The present study was performed toevaluate the effect of aqueous-methanolic extract of Osbeckia chinensis roots, on the polyol pathway enzymes i.e., aldose reductase (AR) and sorbitol dehydrogenase (SDH) in normoglycemic and diabetic mice of two different age groups (six- and one-month old). Polyol pathway under hyperglycemic condition has been associated with the pathogenesis of diabetic complications. Varying doses (50-250 mg/kg b.w.) of extract was administered intraperitoneally to six-month normoglycemic mice in alternate days for upto 4 weeks. The optimised dose of 150 mg/kg b.w. was then administered to one-month old normoglycemic and diabetic mice. The activities of AR and SDH was then measured spectrophotometrically in liver, kidney and eye tissues of normoglycemic and diabetic mice of these two age groups treated with extract. Curcumin (20 mg/kg b.w.), a natural product known to inhibit enzymes of the polyol pathway was used as reference.Extract of O. chinensis exhibited the capacity to inhibit AR/SDH activity in selected tissues of both normoglycemic and diabetic mice in both age groups when compared to the control group. However, OCE was more effective in reducing AR activity than SDH. Curcumin showed significant inhibition against both AR and SDH in tissues of normoglycemic and diabetic mice of both age groups.The extract showed differential pattern of AR and SDH inhibition as a function of age, tissue and pathophysiologial condition. These results suggest that O. chinensis extract might contain active components which could represent potential compounds for the prevention and /or treatment of diabetic complications
