Synthesis and Enzymological Characterization of Some 2-(Substitutedphenylamino) quinazolin-4(3H)-one Derivatives as Potent α-Glucosidase Inhibitors In Vitro

Background: α-Glucosidase is an important hydrolytic enzyme playing a vital role in digestion of carbohydrates. It catalyzes the final step of carbohydrates digestion in biological systems and converts unabsorbed oligosaccharides and disaccharides into monosaccharides, thus resulting in hyperglycemia for diabetic patients. In this respect, it has been considered as a therapeutic target for the treatment of type 2 diabetes since the enzyme inhibition delays carbohydrate digestion and monosaccharide absorption and subsequently reduces postprandial plasma glucose levels. Objective: In this study, fourteen 2-(substitutedphenylamino)quinazolin-4(3H)-one derivatives were synthesized and evaluated for their α-glucosidase inhibitory activities. Methods: The structures of the synthesized compounds were confirmed by spectral and elemental analyses. The biological activity and enzyme inhibition kinetic studies were performed by spectrophotometrical method using microplate reader. Physicochemical and drug-likeness properties of selected compounds were predicted by in silico method. Results: The biological activity results revealed that all of the synthesized compounds showed more potent α-glucosidase inhibitory activity in the range of IC50 = 58 ± 2 - 375 ± 15 μM when compared to the standard drug acarbose (IC50 = 892 ± 7 μM). Among the tested compounds, compound 12 bearing chlorine substituent at ortho position on N-phenyl ring displayed the highest inhibition with an IC50 value of 58 ± 2 μM against α-glucosidase. Furthermore, the enzyme inhibition kinetic study of the most active compound 12 indicated that the compound inhibited the α-glucosidase enzyme as uncompetitive with a Ki value of 63.46 μM. On the other hand, physicochemical and drug-likeness properties of selected compounds were predicted by in silico method. According to the results, it can be speculated that synthesized 2-phenylaminoquinazolin-4(3H)-one derivatives possessed favorable drug-likeness and pharmacokinetic profiles. Conclusion: In the light of results, 2-(substitutedphenylamino)quinazolin-4(3H)-one derivatives may serve as lead compounds to develop novel α-glucosidase inhibitors.