The most well-known Chinese medicinal that has been frequently quoted as a classic example of an herbal drug yielding a modern medicine (ephedrine) is mahuang (Ephedra spp.). It is the dried stems of one of three Ephedra species (E. sinica Stapf; E. equisetina Bunge; E. intermedia Schrenk et C.A. Mey) found in China, primarily in northem regions. It has been used in China as a diaphoretic, anti-asthmatic, and diuretic for at least 2000 years, with written records dating back to at least the Shennong Herbal (100 BC-200 AD.). Prescriptions based on mahuang for treating asthmatic conditions are countless, some of which date back to ancient formularies, such as the 3rd-century medical classic, the Shang Han Lun (Theory on Febrile Diseases). Other less known uses of mahuang include the treatment of influenza and rheumatism. In contrast to the diaphoretic properties of mahuang (stem), the root and rhizome of Ephedra species, known as mahuanggen, has antiperspirant properties. It is used to treat night sweat and spontaneous perspiration as well as excessive perspiration. For the latter, it is often used topically in the form of a powder for dusting or decoction for washing affected areas. Furthermore, recent studies have shown it to contain hypotensive flavonoids and alkaloids. The completely different medicinal properties of aboveground and underground parts of Ephedra species serve as another example to highlight the importance of specificity when evaluating and reporting on plant drugs.
One of the most commonly used sedative/hypnotic in Chinese prescriptions for treating insomnia and neurasthenia is suanzaoren (sour date kernel). It is the dried ripe kernels of Ziziphus jujube Mill. var. spinosa (Bunge) Hu ex H.F. Chow (syn. Ziziphus spinosa Hu). Although first recorded 3000 years ago, this medicinal has only recently been evaluated by modern scientific methods and found to indeed possess sedative and hypnotic effects in various experimental animals (Hong and Cao 1987). Spinosin, a flavonoid glycoside, is only partially responsible for these effects (Li and Zhang 1983, Yuan et al. 1987, Zeng et al. 1987). Other active components in this drug still await further investigations.
Sour date kernel is also traditionally known to "calm the heart." Recent studies have demonstrated it to have anti-arrhythmic and other cardiovascular activifies (Xu et al. 1987).
Qian ceng ta is the whole plant of Huperzia serrata (Thunb.) Trev [syn. Lycopodium serratum Thunb.]. Although not as common as the previous two, it is traditionally used as a detoxicant to reduce swelling, break up blood stasis, and to stop bleeding. During its clinical use, patients were observed to exhibit cholinergic-type reactions in varying degrees. Subsequently, two new alkaloids, huperzine A and huperzine B, were isolated from it and shown to have strong and reversible anticholinesterase activity. The action of huperzine A against acetylcholinesterase was found to be three times stronger than that of physostigmine and thirty times that of galanthamine, with lower toxic side effects. Favorable results from a series of studies conducted in rats and mice plus a preliminary study on human subjects over the past two years indicate that these new alkaloids show promise in the treatment of Alzheimer's disease and related disorders (Liu et al. 1986, Wang et al. 1986, Wang et al. 1988, Tang et al. 1986, Xu and Tang 1987, Zhu and Tang 1987, Yan et al. 1987, Lu et al. 1988).
"Detoxicant" is a rather vague term that can mean several things in traditional Chinese medicine. A detoxicant can be used to treat "toxic conditions" such as external sores and ulcers or internal conditions characterized by fevers or inflammations, results of viral or bacterial infections. Well-known Chinese medicinals used for such conditions include honeysuckle flower, qingdai (natural indigo), houttuynia herb [Houttuynia cordata Thunb.], forsythia fruit [Forsythia suspensa, and andrographis herb [Andrographis paniculata (Burm. f) Nees.]. Most of these have been extensively studied chemically and pharmacologically Modern drugs such as indirubin for leukemia and andrographolides for various bacterial infections have been the results of these studies.
Another type of detoxicants that so far have not been examined by modern technics include ginger, mung bean, soybean, and licorice that are routinely used in traditional Chinese medicine for treating drug or food poisoning as well as toxic side effects of cancer chemotherapy and heavy metal poisoning. There is no lack of clinical reports on these uses in the Chinese literature. However, reports on relevant chemical and pharmacological studies on these medicinals are lacking.