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1.
In this research, synthesis, antimicrobial and antioxidant activities of a series of catecholthioethers having benzoxazole and tetrazole moieties are described. Antimicrobial activity was evaluated by minimum inhibitory concentration (MIC) assay. The synthesized compounds were tested in vitro against three Gram-positive bacteria including Staphylococcus aureus (clinical isolated), Staphylococcus aureus ATCC 25922, Enterococcus faecium (clinical isolated), and two Gram-negative bacteria including Klebsiella pneumoniae (clinical isolated) and Pseudomonas aeruginosa 27853 and the yeast Candida albicans in comparison with control drugs. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between 4-256 μg/ml. This shows compounds having tetrazole moiety were the most active against Gram-negative strains, whereas compounds having benzoxazole moiety were more active against Gram-positive ones. Also both of them showed significant antifungal activity against Candida albicans and had lower activity than the compared control drugs (Sulfamethoxazole and Fluconazole). The antioxidant activity was assessed using two methods, including, 1,1-biphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and reducing power assays. Some of the catecholthioether derivatives showed antioxidant activity more than Trolox and butylated hydroxyanisole (BHA) as reference antioxidants.  相似文献   

2.
Chemical fractionation of the methanolic extract of leaves of Leiothrix spiralis Ruhland afforded the flavonoids luteolin-6-C-β-D-glucopyranoside (1), 7-methoxyluteolin-6-C-β-D-glucopyranoside (2), 7-methoxyluteolin-8-C-β-D-glucopyranoside (3), 4'-methoxyluteolin-6-C-β-D-glucopyranoside (4), and 6-hydroxy-7-methoxyluteolin (5), and the xanthones 8-carboxymethyl-1,5,6-trihydroxy-3-methoxyxanthone (6), 8-carboxy-methyl-1,3,5,6-tetrahydroxyxanthone (7). Methanolic extract, fractions, and isolated compounds of the leaves of L. spiralis were assayed against Gram-positive (Staphylococcus aureus, Bacillus subtilis and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella setubal and Helicobacter pylori) and fungi (the yeasts Candida albicans, C. tropicalis, C. krusei and C. parapsilosis). We observed the best minimum inhibitory concentration values for the methanolic extract against Candida parapsilosis, for the fraction 5 + 6 against Gram-negative bacteria E. coli and P. aeruginosa, and compound 7 against all tested Candida strains. The methanolic extract contents suggest that this species may be a promising source of compounds to produce natural phytomedicines.  相似文献   

3.
The use of microorganisms for biological purpose has become an effective alternative to control pathogens. A marine bacterium Pseudomonas aeruginosa was isolated from Eal fish of Baluchistan coast of Pakistan. This strain produced a bactericidal antibiotic against environmental and clinical isolates. In this study, we purified bactericidal antibiotic from the ethyl acetate extract of the cells of P. aeruginosa and analyzed its chemical structure. Based on spectrometric analysis, this compound 1 is proposed to be 1-methyl-1,4 dihydroquinoline and is active against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), Salmonella typhi, Shigella flexneri, Escherichia coli, Proteus mirabilis, Vibrio aliginolyticus, Micrococcus luteus, Enterococcus faecalis, Enterobacter faecium but it is not active against G streptococci, Candida albicans, Aspergillus niger. Minimal inhibitory concentration for Gram-positive bacteria was between 50 and 75 microg mL(-1) and for Gram-negative bacteria 75-100 microg mL(-1).  相似文献   

4.
The essential oils of Stachys spruneri Boiss. (sample A and sample B) were analyzed by GC and GC-MS. (+)-Isoabienol was the dominant component (49.5 and 48.2%, respectively of the total oils) among seventy-two identified constituents. Isoabienol was separated, purified by preparative thin-layer chromatography, and further identified by means ofphysicochemical and spectrometric analysis. The microbial growth inhibitory properties of the essential oil and its main metabolite, the labdane diterpene isoabienol, were determined using the broth microdilution method against eight laboratory strains of bacteria (Gram-positive: Staphylococcus aureus, S. epidermidis, Micrococcus luteus, Enterococcus faecalis, Bacillus subtilis, and Gram- negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two strains of the yeast Candida albicans. Both essential oil and isoabienol showed considerable activity against all the microorganisms tested, with the isolated compound being most active.  相似文献   

