Traditional Chinese Medicine: Herbal Medicines
Overview
Background
Thousands of herbs exist in China with about 300 to 400 in common use1-3,4,5. Estimated numbers vary from six1 to 10 thousand5 depending upon the inclusion or exclusion of fungi, animal parts, herbs that are also known in the West or herbs that have been recently discovered in Tibet, Xinjiang or Manchuria. Also, single herbs may be known by different names and different herbs may bear the same name3.
Traditional folk knowledge of medicinal herbs varies by region according to the plants common in each area. This knowledge was first codified around 100 B.C., and it has since evolved into many branches of written commentary and practice1-3,6. In the early 1990s, the pharmacologist Kee Chang Huang listed over 500 medicinal herbs based upon their inclusion in Chinese pharmacological works published since 19503. In the 1940s, the Chinese Communist government decided to investigate their own native medical practices rather than relying solely on conventional Western medicine. Committees were appointed that surveyed the entire set of traditions, deleted the superfluous ones and standardized the remainder1.
Many herbs within the Chinese medicinal traditions cannot be distinguished from ordinary foods and are incorporated into traditional oriental diets because of their appealing tastes or because they are simply "good for you." Other herbs may not taste particularly pleasant, but are used because of certain functions such as ridding the body of heat (anti-inflammatories)2.
Doctors of oriental medicine address health challenges by selecting medicinal herbs based upon the eight principles of diagnosis and treatment:
- Yin and yang
- Cold and hot
- Internal or external
- Deficiency or excess
Within the framework of these eight principles, consideration is given to selecting herbs based upon their taste, shape, texture, color, tendency to consolidate or disperse, affinity to the body constituents of Qi, moisture, blood, the organ networks (liver, heart, spleen, lung, kidney) and the relationships between different organ networks (liver-lung, lung-heart, etc.)1,2.
Licensure and Certification
The complexity inherent in herbal formulas requires extensive training so seven to nine years of study are required for licensed doctors of TCM in mainland China, Korea and Japan7. Hong Kong is currently drawing up regulations to ensure the quality of herbal medicines and the qualifications of practitioners5. In the United States requirements for the practice of herbal medicine are the responsibility of individual states. The National Certification Commission for Acupuncture and Oriental Medicine (NCCAOM), established in 1982, provides certification in Chinese herbology based upon a written examination following graduation from an approved program and/or apprenticeship with an approved instructor for three to six years. This certification is required for licensure in most states8. The State of Texas does not provide specific licensing of herbal practitioners; however, it does require that 450 hours of herbal training be included as part of the required 1800 hours for a Texas acupuncturist license.
Herbal Combinations
Practitioners of TCM almost always prescribe herbs in combinations rather than as single herbs, and resulting formulas may require from four to 12 herbs to address particular patterns of symptoms. The roles of individual herbs in a formula are analogous to positions within a royal court or a family, with each herb playing a specific role. One herb may either enhance the effects or control the side effects of another herb1,7. According to Huang, possible incompatibility between herbs was not traditionally considered, and the reasons for inclusion of some herbs are "incomprehensible"3. Major combinations of Chinese herbs have been compiled and are described in English by Bensky and Barolet9.
Single Herbs
Although single herbs are rarely used in TCM, some specific herbs have been recognized or are under investigation for their anti-cancer properties or other potential support for patients with cancer. Comprehensive Chinese herbal references in English have been compiled by Huang3, Wong10, Bensky9 and Sun11,12. A history and list of the best-known historical Chinese documents on medicinal plant use has been compiled by the American Botanical Council13.
Even within single herbs, medicinal and other use is related to which part of the plant is used (root, stem, leaf, fruit, seed), how it is prepared and where it is grown9. The chemical structures of many active plant components have been described, but many are not fully understood. These components may vary from plant to plant within the same species, and potency depends on growing conditions such as soil nutrients, rainfall and duration of the growing cycle. The following brief descriptions are only a few examples of herbs or plant compounds being investigated in reference to the treatment of cancer or support of patients with cancer.
Astragalus (Astragalus membranaceus), or huang qi in Chinese, is one herb within a commonly used tonic known as Fu-zheng, designed to "promote or enhance the natural host defense mechanism"11. Based on laboratory and animal studies, astragalus may possess immune stimulating properties, although research in humans is not conclusive according to a Memorial Sloan-Kettering review of astragalus.
