Phytochemical profile, antioxidant, alpha-amylase inhibition, binding interaction and docking studies of Justicia carnea bioactive compounds with alpha-amylase

摘要

The present study investigated the antioxidant and in vitro antidiabetic capacities of Justicia carnea aqueous leaf extract (JCAE) using alpha-amylase inhibition model. alpha-Amylase binding-interaction with JCAE was also investigated using fluorescence spectroscopy and molecular docking. Phytochemical screening and Gas Chromatography-Mass Spectrometry (GC-MS) analysis indicated presence of bioactive compounds. Phenolic (132 mg GAE/g) and flavonoid contents (31.08 mg CE/g) were high. JCAE exhibited high antioxidant capacity and effectively inhibited alpha-amylase activity (IC50, 671.43 +/- 1.88 ng/mL), though lesser than acarbose effect (IC50, 108.91 +/- 0.61 ng/mL). alpha-Amylase intrinsic fluorescence was quenched in the presence of JCAE. Ultraviolet-visible and FT-IR spectroscopies affirmed mild changes in a-amylase conformation. Synchronous fluorescence analysis indicated alterations in the microenvironments of tryptophan residues near a-amylase active site. Molecular docking affirmed non-polar interactions of compounds 6 and 7 in JCAE with Asp-197 and Trp-58 residues of a-amylase, respectively. Overall, JCAE indicated potential to prevent postprandial hyperglycemia by slowing down carbohydrate hydrolysis.