Design, synthesis, and biological evaluation of new 4-thiazolidinone derivatives substituted with benzimidazole ring as potential chemotherapeutic agents

In search of novel antiviral and anticancer agents with promising pharmacotoxicological profile, a study was initiated to synthesize new 2-thioxo-4-thiazolidinones as well as 2-phenylimino-4-thiazolidinones substituted with benzimidazole ring system. The compounds were screened primarily for their antiviral as well as anticancer activities. The synthesis of some novel 5-substituted thiazolidinones was also described. None of the tested compounds showed inhibitory activity against Hepatitis C virus replication. Two 2-phenylimino-4-thiazolidinone derivatives (9a and 10) exhibited significant antiproliferative activity against human colon carcinoma cell line HCT 116 and human hepatocellular carcinoma HEPG2 cell line, respectively. Results also indicated that six thiazolidinone derivatives (5a, 5d, 5e, 5f, 5h, and 9d) showed moderate antiproliferative activity against human breast adenocarcinoma cell line MCF7 in comparison to the standard drug Doxorubicin. Moreover, a docked pose of the most potent three cytotoxic compounds 5a, 5h, and 9d against MCF7 was obtained bound to Human N-acetyl transferase1 NAT1 binding pocket by molecular operating environment module.     

New eremophilane-type sesquiterpenes from an Antarctic deep-sea derived fungus,Penicillium sp. PR19 N-1

Chemical investigation of an Antarctic deep-sea derived fungus Penicillium sp. PR19 N-1 yielded five new eremophilane-type sesquiterpenes 1–5 and a new rare lactam-type eremophilane 6, together with three known compounds 7–9. The structures of these diverse sesquiterpenes were determined by extensive NMR and mass spectroscopic analyses. Compounds 1, 2, 4–6, 8 and 9 were evaluated for their cytotoxities against HL-60 and A-549 human cancer cell lines, and 5 was the most active one with IC₅₀ value of 5.2 μM against the A-549 cells.     

Cytotoxic dibenzocyclooctadiene lignans from Kadsura coccinea

Three new dibenzocyclooctadiene lignans, kadusurain A–C (1–3), together with two known compounds kadsuphilin A (4) and B (5), were isolated from an EtOAc fraction of the 80 % acetone extract of Kadsura coccinea (Lem.) A. C. Smith. Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy. Anti-proliferative effect of isolated compounds was evaluated against four human tumor cell lines (A549, HCT116, HL-60, and HepG2), and it was found that compound 1 exhibited significant antiproliferative effects with IC₅₀ values ranging from 1.05 to 12.56 μg/ml.     

Synthesis, molecular modeling, and biological evaluation of 1,2,4-triazole derivatives containing pyridine as potential anti-tumor agents

There is an accumulating body of experimental evidences validating focal adhesion kinase (FAK) as a therapeutic target and offering opportunities for anti-tumor drug development. In present study, we sought to synthesize twenty-eight potential FAK inhibitors as anti-tumor agents based on 1,2,4-triazole skeleton. The bioassay assays demonstrated that compounds 3e and 6j showed the most potent activity, 3e inhibited the growth of HCT116 and HepG2 cell lines with IC₅₀ values of 8.17 and 7.04 μM, while compound 6j showed the most potent biological activity against HCT116 cell line (IC₅₀ = 1.99 μM). Besides, compound 6j also exhibited significant FAK inhibitory activity (IC₅₀ = 2.41 μM). The results of flow cytometry and western-blot assay demonstrated that compounds 3e and 6j possessed good anti-proliferative activity. Docking simulations were performed to position compounds 3e and 6j into the active site of FAK to determine the probable binding model.     

Synthesis and evaluation of isonicotinoyl hydrazone derivatives as antimycobacterial and anticancer agents

A new series of isonicotinoyl hydrazone derivatives (3a–3o) have been synthesized, characterized and evaluated for in vitro antimycobacterial activity against M. tuberculosis H37Rv and two clinical isolates using tetrazolium microplate assay (TEMA). Some of these compounds showed moderate to good antimycobacterial activity at micro molar concentrations. Among them, 3k and 3m were the most potent analogues with an inhibition concentration at 0.59 and 0.65 μM, respectively, against M. tuberculosis H37Rv compared to parent drug, isoniazid (0.57 μM). Additionally, all the synthesized compounds were subjected to in vitro anticancer activity against human colorectal cancer cell lines (HCT 116). Compounds 3b and 3l displayed antiproliferative activity at inhibitory concentration 3.1 and 0.29 μM, respectively, when compared to standard, 5-fluorouracil (5 μM). These results can be considered as an important start point for the rational design of new leads for antitubercular and anticancer drug discovery.     