5.
Thiosemicarbazones(7–10)/semicarbazones(11–14) were synthesized in good yields via the condensation of α-gluco-, β-gluco-, galacto-, manno- chloralose derived 1,4-furanodialdoses (1-4) with thiosemicarbazide(5)/semicarbazide(6). The structures of all products were characterized by FTIR, NMR spectroscopic methods and elemental analysis. The compounds have been found to display moderate antimicrobial activity against Gram-positive, Gram-negative bacteria and antifungal activity against a Candida albicans. MIC values of the compounds range from 260 to 1510 μg/mL.  相似文献   

6.
We report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobial activity of the new compounds against Gram-positive [Listeria monocytogenes,Staphylococcus aureus, Bacillus subtilis], Gram-negative [Psedomonas aeruginosa,Escherichia coli, Salmonella enteritidis], as well as Candida spp., using both reference and clinical multidrug resistant strains to establish the minimal inhibitory concentration (MIC)values. Our results showed that the tested compounds exhibited specific antimicrobial activities, both concerning the spectrum of antimicrobial activity and the corresponding MIC values, which ranged widely between 1024 and 32 mug/mL, depending on the nature and position of the substituents on the benzene ring. The most active compounds were N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(2,6-dichlorophenyl)-thiourea (5 g) and N-[2-(4-chlorophenoxymethyl)-benzoyl]-N'-(4-bromophenyl)-thiourea (5h), which showed a broad spectrum of antimicrobial activity against enterobacterial strains (E. coli and S. enteritidis),P. aeruginosa, S. aureus and Candida spp. All the tested compounds except 5f were highly active against S. aureus (MIC=32 mug/mL), suggesting their possible use in the treatment of MRSA infections. Four of compounds also exhibited antifungal activity (MIC =256-32 microg/mL) against C. albicans, but L. monocytogenes as well as B. subtilis were resistant to all tested compounds. Our studies thus demonstrated that among other biological activities,the thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid also exhibit selective and effective antimicrobial properties that could lead to the selection and use of these compounds as efficient antimicrobial agents, especially for the treatment of multidrug resistant infections.  相似文献   

7.
Seventeen flavonoids isolated from the extracts of the stem of Entada phaseoloides were investigated for their anticomplement (both classic and alternative pathways) and antimicrobial activities against Gram-positive bacteria (MRSA, MSSA, Standard Enterococcus and Bacillus subtilis), Gram-negative bacteria (Escherichia coli, Pseudomonas aeuroginosa) and the yeast-like pathogenic fungus Candida albicans. The anticomplement studies revealed a dose-dependent activity among isolated quercetin, luteolin, apigenin, galangin, 5,2',5'-trihydroxy-3,7,4'-trimethoxyflavone-2'-O-beta-D-glucoside (+)-3,3',5',5,7-pentahydroflavanone, (+)-dihydrokaempferol, (-)-epicatechin, (+)-catechin, naringenin, and 5,7,3',5'-tetrahydroxyflavanone, and the antimicrobial results indicated that quercetin, 5,7,4'-trihydroxy-3'-methoxyflavonol and galangin produced the inhibitory activities against MRSA, MSSA, and Standard Enterococcus, while luteolin and rhamnocitrin displayed inhibition against only MRSA and MSSA. To the best of our knowledge, this is the first report that describes the anticomplement and antimicrobial activities of the stem of E. phaseoloides.  相似文献   

8.
The essential oils from fresh aerial parts of Monticalia greenmaniana (Hieron) C. Jeffrey (Asteraceae) collected in March, were analyzed by GC/MS. Oil yields (w/v) of 0.1% (flowers), 0.07%, (stems) and 0.1% (leaves) were obtained by hydrodistillation. Thirteen, sixteen and eighteen components, respectively, were identified by comparison of their mass spectra with those in the Wiley GC-MS Library data base. The major components of the flower and stem oils were 1-nonane (38.8% flowers; 33.5% stems), alpha-pinene (29.0% flowers; 14.8% stems) and germacrene D (15.6% flowers; 18.6% stems). However, in the leaf oil, germacrene D was observed at 50.7%, followed by beta-cedrene at 8.4%. The leaf essential oil showed a broad spectrum of antibacterial activity against the important human pathogenic Gram-positive and Gram-negative bacteria Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 25955) with MIC values ranging from 75 to 6000 ppm.  相似文献   

