Evaluation of Antioxidant and Anti-Diabetic Potentials of the Ethyl Acetate Leaf Extracts of some Commonly used Medicinal Plants in Ogbomoso, Nigeria

Medicinal plants are used as alternatives for treating diabetes mellitus and are considered safe when used alone or combined with synthetic drugs to ensure their effectiveness and also reduced the toxic effects of orthodox medicines. Using in-vitro antioxidant and antidiabetic indices, this study evaluated some commonly used medicinal plants for the treatment and management of diabetes mellitus in Ogbomoso. Four commonly used medicinal plants identified include; Croton zambezicus (CZ), Markhamia tomentose (MT), Asphilia africana (AA), and Albizia ferruginea (AF). The ethyl acetate leaf extracts of the plants were prepared using Soxhlet extraction and dried. Total flavonoid content, percentage 1, 1-diphenyl, 2- picrylhydrazyl (DPPH) and hydroxyl radical (OH) scavenging activity, percentage inhibition of lipid peroxidation, as well as alpha amylase and alpha glucosidase activities, were determined using standard international methods. Total flavonoids content quercetin equivalent (QE) of CZ, MT, AA, and AF obtained, are 170 mg/g QE, 20 mg/g QE, 68 mg/g QE, and 16 mg/g QE respectively in this order CZ >AA>MT>AF at maximum concentrations (400 µg/ml). Percentages of DPPH and OH radical scavenging activities of CZ, MT, AA, and AF are (89.6, 40.7%), (22.83, 35.5%), (16.5, 28.6%), and (31.7, 51.3%) at maximum concentration. The extracts also inhibited lipid peroxidation with these values 56%, 69%, 60% and 72 % at maximum concentration (400 µg/ml). Interestingly, CZ, MT, AA, and AF inhibited alpha amylase and alpha glucosidase activities with these values (21.1, 80.0%), (62.2, 70.9%), (64.2, 63.2%) and (10.5, 85.3%) respectively. Properties exhibited by these plants are antioxidant and anti-diabetics which provide scientific basis for their usage in traditional medicine for the treatment and management of diabetes mellitus in Ogbomoso.