Antihyperglycaemic and antioxidant effect of rutin, a polyphenolic flavonoid, in streptozotocin-induced diabetic Wistar rats

Flavonoids are non-nutritive dietary components that are widely distributed in plants. The present study investigated the antihyperglycaemic and antioxidant effect of rutin, a polyphenolic flavonoid in normal and streptozotocin-induced diabetic Wistar rats. Diabetes as induced in rats by an intraperitoneal injection of streptozotocin. Rutin was orally administered to normal and diabetic rats for a period of 45 days. Fasting plasma glucose, glycosylated haemoglobin, thiobarbituric acid reactive substances and lipid hydroperoxides were significantly (P < 0.05) increased, whereas insulin, C-peptide, total haemoglobin, protein levels, non-enzymic antioxidants (glutathione, vitamin C, vitamin E and ceruloplasmin) were decreased significantly (P < 0.05) in diabetic rats. Oral administration of rutin to diabetic rats significantly (P < 0.05) decreased fasting plasma glucose, glycosylated haemoglobin and increased insulin, C-peptide, haemoglobin and protein levels. Administration of rutin also decreased thiobarbituric acid reactive substances and lipid hydroperoxides and increased the non-enzymic antioxidants significantly (P < 0.05). Treatment of normal rats with rutin did not significantly (P < 0.05) alter any of the parameters studied. These results show that rutin exhibits antihyperglycaemic and antioxidant activity in streptozotocin-induced diabetic rats.