Discovery of potent α-glucosidase inhibitors through structure-based virtual screening of an in-house azole collection

Alpha-Glucosidase Inhibitory Effects of Flavonoids, Phenolic Acids and Iridoids Isolated From Vinca Soneri: In Vitro and In Silico Perspectives

Various Vinca species have been traditionally used for their antihypertensive, sedative, and hemostatic properties, as well as for treating diabetes. In this study, some flavonoids, phenolic acids and iridoids were isolated from an endemic Vinca species, Vinca soneri for the first time. α-Glucosidase inhibitory effects of the isolates were tested and kaempferol-3-O-α-rhamnopyranosyl (1→6) β-galactopyranoside (1) was found to be the most active one with an IC50 value of 285.73 ±7.35 μM. Enzyme kinetic assay revealed that it inhibited α-glucosidase in competitive manner. Molecular geometry of 1 was predicted and Frontier molecular orbital analysis was performed using Density Functional Theory (DFT) calculations. Molecular docking and MM-GBSA calculations predicted good fit for 1 in the enzyme active site and key interactions with the catalytic residues. As a result, current study identifies 1 as a promising competitive α-glucosidase inhibitor to be developed as a potential antidiabetic drug candidate.

Coumarin linked thiazole derivatives as potential α-glucosidase inhibitors to treat diabetes mellitus

Diabetes is a leading cause of kidney failure, blindness, heart attacks and lower limb amputation. Prevalence of diabetes is rising globally. α-glucosidase is validated target for controlling hyperglycemia because of its role in catalysing hydrolysis of carbohydrates to glucose in GIT. In an attempt to find novel safe and effective α-glucosidase inhibitors, coumarin linked thiazole was identified as potential scaffold on the basis of its interactions with the active site of α-glucosidase studied in silico. A series of coumarin linked thiazole derivatives were synthesized and analyzed for α-glucosidase inhibitory potential in an in-vitro assay. The synthesized molecules showed potent inhibition of α-glucosidase with IC50 values ranging from 0.14 to 9.38 μM. The most potent compound 2-[(4-bromophenyl) amino)-N-(4- (2-oxo-2H-chromen-3-yl) thiazol-2-yl] acetamide was further docked with α-glucosidase and molecular dynamics studies were carried out for 100 ns which suggested the stability of protein and ligand in the protein active site over the simulation period and role of hydrophobic interactions slightly more than the electrostatic/polar interactions in ligand- receptor stability. In summary, our results demonstrate efficacy of coumarin-linked thiazole as potential leads for further optimization and development.

Effective α-glycosidase inhibitors based on polyphenolic benzothiazole heterocycles

α-Glycosidase inhibition is one of the main approaches to treat Diabetes mellitus. Polyphenolic moieties are known to be responsible for yielding exhibit potent α-glycosidase inhibitory effects. In addition, compounds containing benzothiazole and Schiff base functionalities were previously reported to show α-glycosidase inhibition. In this paper, the synthesis of seven new phloroglucinol-containing benzothiazole Schiff base derivatives through the reaction of 6-substituted-2-aminobenzothiazole compounds with 2,4,6-trihydroxybenzaldehyde using acetic acid as a catalyst was reported. The synthesized compounds were characterized using spectroscopic methods such as FT-IR, 1H NMR, 13C NMR, and elemental analysis. The synthesized compounds were evaluated for their inhibitory effects on α-glycosidase, compounds 3f and 3g were found to show significant inhibitory properties when compared to the positive control. The IC50 values of 3f and 3g were calculated as 24.05 ± 2.28 and 18.51 ± 1.19 µM, respectively. Kinetic studies revealed that compounds 3f and 3g exhibited uncompetitive mode of inhibition against α-glycosidase. Molecular modeling predicted druglikeness for the title compounds and underpinned the importance of phloroglucinol hydroxyls for interacting with the key residues of α-glycosidase.