9.
This study reported the antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben inflorescences. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanolic extracts were determined according to the Clinical Laboratory Standards Institute guidelines. Individual phenolic acids and flavonoids were detected by a high performance liquid chromatography (HPLC-DAD) method. The samples showed a comparable antimicrobial activity, although the natural site extract possessed the lower MIC values. The best activity was detected against Gram-positive bacteria, such as Staphylococcus aureus including methicillin resistant strains (MIC and MBC values ranging from 7.81 to 62.50?μg?mL(-1) and from 500 to 2000?μg?mL(-1) respectively). In contrast, a low activity was found on Gram-negative bacteria and Candida albicans. The HPLC-DAD analysis revealed ten phenolic acids and four flavonoids with a major amount of m-coumaric acid, naringin and quercetin in the natural site extract.  相似文献   

10.
6-chloro-5-ethyl-, n-propyl- and isopropyluracils 5a-c were efficiently prepared from the corresponding 5-alkybarbituric acids 3a-c via treatment with phosphorus oxychloride and N,N-dimethylaniline to yield the corresponding 5-alkyl-2,4,6-trichloro-pyrimidines 4a-c, which were selectively hydrolyzed by heating in 10% aqueous sodium hydroxide for 30 minutes. The reaction of compounds 5a-c with 1-substituted piperazines yielded the corresponding 5-alkyl-6-(4-substituted-1-piperazinyl)uracils 6a-j. The target 8-alkyltetrazolo[1,5-f]pyrimidine-5,7(3H,6H)-diones 7a-c were prepared via the reaction of 5a-c with sodium azide. Compounds 6a-j and 7a-c were tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compound 6h displayed potent broad-spectrum antibacterial activity, while compound 6b showed moderate activity against the Gram-positive bacteria. All the tested compounds were practically inactive against Candida albicans.  相似文献   

11.
A series of 1,4-dihydro-1,3,5-triazine derivatives were designed and synthesized and their antibacterial and antifungal activities were evaluated. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains(including multidrug-resistant clinical isolates) and Gramnegative bacterial strains, with minimum inhibitory concentrations(MICs) in the range of 2.1–181.2 mmol/L. Compounds 7a and 7c presented the most potent inhibitory activities against Grampositive bacteria(e.g., Staphylococcus aureus 4220), Gram-negative bacteria(e.g., Escherichia coli 1924),and the fungus Candida albicans 7535, with MICs of 2.1 or 4.1 mmol/L. Especially, compound 7a was the most potent, with an MIC of 2.1 mmol/L against four multidrug-resistant, Gram-positive bacterial strains.The cytotoxic activity of the compound 7a, 7c and 7f was assessed in HepG2 cells, and the results suggest that 1,4-dihydro-1,3,5-triazine derivatives bearing a 6-benzyloxynaphthalen moiety are interesting scaffolds for the development of novel antibacterial agents.  相似文献   

12.
The chemical compositions of selected essential oils from North Africa, especially Morocco, of geranium, wild Moroccan chamomile and rosemary as well as absolutes of rose and geranium were determined using GC/FID and GC/MS. These oils and absolutes were tested concerning their antimicrobial activity against some food spoilage strains obtained from fresh milk and minced meat products, like sausages and pork fillet, in accordance with ISO testing procedures. Gram-positive (Bacillus cereus and Staphylococcus aureus) and Gram-negative (Escherichia coli, Salmonella abony and Pseudomonas aeruginosa) strains were used, as well as the yeast Candida albicans. Using a serial broth dilution method, all samples demonstrated weak antimicrobial activity against the Gram-negative bacteria and the yeast, compared with the activity towards the Gram-positive bacteria.  相似文献   

13.
In this study, a series of 10 novel 1-methyl-3-octyloxymethylimidazolium derivatives carrying various anionic moieties (4-hydroxybenzenesulfonate, benzenesulfonate, carvacroloxyacetate, chloride, formate, propionate, thymoloxyacetate, vanillinoxyacetate, eugenoloxyacetate and trimethylacetate) were synthesized. Compounds were tested for their antimicrobial activity against six microbe strains (Staph-ylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterococcus faecalis, and Candida albicans), cytotoxic activity against the mouse melanoma cell line (B16 F10), and surface active properties. All synthesized compounds exhibited antimicrobial activity (expressed as minimum inhibitory concentration; in range of 0.10–27.82 mM/L), especially against Gram-positive bacteria and fungi. In addition, all compounds demonstrated cytotoxicity on B16 F10 cells (IC50 values 0.0101–0.0197 mM/L). Surface properties defined as CMC values, ranged from 0.72 to 32.35 mmol L-1. The obtained results provide an insight into the promising activity of a novel group of quaternary imidazolium derivatives having ionic liquid properties. The most potent compounds, containing a thymoloxyacetate and eugenoloxyacetate moiety, could be candidates for new antimicrobial agents or surfactants.  相似文献   

