Tomato fruit (Solanum lycopersicum) peel extract improves fasting blood glucose and insulin resistance in type 2 diabetes wistar rats

Insulin resistance serves as a key to the development of type 2 diabetes mellitus (T2DM) and causes hyperglycemia. Hyperglycemia results in an oxidative stress. Tomato (Solanum lycopersicum) contains many antioxidants; the highest amounts of antioxidants are found in the peel. In this study, we evaluate the effect of tomato peel extract on fasting blood glucose and insulin resistance index in experimental type 2 diabetic rats. Twenty male Wistar rats were randomly divided into five groups: negative control/normal group, positive control/diabetic rats without treatment, and 3 groups of diabetic rats treated with a dose levels 50 mg/kg b.w., 100 mg/kg b.w., and 150 mg/kg b.w. tomato peel extract, given for 4 weeks. T2DM was induced in the rats by a high-fat diet for 5 weeks and an intraperitoneally administered low dose of streptozotocin (30 mg/kg). At the end of treatment, fasting blood glucose (FBG) and fasting insulin were measured. Insulin resistance index was measured using homeostasis model assessment of insulin resistance (HOMA-IR). Peel extracts of tomato significantly decreased fasting blood glucose and improved HOMA-IR (p<0.05). Our findings indicate that tomato peel extracts decrease fasting blood glucose and improve insulin resistance in Wistar male rats.