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Tripterygium refers to several of species of the genus Tripterygium that are used in the modern practice of Chinese medicine. The most frequently used variety, called leigongteng (from T. wilfordii) was described in some of the ancient Chinese medical texts, where it is indicated mainly for treatment of swellings, breast abscesses, and skin diseases. It is not available to, and therefore not used by Western practitioners because of its inherent toxicity, but references to it abound in the Chinese medical literature. Its dominant modern use is in the treatment of autoimmune diseases, for which it serves as a successful substitute for prednisone and other corticosteroid drugs. Because it is increasingly mentioned in articles about Chinese treatments for serious diseases, and because samples of medicine tablets made from the herb sometimes appear in the West, many practitioners seek information about the herb. This is only a brief review.
In the History of Medicinal Herbs in Hunan (where most tripterygium is found), it is said that “the herb is bitter in taste and highly toxic in nature, killing bacteria, abating inflammation, and removing toxic materials. Together with lindera it cures herpes zoster when ground to powder and applied directly to the lesion.” In the Dictionary of Chinese Materia Medica it says that tripterygium is “severe in toxicity, especially its bark. Hence, the bark, including the second layer, must be stripped off completely before use.” In general, however, tripterygium is not mentioned in common herb books because its toxicity so far exceeds that of typical Chinese herbs. The toxic effects of the herb, which are not always experienced, usually vanish within three days of ceasing its use, but the side effects can be substantial, including vomiting, abdominal cramping, fever, bone marrow suppression, and convulsion. In overdose, it can cause shock, coma, or death.
To minimize toxicity of the herb (for those who do prescribe it in China), it is recommended that it be stored for at least one year before use, that two cortical layers of the stem be removed to leave only the xylum, which is then decocted for at least three hours. Alternatively, the herb is powdered and used in quantities of just a few milligrams. In modern practice, the root of the plant is often selected, because it can be used in larger quantities (having less of the active constituents). By taking the herb after meals or with antacids or vitamin B6 the chances of gastrointestinal upset can be reduced.
It is considered mandatory to periodically examine the blood picture during prolonged treatment to assure that no toxic effects are occurring. Kidney toxicity is the main problem; in a clinical trial of treatment of psoriasis, 4 of 44 patients treated with tripterygium root decoction experienced serious side effects, with two of them experiencing acute kidney failure and bone marrow suppression. The herb is contraindicated during pregnancy and it can inhibit male fertility. Poisoning (kidney inflammation) has occurred in children from consuming honey derived from bees visiting its flowers. A substantial part of the toxicity may be due to the alkaloid components which contribute relatively little to the anti-inflammatory action; therefore, isolated terpenes provide a safer drug therapy. In fact, during the past decade, many Chinese doctors have prescribed tripterygium glycosides, called triptolides, rather than the whole herb.
Unlike corticosteroids, these compounds are not known to inhibit the adrenal cortex and they have additional therapeutic applications such as inhibition of tumors and leukemias, bacteria, and worms. Therefore, tripterygium is not to be considered merely as a direct substitute for corticosteroid therapy. Western drug companies have been experimenting with the active ingredients in hopes of developing a new anti-inflammatory compound that does not inhibit adrenal function. Such a drug is likely several years away from being marketed.
Despite its toxicity, tripterygium or isolated components, usually in tablet form, is widely used in China because of its remarkable effectiveness for so many diseases that are not readily treated by Western medicine, including thrombocytic purpura, alopecia, hyperthyroidism, and skin diseases caused by autoimmune processes. The anti-inflammatory action is employed with good results for a wide-range of pain syndromes. Among the most common applications in China today are rheumatoid arthritis, systemic lupus erythematosis, and psoriasis (for the latter, the herb can be given internally and/or applied topically in an creme base). The herb is usually prescribed as a single herb remedy, but is sometimes given in complex formulas. For example, tripterygium has been combined with aconite, tang-kuei, carthamus, cinnamon bark, achyranthes, chiang-huo, eucommia, and lycium bark for treatment of rheumatoid arthritis. It is common practice to give tripterygium extract tablets along with a complex herbal formula in decoction form.
As an example of its utilization, in the Chinese Journal of Nephrology (1989; 5(1): 21–25), it is reported that in seventeen cases of biopsy-proved idiopathic IgA nephropathy (an immune-based kidney inflammation), the tripterygium glycosides at a dosage of 20 to 60 mg per day for several months (1.5 to 8.5 months) yielded significant reductions in proteinuria, hematuria, and serum IgA titer which persisted for six months after the treatment was halted. Side effects included hair loss, rashes, menstrual disorders, and reduced appetite; there were three cases of leukopenia; however, all the side effects disappeared after reduction of dosage. In another example, reported in the Chinese Journal of Integrated Traditional and Western Medicine (1988; 8(2): 87–89), 10 patients with multiple sclerosis were given leigongteng tablet (20 mg of the vine per tablet, two tablets, three times daily) for three weeks. A control group of 11 patients were given dexamethasone and another control group was given ACTH; after two weeks, these drugs were replaced by prednisone which was then gradually withdrawn. A negative control group was given only vitamin therapy with vitamin C and B complex. According to the report, 8 of the 10 patients treated with leigongteng had clinical remission; there were similar benefits from using dexamethasone (9 of 11 patients benefited), and somewhat less with ACTH (4 of 7 patients benefited), but there was no clinical response to the vitamins. In both studies, it was concluded that tripterygium was a satisfactory treatment method for the disease.