Apigenin is a natural
flavone. It has recently been used as a chemopreventive agent. It may also have some beneficial effects to treat
prostate cancer by inhibiting
androgen production. The objective of the present study was to investigate the effects of
apigenin on the steroidogenesis of rat immature Leydig cells and some human
testosterone biosynthetic
enzyme activities. Rat immature Leydig cells were incubated for 3h with 100μM
apigenin without (basal) or with 1ng/ml
luteinizing hormone (LH), 10mM
8-bromoadenosine 3',5'-cyclic monophosphate (8BR), and 20μM of the following
steroid substrates: 22R-hydroxychloesterol (22R),
pregnenolone (P5),
progesterone (P4), and
androstenedione (D4). The medium levels of 5α-androstane-3α, 17β-diol (DIOL), the primary
androgen produced by rat immature Leydig cells, were measured.
Apigenin significantly inhibited basal, 8BR, 22R, PREG, P4, and D4 stimulated DIOL production in rat immature Leydig cells. Further study showed that
apigenin inhibited rat 3β-hydroxysteroid
dehydrogenase, 17α-
hydroxylase/17, 20-lyase, and 17β-hydroxysteroid
dehydrogenase 3 with IC50 values of 11.41±0.7, 8.98±0.10, and 9.37±0.07μM, respectively.
Apigenin inhibited human 3β-hydroxysteroid
dehydrogenase and 17β-hydroxysteroid
dehydrogenase 3 with IC50 values of 2.17±0.04 and 1.31±0.09μM, respectively.
Apigenin is a potent inhibitor of rat and human steroidogenic
enzymes, being possible use for the treatment of
prostate cancer.