The Extract of Viola odorata Flowers Improves the Biochemical, Pancreas Histological, and Insulin Resistance Parameters in an Animal Model of Diabetes

Background: The antioxidant defense in the pancreas is low because they are exposed to toxic substances daily. This study aimed to evaluate the ameliorating effect of Viola odorata flowers Extract (VOE) on the pancreas histology and function in Streptozotocin (STZ)-induced diabetic rats. Methods: Forty male rats were divided into five groups, consisting of controls; STZ; and STZ plus various doses of VOE (100, 200 or 400 mg/kg). The amylase, lipase, insulin and total antioxidant capacity levels were measured in the sera. The homeostatic model assessment of insulin resistance was also measured. The histopathological alterations of the rats’ pancreases were examined microscopically. Results: The serum amylase and total antioxidant activities were reduced in diabetic rats (P=0.001). Varying doses of VOE reduced the serum amylase and glucose levels, and increased the total antioxidant activities compared to that of the diabetic rats (P<0.05). There were no significant differences in the serum lipase and insulin levels among the groups. Treatment with VOE at all doses significantly lowered the insulin resistance compared to that of the diabetic group (P=0.001). Significant reductions were observed in the areas of the pancreatic Langerhans islets and the number of beta cells in the STZ group (P=0.001). Conclusion: This study demonstrated that VOE ameliorated the adverse effects induced by STZ in the rat’s pancreas in the short-term. These effects are likely to be due to the reduced insulin resistance and amylase activity, and increased total antioxidant activity along with the histopathological alterations in the pancreas.