1,2,3-Triazoles based 3-substituted 2-thioquinoxalines: Synthesis, anti-bacterial activities, and molecular docking studies

Virtual screening, ADME prediction, drug-likeness, and molecular docking analysis of Fagonia indica chemical constituents against antidiabetic targets

Fagonia indica from Zygophyllaceae family is a medicinal specie with significant antidiabetic potential. The present study aimed to investigate the in vitro antidiabetic activity of Fagonia indica crude extract followed by an in silico screening of its phytoconstituents. For this purpose, crude extract of Fagonia indica was prepared and divided in three different parts, i.e., n-hexane, ethyl acetate, and methanolic fraction. Based on in vitro outcomes, the phytochemical substances of Fagonia indica were virtually screened through a literature survey and a screening library of compounds (1-13) was prepared. The clinical potential of these novel drug candidates was assessed by applying an ADME screening profile. Findings of SwissADME indicators (Absorption, Distribution, Metabolism, and Excretion) for the compounds (1-13) presented relatively optimal physicochemical characteristics, drug-likeness, and medicinal chemistry. The antidiabetic action of these leading drug candidates was optimized through molecular docking analysis against 3 different human pancreatic α-amylase macromolecular targets with (PDB ID 1B2Y), (PDB ID 3BAJ), and (PDB ID: 3OLI) by applying Virtual Docker (Molegro MVD). Metformin was taken as a reference standard for the sake of comparison. In vitro antidiabetic evaluation gave good results with promising α-amylase inhibitory action in the form of IC50 values, as for n-hexane extract = 206.3 µM, ethyl acetate = 41.64 µM, and methanolic extract = 9.61 µM. According to in silico outcomes, all 13 phytoconstituents possess the best binding affinity with successful MolDock scores ranging from - 97.2003 to - 65.6877 kcal/mol and show a great number of binding interactions than native drug metformin. Therefore, the current work concluded that the diabetic inhibition prospective of extract and the compounds of Fagonia indica may contribute to being investigated as a new class of antidiabetic drug or drug-like candidate for further studies.

One-pot synthesis of polyhydroquinoline-1,2,3-triazole hybrids in deep eutectic solvent as anti-leishmanial agents and molecular modeling studies

The novel hybrids with 1,2,3-triazole and polyhydroquinoline scaffolds were successfully synthesized by multicomponent reaction of propargyloxybenzaldehyde, 1,3-cyclohexadione, ethylacetoacetate and ammonium acetate followed through click reaction in the presence of deep eutectic solvent ChCl/ZnCl2 as an efficient catalyst. Their anti-leishmanial activity was evaluated against amastigote and promastigote forms of L. tropica, L. major, and two different species of L. infantum. Furthermore, to determine the cytotoxicity of the hybrids, they were evaluated against the murine macrophage cell line J774.A1. Based on the results, three hybrids showed the highest antileishmanial activity. However, they revealed low cytotoxicity. Hybrid 6j was the most potent compound against both the forms of all leishmanial types, with IC50 = 13.5 and 11.9 µg/mL for L. major, 37.5 and 25 µg/mL for L. tropica, 17.5 and 20 µg/mL for L. infantum (MCAN/IR//96/LON49) and 35.5 and 30 µg/mL for L. infantum (MCAN/ES/98/LIM-877), respectively. Finally, molecular docking and molecular dynamics simulations were also performed to identify possible mechanism antileishmanial activity.Communicated by Ramaswamy H. Sarma.

