Abstract: Objective: To investigate the effect of kiwifruit peel polyphenols on lipid metabolism in rats fed on high fat diet and its underlying mechanism. Methods: Male SD rats were randomly divided into five groups: normal control (NC), high fat diet (HF), and low-dose (LKP), middle-dose (MKP), and high-dose kiwifruit polyphenols (HKP) groups. At the end of the 9-week feeding period, all rats were sacrificed. The liver index, fat index, mesenteric fat mass, abdominal fat mass, and epididymal and perirenal fat pad mass, and serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and free fatty acids (FFA) were examined. The mRNA expression of fatty acid synthase (FAS), acetyl CoA-carboxylase (ACC), carnitine palmityl transferase 1 (CPT-1) and peroxisome proliferator activated receptor α (PPAR-α) genes in liver were assayed. Results: Compared with the HF group, the liver index in all intervention groups and the fat index in the MKP and HKP groups were significantly decreased (P < 0.05). The masses of mesenteric fat and epididymal and perirenal fat pads in the MKP and HKP groups were significantly lower than those in the HF group (P < 0.05) while there was no significant difference in abdominal fat mass. Serum TG and LDL-C were significantly decreased in each intervention group (P < 0.05). In the MKP and HKP groups, TC and FFA were decreased significantly whereas HDL-C was increased significantly (P < 0.05). The expression of fat synthesis-related genes (ACC and FAS) was significantly down-regulated (P < 0.05), while the expression of fat decomposition-related gene (CPT-1) was significantly upregulated in all intervention groups (P < 0.05). Moreover, the expression of PPAR-α in the MKP and HKP groups was also significantly upregulated (P < 0.05). Conclusion: Kiwifruit peel polyphenols can alleviate lipid metabolism disorder caused by high fat diet. The underlying mechanism is related to the inhibition of fatty acid synthesis in the liver and the promotion of oxidative decomposition of fatty acids.

Key words: kiwifruit; polyphenols; high-fat diet; lipid metabolism