Zhang_2026_Food.Res.Int_230_118558

Non-alcoholic fatty liver disease (NAFLD) accounts for a major share of liver damage worldwide. Studies investigating dietary anthocyanins as a promising strategy are attracting attention. In this study, the hepatoprotective effects of the purified anthocyanin-rich extract (PAE) from purple highland barley bran were investigated in vitro and in vivo. Results indicated that PAE at 1.2 mg/mL significantly (p < 0.05) inhibited pancreatic lipase and cholesteryl esterase activities by 63.11% and 60.21%, respectively. PAE induced resistant starch formation by increasing the degree of starch structure. In a high-fat diet (HFD)-induced NAFLD model, PAE intervention at 400 mg/kg/d significantly (p < 0.05) reduced hepatic weight, total glyceride (TG) and total cholesterol (TC) by 25.51%, 35.15% and 34.2%, respectively, compared with HFD group. PAE exerted significant beneficial effects on oxidative stress and inflammation. Western blot analysis in oleic acid (OA)-induced HepG2 cells revealed that the underlying mechanism was partially involved in the activation of the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway and inhibition of p38 mitogen-activated protein kinase (MAPK) pathway. At 400 microg/mL, PAE significantly (p < 0.05) increased nuclear Nrf2 level by 1.24-fold and decreased p38 MAPK phosphorylation by 27.47% compared with the OA-treated group. Additionally, PAE significantly (p < 0.05) improved intestinal barrier function by increasing mucus thickness and goblet cell number by 25.63% and 33.99%, respectively, and alleviated gut dysbacteriosis compared with HFD group. The colon metabolic profile was significantly altered by PAE, with differential metabolites mainly involved in flavonoid biosynthesis and the biosynthesis of arginine, phenylalanine, tyrosine, and tryptophan. Correlation analysis revealed strong links (p < 0.05) between the NAFLD-related traits, intestinal flora and metabolites, implying that PAE mitigated NAFLD via the gut-liver axis.