Synthesis, biological assessment, and computational investigations of nifedipine and monastrol analogues as anti-leishmanial major and anti-microbial agents

Leishmaniasis includes a range of parasitic diseases caused by numerous types of the protozoan kinetoplastid parasite. Fungal and bacterial pathogens have led to infectious illnesses causing some main public health problem in current years. A series of dihydropyridine and tetrahydropyrimidine derivatives having fluoro, bromo, and nitro substituents at para-phenyl ring on C4 of dihydropyridine and tetrahydropyrimidine rings were synthesized. Then, anti-leishmanial and antimicrobial potencies of compounds were assessed. All compounds were synthesized via Hantzsch and Biginelli reactions. All derivatives were evaluated for their anti-leishmanial and antimicrobial activities. Moreover, docking and molecular dynamics simulation calculations of the compounds in PRT1 binding site were performed to report the results of anti-leishmanial and antimicrobial activities. Compounds 4a and 4b showed the highest anti-amastigote and anti-promastigote activities. Compound 4a revealed the highest antimicrobial activity against E. coli, P. aeruginosa, and C. albicans strains. In addition, compound 4c showed the highest activity against S. aureus. The fluoro, bromo, and nitro substituents in para-position of phenyl group at C4 of dihydropyridine and tetrahydropyrimidine moieties as well as the bulk and length of the chain linking to the ester moieties are essential for anti-leishmanial and anti-microbial activities of these derivatives. Low cytotoxicity was shown by most of derivatives against macrophages. The molecular docking studies were in agreement with in vitro assay. Moreover, hydrogen binds, RMSF, RMSD, and Rg, strongly showed the steady binding of 4a and 4b compounds in PRT1 active site.

Synthesis of Tetracyclic Spirooxindolepyrrolidine-Engrafted Hydantoin Scaffolds: Crystallographic Analysis, Molecular Docking Studies and Evaluation of Their Antimicrobial, Anti-Inflammatory and Analgesic Activities

In a sustained search for novel potential drug candidates with multispectrum therapeutic application, a series of novel spirooxindoles was designed and synthesized via regioselective three-component reaction between isatin derivatives, 2-phenylglycine and diverse arylidene-imidazolidine-2,4-diones (Hydantoins). The suggested stereochemistry was ascertained by an X-ray diffraction study and NMR spectroscopy. The resulting tetracyclic heterocycles were screened for their in vitro and in vivo anti-inflammatory and analgesic activity and for their in vitro antimicrobial potency. In vitro antibacterial screening revealed that several derivatives exhibited remarkable growth inhibition against different targeted microorganisms. All tested compounds showed excellent activity against the Micrococccus luteus strain (93.75 µg/mL ≤ MIC ≤ 375 µg/mL) as compared to the reference drug tetracycline (MIC = 500 µg/mL). Compound 4e bearing a p-chlorophenyl group on the pyrrolidine ring exhibited the greatest antifungal potential toward Candida albicans and Candida krusei (MIC values of 23.43 µg/mL and 46.87 µg/mL, respectively) as compared to Amphotericin B (MIC = 31.25 and 62.50 µg/mL, respectively). The target compounds were also tested in vitro against the lipoxygenase-5 (LOX-5) enzyme. Compounds 4i and 4l showed significant inhibitory activity with IC50 = 1.09 mg/mL and IC50 = 1.01 mg/mL, respectively, more potent than the parent drug, diclofenac sodium (IC50 = 1.19 mg/mL). In addition, in vivo evaluation of anti-inflammatory and analgesic activity of these spirooxindoles were assessed through carrageenan-induced paw edema and acetic acid-induced writhing assays, respectively, revealing promising results. In silico molecular docking and predictive ADMET studies for the more active spirocompounds were also carried out.

