Background/Objectives: This research investigated the effects of myricitrin on hypercholesterolemia and non-alcoholic fatty liver disease (NAFLD) in mice given a high-cholesterol diet (HCD). Methods: C57BL/6J mice were maintained for 20 weeks on an HCD with or without myricitrin. Results: Myricitrin had no impact on the food consumption, body weight, or plasma triglyceride concentrations. However, myricitrin-supplemented mice had lower plasma total cholesterol (TC) concentrations and LDL + VLDL-cholesterol/TC proportion, and higher HDL-cholesterol/TC proportion than control mice, which resulted in a markedly decreased atherogenic index. Moreover, the levels of plasma C-reactive protein, oxidized LDL, lipoprotein(a), and plasminogen activator inhibitor-1, which are indicators for cardiovascular disease (CVD), were reduced, while levels of plasma paraoxonase, a cardioprotective enzyme, were greater in myricitrin-supplemented mice than in control mice. Myricitrin also meaningfully reduced liver weight and hepatic cholesterol content, and slightly alleviated fatty liver and fibrosis caused by an HCD. The plasma and hepatic cholesterol-lowering effects of myricitrin were partly associated with decreased activities of hepatic 3-hydroxy-3-methylglutaryl-CoA reductase and acyl-CoA:cholesterol acyltransferase, which are involved in cholesterol synthesis and esterification, respectively, as well as mRNA expression. Myricitrin also altered other hepatic genes implicated in cholesterol homeostasis, including the downregulation of SREBP2 and ABCA1 mRNA expression and the upregulation of LDLR mRNA expression. Moreover, myricitrin decreased TBARS levels in the liver and erythrocytes by activating antioxidant enzymes (SOD and catalase). Conclusions: These results indicate that dietary myricitrin may offer therapeutic benefits for HCD-caused hypercholesterolemia and NAFLD, and may help reduce CVD risk.
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