Preventive Effect of Irvingia Wombolu Pulp and Peel Extracts against High Fat-High Fructose Diet Induced Insulin Resistance in Rats

Production of free radicals is a normal metabolic process which if uncontrolled can result in metabolic disturbances such as hyperglycaemia and insulin resistance. The management of metabolic syndrome as well as  type II diabetes, therefore should take into account the existence of these conditions: free radical production, hyperglycemia and insulin resistance. Irvingia wombolu (IW) has been previously shown to have antioxidant and antihyperglycemic potential in streptozotocin induced diabetic rats. This study was conducted to establish the preventive effect of the aqueous pulp extracts (APE) and hydroethanolic peel extracts (HPE) of IW on a high fat-high fructose (HFHF) diet induced insulin resistance in rats. Chemical analysis and antioxidant capacity of the extracts were determined. The animals were divided randomly into four groups of five rats each; the control group (C), those receiving only HFHF diet; rats receiving HFHF diet + APE and the group receiving HFHF + HPE. After an experimentation period that lasted six weeks, fasting blood glucose levels, triglycerides and total cholesterol concentrations, body and liver weight were measured. A protective effect of extracts during induction of insulin resistance by diet was notified by less increase of: fasting plasma glucose and triglycerides, post-prandial glycaemic peak.  Antioxidant status measured by FRAP antioxidant capacity; SOD, catalase, reduced glutathione and the level of reduced protein groups were also ameliorated. These results suggest that early APE and HPE administration to HFHF fed rats could prevent diabetes complications and modulate insulin resistance.