Total Flavonoids from Berberis kaschgarica Rupr. Ameliorate Atherosclerosis in ApoE−/− Mice by Regulating Lipid Metabolism and Gut Microbiota

Background: Atherosclerosis is the major pathological basis of cardiovascular diseases, while current lipid-lowering therapies remain limited by suboptimal efficacy and safety. Natural flavonoids, with their multi-target pharmacological activities, are promising candidates for anti-atherosclerotic intervention. This study investigated the protective effects and mechanisms of total flavonoids from Berberis kaschgarica Rupr. (BTF) against high-fat diet (HFD)-induced atherosclerosis in ApoE−/− mice. Methods: Bioavailable constituents of BTF were identified by UPLC-Q-TOF-MS. Network pharmacology and bioinformatics analyses were performed to predict therapeutic targets and pathways. Male ApoE−/− mice were fed an HFD and treated with low, medium, or high doses of BTF or atorvastatin. Serum lipid profiles, oxidative stress markers, and aortic histopathology were evaluated. Hepatic proteins related to lipid metabolism were measured by Western blotting, and fecal gut microbiota were analyzed by 16S rRNA sequencing. Results: Seven flavonoid monomers, including kaempferol, apigenin, calycosin, and dihydromyricetin, were identified as absorbed constituents in serum. Bioinformatics suggested that BTF regulates targets involved in lipid metabolism, oxidative stress, and inflammation. BTF dose-dependently decreased serum TC, TG, LDL-C, MDA, and LDH, while increasing HDL-C and the activities of SOD, GSH, and CAT. BTF also reduced atherosclerotic plaque formation and preserved aortic wall structure. Mechanistically, BTF downregulated hepatic SREBP1, ACC1, FAS, APOB, and MTP expression and improved HFD-induced gut microbiota dysbiosis by enriching Akkermansia and Lactobacillus. Conclusions: BTF attenuated HFD-induced atherosclerosis by improving lipid metabolism, enhancing antioxidant capacity, and modulating gut microbiota composition, supporting its potential as a natural anti-atherosclerotic agent.