Serial Broth Dilution Method Research Articles

Evaluation of Antibacterial Efficacy of Wax Apple (Syzygium samarangense) Fruit Extracts Against Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans – An In vitro Study

Objective: The objective of this study was to evaluate the antibacterial efficacy of wax apple (Syzygium samarangense) fruit extracts (aqueous and ethanol) against Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans. Methodology: The stock solution was prepared for microbial analysis (100 mg/ml). A disc diffusion test to determine the zone of inhibition and the serial broth dilution test to determine the minimum inhibitory concentration were done to assess the antimicrobial activity. Data obtained were appraised observationally and interpreted. Results: When assessed for antibacterial activity of extracts by disc diffusion method, both aqueous and ethanolic extracts did not show a zone of inhibition on P. gingivalis and A. actinomycetemcomitans. However, the aqueous extract showed an inhibition zone of 8 mm at the concentration of 50 and 75 µl/ml against F. nucleatum. Similarly, the ethanolic extract showed an inhibition zone of 8 mm at 50 µl/ml and 9 mm at 75 µl/ml volume against F. nucleatum. When assessed for antibacterial activity of extracts by serial broth dilution method, only P. gingivalis (both aqueous and ethanolic extracts at 50 µg/ml) and F. nucleatum (aqueous extracts at 1. 6 µg/ml and ethanolic extract at 0.4 µg/ml) exhibited antibacterial effect, whereas A. actinomycetemcomitans was completely resistant to both extracts at all the concentrations. Conclusion: In the present in vitro study, S. samarangense (wax apple) showed its antibacterial activity against F. nucleatum only by exhibiting MIC at 1.6 µg/ml for aqueous and 0.4 µg/ml for ethanolic extract, but no antibacterial activity was shown against P. gingivalis and A. actinomycetemcomitans.

Antibacterial Activity of Bioactive Compound Produces by Endophtic Fungi Isolated from Mangifera casturi Kosterm Endemic Plant from South Kalimantan, Indonesia

One of promising bio-prospect as producer of an antibacterial compound is endophytic fungi that live in endemic plants. This research is aimed to evaluate the endophytic fungi antibacterial compound from Mangifera casturi, an South Kalimantan endemic plant that has ethnobotanical utilisation in the pharmaceutical field. The bioactive compounds of 13 endophytic fungi were extracted using ethyl acetate and evaluated for antibacterial activity using disc diffusion assay. The minimum inhibitory concentration (MIC) was measured by the serial broth dilution method. Scanning Electron Microscopy (SEM) was used to examine cell damage due to the effect of the extract. The antibacterial compounds then were detected using GC-MS analysis. The endophytic fungi were identified morphologically and molecularly based on ITS rDNA sequence. Among 13 isolates, endophytic fungi identified as Botryosphaeria rhodina AK32 able to produce antibacterial compounds that exhibited the highest activity and have a broad spectrum, moreover capable against resistant bacteria (MRSA) with 1.56% of MIC value for all of the test bacteria. AK32 ethyl acetate extract was inhibiting the cell wall synthesis and penetrate the outer membrane of bacteria. Based on GC-MS, antibacterial compounds of AK32 ethyl acetate extract were di-n-octylphthalate, phenol, 2-methyl-, 4-pentadecyne, 15-chloro-, benzeneacetonitrile, and benztriazole.

Benzothiazole Clubbed Imidazolone Derivatives: Synthesis, Molecular Docking, DFT Studies, and Antimicrobial Studies.