Synthesis and in vitro cytotoxicity study of 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones

A series of 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones 3a–l were synthesized in good to excellent yield by Michael addition of indole 1 with α,β-unsaturated ketones 2a–l in presence of indium(III) sulphate (20 mol%). The structure of the title compounds were established by ¹H NMR, ¹³C NMR, mass and elemental analysis. All the synthesized compounds were evaluated for in vitro cytotoxicity against five different cancer cell lines such as ACHN (human kidney adenocarcinoma), Panc1 (pancreatic), Calu1 (lung), H460 (non small cell lung), HCT116 (human colon cancer cell) and MCF10A (normal breast epithelium) using propidium iodide staining assay protocol. The result showed that the compounds 3e and 3l have excellent cytotoxic activity with the IC₅₀ value ranging from 1.4–2.7 to 2.4–3.4 μM, respectively, in comparison with the other compounds, Flavopiridol and Gemcitabine were employed as a positive control. The findings conferred 3-(1H-indol-3-yl)-1,3-diphenylpropan-1-ones seem to be promising candidates for the development of new anticancer drugs.     

Synthesis of water soluble copper(II) complexes: crystal structures,DNA binding,oxidative DNA cleavage,and in vitro anticancer studies

Two ternary copper(II) complexes of dl-threonine and polypyridyl ligands with formula of [Cu(Thr)(Byp)Cl]·H₂O (1) and [Cu(Thr)(Phen)H₂O]Cl·2H₂O (2) were synthesized. The complexes were characterized by spectral (NMR, FT-IR, and UV–Vis), CHN elemental analysis and have been structurally elucidated by X-ray crystallography. Both of the complexes formed slightly distorted square-pyramidal coordination geometry. The electronic absorption spectra of the complexes showed a very low intensity d–d electronic band in the range of 610–620 nm in Tris–HCl/NaCl (5:5 mM) pH 7.2 buffer solution. The DNA binding interaction with calf-thymus DNA (CT-DNA) was investigated by electronic absorption spectral titration and viscosity measurements. The results revealed that the phenanthroline complex (2) interact with CT-DNA through intercalation while bipyridyl complex (1) through the groove binding mode. The calculated intrinsic binding constant (K _b) of (1) and (2) were 0.5 and 4.4 × 10⁵ M^?1, respectively. Both the complexes were found to promote efficient DNA cleavage activities at low concentration in the presence of H₂O₂. The results showed that (2) has the highest DNA binding and nuclease activity. Furthermore, both the complexes were tested against human colon cancer (HCT 116) and breast cancer (MCF-7) cell lines and showed a dose-dependent antiproliferation effect.     

New azetidine-3-carbonyl-N-methyl-hydrazino derivatives of fluoroquinolones: synthesis and evaluation of antibacterial and anticancer properties

A series of nine new N-(substituted azetidine-3-carbonyl)-N-methyl-hydrazino derivatives at C-7 position of fluoroquinolones were designed and synthesized through multistep synthesis. The synthesized compounds were characterized by ¹H NMR, ¹³C NMR, ESI–MS and IR. The new compounds were tested for their in vitro antimicrobial and anti-proliferative activity. Out of the nine derivatives, compound 6i exhibited good antibacterial activity by inhibiting the growth of Methicillin-sensitive Staphylococcus aureus, Methicillin-resistant S. aureus and ATCC 35218 Escherichia coli (MIC: 0.25–16.00 μg/mL). Compounds 6c, 6g–h are displayed good growth inhibition against MCF-7 Breast carcinoma, HCT-116 Colon carcinoma and A549 Lung adenocarcinoma cell lines. Compound 6h is the most active against MCF-7 cell line with superior growth inhibition compared to ciprofloxacin and reference anticancer drug SAHA.     

New 4-thiazolidinones from 5-ethyl pyridine-2-ethanol: their antibacterial,antifungal, and antitubercular activity

New thiazolidinones 5a–o were prepared from Schiff base 4a–o and thioglycolic acid in the presence of ZnCl₂ from 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR ¹³C NMR, and mass spectral data. All the compounds were screened against different strains of bacteria and fungi. Compounds 4e, 4n, 4m, 4o, 5e, 5f, 5j, and 5m possessed very good activity against bacterial and fungal species. These active compounds impelled us to study their antitubercular activity. Schiff base 4n and 4e showed M. tuberculosis MIC value 25 and 62.5 μg/ml, respectively. Thiazolidinone 5m displayed M. tuberculosis MIC at 25 μg/ml, which is better antitubercular activity compared with rifampicin.     

