Search

A series of novel 2,4,5‐trisubstituted imidazole motifs have been synthesized by a magnetically‐tuned halloysite‐supported sulfonic acid catalyst. The prepared supported sulfonic acid catalyst was well characterized by High‐resolution transmission electron microscopy (HR‐TEM), Scanning electron microscopy (SEM), Energy dispersive X‐rays spectroscopy (EDS), Fourier transform infrared (FTIR), X‐ray powder diffraction (XRD), Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and Vibrating–sample magnetometry (VSM) techniques; and compounds were confirmed by 1H, 13C‐Nuclear magnetic resonance (NMR) and High resolution mass spectrometry (HRMS) techniques. The purity of compounds was established by High performance liquid chromatography (HPLC). All the prepared compounds were screened for their in vitro antidiabetic activity by using α‐amylase and α‐glucosidase inhibition assay taking acarbose as a reference standard and were found to exhibit significant α‐amylase inhibitory potentials, whereas for α‐glucosidase inhibition, compounds were equipotent to the reference standard. Compound bearing ferrocene moiety was identified as the strongest α‐amylase inhibitor of the series with IC50=47.83±0.63 μM, a five‐fold more potency compared to acarbose (IC50 =269.39±0.29 μM). The presence of substituents in the second position of imidazole pharmacophore plays a key role in inhibitory activity. To find the possible binding interaction of compounds, in silico molecular docking study was performed. [ABSTRACT FROM AUTHOR]

Cancer continues to have overwhelming impacts on human health and the development of new chemotherapeutics. Molecular hybridization has thus been valued as a structure-based drug design approach to drugs with enhanced efficacy. Herein, we report the multistep synthesis of quinoline–2-mercapto-1,3,4-oxadiazole conjugates and their cytotoxicity evaluation. Compound 4j 2-[(5-bromopentyl)thio]-5-[(quinolin-8-yloxy)methyl]-1,3,4-oxadiazole showed the best cytotoxicity to pancreatic (MIA PaCa-2) and colorectal (HCT116) cancer cells with IC50 values of 29.19 ± 0.99 and 75.10 ± 1.87 µM, respectively. The compound is also less cytotoxic to non-cancerous human primary dermal fibroblast cells with IC50 = 91.87 ± 1.29 µM compared to the parent compound 8-hydroxyquinoline (IC50 = 72.36 ± 4.23 µM). ADME properties prediction suggested the drug-likeness of potent compounds while molecular docking and molecular dynamics simulations with doublecortin-like kinase (DCLK1) revealed the compounds' stable binding interactions at the kinase domain. Overall, the results illuminate compound 4j as a structural model to furnish new cytotoxic agents against pancreatic and colorectal cancer. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a multifaceted metabolic disorder that remains a major threat to global health security. Sadly, the clinical relevance of available drugs is burdened with an upsurge in adverse effects; hence, inhibiting the carbohydrate-hydrolyzing enzymes α-glucosidase and α-amylase while preventing oxidative stress is deemed a practicable strategy for regulating postprandial glucose levels in DM patients. We report herein the α-glucosidase and α-amylase inhibition and antioxidant profile of quinoline hybrids 4a–t and 12a–t bearing 1,3,4-oxadiazole and 1,2,3-triazole cores, respectively. Overall, compound 4i with a bromopentyl sidechain exhibited the strongest α-glucosidase inhibition (IC50 = 15.85 µM) relative to reference drug acarbose (IC50 = 17.85 µM) and the best antioxidant profile in FRAP, DPPH, and NO scavenging assays. Compounds 4a and 12g also emerged as the most potent NO scavengers (IC50 = 2.67 and 3.01 µM, respectively) compared to gallic acid (IC50 = 728.68 µM), while notable α-glucosidase inhibition was observed for p-fluorobenzyl compound 4k (IC50 = 23.69 µM) and phenyl-1,2,3-triazolyl compound 12k (IC50 = 22.47 µM). Moreover, kinetic studies established the mode of α-glucosidase inhibition as non-competitive, thus classifying the quinoline hybrids as allosteric inhibitors. Molecular docking and molecular dynamics simulations then provided insights into the protein–ligand interaction profile and the stable complexation of promising hybrids at the allosteric site of α-glucosidase. These results showcase these compounds as worthy scaffolds for developing more potent α-glucosidase inhibitors with antioxidant activity for effective DM management. [ABSTRACT FROM AUTHOR]