This study aims to synthesize antimicrobial agents and their molecular docking, and DFT studies of benzothiazole-imidazolone scaffolds. Benzothiazole and imidazolone analogues are of interest due to their potential activity against microbial infections. In search of suitable antimicrobial compounds, we report here the synthesis, characterization, and biological activities of benzothiazole and imidazolone analogues (4a-l). The benzothiazole clubbed imidazolone motifs were synthesized, characterized, and screened for their antimicrobial activity. Molecular docking was carried out for the development of antimicrobial agents based on the results of biological activity obtained. We have synthesized a new series of benzothiazole-clubbed imidazolone hybrids by using multi-step reactions in the search for antimicrobial agents (4a-l). The structures were determined by 1H NMR, 13C NMR, IR, and mass spectroscopy techniques. Moreover, synthesized compounds were evaluated for their antimicrobial activity by using a Serial Broth Dilution method. In addition, molecular electrostatic potential, geometric optimization, and molecular reactivity analyses (HOMO-LUMO) of 4c, which is one of the compounds with the highest antibacterial activity, were performed. The in vitro antimicrobial activity was evaluated against pathogenic strains. Among them, compounds 4c showed the most potent biological activity against Gram-negative bacteria, E. coli with MIC values of 50 μg/mL, and compound 4c active against A. clavatus with MIC values of 100 μg/mL. Active compound 4c HUMO-LUMO energies, molecular electrostatic potential analysis, and geometric optimization parameters were calculated with a 6-31G ** base set using DFT/B3LYP theory, and the results were displayed. Molecular docking studies were performed on E. coli DNA Gyrase B to understand the binding interaction of compound 4c, and it was observed that compound 4c interacted with Arg76 amino acid of the active site through hydrophobic interaction. Benzothiazole-clubbed imidazolone hybrids (4a-l) indicated promising antimicrobial activity. Among them, compounds 4b (MIC=50 μg/mL C. albicans), 4c (MIC=50 μg/mL, E. coli), 4e (MIC= 100 μg/mL, A. niger), and 4g (MIC= 50 μg/mL, S. pyogenes) with electronwithdrawing bromo, chloro, and fluoro group at the para position of the phenyl ring on benzothiazole-imidazolone hybrids indicated remarkable potency compared to the standard drug. The geometric optimization, molecular reactivity, and MESP analyses of 4c were calculated with the B3LYP/6-31G ** base set and ΔE = ELUMO-EHOMO, which was found to be - 0.12096 eV. In addition, the binding affinity scores correlated well with the in vitro antimicrobial activity (4c), while their binding modes proposed the involvement of steric, electrostatic, and hydrogen- bonding interactions with the active site.

Trace Element Analysis and in vitro Bioactivity of Parkia roxburghii and Rhus semialata extracts

A study on the fruit of Parkia roxburghii and Rhus semialata, specifically found in Nagaland, is being done in this work which includes its phytochemical screening, trace element determination, anti-bacterial and antioxidant studies. Acetone and Ethanol were used for the extraction purpose. Furthermore, in vitro antioxidant studies for determining its free radical scavenging activity were carried out through the DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assay as compared with the reference standards Trolox and Ascorbic acid. The extracts were also evaluated for their anti-bacterial activity against four strains of bacteria and to further quantify the anti-bacterial studies, the MIC (Minimum Inhibitory Concentration) of both the samples were carried out by means of two-fold serial broth dilution method.

Synthesis, molecular structure, FMO, spectroscopic, antimicrobial and in-silico investigation of (E)-1-(benzo[d][1,3]dioxol-5-yl)-3-(4-aryl)prop-2-en-1-one derivative: Experimental and computational study

In the present investigation five (E)-1-(benzo[d][1,3]dioxol-5-yl)-3-(4-aryl)prop-2-en-1-one derivatives were prepared by Claisen Schmidt condensation. They are characterized by FT-IR, 1H NMR, 13C NMR, and HRMS spectroscopic methods. Theoretical investigation of these synthesized compounds was carried out by density functional theory (DFT) at the B3LYP/6–31+G(d,p) level of theory. The specifications for optimized geometries, frontier molecular orbitals, global reactivity descriptors, molecular electrostatic potential and harmonic vibrational wavenumber were calculated and addressed. All compounds were evaluated for in vitro antibacterial activities against Escherichia coli (MTCC 443), Pseudomonas aeruginosa (MTCC 1688), Staphylococcus aureus (MTCC 96) and Streptococcus pyogenes (MTCC 442) strains, and in vitro antifungal activities against Candida albicans (MTCC 227), Aspergillus niger (MTCC 282) and Aspergillus clavatus (MTCC 1323) strains by using serial broth dilution method. Synthesized compounds show good antibacterial activity. In silico pharmacokinetics study is also carried out and study shows they have good ADME characteristics and might be used as antimicrobial agent.

