Evaluation of the anti-diabetic properties of Averrhoa bilimbi in animals with experimental diabetes mellitus

Abstract

Oral glucose tolerance test (OGTT) studies have shown that the ethanolic leaf extract of A.bilimbi (ABe) increased glucose tolerance in streptozotocin (STZ)-induced diabetic Sprague-Dawley (SD) rats. The extract exhibited potent anti-diabetic as well as hypolipidemic activities in these rats when administered per orally at a dose of 125 mg/kg body weight for 2 weeks. Among the semi-purified fractions of ABe, the aqueous fraction (AF) and the butanol fraction (BuF) showed significant improvement in glucose tolerance in both STZ and HFD (high fat diet)-STZ-diabetic rats. Moreover, AF was more potent than BuF in the protection of beta cells against STZ toxicity. Purification of these fractions led to the identification and characterization of active components, nicotinic acid (NA) and magnesium (Mg). Further studies in STZ/HFD-STZ-diabetic rats and STZ/HFD-diabetic C57BL6j mice showed that the administration of both NA and Mg together improved the glucose tolerance significantly than Mg or NA alone. This synergistic interaction of NA and Mg in A. bilimbi extract could be one of the reasons for the amelioration of diabetes in animals.