Preliminary phytochemical screening, antioxidant and antihyperglycaemic activity of Moringa oleifera leaf extracts

Moringa oleifera plant has been widely used for a vast number of folkloric medicinal purposes. The research aimed to investigate the antioxidant and antihyperglycaemic activity of Moringa oleifera leaf extracts obtained using different solvent systems for extraction. The solvent extracts of Moringa oleifera were: water extract (100% MoWE), 50% Methanolic extract (50% MoME), 100% Methanolic extract (100% MoME), 50% Ethanolic extract (50% MoEE), and 100% Ethanolic extract (100% MoEE). The in vitro antioxidant activity was evaluated by the use of the 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging assay which showed the hydro-alcoholic extracts to have the highest reducing power, though lower than that of the standard, vitamin C. The hypoglyceamic activity was evaluated for the extracts at graded doses of 200mg/kg, 300mg/kg and 400mg/kg in wistar rats. Relative to the positive control, all treatment groups showed a significant statistical decrease in blood glucose levels. The decrease trends as metformin (84.14%) >50% MoEE 300mg/kg (83.72%) >MoWE 300mg/kg (82.42%) > 50% MoEE 200mg/kg (82.32%) >100% MoEE 400mg/kg (81.96%) >50% MoME (80.69%) >100% MoME 300mg/kg (78.47%) >50% MoME 200mg/kg (66.34%). Overall, the 50% MoEE at a dose of 300mg/kg showed superior antioxidant properties, weight restorative and pronounced hypoglyceamic effects. The weight restorative effect of high dose alcoholic extract of Moringa oleifera was also observed in the study. This study establishes novel and foundational considerations for further isolation and characterization studies for the hypoglyceamic compounds in the plant.