Synthesis, Characterization, In vitro Antimicrobial Evaluation and Molecular Docking Studies of Pyrazole Based Pyrimidine and Pyrazolone Motifs

Background: In the past few decades, mankind is suffering from tormented life-threatening infectious diseases caused by multidrug-resistant bacteria. As a result, new antimicrobial classes with distinct modes of action are required to combat multidrug-resistant infections. Objective: The pyrazole-based pyrimidine and pyrazolone motifs were synthesized, characterized, and screened for their antimicrobial activity. Molecular docking was carried out for the development of antimicrobial agents based on the results of biological activity obtained. Methods: We have synthesized a new series of pyrazole containing pyrimidine-pyrazolone hybrids by using multi-step reactions in the search of antimicrobial agents (7a-o). The structures were determined by 1H NMR, 13C NMR, IR, and mass spectroscopy techniques. Moreover, synthesized compounds were evaluated for their antimicrobial activity by using serial Broth dilution method. Results: Antimicrobial activity of synthesized compounds has been tested against bacterial and fungal strains. Compound 7o was most effective against S. aureus with MIC = 0.096 M/mL. A molecular docking study against microbial DNA gyrase revealed important information about the mechanisms underlying antimicrobial efficacy. Through significant interactions with active site residues, all of the compounds were able to dock well into the enzyme's active site. Furthermore, Compounds 7a (0.531 M/mL), 7b (0.456 M/mL), and 7m (0.485 M/mL) showed excellent antifungal activity against C. albicans compared to the positive control griseofulvin. Conclusion: It has been concluded that compounds containing electron-donating groups are found to be most active against bacterial strains while compounds having both electron-donating as well as electron-withdrawing groups are most favorable for antifungal activity.

An in silico-in vitro antimalarial and antimicrobial investigation of newer 7-chloroquinoline based Schiff-bases

New fifteen 7-chloroquinolines (M1a-o) were synthesized by microwave irradiation and conventional route via Schiff-base reaction. The key intermediate 4-((7-chloroquinolin-4-yl) oxy) benzaldehyde (3) was clubbed to the various amines to afford final compounds. The synthesized compounds were characterized by using FT-IR, 1H NMR, 13C NMR and mass spectrometry. Final compounds were evaluated for their antimalarial and antimicrobial activities using the 96 well microtiter plates and serial broth dilution method, respectively. The tested compounds showed good to moderate antimalarial activity with IC50 values between 0.56 to 1.65 µg/mL, when compared to references quinine and chloroquine. Among them, compounds M1b and M1g showed the most promising activity against P. falciparum strains with IC50 values of 0.56 and 0.58 µg/mL, respectively. These compounds were subjected to ADMET tests to determine their drug-likeness and toxic properties. In addition, in silico molecular docking and molecular dynamics studies were also carried out to investigate the binding affinities of all compounds with the target proteins (7DI7), and the results were in good correlation with the experimental findings.

Antimicrobial Effects of L-Chg10-Teixobactin against Enterococcus faecalis In Vitro.

Objective: Teixobactin and its analogues are a new class of antibiotics that have no detectable bacterial resistance. This study was designed to determine the antibacterial and antibiofilm activities of a novel teixobactin analogue, L-Chg10-teixobactin, against two strains of Enterococcus faecalis (E. faecalis). Materials and Methods: The efficacy of L-Chg10-teixobactin against two strains of E. faecalis (ATCC 29212 and 47077) was determined using Clinical and Laboratory Standards Institute methods. L-Chg10-teixobactin was prepared at a stock concentration of 1 mg/mL in 5% DMSO. The minimum inhibitory concentration (MIC) was calculated using a two-fold serial broth dilution method, utilizing a 96-well plate. The minimum bactericidal concentration (MBC) was determined by plating the bacteria onto agar to define the concentration that resulted in 99.9% of bacterial death. Ampicillin was used as the control. The effect of L-Chg10-teixobactin on the inhibition of ATCC 47077 strain biofilm formation was determined by measuring the minimum biofilm inhibitory concentration (MBIC) using the safranin assay, while the eradication of the preformed biofilm was determined by measuring the minimum biofilm eradication concentration (MBEC) using the XTT assay. For nonlinear data, the log dose–response curve was plotted to calculate the optimum concentration using Excel (version 16.51, Microsoft® excel. 2021, Microsoft Corporation, Reymond, WA, USA). The data are presented as mean ± standard deviation (SD). Results: The MIC and MBC values of L-Chg10-teixobactin against both strains of E. faecalis were 0.8 μg/mL. The MIC of ampicillin was 1.25 μg/mL for ATCC 29212 and ranged from 1.25 to 5 μg/mL for ATCC 47077. The MBC of ampicillin for ATCC 29212 and ATCC 47077 was 10 and 20 μg/mL, respectively. The MIC and MBC of ampicillin were much higher compared with those of L-Chg10-teixobactin. The MBEC80 of L-Chg10-teixobactin was 4.60 μg/mL for ATCC 47077, which was much lower than that of ampicillin (20 μg/mL). Conclusions: L-Chg10-teixobactin demonstrated potent antibacterial and antibiofilm effects against E. faecalis, suggesting its potential role an effective antibacterial and antibiofilm agent in endodontic treatment.

