Phytochemical screening and evaluation for the antioxidant and hypoglycemic effects of Diospyros malabarica (Desr.) Kostel root bark extracts

Oxidative stress can trigger many diseases, including diabetes. This study investigated the phytochemical composition, antioxidant, and anti-diabetic activity of crude extracts of Diospyros malabarica root bark. Phytochemical analysis revealed saponins, tannins, glycosides, steroids, alkaloids, phenols, and flavonoids as major phytochemicals in the extracts. Antioxidant potentials of extracts were measured using in vitro total phenolic content, total flavonoid content, DPPH radical scavenging, and ferric reducing power assays. The anti-diabetic potential was measured by in vitro α-amylase inhibitory and in vivo oral glucose tolerance tests in mice. Findings suggest that hydroalcoholic extract (CHE) possessed a higher amount of phenolic and flavonoid contents together with substantial DPPH radical scavenging and ferric reducing capacity compared to other fractions. It also showed 29.59 ± 2.04 % of α-amylase inhibitory capacity at 2 mg/mL and reduced blood glucose by 59.04 ± 1.67 % at 120 minutes. In all cases, CHE exhibited better activities than the petroleum ether fraction (PEF), chloroform fraction (CHF), ethyl acetate fraction (EAF), and aqueous fraction (AQF) of the plant. Taken together, Diospyros malabarica root bark might be a good source of antioxidant and anti-diabetic phytoconstituents and may be useful for reducing oxidative stress and relevant complications, for example, diabetes.