Glabrol, an acyl-coenzyme A: Cholesterol acyltransferase inhibitor from licorice roots

Acyl-coenzyme A: cholesterol acyltransferase (ACAT) esterifies free cholesterol in the liver and the intestine. It has relations with production of lipoproteins and accumulation of cholesteryl esters of the atheroma. Therefore, ACAT inhibitors may act as antihypercholesterolemic and antiatherosclerotic agents. One isoprenyl flavonoid was isolated from ethanol extract of licorice roots. On the basis of spectral evidences, the compound was identified as glabrol (1). Compound 1 inhibited rat liver microsomal ACAT activity with an IC50 value of 24.6 μM and decreased cholesteryl ester formation with an IC50 value of 26.0 μM in HepG2 cells. In addition, 1 showed a non-competitive type of inhibition against ACAT.