Metabolites in Conocarpus erectus leaves attenuate α-amylase activity by modulating amino acid residues of α-amylase: an in vitro and docking study

The antioxidant activity and the inhibitory potential of alpha-amylase of lyophilized hydroethanolic extracts of Conocarpus erectus leaves obtained by ultrasonication were determined. The most potent extract was subjected to ultra-high performance liquid chromatography system equipped with mass spectrometer for metabolite identification. The identified metabolites were docked in alpha-glucosidase to assess their binding mode. The results revealed that 60% ethanolic extract exhibited highest ferric reducing antioxidant power (4.08 +/- 0.187 mg TE/g DE) and alpha-amylase inhibition (IC50 58.20 +/- 1.25 mu g/mL. The metabolites like ellagic acid, 3-0-methyl ellagic acid, ferujol, 5, 2'-dihydroxy-6,7,8-trimethyl flavone and kaempferol glucoside were identified in the extract and subjected to molecular docking studies regarding alpha-amylase inhibition. The comparison of binding affinities revealed 3-O-methyl ellagic acid as most effective inhibitor of alpha-amylase with binding energy of -14.5911 kcal/mol comparable to that of acarbose (-15.7815 kcal/mol). The secondary metabolites identified in the study may be extended further for functional food development with antidiabetic properties.