Effect of a stilbene glycoside-rich extract from Polygoni Multiflori Radix on experimental non-alcoholic fatty liver disease based on principal component and orthogonal partial least squares discriminant analysis

Polygoni Multiflori Radix is a traditional Chinese medicine used clinically to support the functions of the liver and kidneys and to treatment hyperlipidemia. In previous studies, an effective fraction, rich in 2,3,5,4'-tetrahydroxy stilbene-2-O-β-D-glucoside (TSG), was separated from Polygoni Multiflori Radix and demonstrated hypolipidemic activity. The present study aimed to systematically assess the effect of this fraction on non-alcoholic fatty liver disease (NAFLD). A NAFLD model was established by feeding Sprague-Dawley rats a high-fat diet with 10% fructose solution for 18 weeks. Hematoxylin and eosin staining was applied for hepatic histopathological analysis. In addition, enzyme activities, lipid metabolism, inflammatory factors and insulin resistance indices were measured using a fully automatic blood biochemistry analyser and ELISA. Furthermore, cytochrome P450 2E1 (CYP2E1) and peroxisome proliferator-activated receptor α (PPARα) mRNA and protein expression were evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analysis. Principal component analysis and orthogonal partial least squares discriminant analysis were used to analyse the data. The results revealed that the TSG-rich fraction (TSGP) significantly lowered the serum total cholesterol and triglyceride levels, and the liver free fatty acid, CYP2E1 mRNA and malondialdehyde levels, in addition to mitigating hepatic enlargement and alleviating liver steatosis. Furthermore, it upregulated PPARα mRNA expression in the liver tissue. The results indicated that TSGP exhibited a protective effect against NAFLD and the underlying mechanism may involve augmentation of anti-lipid peroxidation capacity via regulation of PPARα and CYP2E1-mediated pathways.