COPPER(II) COMPLEX WITH PYRAZINE- AND TRIAZINE-MODULATED TRIPYRIDYLDIAMINE LIGAND: SYNTHESIS, CRYSTAL STRUCTURE, MAGNETIC, AND ANTIMICROBIAL PROPERTIES

Extreme environments harbor a number of microbes producing novel bioactive compounds. The aim of our study is to isolate and identify bioactive compound producing halophiles. Marine soil sediments were collected from the solar saltpans of Thoothukudi District, Tamil Nadu, India. Based on colony morphology, two species were isolated and identification was done by using morphological and biochemical tests. The extracts of cell-free supernatant of the two halophilic isolates were screened for bioactive compound and tested for antimicrobial activity against human pathogenic bacteria such as Staphylococcus aureus, Pseudomonas sp, Klebsiella sp, Vibrio sp, Escherichia coli and fungi Aspergillus niger and Penicillium chrysogenum by the agar cup diffusion method. The results were then compared to standard antibiotics which showed 80% of similar activity in 50 μL/g concentration. In addition, the arbitrary unit of two isolates was calculated against S. aureus which produced enhanced inhibitory results. Hence our finding illustrated that Thoothukudi saltpan might be considered as a resource for novel bioactive compounds. Key words: Halophilic bacteria, bioactive compound, anti-microbial activity, arbitrary unit, Thoothukudi saltpan. &nbsp

Phytochemical analyses as well as antimicrobial and antioxidant activities of the extracts of C. sumatrensis aerial parts were investigated in this study. METHODS : The aerial parts of C. sumatrensis were air dried, weighed and exhaustively extracted with hexane, ethyl acetate and methanol successively. The crude extracts were screened for metabolites. These extracts of the plant were evaluated for antimicrobial and antioxidant activities using agar diffusion and DPPH method respectively. The extracts were also analysed using Gas chromatography – Mass spectrometry, and the chromatogram coupled with mass spectra of the compounds were matched with a standard library. RESULTS : Preliminary phytochemical investigation of rude n-hexane, ethyl acetate and methanol extracts of the aerial parts of Conyza sumatrensis revealed the presence of anthraquinones, flavonoids, terpenoids, phenolics, tannin, glycosides and carbohydrate. All the crude extracts gave a clear zone of inhibition against the growth of the test bacteria ( Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomona aeruginosa, Salmonella typhi, Klebsiellae pneumonae ) at moderate to high concentrations, as well as test fungi ( Candida albicans, Aspergillus niger, penicillium notatum and Rhizopus stolonifer ) at high concentration. Methanolic extract exhibited significant radical scavenging property with IC 50 of 17.08 μg/mL while n-hexane and ethyl acetate extracts showed no significant antioxidant activity. GC-MS of N-hexane extract showed a total number of eleven chemical constituents with α-Farnesene and spathulenol being the most abundance compounds constituting 20.27 and 22.28% of the extract respectively. Ethyl acetate extract revealed thirteen compounds with two most abundant compounds, cis-β-farnesene (16.64 %) and cis-pinane (21.09 %). While methanolic extract affords seventeen compounds with Ephytol being the most abundant compound (19.36 %). © JASEM Keywords : Antimicrobial activity, Antioxidant, GC-MS analysis, Phytochemicals, Conyza sumatrensis

The antimicrobial activity of submicron particles of new photocatalytic active complex metal oxide CsTeMoO6 against bacteria Escherichia coli and Staphylococcus aureus and fungi Aspergillus niger and Penicillium chrysogenum (spores and vegetative mycelium) was studied. It has been established that CsTeMoO6 has the antimicrobial activity in both under dark and visible light conditions in relation to all test cultures of microorganisms. The most inhibitory effect of CsTeMoO6 was noted for E. coli. The light enhanced the antimicrobial effect of the test compound against all cultures of bacteria and fungi, which is associated with the presence of photocatalytic activity of CsTeMoO6. The antifungal activity of CsTeMoO6 increased against spores and vegetative mycelium of fungi under light condition, and this effect increased with an increasing duration of time exposure. The different degree of survival rate of the studied microorganisms in the presence of this compound (under both dark and light) may be associated with the physiological and biochemical characteristics of the used microorganisms, including different mechanisms of resistance against complex metal oxide and reactive oxygen species.

