Antimicrobial activity and phytochemical screening of Arbutus unedo L.

In this study, antimicrobial activities of water and methanol extract, and three phenolic fractions of the roots of Arbutus unedo L. were investigated. Poor antibacterial activity against both Staphylococcus aureus and Pseudomonas aeruginosa bacteria was shown with water and methanol extract. However moderate antibacterial activity was shown by water extract and phenolic fractions against Escherichia coli and S. aureus, respectively. The phytochemical screening of roots of A. unedo revealed the presence of quinones, anthraquinones reducteurs compounds, anthocyanins, tannins and flavonoids. Quantitative analysis showed that the roots were strongly dominated by anthocyanins compounds (3.65 mg g^?1) followed by total flavonoids (0.56 mg^?1) and flavones & flavonols (0.17 mg g^?1).     

Synthesis and antimicrobial activity of 2<Emphasis Type="Italic">H</Emphasis>-pyrimido[2,1-<Emphasis Type="Italic">b</Emphasis>]benzothiazol-2-ones

4-Phenyl-2H-pyrimido[2,1-b]benzothiazol-2-ones have been synthesized in quantitative yields by the reaction of 2-aminobenzothiazoles with alkynoic acid. The antimicrobial activity of the synthesized compounds was tested against bacterial species, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa. The synthesized compounds have shown significant activity against microorganisms which can be correlated with the fused heterocyclic systems.     

Characterization of Citrus nobilis Peel Methanolic Extract for Antioxidant,Antimicrobial, and Anti-Inflammatory Activity

Currently, the potential utilization of fruits and vegetable waste as a source of micronutrients and antioxidants has increased. The present study, therefore, aimed to determine the antimicrobial and anti-inflammatory activities of Citrus nobilis peel extract. A modified solvent evaporation technique was employed for peel extract preparation. For effective utilization of the natural product, quantitative analysis of phenolic compounds was carried out using liquid chromatography and mass spectroscopy technique. Phenolic and flavonoids were present in high amounts, while β-carotene and lycopene were present in vestigial amounts. The antimicrobial efficiency of peel extract was evaluated against four bacterial strains including Staphylococcus aureus (MTCC 3160), Klebsiella pneumoniae (MTCC 3384), Pseudomonas aeruginosa (MTCC 2295), and Salmonella typhimurium (MTCC 1254), and one fungal strain Candida albicans (MTCC 183), and zone of inhibition was comparable to the positive control streptomycin and amphotericin B, respectively. The extract of Citrus nobilis peels showed effective anti-inflammatory activity during human red blood cell membrane stabilization (HRBC) and albumin denaturation assay. The extracts also exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity ranging from 53.46 to 81.13%. Therefore, the obtained results suggest that Citrus nobilis peel could be used as an excellent source of polyphenols and transformed into value-added products.     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.     

Iron oxide superparamagnetic nanocarriers bearing amphiphilic N‐heterocyclic choline analogues as potential antimicrobial agents

Magnetic nanoparticles represent an advanced tool in biomedicine because they can be simultaneously functionalized and guided using a magnetic field. Iron oxide magnetic nanoparticles precoated with oleic acid and bearing novel antimicrobial N‐heterocyclic choline analogues, namely O‐, N‐ and O,N‐bis‐undecyl‐substituted N‐(2‐hydroxyethyl)‐1,2,3,4‐tetrahydroisoquinolinium derivatives, have been obtained as potential biomedical agents for drug delivery and antimicrobial therapy. Structural and size determinations for the novel synthesized magnetic nanosystems were carried out based upon magnetogranulometry, dynamic light‐scattering measurements and X‐ray diffraction analysis. The most expected iron oxide core diameter was 6.2–10.5 nm. The magnetization analyses showed that the particles are superparamagnetic at room temperature. Aqueous magnetic fluids of the synthesized nanoparticles were examined in vitro concerning Gram‐positive (Staphylococcus aureus MSCL 334, Bacillus cereus MSCL 330) and Gram‐negative (Escherichia coli MSCL 332, Pseudomonas aeruginosa MSCL 331, Proteus mirabilis MSCL 590) bacterial strains and fungi (Candida albicans MSCL 378, Aspergillus niger MSCL 324). It was found that the samples have magnetic properties and possess antimicrobial activity. The minimum inhibitory concentration against S. aureus for the most active magnetic fluid was determined as 16 µg ml^?1. Copyright © 2015 John Wiley & Sons, Ltd.     

