Isolation and biological activity of thielocins: novel phospholipase A2 inhibitors produced by Thielavia terricola RF-143.

Thielocins A2α, A2β, A3, B1, B2 and B3 were isolated as a novel family of phospholipase A2 inhibitors from the fermentation broth of Thielavia terricola RF-143 together with thielavins and thielocins A1α and A1β. The most potent inhibitory activity (IC50 = 0.0033μM) against rat group II phospholipase A2 was shown by thielocin A1β. Against human group II phospholipase A2, thielocin B3 (IC50 = 0.076μM) was the most potent.