Steroidal saponins from the leaves of Yucca de-smetiana and their in vitro antitumor activity: structure activity relationships through a molecular modeling approach

Four steroidal saponins were isolated from the leaves of Yucca de-smetiana Baker. Their structures were established using one- and two- dimensional NMR spectroscopy and mass spectrometry. The structure of the new steroidal saponin was identified as: (25R)-3β-hydroxy-5α-spirostan-3-O-β-d-xylopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-O-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (desmettianoside C) along with three known spirostanol and furostanol saponins. The isolated saponins were evaluated for their antitumor activity against HCT116, MCF7, HepG2, and A549 cell lines. Saponins 3 and 4 showed potent activity against HCT116, MCF7, and HepG2 cell lines in comparison with the positive control doxorubicin. A molecular modeling approach was performed to establish conformational criteria that could affect the biological activity of the isolated saponins.     

Synthesis and in vitro antiproliferative activity of 2,5-disubstituted-1,3,4-oxadiazoles containing trifluoromethyl benzenesulfonamide moiety

A series of new 2,5-disubstituted-1,3,4-oxadiazoles 6(a–j) have been conveniently synthesized by intermolecular oxidative cyclization of (E)-2-(arylbenzylidene)-2-[(4-methoxyphenyl)amino]acetohydrazides promoted by iodobenzene diacetate as an oxidant. The synthesized compounds were characterized by elemental analyses, FT-IR, LCMS, ¹H NMR, and ¹³C NMR spectral studies. All the compounds were evaluated for their in vitro antiproliferative effect using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay method against four human cancer cell lines (K562, Colo-205, MDA-MB 231, IMR-32) for the time period of 24 h. Among the analogs, compounds 6h and 6i showed good activity on all cell lines, whereas the other compounds in the series exhibited moderate activity.     

Synthesis, in vitro antimicrobial, antiproliferative, and QSAR studies of N-(substituted phenyl)-2/4-(1H-indol-3-ylazo)-benzamides

In this study, N-(substituted phenyl)-2/4-(1H-indol-3-ylazo)-benzamides (1–26) were synthesized and screened for their in vitro antibacterial (Gram positive; S. aureus, B. subtilis and Gram negative; E. coli) and antifungal (C. albicans and A. niger) activities. The antimicrobial activity results indicated that compound, 4-(1H-indol-3-ylazo)-N-(4-nitro-phenyl)-benzamide (12, pMIC_am = 1.61) was the most potent. In general, it was found that the synthesized compounds were bacteriostatic/fungistatic in action except fungicidal for A. niger. The synthesized compounds were also evaluated for their antiproliferative activity against human colon cancer (HCT116), murine leukemia (P388), and breast cancer (MCF7) cell lines. The antiproliferative study results demonstrated 4-(1H-indol-3-ylazo)-N-p-tolyl-benzamide (2, IC₅₀ = 0.0003 μM/mL) and 4-(1H-indol-3-ylazo)-N-p-tolyl-benzamide (21, 0.0003 μM/mL) as lead compounds for the development of novel antiproliferative agents. The QSAR studies indicated the importance of topological parameters, Kier’s alpha second-order shape indice (κα₂) and Wiener index (W) in describing the antimicrobial activity of the synthesized compounds.     

Antifungal, mosquito deterrent, and larvicidal activity of N-(benzylidene)-3-cyclohexylpropionic acid hydrazide derivatives

Hydrazone derivatives possess good antifungal and insecticidal activities and their structures are used in pesticide design. In the present study, for the first time, ten hydrazone derivatives (1–10) were evaluated for their antifungal activity against Colletotrichum, Botrytis, Fusarium, and Phomopsis species and for their biting deterrent and larvicidal activity against Aedes aegypti, the yellow mosquito. The 96-well microbioassay revealed that compounds 3, 5, 7, and 9 showed strong antifungal activity at 30 μM against Phomopsis obscurans, whereas only two compounds (5 and 9) demonstrated strong antifungal activity against Phomopsis viticola. Compound 5 showed the highest biting deterrent activity against Ae. aegypti when compared with N,N-diethyl-meta-toluamide, the positive control at 25 nmol/cm². Compound 9 exhibited the highest larvicidal activity in toxicity bioassay with LD₅₀ values of 57.4 and 4.35 ppm and LD₉₀ values of 297.8 and 19.1 ppm, respectively, at 24 and 48 h post treatment. Compounds 5 bearing 4-fluoro substituent on benzene ring and 9 carrying a 4-isopropyl group on the benzene ring were found to be the most active compounds in both bioassays. These results could be useful information for development of new effective fungicides and insecticides in the near future.     

