Citrus depressa peel extract and its polymethoxyflavones mitigate acetaminophen‐induced chronic liver injury in mice through antioxidant activation, epigenetic regulation, and gut microbiota modulation

BACKGROUND Preventing chronic liver damage is essential for maintaining overall health and reducing the risk of serious liver diseases. Acetaminophen (APAP) overdose can lead to severe liver damage due to oxidative stress, and citrus fruits are rich in bioactive compounds that may have health benefits. The present study aimed to examine the hepatoprotective effects of Citrus depressa peel ethanolic extract (CD‐EE) and its major compounds, nobiletin (Nob) and tangeretin (Tan), in BALB/c mice suffering from chronic liver injury caused by APAP. RESULTS CD‐EE [250 and 500 mg kg −1 body weight (bw)], Nob (50 mg kg −1 bw) and Tan (50 mg kg −1 bw), or N ‐acetylcysteine (NAC, 600 mg kg −1 bw, as a positive control), were orally administered to the mice daily for 9 weeks. Subsequently, starting from the second week, mice received intraperitoneal injections of APAP (400 mg kg −1 bw) twice weekly. We found that APAP‐induced liver damage was reduced through the enhancement of antioxidant enzyme activity, the reduction of lipid peroxidation and the modulation of the Nrf2‐mediated antioxidant pathway by CD‐EE, Nob, Tan and NAC treatments. The levels of DNA methyltransferases and histone deacetylases were influenced by these treatments in epigenetic regulation. Additionally, they partially restored the gut microbiota composition that was altered by APAP. CONCLUSION These results suggest that CD‐EE, Nob, and Tan are associated with hepatoprotection against APAP‐induced chronic liver injury in mice. The modulation of antioxidant mechanisms and epigenetic regulation potentially contributes to this protection, whereas the restoration of gut microbiota composition may represent an additional pathway.