14.
The present work describes the chemical composition and evaluates the antimicrobial and the anti-acetylcholinesterase properties of the flower oil from the Tunisian Ferula lutea obtained by hydrodistillation and analyzed by combination of GC/FID and GC/MS. The chemical composition of the flower oil of this species is reported for the first time. Seventeen compounds were identified accounting for 94.3% of the total oil. The chemical composition of this essential oil was characterized by a high proportion of monoterpene hydrocarbons (80.4%) among which delta-3-carene (31.2%) and alpha-pinene (25.8%) were the predominant compounds. The oxygenated monoterpenes represent the second major fraction (12.0%), 2,3,6-trimethylbenzaldehyde (10.9%) being the predominant one. Furthermore, the isolated oil was tested for its antimicrobial activity using the disc-diffusion and the microdilution assays against six Gram-positive and five Gram-negative bacteria as well as towards eight Candida species. It was found that flower oil of F. lutea exhibited interesting antibacterial and anticandidal activity (MIC = 39 mcirog/mL against Escherichia coli, Staphylococcus aureus and S. epidermidis and MIC = 156 microg/mL against Candida albicans). The anti-acetylcholinesterase effect of this oil was also evaluated in this work. Results showed that this oil exhibits significant activity (IC50 =70.25 +/- 5.41 microg/mL).  相似文献   

15.
Volatile oil composition of hydro-distilled (HD) and supercritical carbon dioxide (SC-CO(2)) essential oil of freshly collected aerial parts of Heracleum thomsonii (Umbeliferae) from the western Himalayas was studied by GC-FID and GC-MS. Results revealed qualitative and quantitative dissimilarity in the composition of hydro-distilled and SC-CO(2) extracted oils. Nineteen constituents, which accounted for 89.32% of total constituents in HD oil, represented by limonene (4.31%), (Z)-β-ocimene (3.69%), terpinolene (22.24%), neryl acetate (36.19%), nerol (9.51%) and p-cymene-8-ol (2.61%) were identified. In SC-CO(2) extracted oil, 24 constituents representing 89.95% of total constituents were identified. Terpinolene (5.08%), germacrene D (2.17%), neryl acetate (51.62%), nerol (9.78%), geranyl acetate (2.06%), α-bisabolol (2.48%) and 1-nonadecanol (4.96%) were the dominating constituents. In?vitro antimicrobial activity of hydro-distilled oil was conducted against microrobial strains including two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and five Gram-negative (Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa) bacteria as well as seven fungi (Candida albicans, Issatchenkia orientalis, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus sydowii and Trichophyton rubrum) using broth microdilution method. The results of bioassay showed that the oil exhibited moderate to high antimicrobial activity against fungi C. albicans (MIC 625 μg?ml(-1)), A. parasiticus (MIC 312.5 μg?ml(-1)), A. sydowii (MIC 312.5 μg?ml(-1)), T. rubrum (MIC 625 μg?ml(-1)), Gram-positive bacteria B. subtilis (MIC 625?μg?ml(-1)) and Gram-negative bacteria P. aeruginosa (MIC 312.5 μg?ml(-1)).  相似文献   

16.
The necessity for the development of new antimicrobial agents due to the ever increasing threat from microbes is causing a rapid surge in research. In the present work, we have shown the efficient antimicrobial activity of a series of amino acid-based hydrogelating amphiphiles through alteration in their counterion. The subtle variation in the counterion from chloride to various organic carboxylates had a significant impact on the antimicrobial properties with notable improvement in biocompatibility toward mammalian cells. Incorporation of a hydrophobic moiety in the counterion augmented the antibacterial property of the amphiphilic hydrogelator as minimum inhibitory concentration (MIC) against the Gram-positive bacterial strain, Bacillus subtilis decreased up to 5-fold (with respect to the chloride) in the case of n-hexanoate. These counterion-varied amphiphilic hydrogelators were also found to be effective against fungal strains (Candida albicans and Saccharomyces cerevisiae) where they exhibited MICs in the range of 1.0-12.5 μg/mL. To widen the spectrum of antibacterial activity, particularly against Gram-negative bacteria, silver nanoparticles (AgNPs) were synthesized in situ within the supramolecular assemblies of the carboxylate hydrogelators. These AgNP-amphiphile soft-nanocomposites showed bactericidal property against both Gram-positive and Gram-negative bacteria. Encouragingly, these carboxylate hydrogelators showed superior biocompatibility toward mammalian cells, HepG2 and NIH3T3, as compared to the chloride analogue at a concentration range of 10-200 μg/mL. Importantly, the AgNP composites also showed sufficient viability to mammalian cells. Because of the intrinsic hydrogelation ability of these counterion-varied amphiphiles, the resulting soft materials and the nanocomposites could find applications in biomedicine and tissue engineering.  相似文献   

