Novel antioxidant quinoxaline derivative: Synthesis, crystal structure, theoretical studies, antidiabetic activity and molecular docking study

New quinoxaline derivative, N-(4-methyl-2-nitrophenyl)-2-(3-methyl-2-oxoquinoxalin-1(2H)-yl)acetamide (NPOQA) has been synthesized and characterized by IR, H-1 &C-13 NMR, ESI-MS and single crystal X-ray diffraction analysis using experimental and theoretical methods. The thermodynamic quantities and quantum chemical parameters were predicted by using B3LYP/6-311G** level to investigate the physical and electronic properties of the compound. Frontier Molecular Orbital FMO and Natural Bond Orbital NBO analyses of the compound were performed to enligten the possible rectivity trend and intramolecular interactions contibuted to the decreasing of the stabilization. In addition, the newly synthesized compound was evaluated for its in vitro antidiabetic activity against alpha-glucosidase and alpha-amylase enzymes and for antioxidant activity by utilizing several tests as DPPH (1, 1-diphenyl-2-picryl hydrazyl), ABTS (2, 2'-azino-bis(3-ethyl benzthiazoline-6-sulfonicacid), reducing power test (FRAP) and Hydrogen Peroxide Activity H2O2. Finally, Molecular docking studies were performed to investigate the binding mode between the quinoxaline derivative NPOQA and alpha-glucosidase and alpha-amylase. Docking calculations showed an important binding affinity as compared to standard drug acarbose, -6.5 and -6.9 kcal/mol successively for alpha-glucosidase and alpha-amylase, which are in agreement with the results of in vitro studies. (C) 2021 Published by Elsevier B.V.

Automated summary

In this study, a new quinoxaline derivative NPOQA was synthesized and characterized by various spectroscopic and analytical techniques, and its physical and electronic properties were investigated. The compound showed promising in vitro antidiabetic and antioxidant activities, with binding affinities to alpha-glucosidase and alpha-amylase comparable to the standard drug acarbose.