Hypoglycemic effects of three medicinal plants in experimental diabetes: inhibition of rat intestinal alpha -glucosidase and enhanced pancreatic insulin and cardiac glut-4 mRNAs expression

Garlic [Allium sativum L., Alliaceae], Persian shallot [Allium ascalonicum L., Alliaceae] and Sage [Salvia offcinalis L., Lamiaceae] are believed to have hypoglycemic properties and have been used traditionally as antidiabetic herbal medicines in Iran. In this study, diabetes was induced by subcutaneous injection of alloxan monohydrate [100 mg kg[-1]] to male Wistar rats. Antidiabetic effects of methanolic extracts of the above mentioned three plants on alloxan-diabetic rats was investigated in comparison with the effects of antidiabetic drugs such as acarbose, glibenclamide and metformin by measuring postprandial blood glucose [PBG], oral glucose tolerance test [OGTT], inhibition of rat intestinal alpha -glucosidase enzymes activities and pancreatic Insulin and cardiac Glut-4 mRNAs expression. In short term period, hypoglycemic effects of A. sativum and A. ascalonicum showed significant reduction of PBG similar to glibenclamide [5 mg kg[-1] bw] while S. offcinalis significantly reduced PBG similar to acarbose [20 mg kg[-1] bw]. After 3 weeks of treatment by methanolic plant extracts, significant chronic decrease in the PBG was observed similar to metformin [100 mg kg[-1] bw]. For OGTT, S. offcinalis reduced PBG in a similar way as acarbose [20 mg kg[-1] bw]. Intestinal sucrase and maltase activities were inhibited significantly by A. sativum, A. ascalonicum and S. offcinalis. In addition, we observed increased expression of Insulin and Glut-4 genes in diabetic rats treated with these plants extracts. Up regulation of Insulin and Glut-4 genes expression and inhibition of alpha -glucosidaseactivities are the two mechanisms that play a considerable role in hypoglycemic action of garlic, shallot and sage

Effects of three medicinal plants extracts in experimental diabetes: antioxidant enzymes activities and plasma lipids profiles in comparison with metformin

In the present study we aimed to evaluate the effects of methanolic extracts of the bulbs of Garlic [Allium sativum L., Alliaceae] and Persian shallot [Allium ascalonicum L., Alliaceae]and leaves of Sage [Salvia officinalis L., Lamiaceae], ASE, AAE and SOE respectively, on the antioxidant enzymes such as superoxide dismutase [SOD], glutathione peroxidase [GPX] and catalase [CAT] activities and on the levels of plasma lipids profiles such as triglycerides [TG], total cholesterol [TC], high-density lipoproteins [HDL], low-density lipoproteins [LDL] and very low-density lipoproteins [VLDL] in Alloxan diabetic Wistar rats. In comparison with diabetic control rats in diabetic treated rats, AAE increases the activities of SOD [65%], GPX [43%] and CAT [55%]. ASE and SOE increase SOD activity by 60% and 33% respectively. ASE reduces TC [34%], SOE decreases TG [40%] and LDL [30%] and AAE reduces VLDL [24%]. Metformin exhibits mild antioxidant and hypolipidemic properties. Results of quantitative phytochemical analysis show that the methanolic garlic and Persian shallot bulbs extracts contain secondary metabolites including alkaloids [3.490% and 3.430%], glycosides [18.023% and 13.301%] and saponins [0.812% and 0.752%]. Methanolic sage leaves extract contains flavonoids [1.014%], glycosides [23.142%] and saponins [2.096%]. The total phenolic contents of ASE, AAE and SOE were in order 4.273, 3.621 and 6.548 mg GAE/g dry weight [DW]. These results suggest that Allium sativum, Allium ascalonicum and Salvia officinalis are beneficial in the control of diabetes by noticeable antioxidant and hypolipidemic properties