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

Aims: This study aimed to investigate the effect of Micromeria graeca on blood glucose levels and lipid parameters in an experimental model of diabetes.

Background: Micromeria graeca (L.) Benth. ex Rchb is a medicinal plant used in Morocco for the treatment of several pathologies including diabetes.

Objective: 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.

Methods: 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.

Results: Single oral administration of M. greaca 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.

Conclusion: AEMG exhibits antihyperglycemic and antihyperlipidemic activities in STZ-induced diabetic rats and a potent antioxidant capacity.

Keywords: Micromeria graeca; antioxidant activity.; aqueous extract; diabetes; lipid profile; phytochimestry.