Synthesis and antiproliferative activity evaluation of imidazole-based indeno[1,2-b]quinoline-9,11-dione derivatives

A series of new imidazole substituted indeno[1,2-b]quinoline-9,11-dione derivatives were synthesized and evaluated for their antiproliferative effects on HeLa, LS180, MCF-7 and Jurkat human cancer cell lines. Antiproliferative effects were evaluated using MTT assay. Prepared compounds exhibited weak to good antiproliferative activity in evaluated cell lines. Prepared compounds were more potent in Jurkat cell line when compared to LS180, HeLa and MCF-7 cell lines. Compounds 29 (IC₁₆ = 0.7 μM) and 31 (IC₁₆ = 1.7 μM) and 33 (IC₁₆ = 1.7 μM) were found to be the most potent molecules on Jurkat cell lines. Moreover; it was found that some of the tested compounds bearing imidazole-2-yl moiety on the C₁₁-position of dihydropyridine ring exhibited superior antiproliferative activity in comparison to cis-platin especially in Jurkat cell line (compounds 29, 31, and 33). It seemed that the introduction of electron-withdrawing groups on the imidazole ring enhanced the antiproliferative potential of these compounds (compounds 27, 29 and 31). The results of this study proposed that some of the imidazole substituted indeno[1,2-b]quinoline-9,11-dione compounds may act as efficient anticancer agents in vitro, emphasizing their potential role as a source for rational design of potent antiproliferative agents.     

Synthesis of fatty acid Schiff base esters as potential antimicrobial and chemotherapeutic agents

Schiff base {4-[(pyridine-3-ylmethylimino)-methyl] phenol} was prepared by reacting 4-hydroxybenzaldehyde with 3-aminomethylpyridine in ethanol for 6 h (85 % yield) followed by their esterification via reaction with fatty acids of varying chain lengths. The structure of these Schiff base esters were elucidated using chromatographic and spectroscopic techniques like GC–MS, ¹H NMR, ¹³C NMR, and ESI–MS. Schiff base esters with shorter chain heptanoic (2a) and decanoic acid (2c) showed good activity against all the tested bacterial and fungal strains. The synthesized esters were also studied for cytotoxicity toward different human tumor cell lines like HeLa, HepG2, A549, MDA-MB-231, and MCF 7 and Neuro2a; however, Schiff base esters with shorter chain (2a, 2b) and medium chain fatty acids (2d, 2i) exhibited good anticancer activity and selectively toward MDA-MB-231 and MCF 7, while long chain fatty acid (2g) Schiff base ester exhibited good anticancer activity selectively toward MDA-MB-231 as compared to the parent molecule, Schiff base (1).     

Synthesis and biological evaluation of novel resveratrol-oxadiazole hybrid heterocycles as potential antiproliferative agents

A novel class of resveratrol-oxadiazole hybrid compounds was synthesized to screen for their in vitro antiproliferative activity against three human cancer cell lines. All the compounds showed superior antiproliferative activity than the reference compound resveratrol. The most promising active compounds in this series were 1g, 2g, 1c, 2c, 2i and 1a (GI₅₀ < 0.1 µM), endowed with excellent antiproliferative activity. Thus, we believe that resveratrol-oxadiazole hybrid compounds may possibly be used as a good leads for the development of new antiproliferative agents. Structures of newly synthesized compounds were confirmed by NMR and IR spectral data.     

