Ameliorative effects and molecular mechanisms of vine tea on Western diet-induced NAFLD
Non-alcoholic fatty liver disease (NAFLD) is worldwide prevalent disease, and its prevention by dietary administration is recently considered as an important strategy. In this study, we administrated mice with vine tea polyphenol (VTP) extracted from Ampelopsis grossedentata, a Chinese herb, to investigate the preventive effect on Western diet (WD)-induced NAFLD. Male C57BL/6N mice were fed either a normal diet (ND) or WD with or without VTP for 12 weeks. Results revealed that VTP supplementation decreased serum levels of cholesterol and triglyceride, and reduced accumulation of hepatic lipid droplets caused by WD. Molecular data revealed that VTP enhanced fatty acid oxidation by reactivating WD-suppressed phosphorylation of AMP-activated protein kinaseα (AMPKα) and the expressions of peroxisome proliferator-activated receptor alpha (PPARα), carnitine palmitoyl transferase IA (CPT1A) and cytochrome P450, family 4, subfamily a1 (CYP4A1). Meanwhile, VTP inhibited hepatic lipogenesis by reducing WD-enhanced the level of mature sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FAS). Moreover, VTP activated nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-mediated expressions of hemeoxygenase-1 (HO-1) and quinone oxidoreductase (NQO1), and reduced hepatic TBARS level to prevent hepatic oxidative stress. On the other hand, VTP also increased intestinal zonula occludens-1 (ZO-1) expression and relative abundance of gut Akkermansia, and reduced the ratio of Firmicutes/Bacteroidetes. Thus, VTP might prevent WD-induced NAFLD by balancing fatty acids oxidation and lipogenesis, hepatic oxidative stress, and gut microbiome at least. These results suggested vine tea, containing high content of bioactive compound dihydromyricetin, is a potential food resource to prevent NAFLD.