Male antifertility compounds from Tripterygium wilfordii Hook f.

Extracts of the Chinese medicinal plant, Tripterygium wilfordii, cause reversible infertility in male animals. Sub-fractionation studies have now revealed that the plant extracts contain a number of compounds which are potent antifertility agents in male mammals, including the diterpenes triptolide and tripdiolide and an isomer of the latter. A triptolide, 12,13-chlorohydrin, which is a transformation product formed reversibly by interaction of triptolide with HCl, was also found to be active.