Some of the laboratory research reviewed was conducted at The University of Texas MD Anderson Cancer Center. Da-Tong Chu and colleagues treated cultured mononuclear cells from the peripheral blood of cancer patients and healthy blood donors and reported that three fractions of astragalus were associated with significant immune restoration, but one fraction actually suppressed immunity14.
Camptothecin is a compound obtained from the fruit of the tree known in Chinese as Xi Zhu (Camptotheca acuminate). Anti-cancer effects have been reported from clinical trials in the U. S., although these trials have also detected significant toxicity15. Investigation of benefits and efforts to reduce toxicity has continued in clinical trials in the U. S.16 and in China15.
Curcumin is a constituent of the root of turmeric (Curcuma L.), or E zhu, and the source of the yellow color in curry. It has also been used as an adulterant or substitute for mustard which comes from a separate plant3,9,16,17. Curcumin is currently being investigated for the prevention of colon cancer in an NCI sponsored phase I clinical trial at the University of Michigan16.
Ginseng is a plant that has been highly valued for its root. Its Chinese name, ren shen, has been translated as "man essence"3 or "man root"9 because the root resembles the shape of the human body. Panax ginseng is its botanical name and Radix Ginseng its pharmaceutical name9. Scientific and common names have varied depending upon the location in which it has been collected. Ginseng collected from Korea has been known as Panax ginseng; that collected from the Appalachian Mountains of North America has been known as American ginseng, or Panax quinquefolius or shi yang seng or xi yang shen3.
Ginseng is used to "tonify the basal qi" along with specific strengthening actions for various organ systems. Thus, it is valued for its diversity in treating a variety of symptoms and illnesses9.
The alcohol, but not water, based extracts can inhibit several forms of cancer in the laboratory3. Ginseng has been reviewed by Memorial Sloan-Kettering.
"Harringtonine" and "Homoharringtonine" are a family of compounds derived from the roots of San Jin Shan (Cephalotoxus fortunei). Traditionally and currently they are used as anti-tumor medicines in Asia6. Inhibition of cell growth, protein synthesis and DNA synthesis have been demonstrated in cellular, animal and human research3,15.
Kanglaite is a compound obtained from seeds of the Coix plant (Yi yi ren), a relative of maize. Coix is used both as a food and a key ingredient in many herbal formulas. Phase II clinical trials of kanglaite are currently being conducted among patients with non-small-cell lung cancer5,9.
Taxol is a component of the dried stem or bark of Taxus chinensis, the same species as the yew tree of North America. It is currently used in the conventional Western treatment of several cancers3.
Wormwood or Qinghao (Artemisia annua) is a relative of the wormwood plants of North America and Europe, some of which have been the source of the liquor known as absinthe17. It has traditionally been used for malaria and other fevers and does kill the parasite responsible for malaria9. Some constituents have been associated with anti-cancer effects in laboratory research3,5,18.
Toxicity
According to Chan, just 10 of the 150 species of commonly used herbs are considered toxic4, but the remaining herbs require extensive knowledge and experience in their harvesting, processing, shipping and prescribing so as to avoid inadvertent contamination with look-alike toxic herbs and excessive or inappropriate doses.
Plants containing arsenic and arsenic itself have had a long history of use in both Chinese and Western medicine, but have recently fallen out of use due to its carcinogenic and other toxic effects. Medicinal use of arsenic has recently re-emerged, however, due to improvements in purification and dose control and is currently being evaluated within clinical trials for cancer19. The National Skin Center of Singapore reviewed 648 cases of skin lesions potentially related to arsenic and identified 17 (2.6%) cases associated with long-term arsenic exposure, of which 14 had taken Chinese proprietary medicines during the 1950s and 1960s20.
Other Toxicity
A widely reported episode of toxicity occurred outside of treatment for cancer and outside of licensed Traditional Chinese Herbal practice. In the early 1990s, cases of renal disease were traced to weight reducing pills prescribed by a Belgian clinic (approximately 5% of 1500 – 2000 patients developed renal disease)21.
