Abstract: Objective To investigate the possible hypolipidemic effects of total stilbene from Cajanus cajan L.(TSC) in rabbits fed with a high-lipid diet and the mechanism of regulation of cholesterol metabolism. Methods Thirty-six male rabbits were divided into six groups: control group, high lipid model group, TSC-treated with 200、100、50 mg/kg，and Xuezhikang treated group. The effects of TSC were investigated by monitoring serum and liver lipid profile in rabbits. THP-1 cells were induced to macrophages by PMA. The macrophages were labeled with [3H]cholesterol. These cells were divided into five groups, i.e, normal group, Cajanin high concentration group (CH), Cajanin mean concentration group (CM), Cajanin low concentration group (CL) and estradiol(E2) group. The cells were cultured for 24 hours in the serum-free RPMI 1640 medium containing 2mg/ml bovine serum albumin(BSA) in the presence or absence of Cajanin (30 μmol/L, 3 μmol/L, 0.3 μmol/L) or 17β-estradiol ( 1 μmol/L) . The macrophages were washed with PBS again and incubated in the serum-free RPMI 1640 medium containing apoA-I (10μg/ml) for 12 hours. The radioactivity of samples of both supernatants and cell lysates were determined using the liquid scintillation counter (Beckman, LS 6000SC, USA). Fractional cholesterol efflux was calculated, and the ABCA1 protein was quantified by Western blot. Results In TSC(200 mg/kg) group，the serum and hepatic TC were reduced by 35.36% and 35.97%（P<0.01）；the TG contents of serum and liver were also lowered by 12.34%（P<0.05）and 41.32%（P<0.01）. At the same time, serum LDL-C decreased by 29.07%（P<0.01） as compared with high lipid model group. The cholesterol efflux percentage from macrophage was increased by 55.39% and 24.97%（P<0.01） respectively in CH and CM group. The expression of the ABCA1 was significantly increased in CH group. Conclusions TSC has potential hypolipidemic effects，possibly via up-regulating the ABCA1 protein expression, subsequently resulting in increased macrophage cholesterol efflux and RCT.

Key words: total stilbene extract from Cajanus cajan L., rabbit with high-lipid diet, hypolipidemic, RCT , ABCA1