Antibacterial effect of Satureja hortensis and Salvia officinalis essential oils against major bovine mastitis bacteria

Treatment of bacterial diseases such as bovine mastitis with antibiotics has problems such as antibiotic resistance and drug residue in animal products. Essential oil of medicinal plants have antibacterial activity and are suitable alternatives. This study examined the antimicrobial activity of Salvia officinalis (sage) and Satureja hortensis (savory) essential oils on major mastitis-causing bacteria, including Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. Chemical compositions of essential oils were determined by gas chromatography-mass spectrometry. Minimum inhibitory concentration and minimum bactericidal concentration of oils were determined with serial broth dilution method using autoclaved whole milk rather than synthetic broth. The effect of sub-minimum inhibitory concentrations of essential oils on the growth curve of tested bacteria in milk was obtained in 0, 1, 2, 4, 10, and 24 hours. Major compositions of sage and savory essential oils were carvacrol (61.01%), thymol (20.41%), 1R-α-pinene (7.88%), eucalyptol (32.45%), thymol (28.24%), and α-pinene (13.42%), respectively. The minimum inhibitory concentration and minimum bactericidal concentration ranged 1.25-2.5% and 2.5-5% for savory, and 0.625-1.25% and 1.25-2.5% for sage, respectively. Savory and sage significantly decreased the S. aureus and S. agalactiae population in 4, 10, and 24 h (p < 0.05) and E. coli population in 10 and 24 h (p = 0.01). The sage and savory essential oils had antibacterial effects against three tested bacteria, and sage had a stronger effect than savory because of stronger antibacterial components (carvacrol and thymol). Further in vivo tests are recommended to evaluate the efficiency of these essential oils on the treatment of bovine mastitis.

Synthesis, Characterization, and Study of Anti-Tubercular and Anti-Microbial Activity of Isonicotinohydrazide Tridentate Schiff Base Ligands

New Schiff bases derived by the condensation of isonicotinoylhydrazide and 2-hydroxy-3-methoxy-benzaldehyde and 2,4-dihydroxybenzaldehyde have been synthesized. Compounds were characterized on the basis of various spectroscopic techniques like IR, 1H, and 13C NMR studies, elemental analysis. The ligands were subjected to anti-microbial and anti-tubercular activity screening using serial broth dilution method and Minimum Inhibitory Concentration (MIC) is determined. The ligands were evaluated for their anti-microbial activity against Gram-positive bacteria (Staphylococcus aureus ATCC 9144) and Gram-negative bacterium (Escherichia coli ATCC 11303). Therefore, newly synthesized ligands showed good biological activity against tested bacteria. Compounds show high levels of activity against Mycobacterium tuberculosis

Synthesis and Decarboxylation of Functionalized 2-Pyridone-3-carboxylic Acids and Evaluation of their Antimicrobial Activity and Molecular Docking.

