Design, synthesis, and cytotoxic evaluation of quinazoline derivatives bearing triazole-acetamides.

A novel series of quinazoline-based agents bearing triazole-acetamides 8a-l were designed and synthesized. All the obtained compounds were tested for in vitro cytotoxic activities against three human cancer cell lines named HCT-116, MCF-7, and HepG2, as well as a normal cell line WRL-68 after 48 and 72 h. The results implied that quinazoline-oxymethyltriazole compounds exhibited moderate to good anticancer potential. The most potent derivative against HCT-116 was 8a (X = 4-OCH3 and R = H) with IC50 values of 10.72 and 5.33 µM after 48 and 72 h compared with doxorubicin with IC50 values of 1.66 and 1.21 µM, respectively. The same trend was seen in the HepG2 cancerous cell line in which 8a recorded the best results with IC50 values of 17.48 and 7.94 after 48 and 72 h, respectively. The cytotoxic analysis against MCF-7 showed that 8f with IC50 = 21.29 µM (48 h) exhibited the best activity, while compounds 8k (IC50 = 11.32 µM) and 8a (IC50 = 12.96 µM), known as the most effective cytotoxic agents after 72 h. Doxorubicin as positive control exhibited IC50 values of 1.15 and 0.82 µM after 48 and 72 h, respectively. Noteworthy, all derivatives showed limited toxicity against the normal cell line. Moreover, docking studies were also presented to understand the interactions between these novel derivatives and possible targets.

Synthesis, molecular docking, and cytotoxicity of quinazolinone and dihydroquinazolinone derivatives as cytotoxic agents.

BACKGROUND: Cancer is the most cause of morbidity and mortality, and a major public health problem worldwide. In this context, two series of quinazolinone 5a-e and dihydroquinazolinone 10a-f compounds were designed, synthesized as cytotoxic agents. METHODOLOGY: All derivatives (5a-e and 10a-f) were synthesized via straightforward pathways and elucidated by FTIR, 1H-NMR, CHNS elemental analysis, as well as the melting point. All the compounds were evaluated for their in vitro cytotoxicity effects using the MTT assay against two human cancer cell lines (MCF-7 and HCT-116) using doxorubicin as the standard drug. The test derivatives were additionally docked into the PARP10 active site using Gold software. RESULTS AND DISCUSSION: Most of the synthesized compounds, especially 5a and 10f were found to be highly potent against both cell lines. Synthesized compounds demonstrated IC50 in the range of 4.87-205.9 µM against HCT-116 cell line and 14.70-98.45 µM against MCF-7 cell line compared with doxorubicin with IC50 values of 1.20 and 1.08 µM after 72 h, respectively, indicated the plausible activities of the synthesized compounds. CONCLUSION: The compounds quinazolinone 5a-e and dihydroquinazolinone 10a-f showed potential activity against cancer cell lines which can lead to rational drug designing of the cytotoxic agents.

Antibacterial and Antifungal Activity of Holothuria leucospilota Isolated From Persian Gulf and Oman Sea.

BACKGROUND: Emergence of antimicrobial resistance toward a number of conventional antibiotics has triggered the search for antimicrobial agents from a variety of sources including the marine environment. OBJECTIVES: The aim of this study was to evaluate the antimicrobial potential of Holothuria leucospilota from Qeshm and Kharg Islands against some selected bacteria and fungi. MATERIALS AND METHODS: In this investigation, sea cucumbers from two coastal cities of Persian Gulf were collected in March and May 2011 and identified by the scale method according to the food and agriculture organization of the United Nations. Antibacterial activity of hydroalcoholic extracts of the body wall, cuvierian organs and coelomic fluid, methanol, chloroform, and n-hexane extracts of the body wall were evaluated by the spot test. In addition, their antifungal activity was assessed by the broth dilution method. RESULTS: The displayed effect was microbiostatic at concentrations of 1000 and 2000 µg/mL rather than microbicidal. The highest activity of hydroalcoholic extracts was exhibited by body wall, cuvierian organs and coelomic fluid against Escherichia coli, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa; Aspergillus niger, A. fumigatus, A. flavus and A. brasilensis. However, none of the methanol, chloroform and n-haxane extracts showed appreciable effects against Shigella dysenteriae, Proteus vulgaris, Bacillus cereus, S. epidermidis and Candida albicans. Moreover, cuvierian organs did not possess any antifungal potential. CONCLUSIONS: Our data indicated that water-methanol extracts from the body wall of H. leucospilota possess antibacterial and antifungal activity. However, additional and in-depth studies are required to isolate and identify the active component(s).

Antinociceptive effect of some biuret derivatives on formalin test in mice.

