Spectroscopic, molecular docking and structural activity studies of (E)-N′-(substituted benzylidene/methylene) isonicotinohydrazide derivatives for DNA binding and their biological screening

Discovery of N-(phenylsulfonyl)thiazole-2-carboxamides as potent α-glucosidase inhibitors

In a search for novel nonsugar α-glucosidase inhibitors for diabetes treatment, a series of N-(phenylsulfonyl)thiazole-2-carboxamide derivatives were designed and synthesized, the α-glucosidase inhibitory activities were then evaluated. Several compounds with promising α-glucosidase inhibitory effects were identified. Among these, compound W24 which shows low cytotoxicity and good α-glucosidase inhibitory activity with an IC50 value of 53.0 ± 7.7 μM, is more competitive compared with the commercially available drug acarbose (IC50  = 228.3 ± 9.2 μM). W24 was identified as a promising candidate in the development of α-glucosidase inhibitors. Molecular docking studies and molecular dynamics simulation were also performed to reveal the binding pattern of the active compound to α-glucosidase, and the binding free energy of the best compound W24 was 36.3403 ± 3.91 kcal/mol.

Novel Coumarin Derivatives as Potential Urease Inhibitors for Kidney Stone Prevention and Antiulcer Therapy: From Synthesis to In Vivo Evaluation

The presence of ammonium ions in urine, along with basic pH in the presence of urease-producing bacteria, promotes the production of struvite stones. This causes renal malfunction, which is manifested by symptoms such as fever, nausea, vomiting, and blood in the urine. The involvement of urease in stone formation makes it a good target for finding urease enzyme inhibitors, which have the potential to be developed as lead drugs against kidney stones in the future. The documented ethnopharmacology of coumarin 2-one against bacterial, fungal and viral strains encouraged us to synthesize new derivatives of coumarins by reacting aromatic aldehydes with 4-aminocoumarin. The synthesized compounds (2a to 11a) were evaluated for their antimicrobial, in vitro, and in silico properties against the urease enzyme. The study also covers in vivo determination of the synthesized compounds with respect to different types of induced ulcers. The molecular docking study along with extended MD simulations (100 ns each) and MMPBSA study confirmed the potential inhibitory candidates as evident from computed ∆Gbind (3a = -11.62 and 5a = -12.08 Kcal/mol) against the urease enzyme. The in silico analyses were augmented by an enzymatic assay, which revealed that compounds 3a and 5a had strong inhibitory action, with IC50 of 0.412 µM (64.0% inhibition) and 0.322 µM (77.7% inhibition), respectively, compared to standard (Thiourea) with 82% inhibition at 0.14 µM. Moreover, the most active compound, 5a, was further tested in vivo for antiulcer activity by different types of induced ulcers, including pyloric ligation-, ethanol-, aspirin-, and histamine-induced ulcers. Compound 5a effectively reduced gastric acidity, lipid peroxidation, and ulceration in a rat model while also inhibiting gastric ATPase activity, which makes it a promising candidate for ulcer treatment. As a result of the current research, 3a and 5a may be used as new molecules for developing potent urease inhibitors. Additionally, the compound 3a showed antibacterial activity against Staphylococcus aureus and Salmonella typhimurium, with zones of inhibition of 41 ± 0.9 mm and 35 ± 0.9 mm, respectively. Compound 7a showed antibacterial activity against Staphylococcus aureus and Salmonella typhimurium, with zones of inhibition of 30 ± 0.8 mm and 42 ± 0.8 mm, respectively. These results prove that the synthesized compounds also possess good antibacterial potential against Gram-positive and Gram-negative bacterial strains.

Novel C-2 Symmetric Molecules as α-Glucosidase and α-Amylase Inhibitors: Design, Synthesis, Kinetic Evaluation, Molecular Docking and Pharmacokinetics

A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a–5h, have been synthesized, characterized by ¹H-NMR and ¹³C-NMR, and evaluated for their in vitro α-glucosidase and α-amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both α-glucosidase and α-amylase. The IC₅₀ of 5g against α-glucosidase was 0.35917 ± 0.0189 µM (standard acarbose IC₅₀ = 6.109 ± 0.329 µM), and the IC₅₀ value of 5g against α-amylase was 0.4379 ± 0.0423 µM (standard acarbose IC₅₀ = 33.178 ± 2.392 µM). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of α-glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 Å, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results

Synthesis, Crystal Structure, Hirshfeld Surface Analysis, DFT, and DNA-Binding Studies of (E)-2-(3-Hydroxy-4-Methoxybenzylidene)Hydrazinecarbothioamide

(E)-2-(3-Hydroxy-4-methoxybenzylidene)hydrazinecarbothioamide 3 was synthesized by reacting thiosemicarbazide with 2-hydorxy-3-methoxybenzaldehyde in dry ethanol. The structure was elucidated by spectroscopic (FT-IR, ¹H NMR, and ¹³C NMR) and single crystal X-ray diffraction techniques. A detailed analysis of the intermolecular interactions has been performed based on the Hirshfeld surfaces and their associated two-dimensional fingerprint plots. DFT, spectroscopic, and electrochemical DNA-binding analysis confirmed that the compound is reactive to bind with DNA. Viscometric studies suggested that compound 3 has a mixed mode of interaction and intercalated into the DNA base pairs predominantly along with the possibility of electrostatic interactions. Graphical Abstract.

