Abstract
The onset of insulin resistant diabetes has been associated with a high-sucrose diet in vertebrates and invertebrates. However, various parts of Spondias mombin reportedly possess antidiabetic potential. However, the antidiabetic efficacy of S. mombin stem bark in high-sucrose diet-induced Drosophila melanogaster model has not been explored. In this study, the antidiabetic and antioxidant effects of the solvent fractions of S. mombin stem bark were evaluated using in vitro, in vivo, and in silico methods. Successive fractionation of S. mombin stem bark ethanol extract was performed; the resulting fractions were subjected to in vitro antioxidant and antidiabetic assays using standard protocols. The active compounds identified from the high-performance liquid chromatography (HPLC) study of the n-butanol fraction were docked against the active site of Drosophila α-amylase using AutoDoc Vina. The n-butanol and ethyl acetate fractions of the plant were incorporated into the diet of diabetic and nondiabetic flies to study the in vivo antidiabetic and antioxidant properties. The results obtained revealed that n-butanol and ethyl acetate fractions had the highest in vitro anti-oxidant capacity by inhibiting 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power, and hydroxyl radical followed by significant inhibition of α-amylase. HPLC analysis revealed the identification of eight compounds with quercetin having the highest peak followed by rutin, rhamnetin, chlorogenic acid, zeinoxanthin, lutin, isoquercetin, and rutinose showing the lowest peak. The fractions restored the glucose and antioxidant imbalance in diabetic flies, which is comparable with the standard drug (metformin). The fractions were also able to upregulate the mRNA expression of insulin-like peptide 2, insulin receptor, and ecdysone-inducible gene 2 in diabetic flies. The in silico studies revealed the inhibitory potential of active compounds against α-amylase with isoquercetin, rhamnetin, rutin, quercetin, and chlorogenic acid having higher binding affinity than the standard drug (acarbose). Overall, the butanol and ethyl acetate fractions of S. mombin stem bark ameliorate type 2 diabetes in Drosophila. However, further studies are needed in other animal models to confirm the antidiabetes effect of the plant.
