Western healers in traditional Chinese medicine

In recent years, some in the West have begun to recognize traditional Chinese medicine (TCM) as a potential source of new drug candidates (Corson & Crews, 2007; Efferth et al, 2007; Li & Zhang, 2008; Schmidt et al, 2007). At the same time, the practice of TCM in Western countries has been increasing (Institute of Medicine, 2005). As TCM is usually thought to have evolved independently of Western medical practices, the two systems are considered to be distinct from one another, with only a few weak connections between them (Food and Drug Administration, 2006). Nevertheless, by analysing both the history of TCM and the compounds used in TCM, we find that TCM and Western medicine are not quite so different after all.

In fact, there have been frequent exchanges of ideas and culture between China and its neighbours over the past 2,000 years, including communication with much of Europe. Not surprisingly, China acquired foreign herbs that were eventually adopted by TCM; common agents such as aloe, olibanum, myrrh, benzoin, styrax, strychnos, saffron, fennel, fenugreek, pepper, garlic, clove, areca seed and evening primrose all came from abroad (Xiao et al, 2001). Even during the last century, new ideas were selectively absorbed by TCM practitioners as modern Western medicine spread to China. Some 80 years ago, Zhang Xi-Chun (1860–1933) combined aspirin, a typical Western drug, and Gypsum fibrosum, a TCM product that has been used for more than 2,000 years (Editorial Committee of Chinese Materia Medica, 1999), to create a new formula to treat febrile arthritis (Yue & Wang, 2004). Today, a large number of TCM formulae contain Western drugs and approximately 10–30% of TCM therapeutics are based on synthetic chemicals (Zhu, 2004).

Furthermore, there are many similarities between TCM components and modern drugs, because around 50% of chemical drugs used today are directly or indirectly derived from natural products (Butler, 2005; Newman & Cragg, 2007). A global structural comparison between approximately 10,000 TCM components recorded in the Traditional Chinese Medicine Database (TCMD) System, and about 8,000 modern Western drugs recorded in the Comprehensive Medicinal Chemistry (CMC) database, revealed that 908 agent pairs are structurally similar and 327 agents are identical in structure (Kong et al, 2008).

It is interesting to note that many of the herbs that contain common agents have a long history of medicinal use in China and elsewhere, such as the leaves or bark of the willow tree from which salicylic acid is extracted (Editorial Committee of Chinese Materia Medica, 1999; Lebwohl, 1999; Lin & Nakatsui, 1998). 5-methoxypsoralen is derived from Zanthoxylum schinifolium and Ammi majus, which grow in the Nile river valley, and both herbs were used by Chinese and Egyptians, respectively, to treat dermatological conditions for more than 2,000 years (Editorial Committee of Chinese Materia Medica, 1999; Scott et al, 1976). Sennosides A and B, which have laxative effects, are contents of Rheum officinale—the laxative potential of which was recorded in ancient Chinese texts (Editorial Committee of Chinese Materia Medica, 1999)—and Cassia angustifolia, a small shrub indigenous to Somalia and Arabia, which has also been used historically as a laxative (Lemli, 1988; Mukhopadhyay et al, 1998). As there was little medicinal communication between China and foreign countries more than 2,000 years ago, we think that the use of similar herbs and/or components in ancient Chinese and Western medicines can be best explained as convergent evolution of different medicinal systems.

In conclusion, several similar compounds or plants have been used in TCM and ancient, as well as modern, Western medicine, which results both from communication between these cultures and convergent evolution of their medicinal systems. At a time when the use of TCM is increasing in Western medicine, it is therefore noteworthy that both systems are in fact not that different, but have been sharing several compounds and therapeutics for thousands of years.