Electrochemical, spectroscopic and theoretical monitoring of anthracyclines' interactions with DNA and ascorbic acid by adopting two routes: Cancer cell line studies

Pharmacodynamic interactions of three anthracycline antibiotics namely doxorubicin (DXH), epirubicin (EpiDXH) and daunorubicin (DNR) with DNA in the absence and presence of ascorbic acid (AA) as natural additive were monitored under physiological conditions (pH = 7.4, 4.7 and T = 309.5K). Route–1 (Anthracycline–AA–DNA) and Route–2 (Anthracycline–DNA–AA) were adopted to see the interactional behavior by cyclic voltammetry (CV) and UV-visible spectroscopy. In comparison to Route–2; voltammetric and spectral responses as well as binding constant (K_b) and Gibb’s free energy change (ΔG) values revealed strongest and more favorable interaction of anthracycline–AA complex with DNA via Route–1. K_b, s (binding site sizes) and ΔG evaluated from experimental (CV, UV-Vis) and theoretical (molecular docking) findings showed enhanced binding strength of tertiary complexes as compared to binary drug–DNA complexes. The results were found comparatively better at pH 7.4. Consistency was observed in binding parameters evaluated from experimental and theoretical techniques. Diffusion coefficients (D_o) and heterogeneous electron transfer rate constant (k_s,h) confirmed the formation of complexes via slow diffusion kinetics. Percent cell inhibition (%C_inh) of anthracyclines for non-small cell cancer cell lines (NSCCLs) H-1299 and H-157 were evaluated higher in the presence of AA which further complimented experimental and theoretical results.

Synthesis of novel (E)-1-(2-(2-(4(dimethylamino) benzylidene) hydrazinyl)-4-methylthiazol-5-yl)ethanone derivatives as ecto-5'-nucleotidase inhibitors

Ecto-5'-nucleotidase (e5'NT), a membrane-bound enzyme and an essential member of ecto-nucleotidases which regulates extracellular purinergic signalling. Their upregulation results in various disease conditions, for example, inflammation, hypoxia and cancer. Therefore, efforts have been made to synthesize potent and selective inhibitors of e5'NT. Here we have synthesized, characterized and evaluated six thiazole derivatives (3a-3f) as potent e5'NT inhibitors. Among all derivatives, the compound (E)-1-(4-methyl-2-(2-(pyridin-3-ylmethylene)hydrazinyl) thiazol-5-yl)ethanone (3a) exhibited maximum inhibition towards both human and rat enzymes. However, their potency against h-e5'NT was 24-fold higher than r-e5'NT. Only two compounds exhibited inhibitory behaviour towards r-e5'NT. The molecular structures of these derivatives were confirmed with the help of solid-state characterization through NMR (¹H and ¹³C), FTIR and elemental analysis. Additionally, molecular docking was also implemented to explain putative bonding interaction between the active site of an enzyme and potent inhibitors.

Sulfonamide-Linked Ciprofloxacin, Sulfadiazine and Amantadine Derivatives as a Novel Class of Inhibitors of Jack Bean Urease; Synthesis, Kinetic Mechanism and Molecular Docking

Sulfonamide derivatives serve as an important building blocks in the drug design discovery and development (4D) process. Ciprofloxacin-, sulfadiazine- and amantadine-based sulfonamides were synthesized as potent inhibitors of jack bean urease and free radical scavengers. Molecular diversity was explored and electronic factors were also examined. All 24 synthesized compounds exhibited excellent potential against urease enzyme. Compound 3e (IC₅₀ = 0.081 ± 0.003 µM), 6a (IC₅₀ = 0.0022 ± 0.0002 µM), 9e (IC₅₀ = 0.0250 ± 0.0007 µM) and 12d (IC₅₀ = 0.0266 ± 0.0021 µM) were found to be the lead compounds compared to standard (thiourea, IC₅₀ = 17.814 ± 0.096 µM). Molecular docking studies were performed to delineate the binding affinity of the molecules and a kinetic mechanism of enzyme inhibition was propounded. Compounds 3e, 6a and 12d exhibited a mixed type of inhibition, while derivative 9e revealed a non-competitive mode of inhibition. Compounds 12a, 12b, 12d, 12e and 12f showed excellent radical scavenging potency in comparison to the reference drug vitamin C.

Design and synthesis of 2,6-di(substituted phenyl)thiazolo[3,2-b]-1,2,4-triazoles as α-glucosidase and α-amylase inhibitors, co-relative Pharmacokinetics and 3D QSAR and risk analysis

Ten fused heterocyclic derivatives bearing the 2,6-di(subsituted phenyl)thiazolo[3,2-b]-1,2,4-triazoles as central rings were synthesized and structures of the compounds were established by analytical and spectral data using FTIR, EI-MS, ¹H NMR and ¹³C NMR techniques. In vitro inhibitory activities of synthesized compounds on α-amylase, α-glucosidase and α-burylcholinesterase (α-BuChE) were evaluated using a purified enzyme assays. Compound 5c demonstrated strong and selective α-amylase inhibitory activity (IC₅₀=1.1μmol/g). 5g exhibited excellent inhibition against α-glucosidase (IC₅₀=1.2μmol/g) when compared with acarbose (IC₅₀=4.7μmol/g) as a positive reference. Compound 5i was found to be most potent derivative against α-BuChE with the IC₅₀ of 1.5μmol/g which was comparable to the value obtained for (4.7μmol/g) positive control (i.e. galantamine hydrobromide). Molecular dockings of synthesized compounds into the binding sites of human pancreatic α-amylase, intestinal maltase-glucoamylase and neuronal α-butrylcholinesterase allowed to shed light on the affinity and binding mode of these novel inhibitors. Preliminary structure-activity relationship (SAR) studies were carried out to understand the relationship between molecular structural features and inhibition activities of synthesized derivatives. These data suggested that compounds 5c, 5g and 5i are promising candidates for hitto- lead follow-up in the drug-discovery process for the treatment of Alzheimer's disease and hyperinsulinamia.