Mulberry leaf polyphenols possess antiatherogenesis effect via inhibiting LDL oxidation and foam cell formation

Oxidized low-density lipoprotein (ox-LDL) and its uptake by machrophage are the hallmark in atherogenesis. In the present study, we aimed to investigate the antiatherogenic effect of mulberry leaf extracts (MLE) and the polyphenolic extracts (MLPE), which contained polyphenols including quercetin (11.70%), naringenin (9.01%) and gallocatechin gallate (10.02%). Both MLE and MLPE inhibited the oxidation and lipid peroxidation of LDL, while MLPE was shown to be more potent. As 1.0 mg/mL MLE reduced 30% of ox-LDL-generated ROS, 0.5 mg/mL MLPE decreased 46% of the ROS and was shown to be more potent on elevating SOD-1 and GPx in macrophages. At the same dose of 0.5 mg/mL, MLPE exhibited 1.5-fold potency than MLE in decreasing the formation of foam cells. Both MLE and MLPE reduced the expression of PPARγ, CD36 and SR-A, implicating the molecular regulation on ox-LDL uptake. These results suggested that MLPE potentially could be developed as an antiatherogenic agent and deserve further investigation.