In the pursuit of pharmacologically important compounds, platinum(II) complexes were synthesized using both green microwave-assisted and thermal methods with the bidentate NS Schiff base ligand benzyl-2-(1-(pyridine-2-yl)ethylidene)hydrazine-1-carbodithioate (HL). This ligand was synthesized through the reaction between benzyl hydrazinecarbodithioate and 1-(pyridine-2-yl)ethan-1-one. The results from both methods were summarized and compared. Microwave-assisted reactions were completed in a shorter time and yielded higher amounts of product compared to thermal methods. The structural characterization of both the ligand and metal complexes was performed using various physicochemical methods. A square planar geometry was inferred for the platinum(II) complexes based on spectral and analytical data. Both the ligand (HL) and the platinum complex, [Pt(L)2] were evaluated for antituberculosis, DNA cleavage, and antimicrobial activities. Additionally, the [Pt(HL)2]Cl2 complex was also investigated for antimicrobial activity. The platinum complex, [Pt(L)2] was found to effectively inhibit the growth of Mycobacterium tuberculosis. DNA cleavage studies suggested that both the ligand and the metal complex, [Pt(L)2] were able to completely cleave Staphylococcus aureus DNA. Antimicrobial testing showed that both the ligand and the metal complexes exhibited activity against two bacteria (Escherichia coli and Bacillus subtilis) and two fungi (Aspergillus niger and Penicillium chrysogenum), demonstrating antibacterial and antifungal effects.

Herein we report a feasible study concerning the synthesis and the in vitro antimicrobial activity of some new homodrimane sesquiterpenoids with a benzimidazole unit. Based on some homodrimane carboxylic acids, on their acyl chlorides and intermediate monoamides, a series of seven N-homodrimenoyl-2-amino-1,3-benzimidazoles and 2-homodrimenyl-1,3-benzimidazoles was synthesized. The syntheses involved the decarboxylative cyclization and condensation of the said acids or acyl chlorides with o-phenylendiamine and 2-aminobenzimidazole, as well as the p-TsOH-mediated cyclodehydration of the said monoacylamides. The structures of the synthesized compounds have been fully confirmed, including by the X-ray diffraction. Their biological activities were evaluated on five species of fungi (Aspergillus niger, Fusarium solani, Penicillium chrysogenum, P. frequentans, and Alternaria alternata) and two strains of bacteria (Bacillus sp. and Pseudomonas aeruginosa). Compounds 7 and 20 showed higher antifungal (MIC = 0.064 and 0.05 μg/mL) and antibacterial (MIC = 0.05 and 0.032 μg/mL) activities compared to those of the standards: caspofungin (MIC = 0.32 μg/mL) and kanamycin (MIC = 2.0 μg/mL), and compounds 4, 10, 14, and 19 had moderate activities.

A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 10(6) CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices.

ABSTRACTIn the present study, Slovenian honey samples produced from different floral sources are evaluated for their antibacterial and antifungal properties. The peroxide contribution to antibacterial activity is also determined. Minimum inhibitory concentration (MIC) of the honeys was assessed against four bacterial species (Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa and Staphylococcus aureus) and against eight fungal species (Aspergillus niger, Aureobasidium pullulans, Candida albicans, Candida parapsilosis, Candida tropicalis, Cladosporium cladosporioides, Penicillium chrysogenum and Rhodotorula mucilaginosa). Honey at concentrations between 1% and 50% (v/v) were tested. Although all of the bacterial species were inhibited by the different honey samples, the chestnut and pasture honeys showed the highest antibacterial activities. The antifungal activities were concentration-dependent, with five (Aureobasidium pullulans, Candida parapsilosis, Candida tropicalis, Cladosporium cladosporioides, Rhodotorula mucilaginosa) inhibited only at honey concentrations greater than 50%. The fungi Aspergillus niger, Candida albicans and Penicillium chrysogenum were not inhibited by any of the tested honeys, even at the highest concentrations. The lowest MICs seen were 2.5% (v/v) for the chestnut, fir and forest honeys against Staphylococcus aureus, and 10.0% (v/v) for the chestnut and pasture honeys against Cladosporium cladosporioides. The non-peroxide action of chestnut honey was tested against Escherichia coli. The MIC of the catalase-treated chestnut honey was 50% (v/v). The antibacterial effect of Slovenian honeys is mostly due to peroxide action. These data support the concept that Slovenian honeys are effective antibacterials and antifungals, and can thus be applied for medicinal purposes.

