The flavonoid quercetin ameliorates liver damage in rats with biliary obstruction

Background/Aims: Our aim was to investigate whether the antioxidant quercetin might protect against liver injury in chronically biliary obstructed rats. Methods: Secondary biliary cirrhosis was induced by 28 days of bile duct obstruction. Animals received quercetin at 75, 150 and 300 mu mol . kg body wt(-1) . day(-1) i.p. through the experimental period or at 150 mu mol . kg body wt(-1) . day(-1) i.p. for the last 2 weeks. Results: Bile duct obstruction resulted in a decrease in the activities of antioxidant enzymes. Liver oxidised/reduced (GSSG/GSH) glutathione ratio, hepatic and mitochondrial thiobarbituric acid reactive substances (TBARS) and collagen content were significantly increased and a marked fibrosis and bile ductular proliferation was observed. Quercetin corrected the reduction in glutathione concentration and partially prevented the increase in collagen concentration, TEARS and GSSG/GSH ratio. Treatment resulted in a significant preservation of the activities of antioxidant enzymes, a less pronounced fibrosis and a marked inhibition of bile ductular proliferation, Maximal effects were reached with the intermediate quercetin dose given for 2 or 4 weeks. Conclusions: Quercetin reduces liver oxidative damage, ductular proliferation and fibrosis in biliary-obstructed rats. These effects suggest that it might be a useful agent to preserve liver function in patients with biliary obstruction.