Corosolic Acid (CA)

Corosolic acid is a pentacyclic triterpene acid, found in Lagerstroemia speciosa, used in dietary supplements as a glucose-lowering agent and insulin mimetic. It is similar in structure to ursolic acid, differing only in the fact that it has a 2-alpha-hydroxy attachment. Corosolic acid may also have some efficacy in the treatment of diabetes, but without induction of anti-insulin antibodies. Recently, corosolic acid from Lagerstroemia speciosa L. leaf extracts has been reported to act via an indirect mechanism (unlike insulin) in animal experiments. The insulin-complementary anti-diabetic therapeutic value observed in these Japanese preliminary clinical trials has led to renewed interest in the biosynthesis of this compound. So far, there has been no clear evidence for a corosolic acid biosynthetic pathway in plants. This article provides possible roles of corosolic acid and hypothetical information on the biosynthetic pathway in plants.