Inhibition of 17α-Hydroxylase/C17,20-Lyase (CYP17) from Rat Testis by Green Tea Catechins and Black Tea Theaflavins

In the course of screening for 17α-hydroxylase/C17,20-lyase inhibitors from food ingredients, the methanol soluble fraction of green tea and black tea, which were expected to be rich in catechin and theaflavin content, showed potent inhibitory activity. (−)-Epigallocathechin gallate and theaflavin 3-O-gallate with a pirogallol moiety significantly inhibited C17,20-lyase activity on IC50 values of 24.5 μM and 11.5 μM respectively. They had potent cytotoxicity against human prostate cancer LNCaP cells (IC50=28.1 μM and 37.4 μM).