PURPOSE: The current study was designed to investigate the antinociceptive effects of several biuret derivatives with N, N`-diphenyl, N-phenyl-N`-alkylphenyl, N,N`-bis alkylphenyl, 2-methylquinoline-4-yl, benzo[d]thiazol-2-ylthio and (1-phenyl-1H-tetrazol-5-yl)thio substituents on the formalin-evoked pain in mice. METHODS: Antinociceptive activity of the nine biurets derivatives were assessed at different doses in mice using formalin test and the results were compared with those of indomethacin(20 mg/kg) and vehicle of the compounds. Area under the pain score curve against time (AUEC) up to 60 minutes was used as the measure of pain behavior. RESULTS: A rather good analgesic effect was seen for most of the tested biuret derivatives. Significant reduction in median AUEC0-5 minutes was observed at the doses of 50 and 25 mg/kg for biurets with either benzyl and 2-methylquinoline-4-yl (C8) or phenylethyl and benzo[d]thiazol-2-ylthio(C9) moieties, respectively(p-value<0.0044). Antinociceptive activities of compound C7 (with bis phenylropyl substituent), C8 and C9 during the late phase of formaldehyde-induced pain were comparable to that of indomethacin. CONCLUSION: Unlike indomethacin, the tested biuret compounds are able to induce antinociception in both phases of formalin test and could be considered comparable to indomethacin at the selected doses.

In silico and in vitro comparative activity of novel experimental derivatives against Leishmania major and Leishmania infantum promastigotes.

This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC50 and IC90). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC50 of 6.8 µM and an IC90 of 40.2 µM, whereas for L. infantum promastigotes was K8 with IC50 of 7.8 µM. The phenylethyl derivative (K7) showed less toxicity (IC50s>60 µM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 µM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1.

Development and Validation of a High-Performance Liquid Chromatography Method With UV Detection for Determination of 1-(2-phenylethyl)-5- (quinaldin-4-yl) Biuret in Rat Plasma.

BACKGROUND: Recently, biuret derivatives have been reported as showing moderate to good cytotoxic effect against certain cancer cell lines. In this study, a high-performance liquid chromatography method was developed for determination of 1-(2-phenylethyl)-5-(quinaldin-4-yl) biuret (PEQB) in rat plasma to use in future studies on this compound and related derivatives. OBJECTIVES: In this study, we describe a simple and sensitive high-performance liquid chromatography method with UV detection for determination of 1-(2-phenylethyl)-6-(quinaldin-4-yl) biuret (PEQB) in rat plasma. MATERIALS AND METHODS: Separations were performed on a Nucleosil-100 CN HPLC column (125 × 4.0 mm) (5 µm), using a mixture of acetonitrile: methanol: potassium dihydrogen phosphate buffer (0.05 M, pH 3.5) (10:10:80) as mobile phase delivered at a flow rate of 1 mL/minute. Detection of PEQB and internal standard (1-([[3-(1,3-benzothiazol-2-ylsulfanyl)propyl]carbamoyl]amino)-N-phenylformamide) was performed at 235 nm and ambient temperature. Plasma samples (200 µL) were prepared by addition of 40 µL internal standard (100 µg/mL), and 400 µL acetonitrile. After vortex mixing and centrifugation at 10000 g, 50 µL of the clear supernatant was directly injected onto the chromatography column. Calibration curves were constructed by fitting the peak area ratio of the biuret to internal standard against concentration of biuret to a power model using generalized least squares nonlinear regression method. RESULTS: Under the above chromatography condition, biuret compound (PEQB) and the internal standard were detected at 4.5 and 13.5 minutes, respectively. Limit of quantitation of the PEQB was 0.1 µg/mL. Accuracy of the method over the concentration range of 0.1-100 µg/mL was between 88-109%. Inter- and intraday precisions were 4-19% and 6-8%, respectively. A good relationship in the form of a power model was found for two separate concentration ranges of 0.1-1 and 2.5-100 µg/mL (R (2)> 0.99). CONCLUSIONS: The presented simple HPLC method is sufficiently accurate, precise and sensitive for the quantitation of 1-(2-phenylethyl)-5-(quinaldin-4-yl) biuret in rat plasma.

Discovery of a novel nitroimidazolyl-oxazolidinone hybrid with potent anti Gram-positive activity: Synthesis and antibacterial evaluation.

A number of linezolid analogues containing a nitroaryl-1,3,4-thiadiazole moiety, were prepared and evaluated as antibacterial agents against a panel of Gram-positive and Gram-negative bacteria. Among synthesized compounds, nitrofuran analogue 1b exhibited more potent inhibitory activity, with respect to other synthesized compounds and reference drug linezolid. The target compounds were also assessed for their cytotoxic activity against normal mouse fibroblast (NIH/3T3) cells using MTT assay. The results indicated that compound 1c exhibit potent antibacterial activity against Gram-positive bacteria at non-cytotoxic concentrations.