17.
In an effort to explore the antibacterial potential of the marine natural product halocyamine A, a series of analogues including desbromo and alanine-substituted variants were synthesised and evaluated for biological activity against a panel of Gram-positive and –negative bacteria. The analogues were synthesised by a combination of solid-phase peptide synthesis and ruthenium complex/ytterbium triflate catalysed hydroamidation chemistry. Single alanine substitutions ([Ala1]-halocyamine A and [Ala2]-halocyamine A) gave only modest increases in activity towards Gram-positive bacteria, while di-alaninyl variants exhibited more potent activity with MIC values of 12.5–50?μM towards the Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis. A lipophilic trityl-protected intermediate of [Ala2]-halocyamine was the most active against the Gram-negative bacterium Escherichia coli.  相似文献   

18.
Ethanol extract and fractions obtained from fresh and dry aerial parts of Lippia alba were examined in order to determine their phytochemical composition, antioxidant capacity and antibacterial activities. The ethanol extracts and fractions exhibited an antioxidant effect by the DPPH assay, especially samples of fresh plant. HPLC analysis of the ethyl acetate fractions identified the presence of phenolic acids and flavonoids. The ethanol extract and fractions showed activity against reference and multidrug-resistant strains of Staphylococcus aureus and Enterococcus faecalis (MIC range 2000–250 μg/mL). The hexane and dichloromethane fractions of fresh plant showed better activity against reference strains of Escherichia coli (MIC of 250 and 125 μg/mL, respectively), but all extracts and fractions were less active against multidrug-resistant strains of all the Gram-negative species evaluated. The results showed that the extract and fractions of L alba aerial parts showed antibacterial activity, even against multidrug-resistant Gram-positive bacteria, and antioxidant effect (DPPH assay).  相似文献   

19.
A new series of 4-((4,4-dimethyl-2,6-dioxocyclohexylidene)methylamino)-N-(substituted)benzenesulfonamide 317, monosubstituted 2-((4-((4-aminophenyl)sulfonyl)phenyl)amino)methylene 18, and its disubstituted derivative 19 were synthesized from the starting material 2-((dimethylamino)methylene)-5,5-dimethylcyclohexane-1,3-dione 2. The crystal structures of compounds 2, 7 and 13 were reported by us through X-ray crystallography. All the prepared compounds were evaluated for their antibacterial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Clostridium sporogenes), Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), and antifungal activity against Aspergillus fumigatus, Penicillium chrysogenum, Fusarium oxysporum, Candida albicans. The synthesized compounds displayed interesting antimicrobial activity. Compounds 4 and 12 were the most potent in this study and displayed higher activity compared to the reference drugs, with MIC value of 3.9–31.3 μg/mL against a panel of Gram-positive, Gram-negative bacteria and fungi. Molecular modeling was performed inside the active site of dihydropteroate synthase. The synthesized compounds showed similar orientation and binding interactions to that of the co-crystallized ligand inside the binding pocket.  相似文献   

20.
The chemical composition of the steam volatile oil of the whole aerial part of Scutellaria grossa Wall ex Benth. (Lamiaceae), obtained by steam distillation, has been analysed by capillary GC and GC-MS. The oil was found to be rich in oxygenated monoterpenes (88.6%). A total of 50 constituents were identified, representing 94.4% of the total oil composition. Linalool (37.0%) and 1-octen-3-ol (32.0%) were found to be the principal constituents. The antibacterial activity of the oil was determined against 10 bacterial strains by measuring the growth inhibitory zones. The oil showed significant antibacterial activity against Gram-positive bacteria, Bacillus subtilis and Enterococcus faecalis, and the Gram-negative, Klebsiella pneumoniae and Salmonella enterica enterica. A minimum inhibitory concentration of 31.25?μL mL(-1) was observed against E. faecalis.  相似文献   

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