Antimicrobial activities,toxicity and phenolic composition of Asphodeline anatolica E. Tuzlaci leaf extracts from Turkey

The antimicrobial activity of acetone, methanol and aqueous extracts of Asphodeline anatolica E. Tuzlaci leaves was evaluated against American type culture collection, food and clinical isolates (Listeria monocytogenes and Staphylococcus aureus including methicillin-resistant strains-MRSA). Biofilm formation, toxicity and characterisation of the polyphenolic content were analysed. The acetone extract demonstrated a higher antibacterial activity against S. aureus including MRSA strains, L. monocytogenes and Pseudomonas aeruginosa than against other extracts. No effect was observed in biofilm formation. The extracts resulted non-toxic against Artemia salina Leach. The phytochemical screening of extracts indicated that they mainly contained six polyphenols identified as catechin 3-O-gallate, protocatechuic acid, diosmin, rutin, cirsimaritin and kaempferol glucoside. This study is the first report on antimicrobial activity and phenolic content of A. anatolica and contributes to enrich the literature data on the biological properties of this plant. A. anatolica leaves have a potential as source of natural antimicrobial compounds.     

An indole diterpenoid isolated from the fungus Drechmeria sp. and its antimicrobial activity

One new indole diterpenoid, drechmerin I (1), was isolated from the fermentation broth of Drechmeria sp. isolated from the root of Panax notoginseng. Its structure was elucidated based on 1 D and 2 D nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectrum (HRESIMS), and electronic circular dichroism (ECD) spectroscopic analyses as well as TD DFT calculations of ECD spectra. Drechmerin I (1) was assayed for its antimicrobial activity against Candida albicans, Staphylococcus aureus, Bacillus cereus, B. subtillis, Pseudomonas aeruginosa, and Klebsiella pneumonia, respectively. Drechmerin I (1) showed antimicrobial activities against B. subtillis with an MIC value of 200 μg/mL. The interaction of S. aureus peptide deformylase with drechmerin I (1) was investigated by molecular docking.     

Simple,Multicomponent, Ecofriendly,Microwave-Mediated Route for the Synthesis of Antimicrobial 2-Amino-6-aryl-4-(3H)-pyrimidinones

In this work, we describe a multicomponent microwave-mediated synthesis of 10 2-amino-6-aryl-4-oxo-1,6-dihydro-pyrimidine-5-carbonitriles in good chemical yields (44–67%), four of them not related in earlier literature. All pyrimidinones synthesized herein had their antimicrobial activity evaluated against the following microorganisms: Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Two of the synthesized substances displayed good antimicrobial activity against P. aeruginosa and S. aureus, two bacteria responsible for nosocomial infections.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Synthesis and in vitro Antibacterial Activities of 5‐(2,3,4,5‐Tetrahydro‐1H‐chromeno[2,3‐d]pyrimidin‐5‐yl)pyrimidione Derivatives

A series of novel 5‐(2,3,4,5‐tetrahydro‐1H‐chromeno[2,3‐d]pyrimidin‐5‐yl)pyrimidione derivatives have been synthesized from substituted salicylaldehydes and barbituric acid or 2‐thiobarbituric acid in water catalyzed by phase transfer catalysis of triethylbenzyl ammonium chloride (TEBA). Elemental analysis, IR, ¹H NMR, and ¹³C NMR elucidated the structures of all the newly synthesized compounds. In vitro antimicrobial activities of synthesized compounds have been investigated against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa. These newly synthesized derivatives exhibited significant in vitro antibacterial activity.     