The functionalized 2-pyridone-3-carboxylic acids were synthesized starting from 3-formylchromone. Meanwhile, a decarboxylation reaction of 2-pyridone-3-carboxylic acid was performed by potassium carbonate in toluene. All compounds were evaluated against two Gram-negative bacteria (Escherichia coli (E. coli), Acinetobacter baumannii (A. baumannii)) and two Gram-positive (Staphylococcus aureus (S. aureus)) and fungus (Candida albicans (C. albicans)) using serial broth dilution method. The antimicrobial screening revealed that S. aureus is the highest sensitive microorganism towards the synthesized compounds. Among all analogs, derivatives, 4p and 5c showed excellent activities in comparison with the other compounds against S. aureus. Molecular docking showed that the most active anti S. aureus are compounds 4p and 5c exhibiting primary interaction as with fluoroquinolones by cross-linking over DNA gyrase active site via metal ion bridge and H-bonding interaction with Ser84 and Glu88 from GyrA subunit along with Arg458 and Asp437 located at GyrB subunit. In addition, based on the molecular dynamic simulation as like the standard fluoroquinolones, the mentioned compounds were stabilized for significant amount of simulation time over DNA gyrase which potentiate the importance of the mentioned residues in the DNA gate region of DNA gyrase.

Manganese (II) and Cobalt (II) Acetylacetonates as Antimicrobial Agents

Mn(II) and Co(II) complexes were prepared by reaction of the metal chlorides with acetylacetone in ammonical aqueous medium. The metal complexes were prepared in order to investigate their antimicrobial activity on some selected pathogens. The characterisation of the complexes was on the basis of various spectroscopic techniques like infrared and ultraviolet studies. The compounds were subjected to antimicrobial activity screening using serial broth dilution method. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) were determined. Mn(II) complex has shown significantly both antibacterial and antifungal activity with a MIC of 1.25 μg/mL while Co(II) complex was noticeable for antifungal activity at the same concentration. Whereas Mn(II) acetylacetonate is a more potent bactericide while Co(II) acetylacetonate is a more potent fungicide, both with MBC/MFC value of 2.5 μg/mL. Antimicrobial agent of the ligand has enhanced on complexation with Mn(II) and Co(II) ions. Though, the potency of the prepared antibiotics on the tested microbes is less compared to the standard drugs (Ciprofloxacin and Fulcin).

Exploring of Anticariogenic Activity of Herbal Formulation from Selected Five Medicinal Plants Leaves

Background: Oral diseases continue to be a major health problem worldwide. Plant leaves extracts of formulation have great source as anticariogenic compound against oral pathogenic microorganisms, which can be used to treat infectious diseases. Objective: The leaf and their formulation extracts were tested for their effect on anticariogenic organisms under in vitro condition. Attempt was also made to characterize bioactive compounds at primary level. Material and Methods: The dried plant leaves materials are extracted by cold extraction using hexane, ethyl acetate, methanol, and distilled water. The solvents were evaporated, and the dried masses were suspended in dimethyl sulfoxide and used for anticariogenic activity by agar well diffusion method. 12 different herbal formulations prepared and evaluation their their efficacy against anticariogenic bacteria. Minimum inhibitory concentration (MIC) was evaluated by two-fold serial broth dilution method. Preliminary phytochemical analysis of effective formulation was carried out by thin-layer chromatography (TLC). Results: Plant leaves (Lantana camara var.aculcata (L.) Mold; Manilkara hexandra (Roxb.) Dub; Mangifera indica L; Piper betle L; Syzygium rubicundum Wight &amp; Arn extracts and twelve different formulation prepared by leaves extracts was analysis for their anticariogenic activities against oral microorganisms. All the crude plant leaves extracts and different formulation prepared by leaves extracts exhibited varying degree of growth inhibition in all the oral microorganisms. The activity was determined against, Lactobacillus acidophilus, Lactobacillus casei, Staphylococcus aureus and Streptococcus pyogenes. Maximum zone of inhibition (22 mm) was found when plant leaves extracts of formualtion tested against Lactobacillus casei. Preliminary phytochemical analysis of formulation present the Tannins, Saponins, Steroids and phenolic compound are present.