Design, synthesis and in vitro antimicrobial activity of novel phenylbenzamido-aminothiazole-based azasterol mimics

Phenylbenzamide framework as a mimic of the azasterol structure was investigated by synthesizing 4-phenylbenzamido-2-aminothiazole 4, and evaluating its MIC against Escherichia coli, Enterobacter cloacae, Bacillus licheniformis and Mycobacterium tuberculosis (MTB) H₃₇Rv as well as antifungal activity against three test phytopathogenic fungi. Further, the bioisosterism strategy was implemented to synthesize a series of azo-derivatives of 4 (6a–6j). All the azo-compounds were screened for their antibacterial and antifungal activity. The electronic (UV–vis) absorption characteristics of the final compounds were examined. Resazurin-mediated microtitre plate-antibacterial assay was implemented for first time on these azo-derivatives. Compounds 4 and 6b had significant antibacterial activity. For the compound 4, MIC against Escherichia coli is 7.8 × 10^?3 mg/mL and MIC against Mycobacterium tuberculosis (MTB) H₃₇Rv is 16 μg/mL were identified. Compounds 4, 6d, 6g and 6h showed excellent antifungal activity, when compared to the standard nistatin, against three test phytopathogenic fungi.     

Synthesis and characterization of flurbiprofen hydrazide derivatives as potential anti-HCV, anticancer and antimicrobial agents

A novel series of new flurbiprofen hydrazide derivatives 2-(2-fluorobiphenyl-4-yl)-N′-[(substituted phenyl/5-nitro-2-furyl)methylene]propanehydrazide (3a–k), 2-(2-fluorobiphenyl-4-yl)-N-(2-substituted-4-oxo-1,3-thiazolidine-3-yl)propanamide (4a–b, 4d–k), 2-[2-(2-fluorobiphenyl-4-yl) propanoyl]-N-substituted hydrazinecarbothioamide (5a–h) and 2-(2-fluorobiphenyl-4-yl)-N′-[(3-methyl-4-oxo-1,3-thiazolidin-2-ylidene]propanehydrazide (6a–b, 6e and 6g) has been synthesized in this study. All synthesized compounds were screened for antimicrobial activity against various bacterial and fungal strains. Additionally, compounds were evaluated for the ability to inhibit Hepatitis C virus NS5B polymerase. The most active 4-thiazolidinone compound was 4k (SGK119) with 67.0 % and thiosemicarbazide compound was 5d (SGK123) with 69.50 % inhibition at 200 μM against hepatitis C virus NS5B RNA polymerase. Anticancer activity of the selected compounds (3i, 3j, 3h, 4d, 4i and 6b) was determined at a single dose towards the full panel of 60 human cancer cell lines by the National Cancer Institute (NCI). 2-(2-Fluoro-4-biphenylyl)-N-[2-[4-(trifluoromethyl)phenyl]-4-oxo-1,3-thiazolidine-3-yl]propanamide 4d, containing thiazolidinone ring, demonstrated the most marked effect with 20.80 % growth percent on leukaemia cancer cell line SR at 10^?5 M. The results demonstrated that none of the compounds tested have anticandidal and antifungal activities, but two of them (4a and 4i) showed antibacterial inhibition against Micrococcus luteus, and Staphylococcus cohnii and Staphylococcus aureus, respectively.     

Synthesis and biological evaluation of novel 4,5-dihydropyrazole derivatives as potent anticancer and antimicrobial agents

A focused library of 4,5-dihydropyrazole dervivatives (4, 5, 6, 7a–h, 8, 9a–g, and 10a–g) were synthesized from novel 5-(2,6-difluorophenyl)-3-phenyl-4,5-dihydropyrazole-1-carbothioamide 4. The synthesized compounds were characterized using elemental analysis and spectral data (IR, mass spectra, ¹H and ¹³C NMR) and evaluated for antimicrobial activity by broth dilution method and in vitro anticancer activity. Among the synthesized compounds 7a, 9c, 9g, and 10d exhibit broad spectrum antimicrobial activity against tested microbial strains. The in vitro cancer results ascertain 7a, 9c, and 10d are most potent molecules in comparison to reference standard cisplatin.     

Synthesis and antifungal activity of the novel triazole derivatives containing 1,2,3-triazole fragment

A series of fluconazole analogues containing 1,2,3-triazole fragment have been designed and synthesized on the basis of the active site of the cytochrome P450 14α-demethylase (CYP51). Their structures were characterized by ¹H NMR, ¹³C NMR and LC–MS. The MIC₈₀ values indicate that the target compounds 1a–r showed higher activities against nearly all the fungi tested to some extent except against Aspergillus fumigatus. Compounds 1c, e, f, l and p showed 128 times higher activity (with the MIC₈₀ value of 0.0039 mg/mL) than that of fluconazole against Candida albicans and also showed higher activity than that of the other positive controls.