The weight loss pills were found to have been contaminated with a Chinese herb known as Aristolochia fanchi, a well-known carcinogen as demonstrated in earlier animal and human studies21-24. Additional cases of aristolochia contamination were subsequently linked with kidney fibrosis and renal carcinoma in France, Spain, Japan, Taiwan, the United Kingdom and the U. S.21,25-28. A study of cases linked with the Belgian clinic determined that the development of actual carcinoma was dose-related26 and that individual susceptibility likely differed due to differences in dose, duration of intake, interactions with other drugs and genetic factors affecting metabolic breakdown pathways21. Some of those taking the weight reducing pills were also taking other drugs and smoking29,30. (Although analysis within one study did not detect any significant interactions, that study only included persons with end-stage renal disease31.)
It is easy to understand the potential for inadvertent contamination with aristolochia when one considers that the original weight reducing formula was designed to contain fang ji from the root of the S. tetrandra plant, but instead contained guang fang ji from the root of Aristolochia fangchi32 and that both substances have been marketed under the same name of fang ji21.
This toxicity associated with weight loss pills has been cited as an example of the inappropriate prescribing of Chinese herbs by physicians who were not trained in their use32,33. Although herbs containing aristolochia are sometimes used in Chinese medicine, they are not used for weight control and are only used for short periods of time32, whereas the Belgian clinic had prescribed them from one to two years34. (Aristocholic acid poisonings have, however, sometimes occurred among patients treated by TCM practitioners)33.
Less common examples of toxic contamination have included anticholinergic poisonings in Hong Kong and Taiwan from herbs such as Datura or yangjinhua4 and hepatotoxicity in England from contamination with the herb, Dictamnus dasycapus35.
Toxicity concerns within Traditional Chinese Herbal Medicines involve quality control issues inherent in the development of any medicinal substances.
Focus of Traditional Chinese Medicine
Although cancer has been the focus of this review, the broader focus of TCM is Fu Zheng (supporting the normal)36. Thus, considerations of Traditional Chinese herbal medicines should include possibilities for support of patients through biological response modification, symptom control and other aspects of well-being37.
TCM Herbal Reference List
Boik J. Cancer and Natural Medicine: A Textbook of Basic Science and Clinical Research. Princeton, MN: Oregon Medical Press, 1995.
Beinfield H , Korngold E. Between heaven and earth: a guide to Chinese medicine. Paperback ed. New York and Toronto: The Ballantine Publishing Group, 1991.
Huang. The Pharmacology of Chinese Herbs. Boca Raton, FL: CRC Press, 1993:271.
Chan T. Anticholinergic poisoning due to Chinese herbal medicines. Vet Human Toxicol 1995;37(2):156-7.
Normile D. The New Face of Traditional Chinese Medicine. Science 2003 Jan;299:188-90.
Quan-Sheng D. *Herbal* *medicine* in China. Drugs of Today. 1987;23(8):467-76.
Liang S. Personal Communication. 2002.
National Certification Commission for Acupuncture and Oriental Medicine. NCCAOM Certification Programs [Web Page]. 1982. (Accessed 2003 Jul 3).
Bensky D, Barolet R. Chinese herbal medicine: formulas & strategies. Seattle, Washington: Eastland Press , 1990.
Wong CK, Leung KN, Fung KP, Choy YM. Immunomodulatory and anti-tumour polysaccharides from medicinal plants. [Review] . Journal of International Medical Research 1994 Nov-1994 Dec;22(6):299-312.
Sun Y. Current status of research on new anticancer drugs in China. Gan to Kagaku Ryoho [Japanese Journal of Cancer & Chemotherapy] 1992 Jul;19(8 Suppl):1126-33.
Sun Y. The role of traditional chinese medicine in supportive care of cancer patients. Recent Results in Cancer Research 1988;108:327-34.
American Botanical Council. Chinese Medicinals. HerbalGram 1990;(23):21.
Chu D-T, Wong WL, Mavligit M. Immunotherapy with Chinese medicinal herbs. II. Reversal of cyclophosphamide-induced immune suppression by administration of fractionated astragalus membranaceus in vivo. Journal of Clinical & Laboratory Immunology 1988;25:125-29.
Hsu B. The use of herbs as anticancer agents. American Journal of *Chinese* Medicine. 1980;8(4):301-6.
