Effects Of Pomegranate Peel Polyphenols On Lipid Peroxidation And The Activity And Expression Of HMG-CoA Reductase In Hepatocyes

In this study, purified pomegranate peel polyphenols (PPPPs), Punicalagin(PC) and Pomegranate ellagic acid(PEA)were the research objects. The function of PPPs on lipid peroxidation in vitro and cholesterol synthesis on L-02hepatocytes was observed.The main research findings are as follows:1、The function of anti-lipid perxidation and the main active composition of PPPs were determined. Results showed that PPPs could provide good protection against metal ions-induced lipid peroxidation in vitro and the antioxidant activity exhibited a dose-effect relationship relevant to the content of polyphenols, the trend in anti-lipid peroxidation activity was:PC>PEA>PPPPs, Thus, it was concluded that Punicalagin the key anti-lipid peroxidation component in pomegranate peel polyphenol mixtures.2、The function of cholesterol-lowering、active composition and the optimal model of action of PPPs were determined. When cultured with RPMI-1640medium rich in50%fetal bovine serum for48h, the quantity of Lipid droplets and the content of TG in cells were increased significantly, concluding that the model of steatotic hepatoeytes were established successfully. Compared with model group, different contents of PPPs could decrease the formation of lipid droplets and the amounts of TC and CE after48h treatment, the cholesterol-lowing function was:PC>PPPPs> PEA. Meanwhile, the treatment groups and the prevention groups could both express the cholesterol-lowing function.especially in the prevention groups.3、The molecular mechanisms of cholestesterol-lowering of PPPs was identified. Compared with normal group, the activity and mRNA expression of HMG-CoAR were both increased significantly in model group. Compared with the model group, the activity and mRNA expression of HMG-CoAR were decreased both in the treatment groups and the prevention groups, especially in the prevention groups. Meanwhile, the inhibition of the activity and expression of HMG-CoAR was P> PPPPs> PEA. In addition, when putting the HMG-CoAR with different content of PPPs directly in burette, the result of HMG-CoAR activity assay showed that there was no statistical difference between PPPs treatment group and normal group. These data provided further conclution that PPPs mainly through weakened the expression of HMG-CoAR mRNA to inhibit the activity of HMG-CoAR, thereby reducing the content of cholesterol in the steatotic hepatoeytes. Punicalagin was the key cholesterol-lowering component in pomegranate peel polyphenol mixtures.