Antihyperglycemic Activity of Micromeria graeca Aqueous Extract in Streptozotocin-Induced Diabetic Rats.

Abstract

This study aimed to investigate the effect of Micromeria graeca on blood glucose levels and lipid parameters in an experimental model of diabetes. Micromeria graeca (L.) Benth. ex Rchb is a medicinal plant used in Morocco for the treatment of several pathologies including diabetes. This study aimed to evaluate the antihyperglycemic and antihyperlipidemic effects of the aqueous extract of Micromeria graeca (M. graeca) aerial parts (AEMG) under physiological (normal rats) and pathological (STZ-induced diabetic rats) conditions. Additionally, we analyzed the phytochemical composition and antioxidant capacity. The effects of the acute and sub-chronic administration of AEMG (20 mg/kg) on blood glucose levels and lipid profiles were evaluated in normal and streptozotocin-induced diabetic rats. Moreover, the phytochemical analysis was carried with standard tests and estimation of total phenolics compounds by Folin-Ciocalteu reagent. The antioxidant activity was realized by the DPPH method. Single oral administration of M. graeca aqueous extract decreased blood glucose levels 4 and 6 hours (p<0.01) after treatment in diabetic rats. In accordance, the repeated oral administration of M. graeca showed a significant reduction in blood glucose levels in diabetic rats since the second day to the end of the period experiment (p<0.0001). In addition, two weeks of treatment with M. graeca reduced total cholesterol levels (p<0.05) with a significant increase of HDL-c level (p<0.01) in diabetic rats. Moreover, M. graeca scavenged DPPH radical in a dose-dependent manner (IC50=0.48 mg/ml), whereas IC50 was 0.55 mg/ml for BHT. Phytochemical analysis showed the richness of Micromeria graeca on polyphenols (281.94±4.61 mg GAE/1 g), flavonoids, tannins, glycosides, saponins, sterols, sesquiterpenes, and terpenoids. AEMG exhibits antihyperglycemic and antihyperlipidemic activities in STZ-induced diabetic rats and a potent antioxidant capacity.