Biochemical applications of Kigelia africana (Lam.) Benth. fruit extracts in diabetes mellitus

The use of Kigelia africana plant is beneficial in many medicinal applications. This study investigated the chemical compounds as well as antioxidant and antidiabetic activities of KA fruits in vitro and in vivo. Molecular docking study was used to predict the activities of these metabolites in relation to diabetes mellitus. From the result of GC-TOFMS, phenol-2,4-bis(1,1-dimethylethyl)-, benzene propanoic acid-3,5-bis(1,1-dimethylethyl)-4-hydroxymethylester, naphthalene-2-methyl-, and oxalic acid-4-chlorophenyl nonyl-ester were newly identified and revealed a strong binding affinity of − 6.1, − 6.3, − 6.8, and − 6.2 kcal/mol respectively. The hexane and ethyl acetate fractions had the highest antioxidant activities with 0.14 and 0.025 mg/mL for DPPH; 91.31 and 99.20 mg AAE/g for FRAP; and 80.61 and 98.88 mg AAE/g for TPC, respectively. Hexane fraction (HF) had the lowest IC₅₀ value (1.97 mg/mL) against α-amylase. At low and middle doses, HF showed significant ameliorative activities by restoring islet cells, increasing the number of β cells, and reducing fasting blood glucose levels. Significant differences were observed in the activities of GGT and G-6-PDH. KA fruit exhibited high antidiabetic and antihyperglycemic activities in STZ-induced diabetic rats. According to molecular docking study, the use of the base structure of 2,4-ditert-butylphenol identified from K. africana fruit may serve as the novel approach to the treatment of diabetes mellitus.