New Derivatives of 5-((1-Methyl-Pyrrol-2-yl) Methyl)-4-(Naphthalen-1-yl)-1,2,4-Triazoline-3-Thione and Its Coordination Compounds with Anticancer Activity

A new ligand 5-((1-methyl-pyrrol-2-yl) methyl)-4-(naphthalen-1-yl)-1,2,4-triazoline-3-thione (C15) and its metal complexes with formulae: Mn(C15)Cl₂MeOH (1), Fe(C15)Cl₂MeOH (2), Ni(C15)Cl₂MeOH (3), Cu(C15)₂Cl₂ (4) and Zn(C15)₄Cl₂ (5) have been synthesized. The C15 ligand and complexes were characterized by NMR, elemental analysis, FT-IR, EPR, magnetic and TGA studies. The anticancer activities of the organic ligand (C15) and complexes (1–5) were evaluated against human colon adenocarcinoma (HT29) and human lung (A549) cancer cell lines. The complex (1) exhibited potential activity at concentration of 794.37 μM (A549) and 654.31 μM (HT29) in both cancer cells. The complex (3) showed significant activity against the HT29 cancer cell line with an IC₅₀ value of 1064.05 μM. This article highlights some of the metals that have become important in the development of new coordination complexes and the treatment of cancer. Additionally, for C15, the toxicity was predicted by ADMET analysis and molecular docking.

Recent Advances in Bioactive Flavonoid Hybrids Linked by 1,2,3-Triazole Ring Obtained by Click Chemistry

As a result of the biological activities of natural flavonoids, several synthetic strategies aiming to obtain analogues with improved potency and/or pharmacokinetic profile have been developed. Since the triazole ring has been associated with several biological activities and metabolic stability, hybridization with a 1,2,3-triazole ring has been increasingly reported over the last years. The feasible synthesis through copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) has allowed the accomplishment of several hybrids. Since 2017, almost 700 flavonoid hybrids conjugated with 1,2,3-triazole, including chalcones, flavones, flavanones and flavonols, among others, with antitumor, antimicrobial, antidiabetic, neuroprotective, anti-inflammatory, antioxidant, and antifouling activity have been reported. This review compiles the biological activities recently described for these hybrids, highlighting the mechanism of action and structure-activity relationship (SAR) studies.

In-vitro evaluation of antioxidant and anticholinesterase activities of novel pyridine, quinoxaline and s-triazine derivatives

Cholinesterase enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) cause hydrolysis of acetylcholine (ACh), a neurotransmitter responsible for the cognitive functions of the brain such as acquiring knowledge and comprehension. Therefore, inhibition of these enzymes is an effective process to curb the progressive and fatal neurological Alzheimer's disease (AD). Herein, we explored the potential inhibitory activities of various pyridine, quinoxaline, and triazine derivatives (3a-k, 6a-j and 11a-h) against AChE and BuChE enzymes by following the modified Ellman's method. Further, anti-oxidant property of these libraries was monitored using DPPH (2,2'-diphenyl-1-picryl-hydrazylhydrate) radical scavenging analysis. From the studies, we identified that compounds 6e, 6f, 11b and 11f behaved as selective AChE inhibitors with IC₅₀ values ranging from 7.23 to 10.35 μM. Further studies revealed good anti-oxidant activity by these compounds with IC₅₀ values in the range of 14.80-27.22 μM. The kinetic studies of the active analogues demonstrated mixed-type of inhibition due to their interaction with both the catalytic active sites (CAS) and peripheral anionic sites (PAS) of the AChE. Additionally, molecular simulation in association with fluorescence and circular dichroism (CD) spectroscopic analyses explained strong affinities of inhibitors to bind with AChE enzyme at the physiological pH of 7.2. Binding constant values of 5.4 × 10⁴, 4.3 × 10⁴, 3.2 × 10⁴ and 4.9 × 10⁴ M^-1 corresponding to free energy changes -5.593, -6.799, -6.605 and -8.104 KcalM^-1 were obtained at 25 °C from fluorescence emission spectroscopic studies of 6e, 6f, 11b and 11f, respectively. Besides, CD spectroscopy deliberately explained the secondary structure of AChE partly unfolded upon binding with these dynamic molecules. Excellent in vitro profiles of distinct quinoxaline and triazine compounds highlighted them as the potential leads compared to pyridine derivatives, suggesting a path towards developing preventive or therapeutic targets to treat the Alzheimer's disease.