Effects of an aqueous extract of purple sweet potato on nonalcoholic fatty liver in high fat/cholesterol-fed mice

Purpose: Anthocyanins from purple sweet potato (PSP) have been investigated in vitro and in animals and found to have a protective effect against oxidative hepatic damage. In this study, we investigated that aqueous extract of PSP can ameliorate the dysfunction of lipid metabolism in mice fed a high fat/cholesterol diet. Methods: Forty C57BL/6J mice were randomly divided into 5 groups (n = 8) and fed one of the following diets for 8 weeks; normal fat (NF) diet; high fat/ cholesterol (HFC) diet; HFC with 1.25% PSP (HFPL) diet; HFC with 2.5% PSP (HFPM) diet; HFC with 5% PSP (HFPH) diet. Results: Non-alcoholic fatty liver was manifested in the HFC group by showing increased levels in plasma alanine aminotransferase (ALT) activity, total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), increased level of TC and presence of many large lipid droplets in the liver, and increased fat cell size in the HFC group compared with the NF group. However, administration of HFC induced a significant decrease in food intake, resulting in decrease in fat mass. Coadministration of PSP did not lead to reversal of body weight changes, ALT activity, and lipid levels in plasma and the liver, but suppressed excess enlargement of the fat cell size through increasing carnitine palmitoyltransferase-1 (CPT-1) gene expression in the liver. Accordingly, the number of fat droplets in the liver was reduced in PSP administered groups. Conclusion: Taken together, these results suggest that PSP may have a protective effect on the dysfunction of lipid metabolism. Conduct of further studies on the coordinated regulation of PSP for lipid metabolic homeostasis at the liveradipose tissue axis is needed.