[Hypocholesterolemic effect of stilbene extract from Cajanus cajan L. on serum and hepatic lipid in diet-induced hyperlipidemic mice].

Cajanus cajan L. is a natural plant, which contains a lot of potential active components. In the present study, we identified the effects of the stilbene extract from Cajanus cajan L. (sECC) on hepatic cholesterol metabolism in diet-induced (for 4 weeks) hyperlipidemic Kunming mice. All experimental mice were divided into 5 groups: control group, high lipid model group, sECC-treated with 200 or 100 mg kg(-1), and simvastatin (Sim, 12 mg kg(-1)) treated group. The mice were fed with fat and cholesterol-enriched chow except control mice that were fed with standard diet. The effects of sECC were investigated by monitoring serum and liver lipid profile (i. e. cholesterol homeostasis) in mice. To further explore the mechanism of sECC, hepatic cholesterol 7alpha-hydroxylase (CYP7A1) and low density lipoprotein (LDL) receptor expressions in cholesterol homeostasis were analyzed by reverse transcription PCR. After 4 weeks pretreatment, the mice in the high lipid model group showed markedly higher serum and hepatic lipid contents than control group (P< 0.01). Compared with high lipid model group, the increased serum and hepatic lipid contents were markedly attenuated by sECC (200 mg kg(-1)), the serum and hepatic total cholesterol were reduced by 31.5% and 22.7% (P<0.05), respectively. The triglyceride contents of serum and liver were also lowered by 23.0% and 14.4%, respectively. At the same times, serum LDL cholesterol decreased by 53.0% (P<0.01). The mRNA expressions of hepatic CYP7A1 and LDL-receptor were significantly enhanced in the mice administered with sECC (200 mg kg(-1)), whereas those expressions were suppressed by the fat and cholesterol-enriched diet. These data indicate that sECC reduces the atherogenic properties of dietary cholesterol in mice. It is indicated that expression enhancement of hepatic LDL-receptor and cholesterol 7alpha-hydroxylase may be responsible for the hypercholesterolemic effect.