Antibacterial Activity of Hypogymnia Physodes Extract and its Combinations with Antibiotics Against Enterococci

Objective : to study antibacterial properties of Hypogymnia physodes extract and its combinations with antibiotics against vancomycin-sensitive and vancomycin-resistant strains of enterococci. Material and methods. Minimum inhibitory concentrations (MICs) of the acetone extract of H. physodes for reference and clinical isolates of Enterococcus faecalis were determined by the serial broth dilution method. Evaluation of efficiency of the combined effect of the H. physodes extract in combination with antibiotics was carried out using the modified disc-diffusion method and «chessboard» method. Results. We have revealed marked antibacterial activity (MIC 32-64 mcg/ml) of the acetone extract of H. physodes against vancomycin-sensitive and vancomycin-resistant strains of enterococci and found a synergistic effect (ΣFIC from 0.125 to 0.375) of the combination of the H. physodes extract and aminoglycosides against E. faecalis , including vancomycin-resistant strains. Conclusion. H. physodes is a promising source of compounds with antibacterial activity, further research is required to identify and isolate a secondary metabolite having synergistic activity in combination with aminoglycosides from the lichen extract.

Relationship of antimicrobial activity and chemical structure of the arylaliphatic aminoalcohol derivatives

Arylaliphatic aminoalcohols appeared to be the new promising class of compounds for the development of antibacterial and antifungal agents. The aim of the presented study was to analyze the «chemical structure-antimicrobial activity» relationship for further activity-directed synthesis of compounds of this class.&#x0D; The antimicrobial activity of the compounds was investigated by serial broth dilution method. Primary analysis of the effect of substituents’ structure on the ability of the derivatives to inhibit the growth of test-microorganisms was carried out by empirical method. Molecular structural characteristics of arylaliphatic aminoalcohols (surface area, volume, partition coefficient logP and dipole moment) were calculated by means of «Hyperchem 8.0.8» software. Relationship between the antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and molecular characteristics was investigated by correlation analysis using the Spearman test. Statistical processing was performed by «StatSoft Statistica 6.0», the data obtained were evaluated using Chaddock scale.&#x0D; The data obtained suggest, that the presence of both antibacterial and antifungal activity in arylaliphatic aminoalcohols depends on the amino group structure and composition of aryl(alkyl)oxy-radical (4-(1,1,3,3-tetramethylbutyl)phenyl, 1-adamantyl, 4-(1-adamantyl)phenyl, 4-phenyl-phenyl or 2,4-ditretbutyl phenyl). The correlation analysis revealed an inverse relationship between the antimicrobial action and surface area, volume, and lipophilicity of compounds. The tightest correlation was found between these parameters and antistaphylococcal activity. Our results indicate the promises of the synthesis, directed to the reducing of the molecule size and lipophilicity of tetramethylbutylphenyl aminoalcohols, for further development of broad-spectrum antimicrobial agents.

Antimicrobial Activity and Phytochemical Analysis of Moringa oleifera Lam. Crude Extracts Against Selected Bacterial and Fungal Strains

The n- Hexane, ethyl acetate, methanol and distilled water Leaf, Stem, Flower and Fruit extracts of Moringa oleifera were evaluated for their antibacterial activity against six Gram-Negative and Gram-Positive bacteria and antifungal activity against seven fungal strains using Ciprofloxacin, Doxycycline, Fluconazole and Ketacozole as positive control. The activity was analyzed by well diffusion and two-fold serial broth dilution method of different extract. The study revealed that all the extracts irrespective of their types, in different concentrations inhibited growth of the test pathogens to varying degrees. Ethyl acetate extract showed maximum activity against all the bacterial strains followed in descending order by methanol, n-.Hexane and distilled water extracts. Ethyl acetate extract showed high antibacterial activity against Serratia marcescens (22mm) Methanol and n-Hexane extract were effective against Enterococcus faecalis and Bacillus subtilis (10mm) respectively. Aqueous extract showed maximum number of inhibition against Staphylococcus aureus (27mm) and Micrococcus luteus (18mm). Ethyl acetate extract showed maximum inhibition against Trichoderma harzianum (16mm) than other extracts were ineffective against selected fungus. MIC values were recorded as 0.125 to 4mg/ml. The phytochemical screening revealed the presence of phenols and flavonoids. Expression to these results it may be concluded that M. oleifera may be a potential source for the curing of various infectious diseases caused by the resistant microbes