A series of 5,5′-(phenylmethylene)bis(6-amino-2-thiouracil) derivatives (1–13) were synthesized by the condensation of 6-amino-2-thiouracil and benzaldehyde derivatives under reflux in glacial acetic acid. Nine compounds (3, 5 and 7–13) were novel. Good binding affinity (BE) in the active site of Eg5 was shown by all compounds, which ranged between −5.0 kcal mol−1 to −26.7 kcal mol−1. Most compounds in the series exhibited a stronger interaction than 5-fluorouracil (BE = −8.0 kcal mol−1) with Eg5. The docking results were supported by cytotoxicity studies of the synthesized compounds against HeLa (cervical cancer) cell lines, where all compounds exhibited better anti-cancer activity than 5-fluorouracil (IC50 = 12.08 µg mL−1) at the lowest concentration (10 µg mL−1) with IC50 values ranging from 4.18 to 10.20 µg mL−1. [ABSTRACT FROM AUTHOR]

A library of novel pyrazole–imidazo[1,2‐α]pyridine scaffolds was designed and synthesized through a one‐pot three‐component tandem reaction. The structures of synthesized conjugates were confirmed by spectroscopic techniques (NMR, IR and HRMS). In vitro antibacterial evaluation of the twelve synthesized molecules (7a, 8a–k) against methicillin‐resistant Staphylococcus aureus and normal strains of Escherichia coli, Salmonella typhimurium, Klebsiella pneumonia and Pseudomonas aeruginosa established 8b, 8d, 8e, 8h and 8i as potent antibacterial agents with superior minimum bactericidal concentration, compared with standard drug ciprofloxacin. Molecular docking studies of all active compounds into the binding site of glucosamine‐6‐phosphate synthase were further performed in order to have a comprehensive understanding of putative binding modes within the active sites of the receptor. [ABSTRACT FROM AUTHOR]

A library of 1H-1,2,3-triazole-tethered ospemifene–isatin and ospemifene–spiroisatin conjugates have been synthesized and evaluated for their anti-proliferative activities against MCF-7 and MDA-MB-231 cell lines. The evaluation studies revealed that compound 11j was the most potent with an IC50 value of 1.56 μM against the MCF-7 cell line. Compounds 11k and 11l also displayed a similar trend, with several-fold lower effective concentrations in ER+ cells than in ER− cells. SAR studies revealed that conjugates having a bromo-substituent at the C-5 and C-7 positions of the isatin ring with ethyl/propyl as the spacer were observed to be active with the most potent compound being ∼30 times more potent than Tamoxifen against the MCF-7 cell line. The evaluation results were further supported by docking studies and the stronger binding affinity of the synthesized conjugates was attributed to their greater structural bulk and greater occupation of the ERα active site. [ABSTRACT FROM AUTHOR]

An electrokinetic chromatographic method was developed for the chiral separation of neotame, a new high intensity artificial sweetener, using a chiral separating agent heptakis 2,3,6-tri-o-methylbetacyclodextrin. The purpose of this study was to better understand diastereomer-resolution interactions between neotame and the chiral separating agent. Molecular docking studies were performed to elucidate the mechanism of the separation. The optimum conditions were 50 mM phosphate buffer, pH 5.5, applied voltage 20 kV, cassette temperature of 30°C, and a 4 s sample injection time. The calibration curve showed good linearity (r2 > 0.99) with recoveries for both diastereomers, ranging from 95.66–99.00% and the limits of detection for L,L-neotame and D,D-neotame were 0.01857 and 0.08214 mM, respectively. The developed method showed analytical precision with relative standard deviations (n = 5) of 1.20% and 1.17% with respect to migration time and peak area, respectively. A large difference in the interaction energies observed between the diastereomers represents a significant differentiation. The results showed that both electrostatic and hydrophobic interactions played a significant role in stabilizing their inclusion complexes and consequently supported the elution order based on their differential stabilities. [ABSTRACT FROM PUBLISHER]

This paper reports on a newly developed electrokinetic chromatographic method for the simultaneous separation and determination of steviol glycosides in real stevia samples by capillary electrophoresis and supported by molecular docking studies. Our results obtained using 30-mM heptakis-(2,3,6-tri- o-methyl betacyclodextrin) as a separating agent, suggest that at optimum experimental conditions the detection limits of 2.017 × 10 and 7.386 × 10 M and relative standard deviations ( n = 5) of 1.10 and 1.17 were obtained for rebaudioside-A and stevioside, respectively. In addition, the molecular docking studies explained to a certain extent why the separation was successful. The calculated binding free energy results for the rebaudioside-A and stevioside complexes formed with the separating agent showed that although both ligands penetrated deeply into the hydrophobic cavity of the separating agent, the presence of additional hydrogen bonding in the case of stevioside is probably responsible for its stronger binding affinity than that of rebaudioside-A. [ABSTRACT FROM AUTHOR]