Quaternary ammonium compounds (QACs) are a group of compounds of great economic significance. They are widely used as emulsifiers, detergents, solubilizers and corrosion inhibitors in household and industrial products. Due to their excellent antimicrobial activity QACs have also gained a special meaning as antimicrobials in hospitals, agriculture and the food industry. The main representatives of the microbiocidal QACs are the benzalkonium chlorides (BACs), which exhibit biocidal activity against most bacteria, fungi, algae and some viruses. However, the misuses of QACs, mainly at sublethal concentrations, can lead to an increasing resistance of microorganisms. One of the ways to avoid this serious problem is the introduction and use of new biocides with modified structures instead of the biocides applied so far. Therefore new BAC analogues P13–P18 with pyridine rings were synthesized. The new compounds were characterized by NMR, FT-IR and ESI-MS methods. PM3 semiempirical calculations of molecular structures and the heats of formation of compounds P13–P18 were also performed. Critical micellization concentrations (CMCs) were determined to characterize the aggregation behavior of the new BAC analogues. The antimicrobial properties of novel QACs were examined by determining their minimal inhibitory concentration (MIC) values against the fungi Aspergillus niger, Candida albicans, Penicillium chrysogenum and bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The MIC values of N,N-dimethyl-N-(4-methylpyridyl)-N-alkylammonium chlorides for fungi range from 0.1 to 12 mM and for bacteria, they range from 0.02 to 6 mM.

The antibacterial and antifungal effects of six plant-derived essential oils (EOs) and two types of citrus extracts (CEs) were studied against two pathogenic bacteria (Salmonella Typhimurium and Escherichia coli O157:H7) and three fungi (Aspergillus niger, Penicillium chrysogenum, and Mucor circinelloides). A broth microdilution assay and checkerboard method were used to measure the minimal inhibitory concentration (MIC) of each extract and the possible interactions between them. The MIC assay showed that cinnamon EO, Mediterranean EO, Southern formulation, citrus EO, organic citrus extract (OCE), and natural citrus extract (NCE) had the highest antimicrobial and antifungal activity. The checkerboard method showed that the Mediterranean EO+OCE combination acted in synergy against all tested pathogens. A centroid mixture design was used to develop active formulations by predicting optimal concentrations of EO/CEs for increased antibacterial/antifungal activity. A mixture of four formulations (625ppm OCE, 313ppm Mediterranean EO, 625ppm citrus EO, and 313ppm cinnamon EO) named as active formulation 1, and the mixture from five formulations (625ppm NCE, 625ppm Asian formulation, 313ppm Southern formulation, 625ppm cinnamon EO, and 313ppm savory thyme EO) named as active formulation 2, were formulated and tested because of their high microbicidal effectiveness. In situ tests with rice showed a significant reduction (P ≤0.05) of all tested pathogenic bacteria and fungi from the vapor of active formulations 1 and 2 after 28 days of storage. PRACTICAL APPLICATION: Active formulations (essential oils and citrus extracts) developed in the study are highly effective against foodborne pathogens. Active formulations in this study could be used as natural preservatives in the food industry for controlling foodborne diseases and spoilage organisms in stored foods.

