Thielavin A is a fungal metabolite originally isolated from T. terricola that is related to thielavin B . Thielavin A inhibits COX, blocking both the conversion of arachidonic acid to prostaglandin H2 and the conversion of PGH2 to PGE2 . Thielavin A also inhibits glucose-6-phosphatase in rat liver microsomes (IC50 = 4.6 μM). It is a non-competitive inhibitor of α-glucosidase from S. cerevisiae (IC50 = 23.8 μM; Ki = 27.8 μM).

Thielavin B, produced by Thielavia terricola, functions as an inhibitor of prostaglandin biosynthesis, specifically targeting the synthesis of prostaglandin E2 from the endoperoxide. It demonstrates significant efficacy in reducing carrageenan-induced edema in rats when administered intravenously.