Solanum torvum Swartz. fruit containing phenolic compounds shows antidiabetic and antioxidant effects in streptozotocin induced diabetic rats

In this study, quantification of phenolic compounds and the investigation of antidiabetic and antioxidant activities of the fruit of Solanum torvum Swartz. are described. S. torvum fruit methanol extract (STMe) was administered orally at a dose of 200 and 400 mg/kg/day to streptozotocin induced diabetic rats for 30 days. The levels of glucose, insulin, total protein, hemoglobin, glycated hemoglobin, liver glycogen and marker enzymes of carbohydrate metabolism, hepatic function and antioxidants were analyzed. High-performance liquid chromatography (HPLC) analysis revealed that STMe contained high levels of phenolic compounds, mainly rutin (1.36% w/w), caffeic acid (12.03% w/w), gallic acid (4.78% w/w) and catechin (0.46% w/w). STMe at 200 and 400 mg/kg reduced blood glucose level by 17.04% and 42.10%, respectively in diabetic rats. The levels and/or activities of other biochemical parameters were restored significantly compared to diabetic control rats due to treatment with fruit extract. Histology of liver and pancreas in STMe treated groups substantiated the cytoprotective action of the drug. Immunohistochemical observation of islets in extract treated diabetic rats showed apparent β-cells regeneration. These findings suggest that S. torvum fruit containing phenolic compounds has great potential as a natural source of antidiabetic and antioxidant drug.