In vitro inhibition of diacylglycerol acyltransferase by prenylflavonoids from Sophora flavescens

Four prenylflavonoids, kurarinone (1), a chalcone of 1, kuraridin (2), kurarinol (3), kushenol H (4) and kushenol K (5) isolated from the roots of Sophora flavescens were investigated for their inhibitory effects on diacylglycerol acyltransferase (DGAT). The flavonoids inhibited DGAT activity in a dose-dependent manner with IC50 values of 10.9 muM (1), 9.8 muM (2),8.6 muM (3),142.0 muM (4) and 250 muM (5). The prenylflavonoids without C3-OH (1, 2,3) showed stronger inhibition than those with C3-OH (4, 5). On the other hand, flavonoids without side chains (hesperetin, naringenin, quercetin and kaempferol) did not inhibit the enzyme activity at a final concentration of 800 muM. These data suggest that the lavandulyl side chain and the position of the hydroxy group are important for high DGAT inhibitory activity. Compound 1 also inhibited de novo synthesis of triacylglycerol (TG) in Raji cells.