Diabetes mellitus (DM) is a chronic disorder and has affected a large number of people worldwide. Insufficient insulin production causes an increase in blood glucose level that results in DM. To lower the blood glucose level, various drugs are employed that block the activity of the α-glucosidase enzyme, which is considered responsible for the breakdown of polysaccharides into monosaccharides leading to an increase in the intestinal blood glucose level. We have synthesized novel 2-(3-(benzoyl/4-bromobenzoyl)-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)-N-arylacetamides and have screened them for their in silico and in vitro α-glucosidase inhibition activity. The derivatives 11c, 12a, 12d, 12e, and 12g emerged as potent inhibitors of the α-glucosidase enzyme. These compounds exhibited good docking scores and excellent binding interactions with the selected residues (Asp203, Asp542, Asp327, His600, Arg526) during in silico screening. Similarly, these compounds also showed good in vitro α-glucosidase inhibitions with IC50 values of 30.65, 18.25, 20.76, 35.14, and 24.24 μM, respectively, which were better than the standard drug, acarbose (IC50 = 58.8 μM). Furthermore, a good agreement was observed between in silico and in vitro modes of study.
Three series of 4-hydroxy-N'-[benzylidene/1-phenylethylidene]-2-H/methyl/benzyl-1,2-benzothiazine-3-carbohydrazide 1,1-dioxides (9-11)a-l were synthesized and unraveled to be highly potent dual inhibitors of monoamine oxidases (MAO-A and MAO-B). All the examined compounds demonstrated IC50 values in lower micro-molar range for both MAO-A as well as MAO-B. The most active MAO-A inhibitor was 4-hydroxy-N'-(1-phenylethylidene)-2H-benzo[e][1,2]thiazine-3-carbohydrazide 1,1-dioxide (9i) with an IC50 value of 0.11 ± 0.005 μM, whereas, methyl 4-hydroxy-2H-benzo[e][1,2]thiazine-3-carboxylate 1,1-dioxide (3) was the most active MAO-B inhibitor with an IC50 value of 0.21 ± 0.01 μM. Enzyme kinetics studies revealed that the most potent compounds inhibited both MAO enzymes (A & B) in a competitive fashion. Molecular docking studies were also performed to obtain an intuitive picture of inhibition potential for potent inhibitors. The high potency of these compounds is optimally combined with highly favorable ADME profile with predicted good oral bioavailability.