Yu. Kim et al., Testosterone 5 alpha-reductase inhibitors, menaquinone 7 produced by a Bacillus and phenazine methosulfate, BIOL PHAR B, 22(12), 1999, pp. 1396-1399
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 t
he purified microbial metabolite with an IC50 value of 6.6 x 10(-4) M. On t
he basis of this evidence, the inhibitory activities of electron carriers,
menadione, phenazine methosulfate. and 2,6-dichlorophenolindophenol, for ra
t 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 produc
t of the 5 alpha-reductase enzyme reaction and an electron and proton carri
er, 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 inhibiti
on effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for
rat prostate testosterone 5 alpha-reductase was substantially inactive.