Effects of naringin and lovastatin on plasma and hepatic lipids in high-fat and high-cholesterol fed rats

The effects of naringin on lipid metabolism were examined in rats that were fed a high-fat ( 15 g lard 100 g ) and high-cholesterol ( 1 g 100 g ) diet. Low- or high-doses ( 0.02 g or 0.05 g 100 g ) of either naringin or lovastatin were supplemented in an experimental diet for 35 d. The concentrations of plasma total cholesterol were significantly lower in the naringin- and lovastatin-supplemented groups than in the control group fed a basal diet. In addition, both doses of lovastatin and a high-dose naringin significantly lowered plasma triglyceride concentrations compared to the control group. All naringin and lovastatin supplements, except for the high-dose lovastatin, significantly lowered the hepatic cholesterol concentration compared to the control group. The concentrations of hepatic triglyceride in the naringin-supplemented groups (0.34±0.06 mmol/g and 0.30±0.06 mmol/g) and control (0.33±0.06 mmol/g) were significantly lower than in the lovastatin-supplemented groups (0.40±0.03 mmol/g and 0.42±0.05 mmol/g). High and low doses of naringin significantly lowered the activities of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase by 54% and 39%, respectively, compared to the control group, while lovastatin did not demonstrate any inhibitory activity on this enzyme. The activities of acyl coenzyme A:cholesterol O-acyltransferase (ACAT) were significantly lower in all experimental groups than in the control. Accordingly, lipid-lowering action of naringin seems to be different from that of lovastatin in a high-fat and high-choleterol fed rats.