A refined extract from the root xylem of Tripterygium wilfordii Hook. f. (the so-called multi-glycosides of the plant), available in the market as tablets for the long-term treatment of rheumatoid arthritis and various skin disorders, has recently been shown to possess a powerful antifertility effect in male rats and in men after oral administration at dose levels not showing apparent toxicity or side effects. Fertility appears to be reversible after cessation of treatment. Moreover, preliminary data indicated that the effective antifertility dose in men is only 1/3 of the recommended dose for the treatment of rheumatoid arthritis or skin diseases. This fact supports additional optimism that the side effects of this small dose will be much less as compared with those of the regular dose level. However, a large amount of further investigation is required before one can predict the future of the drug, which seems to hinge upon the successful isolation of the active principle(s) and the careful toxicological evaluation of the safety of the latter. The present paper is a review article summarizing the chemistry, the general pharmacology and the fertility regulatory effect of the plant.
PIP: A refined extract from the root xylem of Tripterygium wilfordii Hook f, a perennial twining vine found in southern China, has been demonstrated to exert a powerful antifertility effect in both rats and human males. For the past 20 years, the herb has been used to treat rheumatoid arthritis, chronic hepatitis and nephritis, ankylosing spondylitis, and skin disorders. When the extract was administered to rats 6 times a week, fertility began to show a decline by the end of the 4th week of medication and all animals were infertile by the end of the 8th week. At that time, there was a dramatic decrease in the density and the motility of spermatozoa from the cauda epididymis, without apparent testicular damage. The fertility of the treated rats began to recover 4 weeks after withdrawal of the herb and was fully restored by 5 weeks. In trials conducted in rheumatoid arthritis patients who were receiving the extract, both the density and motility of ejaculated spermatozoa were significantly lower than in untreated controls and the sperm motility of the treated subjects was zero. No significant side effects were recorded: libido and potency were not affected. Preliminary findings suggest that the effective antifertility dose in men is only a third of the dose required to treat rheumatoid arthritis or skin diseases. The future use of this drug is dependent on successful isolation of the active principles and further toxicological evaluation.