Spasmolytic effect of stachys lavandulifolia vahl. Crude methanolic extract and fractions on rat ileum.

The aim of this study was to investigate the effect of aerial parts of Stachys lavandulifolia Vahl. Extract on the rat ileum contractions. The crude extract was prepared by maceration method (90% methanol) followed by fractionating into chloroform, ethyl acetate, petroleum ether and water. In adult male Wistar rats, ileum was sectioned and mounted in tissue bath and their contractility was recorded is otonically. KCl (60 mM)- induced ileum contractions were attenuated by crude extract and its fractions. The most potent fraction was chloroformic fraction (CF) with IC50 0.018 ± 0.126 = mg/mL. In calcium-free Tyrode solution with high K(+,) the CF (0.01 - 0.04 mg/ml) attenuated CaCl2-induced contractions (p< 0.001). The CF (0.05-0.8 mg/mL) attenuated the carbachol-induced contraction (p<0.001). The CF antispasmodic effect was reduced by naloxone (as a non-selective opioid antagonist), not by propranolol and L-NAME as ß-adrenoceptors antagonist and nitric oxide synthase inhibitor respectively. It was concluded that S . . lavandulifolia can inhibit ileum contractility mainly via disturbing the calcium mobilization and partly by opioid receptors' activation. Our results may support the traditional usage of this herb for treating diarrhea.

Synthesis and cytotoxicity of some biurets against human breast cancer T47D cell line.

Design, synthesis and cytotoxicity of several known and novel biurets against human breast cancer T47D cell line in comparison to doxorubicin are described. Biurets incorporating 2-methyl quinoline-4-yl and benzo[d]thiazol-2-ylthio moieties showed higher cytotoxicity and decreased cell viability in a concentration- and time-dependent manner.

Synthesis and antibacterial activity of isothiazolyl oxazolidinones and analogous 3(2H)-isothiazolones.

The synthesis and antibacterial activity of several new 5-((3-oxoisothiazol-2(3H)-yl)methyl)-3-phenyloxazolidin-2-ones 8 and analogous 2-(4-substituted phenyl)-3(2H)-isothiazolones 3 and 4 substituted at 4 and/or 3-positions of the phenyl moiety with different groups of which some have shown to increase the antibacterial activity of both 3-aryl-2-oxazolidinones and 3(2H)-isothiazolones is described. The most active compounds were isothiazolyl oxazolidinones 8a,j with unsubstituted and 8b with 4-F substituted phenyl rings which showed activities higher than analogous 3(2H)-isothiazolones and comparable or superior to linezolid, vancomycin, and ciprofloxacin against some tested microorganisms. The change in position of F and/or the use of larger substituents gave compounds with reduced or no activity. Evaluation of cytotoxicity to mouse fibroblast (NIH/3T3) cells indicated that these compounds exhibit antibacterial activity at non-cytotoxic concentrations.

Synthesis, aerobic cytotoxicity, and radiosensitizing activity of novel 2,4-dinitrophenylamine tethered 5-fluorouracil and hydroxyurea.

Two novel dual functional agents, 3[3-(2,4-dinitro-phenylamino)-propyl]-5-fluoro-1H-pyrimidine-2,4-dione 7 and N-[3-(2,4-dinitro-phenylamino)-propoxy]urea 8, resulting from linkage of 2,4-dinitrophenylamine through three carbon atoms with 5-fluorouracil 5 and hydroxyurea 6, respectively, were prepared and their in vitro aerobic cytotoxicities in HT-29 cell line with and without radiation were determined. Compounds 7 and 8 unlike their components were not cytotoxic but showed radiosensitizing activity.

Synthesis and antibacterial activity of 2-(4-substituted phenyl)-3(2H)-isothiazolones.

Several new and known 2-(4-substituted phenyl)-3(2H)-isothiazolone derivatives with or without chloro substituent at C-5 position were synthesized and their in vitro antibacterial activity against selected Gram-negative and Gram-positive bacteria were evaluated using agar dilution method. Most of compounds exhibited moderate to high activities against tested microorganisms, and in comparison with the reference drugs some compounds showed comparable or higher activities. In contrast to results of the previous studies, some 5-chloro derivatives showed lower or comparable activities against some tested microorganism, in comparison with analogues without C-5 substitution. In general, most of the compounds bearing electron withdrawing group at 4-position of the phenyl ring were more active against Gram-positive and most of those having piperazine derivatives were more active against Gram-negative bacteria.