Design, synthesis, and in silico studies of quinoline-based-benzo[d]imidazole bearing different acetamide derivatives as potent α-glucosidase inhibitors

In this study, 18 novel quinoline-based-benzo[d]imidazole derivatives were synthesized and screened for their α-glucosidase inhibitory potential. All compounds in the series except 9q showed a significant α-glucosidase inhibition with IC₅₀ values in the range of 3.2 ± 0.3–185.0 ± 0.3 µM, as compared to the standard drug acarbose (IC₅₀ = 750.0 ± 5.0 µM). A kinetic study indicated that compound 9d as the most potent derivative against α-glucosidase was a competitive type inhibitor. Furthermore, the molecular docking study revealed the effective binding interactions of 9d with the active site of the α-glucosidase enzyme. The results indicate that the designed compounds have the potential to be further studied as new anti-diabetic agents.

Antifungal Azole Derivatives Featuring Naphthalene Prove Potent and Competitive Cholinesterase Inhibitors with Potential CNS Penetration According to the in Vitro and in Silico Studies

Cholinesterase inhibition is of great importance in the fight against neurodegenerative disorders such as Alzheimer's disease. Azole antifungals have come under the spotlight with recent discoveries that underline the efficacy and potential of miconazole and its derivatives against cholinesterase enzymes. In this study, we evaluated a library of azoles against acetylcholinesterase and butyrylcholinesterase using in vitro and in silico methods to identify potent inhibitors. Low micromolar IC₅₀ values were obtained for imidazole derivatives, which were further tested and found potent competitive cholinesterase inhibitors via enzyme kinetics study. The active derivatives showed negligible toxicity in in vitro cytotoxicity tests. Molecular modeling studies predicted that these derivatives were druglike, could penetrate blood-brain barrier, and tightly bind to cholinesterase active site making key interactions via the imidazole moiety at protonated state. Thus, current study identifies potent and competitive cholinesterase inhibitor azoles with minor toxicity and potential to pass into the central nervous system.

One-pot multi-component synthesis of novel chromeno[4,3-b]pyrrol-3-yl derivatives as alpha-glucosidase inhibitors

A green and efficient one-pot multi-component protocol was developed for the synthesis of some novel dihydrochromeno[4,3-b]pyrrol-3-yl derivatives through the reaction of arylglyoxals, malono derivatives, and different 4-amino coumarins in ethanol at reflux condition. In this method, all products were obtained in good to excellent yield. Next, all synthesized derivatives were evaluated for their α-glucosidase inhibitory activity. Most of the compounds displayed potent inhibitory activities with IC₅₀ values in the range of 48.65 ± 0.01–733.83 ± 0.10 μM compared to the standard inhibitor acarbose (IC₅₀ = 750.90 ± 0.14 μM). The kinetic study of compound 5e as the most potent derivative (IC₅₀ = 48.65 ± 0.01 μM) showed a competitive mechanism with a K_i value of 42.6 µM. Moreover, docking studies revealed that dihydrochromeno[4,3-b]pyrrol-3-yl effectively interacted with important residues in the active site of α-glucosidase.

Design and synthesis of phenoxymethybenzoimidazole incorporating different aryl thiazole-triazole acetamide derivatives as α-glycosidase inhibitors

A novel series of phenoxymethybenzoimidazole derivatives (9a-n) were rationally designed, synthesized, and evaluated for their α-glycosidase inhibitory activity. All tested compounds displayed promising α-glycosidase inhibitory potential with IC₅₀ values in the range of 6.31 to 49.89 μM compared to standard drug acarbose (IC₅₀ = 750.0 ± 10.0 μM). Enzyme kinetic studies on 9c, 9g, and 9m as the most potent compounds revealed that these compounds were uncompetitive inhibitors into α-glycosidase. Docking studies confirmed the important role of benzoimidazole and triazole rings of the synthesized compounds to fit properly into the α-glycosidase active site. This study showed that this scaffold can be considered as a highly potent α-glycosidase inhibitor.