In vivo evaluation of wound healing effect and antioxidant properties of extracts and fractions of Gymnema sylvestre

Abstract

Among the causes of mortality, wound healing remains a major problem that often results from imbalance between prooxidants and endogenous antioxidants in diabetics. The aim of this study was to evaluate the wound healing activity of Gymnema sylvestre in normoglycemic rat, and its antioxidant properties in type 2 diabetic rat. Evaluation of the healing properties of extracts (aqueous and methanol) and fractions (methylene chloride and methanol) G. sylvestre (10% of fraction or extract) were conducted in female normoglycemic rats and 1% fluoxetine was considered positive control using glycerin as a vehicle, while antioxidant assessments were conducted in male diabetic rats. Type 2 diabetes was induced in male rats by a high sucrose diet for 12 weeks followed by daily intraperitoneal injection of dexamethasone (8 mg/kg) for 5 consecutive days. Animals with a blood glucose above or equal to 140 mg/kg after 12 hours of fasting were considered diabetic. For the evaluation of wound healing 5 groups consisting of 3 female rats each were formed. Fluoxetine (1%), aqueous (Aq) and methanol (MeOH) extracts as well as methylene chloride (F1) and methanol (F2) fractions of the plant were administered at 10% via utopian application on wounds of about 2.5 cm in diameter. For the estimation of oxidative stress parameters in the diabetic rat, 7 groups of 5 animals each were formed, with three control groups including two negative control groups (normoglycemic and diabetic) receiving the vehicle orally (DMSO 3%) and a positive control group receiving metformin (Met, 200 mg/kg). The four experimental groups were treated orally with administration of Aq (100 mg/kg), MeOH, F1 and F2 (7.5 mg/kg). The different treatments were administered once a day for 14 consecutive days. Results showed that G. sylvestre promoted wound healing (P>0.05) in the normoglycemic rat with a stronger effect for F2 and MeOH compared to the untreated group. In the diabetic rat, extracts and fractions of G. sylvestre significantly reduced (P<0.001) the MDA level, while F1 significantly increased (P<0.01) the activity of catalase (CAT) and reduced glutathione (GSH) compared to the untreated diabetes group on day one. These results revealed that G. sylvestre exhibited strong wound healing effects and justify the use of this in traditional pharmacopoeia.