Mentha Longifolia L. Improves Antioxidant Status, Glucose Tolerance, Insulin Resistance and Hepatic Glucose Production In Diet-Induced Obesity

Abstract

Abstract Objectives Obesity is associated with several metabolic abnormalities including insulin resistance (IR), which is a key risk factor of type 2 diabetes mellitus (T2DM). Oxidative stress is linked to both obesity and IR development. Improving antioxidant status using medicinal plants or their bioactive components can be a safe and low-cost alternative approach to reduce obesity and IR thus T2DM development. This study aims to evaluate the antioxidant activities of Mentha longifolia L. (M. longifolia) leaf powder and oil extract on obesity-induced metabolic abnormalities. Methods High-fat-sucrose diet (HFS)-induced obese Wistar rats were orally given M. longifolia essential oil (50 mg/kg), leaf powder (120 mg/kg), or vehicle for 6 weeks. Bodyweight and calorie intake were recorded periodically, and glucose and pyruvate tolerance were evaluated. At the end of the study, plasma insulin and triglyceride levels were measured, and organs weight and the degree of adiposity were determined. Antioxidant status for the plasma was measured using plasma ferric ion reducing antioxidant power test (FRAP). Results M. longifolia leaf powder and oil extract improved glucose tolerance, and hepatic glucose production after being challenged with glucose or pyruvate compared to untreated obese rats. M. longifolia reduced IR (HOMA-IR: oil = 2.30 ± 0.279, powder = 2.13 ± 0.057, HFS = 2.54 ± 0.136). Antioxidant status was also improved in rats treated with M. longifolia (FRAP: oil = 300.5 ± 25.4, powder = 341.8 ± 47.2, HFS = 263.5 ± 13.0). These outcomes were not associated with changes in body weight, calorie intake, adiposity, or plasma triglycerides. Conclusions M. longifolia oil and powder improved the antioxidant status and ameliorated HFS diet-induced metabolic abnormalities, suggesting that this plant a promising natural agent for reducing the risk of T2DM. Further studies are needed to elucidate the mechanism of this action. Funding Sources Deanship of Scientific Research at Jordan University of Science and Technology.