Molecular and biochemical effects of the methanolic extracts of the leaves of Salvia officinalis on diabetic male wistar rats

Common sage (Salvia officinalis L.) is among the plants that are claimed to be beneficial to diabetic patients and previous studies have suggested that this plant has hypoglycaemic effects in normal and diabetic rats. In the current study, we have investigated the effects of methanolic extract of S.officinalis leaves on blood glucose, plasma biochemical parameters, pancreatic Insulin and cardiac Glut-4 mRNAs expression, inhibition of rat intestinal α-glucosidases activities and erythrocyte antioxidant enzymes. Treatment of Alloxan monohydrate -induced diabetic rats with oral administration of sage leaves methanolic extract for 3 weeks, resulted in a significant reduction in blood glucose (Glucose oxidase assay).Total cholesterol (TC), triglycerides (TG), LDL/HDL ratio and VLDL were mildly decreased after treatment of diabetic rats by plant extract. We have also observed significant enhancement in activity of blood antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). we have observed increased expression of Ins and Glut-4 genes in diabetic rats treated with methanolic extract of S. officinalis, compared to control group. The extract showed strong inhibition effect on intestinal α-glucosidases enzymes activities.

Acknowledgement: The authors would like to thank the Cellular and Molecular Department of University of Tehran for financial support.

References: Lin YF, Tsai HL, Lee YC, Chang SJ (2005) Journal of Nutrition 135: 2457–61.

Lu YR and Foo LY (2001) Tetrahedron Lett 42: 8223–8225.

Wang M et al. (1998)J Agric Food Chem 46: 4869–4873.