Pharmacological evaluation of aqueous extract of syzigium cumini for its antihyperglycemic and antidyslipidemic properties in diabetic rats fed a high cholesterol diet—Role of PPARγ and PPARα

In India syzygium cumini (Myrtaceae) is commonly used traditional medicine to treat diabetes. The present study was undertaken to assess an investigation of antihyperglycemic and antidyslipidemic properties of aqueous extract of Syzigium Cumini (SC) in diabetic rats fed a high cholesterol diet. The aqueous extract of SC was screened for antihyperglycemic and antidyslipidemic activity by streptozotocin induced diabetes in rats. Animals were treated with 100, 200 and 400 mg/kg body weight of aqueous extract of SC. Metformin were used as reference antihyperglycemic drugs for comparison. Administration of aqueous extract of SC or metformin for 21 days resulted in a significant (P < 0.05) reduction in serum glucose, insulin and Homeostasis model assessment of insulin resistance (HOMA-IR) compared with diabetic controls. Treatment with 100 mg/kg/day aqueous extract of SC did not result in a significant reduction in serum insulin levels, but 200 mg/kg/day and 400 mg/kg/day, aqueous extract of SC and metformin showed significant reductions 17.89%, 19.60% and 24.40%, respectively. Furthermore, administration of 100, 200 and 400 mg/kg/day, aqueous extract of SC and metformin resulted in significant decrease in insulin resistance of 19.20%, 41.59%, 51.55% and 68.68%, respectively. In high fat diet- streptozotocin (HFD – STZ) treated rats β-cells function (HOMA-B) were markedly reduced (5.8-fold), however observed a significant (P < 0.01) improvement of β-cell function with aqueous extract of SC (400 mg/kg/day) and metformin. The aqueous extract of SC seeds exhibits significant insulin-sensitizing, antidyslipidemic, antioxidant, anti-inflammatory and β-cell salvaging activity in HFD-STZ-induced type 2 diabetic rats via overexpression of PPARγ and PPARα activity, affirming its potential to be used in the prevention and treatment of type 2 diabetes mellitus (T2DM). Further isolation and characterization of active components in SC seed extract are needed to explore the other possible mechanisms and pathways that are involved in its anti-diabetic effect.