Pyrazole nucleus fused tri-substituted imidazole derivatives as antioxidant and antibacterial agents

A novel series of tri-substituted imidazole derivatives were synthesized according to the well-known Radziszewski reaction. The desired molecules were obtained by a reaction of benzil, ammonium acetate and different derivatives of 1H-pyrazole-4-carbaldehyde. Structures of the synthesized entities were confirmed with the support of modern techniques like elemental analysis (CHN) and spectral analysis (FTIR, 1H and 13C NMR and LC–MS). All compounds were screened for their biological potency: antibacterial activity using a serial broth dilution method and antioxidant activity using the DPPH method. Antimicrobial activity was performed against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). The title compounds showed moderate to excellent antimicrobial and antioxidant potency against different bacterial strains and the DPPH radical.

Synthesis, spectroscopic characterization, antimicrobial evaluation and molecular docking study of novel triazine-quinazolinone based hybrids

A new series of 1,3,5-triazine incorporating aromatic quinazolinone moieties as a potential antimicrobial agents is reported. The first chlorine group of the cyanuric chloride (1) was replaced by aniline and the second one was replaced by various aromatic amines. The prepared monochlorotriazine was allowed to react with hydrazine and subsequently it was reacted with 2-methyl-4H-benzo[1,3]oxazin-4-one to obtain novel triazine-quinazolinone based hybrids (9a-f). The chemical structure and purity of the hybrid compounds were evaluated by different techniques such as thin layer chromatography, melting point, Fourier-transform infrared (FTIR), 1H and 13C NMR spectra and elemental analysis. Antimicrobial activity of the hybrid compounds were study by three Gram-negative bacteria (Salmonella entritidis, Escherichia coli, Pseudomonas aeruginosa) and three Gram-positive bacteria (Staphylococcus aureus, Listeria monocitogenes, Bacillus subtilis) as well as Candida albicansas a yeast-like fungus using the serial broth dilution method. Among them, compound 9d with benzenesulfonamide group showed higher antimicrobial activity with a minimum inhibitory concentration (MIC) value of 16 μg/mL. Furthermore, compounds 5d, 9a and 9b showed good activity against several tested strains. In addition, docking simulation was perform to position best antibacterial compounds in to the S. aureus dihydrofolate reductase (DHFR) active site to determine the probable binding conformations.

One pot synthesis of substituted 1H-benzo[f]chromen-3-yl-2H-chromen-2-one derivatives

The title compounds, substituted 1 H -benzo[f]chromen-3-yl-2 H -chromen-2-ones were obtained by reacting 3-aryl-1-(3-coumarinyl)propen-1-ones with 2-napthol catalyzed by DBU (1,8-diazabicyclo[5,4,0]undec-7-ene) and concentrated H 2 SO 4 in ample yields. Their structures were characterized by IR, 1 H NMR, 13 C NMR, mass spectral and elemental analysis. All the synthesized compounds have been evaluated for their in-vitro antibacterial activity against Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa and antifungal activity against Aspergillus Niger and Candida albicans by using serial broth dilution method. Among those compounds 3 band 3c exhibits prominent results.

Synthesis, characterization and antimicrobial studies on 3-((4-(4-nitrophenyl)-6-aryl-1,6-dihydropyrimidin-2-yl)thio)propanenitriles and their derivatives

This study synthesized a series of 3-((4-(4-nitrophenyl)-6-aryl-1,6-dihydropyrimidin-2-yl)thio)propanenitriles and their structures characterized by spectral (1H NMR, 13C NMR, infrared spectroscopy, liquid chromatography-mass spectroscopy) and elemental analysis. Antimicrobial activity was carried out by serial broth dilution method on gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and three fungi (Candida albicans, Aspergillus niger and Aspergillus clavatus) in vitro. Compounds 5d, 5j, 5l and 5m showed potent antimicrobial activity against tested microorganisms. The grades of cytotoxicity studies on a human cervical cancer cell line (HeLa) and a 3T3 mouse embryonic fibroblast cell line indicated that compounds 5c, 5d, 5h and 5j showed low cytotoxicity.