Effect of flavonol glycoside in mulberry (Morus alba L.) leaf on glucose metabolism and oxidative stress in liver in diet-induced obese mice

BACKGROUND: Mulberry therapies on type 2 diabetic patients or streptozotocin-induced diabetic rats have been reported to improve fasting blood glucose levels. We investigated the effects of dietary consumption of mulberry-leaf powder and purified quercetin 3-(6-malonylglucoside), the quantitatively major flavonol glycoside in mulberry leaves, on glucose and lipid metabolism in high-fat diet-induced obese mice. Male C57BL/6J mice aged 8 weeks were assigned to three groups (control, mulberry leaf powder (MLP), and quercetin 3-(6-malonylglucoside) (Q3MG)) and treated with their respective diets for 8 weeks. RESULTS: We found that dietary supplementation of 10 g MLP kg(-1) or 1 g Q3MG kg(-1) in high-fat diet effectively suppressed blood glucose levels. We also noted increased expression of glycolysis-related genes and suppression of thiobarbituric acid reactive substances concentrations in the liver of Q3MG group compared to control mice. CONCLUSION: Dietary consumption of Q3MG, the quantitatively major flavonol glycoside in mulberry leaves, improved hyperglycemia in obese mice and reduced oxidative stress in the liver. (c) 2010 Society of Chemical Industry