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 17et-hydroxylase/ C-17,C-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 C-17,C-20-lyase activity on IC50 values of 24.5 mu m and 11.5 mu M respectively. They had potent cytotoxicity against human prostate cancer LNCaP cells (IC50 = 28.1 mu M and 37.4 mu M).