Mechanisms underlying antidiabetic effects of Ocimum sanctum leaf extracts in animal models of type 1 and type 2 diabetes

Aim: This study investigated mechanisms by which O. sanctum leaf extracts ameliorate hyperglycaemia using animal and cellular models of diabetes. Place and Duration of Study: Diabetes Research Laboratory, University of Ulster, Coleraine, United Kingdom and Research Division, BIRDEM, Dhaka, Bangladesh; 8 months. Methodology: Acute anti-diabetic effects of ethanolic extracts of O. sanctum were examined in normal and chemically-induced type 1 and 2 diabetic rats. Effects of extracts on glucose absorption, intestinal disaccharidase activity and gastrointestinal motility in type 2 diabetic rats and on glucose uptake and insulin action in 3T3-L1 cells were assessed. Results: Treatment with the extract (1.25 g/kg bw) significantly improved oral glucose tolerance in normal and type 2 diabetic rats and suppressed blood glucose elevation after oral sucrose (2.5 g/kg bw) administration. The extract significantly reduced glucose absorption, gastrointestinal motility and disaccharidase activity. A 28-day treatment with O. sanctum decreased serum glucose, increased liver glycogen and enhanced circulating insulin and total oxidant status in type 2 diabetic rats. Glucose transport and insulin action in 3T3-L1 were increased by extract. Conclusion: O. sanctum represents a useful as a source for discovery of novel antidiabetic compounds and as a dietary adjunct for the management of type 2 diabetes and its complications