New dimeric, trimeric and tetrameric quaternary ammonium salts were accomplished by reaction of tertiary alkyldimethyl amines with appropriate bromomethylbenzene derivatives. A series of new cationic surfactants contain different alkyl chain lengths (C4–C18), aromatic spacers and different numbers of quaternary nitrogen atoms. The structure of the products was confirmed by spectral analysis (FT-IR, 1H-NMR, 13C-NMR and 2D-NMR), mass spectroscopy (ESI-MS), elemental analysis, as well as PM5 semiempirical methods. Compound (21) was also analyzed using X-ray crystallography. Critical micelle concentration (CMC) of 1,4-bis-[N-(1-alkyl)-N,N-dimethylammoniummethyl]benzene dibromides (3–9) was determined to characterize the aggregation behavior. The antimicrobial properties of novel QACs (Quaternary Ammonium Salts) were examined to set their minimal inhibitory concentration (MIC) values against fungi Aspergillus niger, Candida albicans, Penicillium chrysogenum and bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa.

The study was conducted in the Fungi Laboratory, University of Kerbala / College of Agriculture, with the aim of molecularly identifying the bacteria Klebsiella Oxytoca and testing its efficiency in inhibiting the fungi contaminating palm samples in tissue culture, which are the fungi Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, and Meyerozyma guilliermondii, and testing their effect on the contamination rate and growth parameters (number of branches, fresh weight, dry weight). The results of the PCR analysis showed that the isolate belongs to the bacteria K. Oxytoca with a matching percentage of (100%), as the bacterial isolate was registered in the National Center for Biotechnology Information (NCBI) under the accession code (PV022086.1). The results also showed the superiority of live cells in inhibiting fungal growth by a percentage of 92.60% for each of A. flavus, P. chrysogenum and M. guilliermondii. The filtrate for the sixth day at a concentration of 10% was also superior with a high inhibition percentage of 92.60% against the fungi A. flavus and P. chrysogenum, while the greatest effect of the filtrate on the third day was 75.92% on the fungus P. chrysogenum, compared to the control treatment, which reached 100%. The results also showed that adding the filtrate of the bacteria K. Oxytoca for the sixth day at concentrations of 5 and 10% on the tissue medium had a positive effect on all the studied traits, including the average number of branches, fresh weight and dry weight, which reached (20.67, 6.25 and 1.05 respectively) for the 10% concentration, while the contamination rate reached 0% for the two concentrations compared to the control treatment of 100%.

Photocatalytic and antimicrobial effects of interior paints

Synthesis and characterization of a new aroylhydrazone ligand and its cobalt(III) complexes: X-ray crystallography and in vitro evaluation of antibacterial and antifungal activities

Petals of red, yellow and white roses (Rosa damascene Mill.) of the family Rosaceae were extracted with (1:1) methylene chloride/methanol and tested for their antimicrobial activities against four species of Gram-positive bacteria (Bacillus cereus, Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus), five species of Gram-negative bacteria (Enterobacter aerogenes, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and Serratia marcescens) and five species of fungi (Penicillium notatum, Aspergillus niger, Rhizopus stolonifer, Saccharomyces cerevisiae and Fusarium oxysporum). All of the crude extracts showed a wide range of antimicrobial activities according to the tested organism and rose's type. Micrococcus luteus was found to be the most susceptible bacteria to all crude extracts. Red and yellow petal extracts showed much higher antibacterial activity than the white petals extract. Bacillus subtilis was found to be the least susceptible to all extracts. The fungus, Penicillium notatum was found to be the most susceptible with white petal extract being the most effective. Saccharomyces cerevisiae and Fusarium oxysporum were the least susceptible to all extracts. White roses extract showed much higher antifungal activities against Penicillium notatum than red or yellow roses, therefore, it was subjected to several bioassay guided chromatographic fractionations and purification to isolate the active chemical(s) responsible for the antifungal activity. Chemical structure of the isolated antifungal compounds were identified by spectroscopy techniques and found to be a γ-sitosterol and (Z,Z)-9,12-octadecadienoic acid. Antibacterial activity of the various types of rose extracts were due to complex mixtures of organic compounds which are still under chemical investigation and will be published later.

Safety evaluation of glucose oxidase from Penicillium chrysogenum