Fermented Cornus officinalis Fruit Protects Against Alcohol-Induced Liver Injury via Regulating Keap1–Nrf2–HO-1/GPX4 Pathway: UPLC-MS/MS Characterization, Network Pharmacology, and Animal Validation

Alcoholic liver injury (ALI) is a major global public health issue, with oxidative stress imbalance as its core pathological mechanism. The Kelch-like ECH-associated protein 1–nuclear factor erythroid 2-related factor 2–heme oxygenase-1/glutathione peroxidase 4 signaling pathway (Keap1–Nrf2–HO-1/GPX4) signaling pathway is a key target for regulating hepatic antioxidant defense. This study integrated Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS), Global Natural Products Social Molecular Networking (GNPS) molecular networking, network pharmacology, and animal experiments to systematically explore the hepatoprotective effect and mechanism of Cornus officinalis yeast-fermentation (COF). Component characterization identified 25 bioactive components, including flavonoids, triterpenic acids, and other fermentation-derived metabolites. Network pharmacology identified 441 common targets and 36 core targets of COF and ALI, which were enriched in oxidative stress regulation, inflammatory response, and the Keap1–Nrf2 pathway via Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Molecular docking showed that icariin and other components had stable interactions with Keap1 and Nrf2 (binding energy < −5 kcal/mol). Animal experiments confirmed that COF reduced the liver index of ALI mice, downregulated serum Alanine Aminotransferase (ALT)/Aspartate Aminotransferase (AST) activities, and ameliorated liver pathological damage. Western blot verified that COF inhibited Keap1 expression, promoted Nrf2 nuclear translocation, and upregulated HO-1/GPX4 expression. In conclusion, COF alleviates hepatic oxidative stress by regulating the Keap1–Nrf2–HO-1/GPX4 pathway, providing a scientific basis for its development as a functional food or candidate drug against ALI and a technical paradigm for fermentation-enhanced medicinal plant research.