• Cu-promoted synthesis of indolo [2,3- b ]quinoxaline-Mannich adducts. • The anti-proliferative activities were assessed on OVCAR-3 and HT-29 cells. • The promising compounds exhibited caspase-mediated apoptotic cell death. • The promising compounds were further studied in silico using the crystal structure of c-Met-kinase. The present work intends to synthesize a new class of small molecules featuring the quinoxaline scaffold. The indolo [2,3- b ]quinoxaline-Mannich adducts were designed, synthesized and their anticancer activities were tested using MTS assay against human ovarian cancer (OVCAR-3) and female colorectal adenocarcinoma cancer cell lines (HT-29). Compounds 6q and 6r efficiently inhibited both cancer cell lines tested, with IC 50 values of 58.57 and 55.90 µM against OVCAR-3 and 31.36 and 42.3 µM against HT-29, respectively. The evaluation results were further supported by caspase-mediated apoptosis and docking studies, which indicated that Tyr1159 and the N-atom of the pyrrolidine moiety formed an additional hydrogen bond that stabilised the c-Met-kinase-6q complex. Overall, the results of our study suggested that Mannich-inspired indolo [2,3- b ]quinoxaline adduct might make interesting lead for the development of cancer chemotherapeutics. Synthesis and anti-proliferative evaluation of Indolo [2,3- b ]quinoxaline-Mannich adducts [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Isoflavone analogues were synthesized from benzoylbenzofuran precursors. • Benzoylbenzofurans and isoflavones inhibited MDA-MB-231 cancer cell proliferation. • Isoflavone derivatives were discovered as potent sirtuin 1 inhibitors. • Isoflavone quinone 39 displayed sirtuin 1 inhibitory activity comparable to that of suramin. • In silico docking studies revealed the binding modes of the active sirtuin 1 inhibitors. Isoflavone derivatives were prepared from benzoylbenzofuran precursors. The synthesized compounds were analyzed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, as well as high-resolution mass spectrometry (HRMS) to confirm their structures. The benzoylbenzofuran and isoflavone analogues were evaluated for inhibition of sirtuin 1 (SIRT1) and cell proliferation in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Several isoflavone and benzoylbenzofuran derivatives exhibited potent antiproliferative effects against the MDA-MB-231 cancer cell line. Most of the isoflavone derivatives attenuated SIRT1 activity to below 50%. The most active compounds were the isoflavone quinones 38 , 39 , and 40 , at IC 50 values of 5.58 ± 0.373, 1.62 ± 0.0720, and 7.24 ± 0.823 μM, respectively. Importantly, the most active compound, 6-methoxy-4′,6′-dimethylisoflavone-2′,5′-quinone (39) displayed SIRT1 inhibitory activity comparable to that of the reference compound, suramin. The in silico docking simulations in the active site of SIRT1 further substantiated the experimental results and explored the binding orientations of potent compounds in the active site of the target. [ABSTRACT FROM AUTHOR]

The increasing incidence of multidrug-resistant Gram-negative bacterial pathogens has focused research on the suppression of bacterial virulence via quorum sensing inhibition strategies, rather than the conventional antimicrobial approach. The anti-virulence potential of eudesmanolide sesquiterpene lactones previously isolated from Vernonia blumeoides was assessed by inhibition of quorum sensing and in silico molecular docking. Inhibition of quorum sensing-controlled violacein production in Chromobacterium violaceum was quantified using violacein inhibition assays. Qualitative modulation of quorum sensing activity and signal synthesis was investigated using agar diffusion double ring assays and C. violaceum and Agrobacterium tumefaciens biosensor systems. Inhibition of violacein production was concentration-dependent, with ⩾90% inhibition being obtained with ⩾2.4 mg ml −1 of crude extracts. Violacein inhibition was significant for the ethyl acetate extract with decreasing inhibition being observed with dichloromethane, hexane and methanol extracts. Violacein inhibition ⩾80% was obtained with 0.071 mg ml −1 of blumeoidolide B in comparison with ⩾3.6 mg ml −1 of blumeoidolide A. Agar diffusion double ring assays indicated that only the activity of the LuxI synthase homologue, CviI, was modulated by blumeoidolides A and B, and V. blumeoides crude extracts, suggesting that quorum sensing signal synthesis was down-regulated or competitively inhibited. Finally, molecular docking was conducted to explore the binding conformations of sesquiterpene lactones into the binding sites of quorum sensing regulator proteins, CviR and CviR′. The computed binding energy data suggested that the blumeoidolides have a tendency to inhibit both CviR and CviR′ with varying binding affinities. Vernonia eudesmanolide sesquiterpene lactones have the potential to be novel therapeutic agents, which might be important in reducing virulence and pathogenicity of drug-resistant bacteria in vivo . [ABSTRACT FROM AUTHOR]

