Abstract
We synthesized a series of indoline derivatives with an amide or urea moiety and examined their inhibitory effects on acyl-CoA : cholesterol acyltransferase (ACAT) activity, lipid-peroxidation and serum cholesterol levels in experimental animals. Among the derivatives synthesized, a series of N-(1-alkyl-4, 6-dimethylindolin-7-yl)-2, 2-dimethylpropanamides potently inhibited rabbit intestinal ACAT activity and lipid-peroxidation of rat brain homogenate. The effect on ACAT activity was related to the length of the alkyl chain at the 1-position of indoline. N-(4, 6-Dimethyl-1-octylindolin-7-yl)-2, 2-dimethylpropanamide hydrochloride (55) showed inhibitory effects on intestinal and hepatic ACAT activity slightly weaker than those of YM-750, and an inhibitory effect on low density lipoprotein (LDL)-peroxidation similar to that of probucol. Compound 55 also reduced serum cholesterol at 10mg/kg/d in hyperlipidemic rats and 20 mg/kg/d in normolipidemic hamsters. The plasma concentration of 55 reached 716ng/ml in dogs (10mg/kg, p.o.), which is an effect concentration against hepatic ACAT activity and LDL-peroxidation. In conclusion, compound 55 is a novel bioavailable ACAT inhibitor with anti-peroxidative activity and is thus a promising anti-atherosclerotic and anti-hyperlipidemic drug. Indoline proved to be a useful pharmacophore for molecular design of new anti-peroxidative drugs.
