Testosterone 5 alpha-reductase inhibitors, menaquinone 7 produced by a Bacillus and phenazine methosulfate.

ABSTRACT

Menaquinone 7 (MW 649, C46H64O2), a natural electron acceptor for steroid ring A dehydrogenations, produced by Bacillus sp. SNU-299, was isolated as a rat prostate testosterone 5 alpha-reductase inhibitor with an IC50 value of 4.0 x 10(-5) M from the cultured broth. Phylloquinone was as active as the purified microbial metabolite with an IC50 value of 6.6 x 10(-4) M. On the basis of this evidence, the inhibitory activities of electron carriers, menadione, phenazine methosulfate, and 2,6-dichlorophenolindophenol, for rat prostate testosterone 5 alpha-reductase were tested, and the IC50 values were 3.1 x 10(-6) M, 4.9 x 10(-8) M, 8.9 x 10(-5) M, respectively. A product of the 5 alpha-reductase enzyme reaction and an electron and proton carrier, NADP+, inhibited the 5 alpha-reduction by rat prostate testosterone 5 alpha-reductase with an IC50 value of 9.2 x 10(-5) M. However, the inhibition effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for rat prostate testosterone 5 alpha-reductase was substantially inactive.