National Cancer Institute. Search for Clinical Trials (Advanced Search Form) [Web Page]. (Accessed 2003 May 3).
Grieve M. A Modern Herbal. New York: Hafner Publishing Co., 1931.
Seo HJ, Surh YJ. Eupatilin, a pharmacologically active flavone derived from Artemisia plants, induces apoptosis in human promyelocytic leukemia cells. Mutation Research 2001 Sep;496(1-2):191-8.
Chen Z, Chen GQ, Shen ZX, Sun GL, Tong JH, Wang ZY, et al. Expanding the use of arsenic trioxide: leukemias and beyond. Seminars in Hematology 2002 Apr;39(2 Suppl 1):22-6.
Wong SS, Tan KC, Goh CL. Cutaneous manifestations of chronic arsenicism: review of seventeen cases. J Am Acad Dermatol 1998;38:179-85.
Arlt Vm, Stiborova M, Schmeiser HH. Aristolochic acid as a probable human cancer hazard in herbal remedies: a review. Mutagenesis 2002 Jul;17(4):265-77.
Cosyns JP, Jadoul M, Squifflet JP, De Plaen JF, Ferluga D, van Ypersele de Strihou C. Chinese herbs nephropathy: a clue to Balkan endemic nephropathy?. Kidney International 1994 Jun;45(6):1680-8.
Cosyns JP, Jadoul M, Squifflet JP, Van Cangh PJ, van Ypersele de Strihou C. Urothelial malignancy in nephropathy due to Chinese herbs. Lancet 1994 Jul;344(8916):188.
Vanherweghem JL, Tielemans C, Simon J, Depierreux M. Chinese herbs nephropathy and renal pelvic carcinoma. Nephrology, Dialysis, Transplantation 1995;10(2):270-3.
Lord GM, Cook T, Arlt VM, Schmeister HH, Williams G, Pusey CD. Urothelial malignant disease and Chinese herbal nephropathy. The Lancet 2001 Nov;358(9292):1515-16.
Nortier JL, Martinez MC, Schmeiser HH, Arlt VM, Bieler CA, Petein M, et al. Urothelial carcinoma associated with the use of a Chinese herb (Aristolochia fanchi). New England Journal of Medicine 2000 Jun;342(23):1686-92.
Cosyns JP, Jadoul M, Squifflet JP, Wese FX, Van Ypersele de Strihou C. Urotherlial lesions in Chinese-herb nephropathy. American J of Kidney Diseases 1999 Jun;33(6):1011-7.
Lord GM, Cook T, Arlt VM, Schmeiser HH, Williams G, Pusey CD. Urothelial malignant disease and Chinese herbal nephropathy. Lancet 2001 Nov;358:1515-6.
Shum S. Chinese herbs and urothelial carcinoma [comment]. N Engl J Med 2000 Oct;343(17):1268-70.
Lu W, Lu W. Chinese herbs and urothelial carcinoma [comment]. New Engl J Medicine 2000 Oct;343(17):1269.
Nortier JL, Vanherweghem J-L, Schmeiser HH. Chinese herbs and urothelial carcinoma. New England J Medicine 2000 Oct;343(17):1268-70.
Li YM. Chinese Herbs and Urothelial Carcinoma [comment]. N Engl J Med 2000 Oct;343(17):1268-70.
Gillerot G, Jadoul M, Arlt VM, van Ypersele de Strihou C, Schmeiser HH, But PPH, et al. Aristolochic acid nephropathy in a chinese patient: time to abandon the term "Chinese herbs nephropathy"? American Journal of Kidney Diseases 2001 Nov;38(5):E26.
Kessler DA. Cancer and Herbs [comment]. The New England Journal of Medicine 2000 Jun;342(23):1742-3.
Vautier G. Spiller RC. Safety of complementary medicines should be monitored [16]. British Medical Journal. 1995;311(7005):633.
Lien EJ. Fungal metabolites and Chinese herbal medicine as immunostimulants. [Review] . Progress in Drug Research 1990;34:395-420.
Wong R, Sagar CM, Sagar SM. Integration of Chinese medicine into supportive cancer care: a modern role for an ancient tradition. Cancer Treatment Reviews 2001;27:235-46.