The diethyl ether extract of Anemarrhenae Rhizoma (rhizomes of Anemarrhena asphodeloides BUNGE) showed testosterone 5α-reductase inhibitory activity. Two major constituents, cis-hinokiresinol (1) and 2,6,4'-trihydroxy-4-methoxybenzophenone (2) were identified as the active principles. The inhibitory activity of 1 was superior to that of ethinylestradiol, but that of 2 was weak.
