AbstractThe present study aims to investigate the effect of hydroxytyrosol in insulin secretion and the antioxidant activity in liver slices in vitro. For this, pancreas and liver slices were incubated in presence of 1g/l or 4g/l glucose (± hydroxytyrosol (HT)) during 40 minutes. We interest to evaluate the action of HT in insulin secretion, antioxidant enzymes activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)), reduced glutathione (GSH), lipid peroxidation, lactate dehydrogenase (LDH) and histological changes in pancreas and liver slices. For the first time, our results show that hydroxytyrosol significantly induces insulin secretion in pancreas incubation. Besides, the present work prove that HT has a good antioxidant activity by preventing the decrease of superoxide dismutase (SOD), catalase (CAT) and gluthation peroxidase (GPX) activities and the reducing glutathione content (GSH) in hepatic slices incubated in high glucose concentration (HG) (4g/l). En parallel, a significant decrease in lipid peroxidation rate andlactate dehydrogenase (LDH) activity are observed after hydroxytyrosol administration in liver slices. Theses beneficial actions of HT are confirmed by histological changes in hepatic and pancreatic tissues. Conclusion: HT supplementation in diabetic can induces insulin secretion and prevents glucose toxicity in pancreas and liver.