Enhanced antifouling and anticoagulant properties of grafted biomolecule polyethersulfone membranes

Polyethersulfone (PES) has been widely used in membrane technology and used to purify water in water treatments application or as a dialyzer to purify blood in hemodialysis. In this work, PES was chemically modified by separately grafting two biomolecules, 4‐aminobenzenesulfonamide (ABS), and 4‐amino‐N‐(5‐methylisoxazol‐3‐yl)benzenesulfonamide (AMBS), on PES backbone, and these modified membranes were blended to unmodified PES, in 1:1 ratio, in order to obtain PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes. The first aim of this study is to measure the anticoagulant properties of the modified membrane by measuring the activated partial thromboplastin time (APTT) and prothrombin time (PT). The second aim of the study is to evaluate the antifouling properties of the modified PES membranes by examining its antimicrobial activity against two Gram‐negative bacteria, which are Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli); two Gram‐positive bacteria, which are Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus); and a fungus, which is Candida albicans (C. albicans). The results showed that grafting of ABS and AMBS improved overall the hydrophilicity properties of the modified PES membranes. PES‐b‐PES‐ABS membranes showed better anticoagulant properties with 13 seconds for PT and 38 seconds for APPT, in comparison with the control sample (pure plasma), which showed 12 seconds for PT and 30 seconds for APPT. For antimicrobial tests, both PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes did not show any antibacterial activity, but when zinc oxide (ZnO) nanoparticles were added to the modified PES membranes in concentrations between 3% to 5% w/w, PES‐b‐PES‐ABS‐ZnO (M‐4 and M‐5), and PES‐b‐PES‐AMBS‐ZnO (M‐8 and M‐9) nanocomposite membranes showed antibacterial activity against P. aeruginosa and S. aureus.     

One‐pot,four‐component synthesis of 1,3,4‐oxadiazole derivatives containing a ferrocene unit and their antimicrobial activity

A four‐component reaction between aromatic carboxylic acids, (N‐isocyanimino)triphenylphosphorane, ferrocenecarbaldehyde and dibenzylamine is reported. This approach is an efficient, simple and high‐yield procedure for the synthesis of 1,3,4‐oxadiazole derivatives containing a ferrocene unit. The antimicrobial activities of the products were investigated against Staphylococcus aureus and Pseudomonas aeruginosa in in vitro and in vivo assays. Copyright © 2015 John Wiley & Sons, Ltd.     

Antimicrobial effects of vanillin-based pyridyl-benzylidene-5-fluoroindolins

In this study, the antimicrobial effect and DNA gyrase inhibitor potential of vanillin-based pyridyl–substituted fluoro-indolines were evaluated. These compounds are synthesized and established through green-chemistry approaches. The inhibition effect on both DNA gyrase A and B was evaluated in silico and in vitro. Agar well diffusion method–based antimicrobial activity against Gram-ve Pseudomonas aeruginosa (MTCC 424) and Escherichia coli (MTCC 443), Gram+ve Streptococcus pyogenes (MTCC 442) and Staphylococcus aureus (MTCC 96), and a clinical isolate of Candida albicans (Fungi) was evaluated. The cytotoxicity of the compounds was assessed over macrophages using the MTT assay. In the results, the target compounds exhibited a broad-spectrum antimicrobial activity against both bacterial types and fungal.     

Polymer complexes. LXXII. Spectroscopic studies,thermodynamics, DNA binding and biological activity of polymer complexes

A novel series of copper polymer complexes ( 1 – 4 ) were synthesized and characterized using various spectroscopic techniques. Spectra of all polymer complexes a tetragonal distorted geometry for the Cu(II) ion. The electronic spectra, magnetic moments and electron spin resonance results indicate tetragonal distortion geometry for the Cu(II) polymer complexes. The effects of various solvents on absorption spectra of the ligand are discussed. A prediction of the interaction of the ligand against anti‐cancer receptors was carried out using AutoDock server. The affinity of the compounds to calf thymus DNA was determined through UV–visible DNA binding titration, and intrinsic binding constant (K_b) was found to be 4.16 × 10³, 3.10 × 10⁵, 3.18 × 10⁴ and 2.91 × 10⁵ for polymer complexes 1 – 4 , respectively. The antimicrobial activity of the polymer complexes against bacterial species (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Enterococcus faecalis and Pseudomonas aeruginosa) and fungal species (Aspergillus niger, Fusarium oxysporum and Candida albicans) was investigated.     

