien (337-422 A.D.) and of Zheng He (1371-1433 A.D.); both of whom visited this country. Taken together with the flow and exchange of information along the ‘Silk Road’ and the ‘Silk Road of the Sea’, perhaps the concept of ‘convergent evolution’ of findings on the medical efficacy of medicinal herbs in geographically separated countries and cultures is no longer universally tenable. (It is with much regret that the writer learned of the demise a few months ago of Professor Farnsworth who was a leading authority on herbal pharmacology. The writer is an Executive Committee Member of the Sri Lanka China Society.)

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