Newbouldia laevis improved glucose and fat homeostasis in a TYPE-2 diabesity mice model

Abstract

Newbouldia laevis (P. Beauv) has a long-standing ethnomedicinal use in the management of diabetes mellitus. However, no scientific evidence has established its potentials in the management of obesity dependent diabetes. This study aimed at filling the gap in knowledge about the antidiabetic activity of the leaf extract of N. laevis in a type-2 diabesity mice model. The ethanol leaf extract was subjected to liquid-liquid partitioning successively with n-hexane, ethyl acetate and butanol to obtain respective fractions soluble in these solvents. The butanol (most active) fraction at 302 and 604mg/kg was further tested on high-fat diet STZ-NAD induced type-2 diabetic mice for 10 weeks with glibenclamide (10mg/kg) and pioglitazone (30mg/kg) as standards. The effect on food intake, body weight, fasting blood glucose, oral glucose tolerance test (OGTT), oral fat tolerance test (OFTT), insulin secretion, insulin resistance and lipid profile were determined prior to treatment, mid-way and at the end of 10 weeks treatment. Higher food consumption was recorded in diabetic (D) animals on high-fat diet (HFD) compared to the normal diet (ND)-fed groups. Treatment of these diabetic mice on HFD with 604mg/kg of butanol fraction produced significant (p<0.05) reduction in body weights of these animals from the 2nd week to the 9th week. Ten weeks treatment with butanol fraction achieved a marked decrease in blood glucose and also an increase in fat clearance. Just like pioglitazone, treatment with butanol fraction at both 302 and 604mg/kg doses produced significant (p<0.05) decrease in HFD mediated elevation of serum insulin and a non-significant (p>0.05) increase in STZ-NAD mediated depletion of serum insulin. Butanol fraction at 604mg/kg also produced reduction in insulin resistance as indicated by significant (p<0.05) decrease in HOMA-IR value on the 5th and 10th week just like pioglitazone (30mg/kg). N. laevis exhibited wide actions in the regulation of glucose and fat homeostasis making it a potential novel agent for the management of diabetes, obesity and their likely associated complications.