Synthesis and Antimicrobial Activities of Some 1-[(N,N-Disubstitutedthiocarbamoylthio)acetyl]-3,5-diaryl-2-pyrazolines

The increasing clinical importance of drug-resistant fungal and bacterial pathogens has lent additional urgency to microbiological research and new antimicrobial compound development. For this purpose, new pyrazoline derivatives were synthesized and evaluated for antimicrobial activity.

Some 1-[(N, N-disubstitutedthiocarbamoylthio)acetyl]-3,5-diaryl-2-pyrazolines derivatives were synthesized by reacting 1-(chloroacetyl)-3,5-diaryl-2-pyrazolines with appropriate potassium salts of secondary amine dithiocarbamic acids. The chemical structures of the compounds were elucidated by IR, ¹ H-NMR, and FAB⁺-MS spectral data. Their antimicrobial activities against Staphylococcus aureus (B-767), Escherichia coli (B-3704), Pseudomonas aeruginosa (ATCC 27853), Proteus vulgaris (NRLL B-123), and Candida albicans (NRRL-27077) were investigated. The results showed that some of the compounds have notable activity against S. aureus and C. albicans.     

Raman spectroscopy of the multi-anion mineral mallestigite Pb3Sb(5+)(SO4)(AsO4)(OH)6·3H2O: a mineral of archaeological significance

In this work we investigated relationship between molecular structure of alkali metal o-, m-, p-anisate molecules and their antimicrobial activity. For this purpose FT-IR spectra for lithium, sodium, potassium, rubidium and caesium anisates in solid state and solution were recorded, assigned and analysed. Microbial activity of studied compounds was tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris. In order to evaluate the dependency between chemical structure and biological activity of alkali metal anisates the statistical analysis (multidimensional regression and principal component) was performed for selected wavenumbers from FT-IR spectra and parameters that describe microbial activity of anisates. The obtained statistical equations show the existence of correlation between molecular structure of anisates and their biological properties.     

Synthesis,Characterization, and Antimicrobial Evaluation of Sulfonamides Containing N-Acyl Moieties Catalyzed by Bismuth(III) Salts Under Both Solvent and Solvent-Free Conditions

Efficient N-acylation of sulfonamides with both readily available carboxylic acid chlorides and anhydrides has been carried out with catalysis by bismuth(III) salts including BiCl₃ and Bi (OTf)₃. The reactions proceed rapidly in both heterogeneous and solvent-free conditions and afforded the corresponding N-acylsulfonamides in good to excellent yields. The mild reaction conditions and low toxicity of bismuth salts make this procedure attractive and in close agreement with the goals of green chemistry. Some of the synthesized compounds were evaluated in vitro as antimicrobial agents against representative strains of Gram-positive (Staphylococcus aureus ATCC 25922, clinical strains of Staphylococcus aureus VISA and Enterococcus spp.) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853, clinical strains of Klebsiella pneumonia and Escherichia coli) and as antifungal agents against Candida albicans (clinically isolated) by both disc diffusion and minimal inhibition concentration (MIC) methods. All these bacteria and fungi studied were screened against some antibiotics to compare with our chemicals' zone diameters.     

