Hepatoprotective effect of isoquercitrin against acetaminophen-induced liver injury

Aims: Acetaminophen (APAP) overdose leads to severe hepatotoxicity. Isoquercitrin exhibited potential hepatoprotective effect in our previous study. The present investigation aimed to evaluate the effect of isoquercitrin against APAP induced liver injury and to explore its possible mechanism. Main methods: Mice were treated intragastrically with isoquercitrin (10, 20, or 50mg/kg) for 3 days before APAP (300 mg/kg) injection. After 24 h from APAP treatment, the levels of serum aminotransferase, hepatic oxidative stress and nitrosative stress biomarkers were determined by commercial kits or western bolt. Activities of UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs) and cytochrome 2E1 (CYP2E1) were evaluated using ELISA methods and standard biochemical procedures. Subsequently, the protein and mRNA levels of inflammatory factors including TNF-alpha, IL-1 beta, IL-6 and iNOS were determined using ELISA methods, western blot or real-time PCR. The effect of isoquercitrin on APAP activated NF kappa B/MAPK pathway was assessed by western bolt. Key findings: Isoquercitrin pretreatments markedly attenuated APAP induced hepatic oxidative stress, nitrosative stress and centrilobular necrosis. In addition to potent antioxidant activity, isoquercitrin was able to regulate the activities of SULTs and CYP2E1, therefore promoted APAP hepatic detoxification. The anti-inflammatory activity of isoquercitrin which involved in the amelioration of iNOS, TNF-alpha, IL-1 beta and IL-6 production via the blockade of NF-kappa B and MAPK pathways also responsible for its hepatoprotective effect. Significance: Our data evidenced that isoquercitrin protected liver from APAP induced injury though inhibition of oxidative stress, nitrosative stress and inflammation, as well as regulation of APAP metabolism, suggesting that isoquercitrin could be a potential hepatoprotective agent. (c) 2016 Elsevier Inc. All rights reserved.