Antioxidative Properties of Blighia sapida K.D. Koenig Stem Bark Extract and Inhibitory Effects on Carbohydrate Hydrolyzing Enzymes Associated with Non-Insulin Dependent Diabetes Mellitus

Background and Aim: In Africa, the fruit, seed, leaf, and stem of Blighia sapida K.D. Koenig are used as remedy for a range of diseases. This study characterized the phytochemicals, assessed the antioxidant and inhibitory properties of the stem bark of Blighia sapida. Materials and Methods: Samples were consecutively extracted using ethanol solvent and investigated for phenol content, DPPH radical scavenging abilities, iron chelation, reducing power, α-amylase and α-glucosidase activities as markers of in vitro anti-diabetic activities. Phytochemicals were analyzed using gas chromatography-mass spectrometry (GC-MS) analysis. Results: The extract had radical scavenging capabilities, iron chelation and reducing power. Furthermore, the results reveal the extract had considerably high α-glucosidase and α- amylase inhibitory activities as the concentration increases with IC₅₀ values of 4.17 ± 0.24 mg/mL and 5.30 ± 1.25 mg/mL, respectively. Enzyme kinetic studies indicated that the extract displayed uncompetitive inhibitor for α-glucosidase and was a competitive inhibitor of α-amylase. The ethanolic extract is rich in several aromatic phenolic compounds and long chain aliphatic acids. Conclusion: These results reveal the bark possessed antioxidant as well as α -glucosidase and α -amylase inhibitory activities.