The synthesis of novel triarylethylene analogs, designed based on well-known Selective Estrogen Receptor Modulators (SERMs), i.e., ospemifene and tamoxifen, as potential anti-breast cancer agents is described. The cytotoxic potential of these analogs against ER-positive (MCF-7) and ER-negative (MDA-MB-231) human breast cancer cell lines was determined and compared with the standards, ospemifene and tamoxifen. In initial screening, analogs 5 , 14 and 15 were found to be much more effective than the standards against both the cell lines. The results showed that these novel analogs inhibit the expression of proteins involved in the migration and metastasis, compound 5 being most effective. Compound 5 inhibited the expression of MMP-9, c-Myc and Caveolin in both MCF-7 and MDA-MB-231 cells, and suppressed the invasion of ER-negative cells in a dose dependent manner. Finally, in silico docking simulations of the representative compounds in the binding sites of the estrogen receptors (ERs) indicated a good binding affinity of the compounds with the ERs, and supported their experimental toxicity against MCF-7 cancer cell lines. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1 H -1,2,3-triazole tethered tacrine-chalcone conjugates and evaluation of their AChE inhibitory activity. • The most potent compounds exhibited in-vitro IC 50s value more than drug tacrine. • In-vivo Scopolamine induced Inclined plane and Elevated plus-maze models. • Evaluation of biochemical parameters GSH and TBARS. • Docking studies were performed to delineate the mechanism of action. The present paper explicates the synthesis of 1 H -1,2,3-triazole tethered tacrine-chalcone conjugates and evaluation of their AChE and BuChE inhibitory activity. In-vitro AChE inhibition assay revealed three compounds, 9h , 9i, and 11f , being more potent than the standard drug tacrine and further evaluated against butyrylcholinesterase. The present study was extended to investigate the anti-amnestic effect of promising compounds on scopolamine-induced behavioral and neurochemical changes in mice. Inclined plane model and Elevated plus-maze model were performed to assess general limb motor activity and anxiety-like behavior, respectively, in mice pre-treated with scopolamine. Oxidative stress parameters reduced glutathione contents (GSH) and lipid peroxidation products (TBARS) in the brain homogenates as estimated using ex-vivo studies. Furthermore, molecular docking studies were performed for the potent compounds to decipher the mechanism of observed activities. [ABSTRACT FROM AUTHOR]

• A series of 4-aminoquinoline-isoindolinedione-isoniazid triads with anti-mycobacterial activities. • The most active compounds exhibited MIC 99 5.1 µM against mc26230 strain of M. tuberculosis. • Docking studies were performed to delineate the mechanism of action. A series of 4-aminoquinoline-isoindoline-dione-isoniazid triads were synthesized and assessed for their anti-mycobacterial activities and cytotoxicity. Most of the synthesized compounds exhibited promising activities against the mc26230 strain of M. tuberculosis with MIC in the range of 5.1–11.9 µM and were non-cytotoxic against Vero cells. The conjugates lacking either isoniazid or quinoline core in their structural framework failed to inhibit the growth of M. tuberculosis ; thus, further strengthening the proposed design of triads in the present study. [ABSTRACT FROM AUTHOR]

A series of 1 H -1,2,3-triazole linked Ferrocenyl-methoxy-methyl-Isatin conjugates was synthesized and assayed for their anti-proliferative activities against estrogen-responsive as well as estrogen non-responsive cell lines. The non-cytotoxic conjugate 7l, with an optimum combination of octyl chain as spacer and methyl-substituent at the C-5 position of isatin, proved to be a promising hit with an IC 50 value of 14.62 μM against MCF-7 and 79.63 μM against MDA-MB-231 cells, respectively. The observed anti-proliferative activities of active conjugates were further corroborated via docking studies carried out on estrogen receptor subtypes α and β. Image 1 • Ferrocenyl-methoxy-methyl-Isatin-conjugates with antiproliferative activity. • The most potent compound exhibited an IC 50 value of 14.62 μM against MCF-7 cells. • Docking studies were performed to delineate the mechanism of action. [ABSTRACT FROM AUTHOR]