Synthesis,Biological Evaluation,and Molecular Docking Studies of Some N‐thiazolyl Hydrazones and Indenopyrazolones

Two new series of N‐thiazolyl hydrazones ( 3a – h ) and indenopyrazolones ( 4a – h ) were synthesized by the reaction of various 2‐acyl‐(1H)‐indene‐1,3(2H)‐diones, thiosemicarbazide, and phenacyl bromide/substituted phenacyl bromides. The in vitro antimicrobial activity of these synthesized compounds was assayed against four bacteria, namely, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and two fungi, namely, Candida albicans and Aspergillus niger, by employing serial dilution method. Ciprofloxacin and fluconazole were used as antibacterial and antifungal reference drugs, respectively. Results of antimicrobial assay showed that the tested compounds have broad range of activity. The compounds 3h and 4a against C. albicans displayed more potency than fluconazole whereas 3b and 3c against B. subtilis showed activity comparable with ciprofloxacin. The synthesized indenopyrazolones ( 4a – h ) were evaluated for their in vitro antioxidant activity by 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging assay using ascorbic acid as reference. Compound 4b exhibited the highest 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging with IC₅₀ value 33.14 μg/mL. The observed results of antimicrobial activity were supported by molecular docking study performed to understand the binding interaction of hydrazones ( 3a – h ) and indenopyrazolones ( 4a – h ) with lanosterol 14α‐demethylase.     

Design,Synthesis and Molecular Modeling of Nonsteroidal Anti‐inflammatory Drugs Tagged Substituted 1,2,3‐Triazole Derivatives and Evaluation of Their Biological Activities

A novel series of 1,4‐disubstituted‐1,2,3‐triazole derivatives 3a – l and 5a – i were one‐pot synthesized via CuAAC‐alkyne click chemistry and evaluated for their antibacterial activity against four organisms and screened for their anticancer activity against human colon cancer cell line HT‐29 and human lung cancer cell line HTB‐29. These hybrid molecules structure elucidation has been performed by IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral analysis. Synthesized nonsteroidal anti‐inflammatory drugs‐triazoles evaluated for their antibacterial activities against bacterial microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia. Final compounds 3i , 3c , and 5b showed magnificent broad spectrum activity against P. aeruginosa, K. pneumonia, E. coli, and S. aureus with zone of inhibition values of 20, 15, 17, and 16 mm, respectively. Among the series of compound, 3j showed the best antibacterial activity against all the strains. Further, the compounds 3i and 5a were more cytotoxic than cisplatin against all tested two human cancer cell lines, with 50.8%, and 52.3% and 73.4% and 75.3% of growth, respectively. The synthesized compounds were tested for kinase inhibitory activity against glycogen synthase kinase‐3 protein kinases, in addition, for cytotoxic activity against two different human cancer cell lines.     

Synthesis,characterization and antimicrobial activity of nalidixic acid derivatives with spirohydantoins

This article presents the synthesis of a series of amides, based on the interaction of several 3-aminospirohydantoins with nalidixic acid. The target compounds were characterized by physicochemical parameters, IR, ¹H and ¹³C NMR spectral data. The antimicrobial activity of the products obtained was determined against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and Salmonella abony, the yeasts Candida albicans and Saccharomyces cerevisiae and the molds Penicillium chrysogenum and Aspergillus niger. The relationship between structure and biological activity of the products obtained was discussed. It was found that the most effective compounds are tetralin (5f) and indane (5g) derivatives, which exhibit a pronounced antimicrobial activity against both tested Gram-positive and Gram-negative bacteria.

     

Analysis of Rhamnolipid Biosurfactants Produced Through Submerged Fermentation Using Orange Fruit Peelings as Sole Carbon Source

The fermentative production of rhamnolipid biosurfactant from Pseudomonas aeruginosa MTCC 2297 was carried out by submerged fermentation using various cost-effective waste materials such as orange peelings, carrot peel waste, lime peelings, coconut oil cake, and banana waste. The orange peel was found to be the best substrate generating 9.18 g/l of rhamnolipid biosurfactant with a surface tension reduction up to 31.3 mN/m. The production was growth independent, and optimum conditions were standardized. The emulsifying activity was highest against kerosene (73.3%). Rhamnolipid components were purified and separated by ethyl acetate extraction, preparative silica gel column chromatography, high-performance liquid chromatography and thin-layer chromatography. The major rhamnolipid components were characterized, by fast atom bombardment mass spectrometry, as a mixture of dirhamnolipids and monorhamnolipids.