Metin Digrak

Antibacterial and antifungal activity of the essential oils of Thymus revolutus Celak from Turkey

The chemical composition of the volatile constituent from flowering parts of Thymus revolutus C., an endemic plant of Turkey, were analysed by GC/MS. Twenty-two components were identified, and carvacrol was found as a predominant compound in the oil. Furthermore, the essential oil was tested against 11 bacteria and four fungi at different concentrations. Results showed that the oil exhibited a significant antibacterial and antifungal activity.

Antimicrobial activities of several parts of Pinus brutia, Juniperus oxycedrus, Abies cilicia, Cedrus libani and Pinus nigra.

In this study, the antimicrobial activities of several parts of various trees grown in the Kahramanmaraş region of Turkey were investigated by the disc diffusion method. Chloroform, acetone and methanol extracts of leaves, resins, barks, cones and fruits of Pinus brutia Ten., Juniperus oxycedrus L., Abies cilicia Ant. & Kotschy Carr., Cedrus libani A. Rich. and Pinus nigra Arn. were prepared and tested against Bacillus megaterium DSM 32, Bacillus subtilis IMG 22, Bacillus cereus FMC 19, Escherichia coli DM, Klebsiella pneumoniae FMC 3, Enterobacter aerogenes CCM 2531, Staphylococcus aureus Cowan 1, Mycobacterium smegmatis RUT, Proteus vulgaris FMC 1, Listeria monocytogenes Scoot A, Pseudomonas aeruginosa DSM 5007, Candida albicans CCM 314, Candida tropicalis MDC 86 and Penicillium italicum K.

Synthesis, Characterization and Stability Constants of Polynuclear Metal Complexes

Unsymmetric tridentate ligands, 4-methyl-2,6-di(4-methyliminomethyl)phenol (HL1), 4-(t-butyl)-2,6-di(4-methylphenyliminomethyl)phenol (HL2), 2,6-di(4-bromophenyliminomethyl)-4-methylphenol (HL3), 2,6-di(4-bromophenyliminomethyl)-4-(t-butyl)phenol (HL4), 2,6-di(4-hydroxyphenyliminomethyl)-4-methylphenol (HL5) and 4-(t-butyl)-2,6-di(4-hydroxyphenyliminomethyl)phenol (HL6), and their binuclear CuII, CoII and NiII complexes were synthesized and characterized by elemental analysis, FT-IR, u.v.-vis spectrometry magnetic moments, 1H(13C)-n.m.r. and mass spectral data. Also, the electrical conductivities of the complexes have been measured using 10-3 M solutions in MeCN. The complexes are weak electrolytes. In the electronic spectra of the complexes of the HL1-HL6 ligands, the 480-410 nm band has been determined as the charge-transfer band. While the HL5 and HL6 ligands have five potential donor atoms, other ligands have only three. Protonation constants of the ligands have been studied in dioxan-water mixtures. In addition, the antimicrobial properties of the ligands and their metal complexes have been studied:Bacillus megaterium, Micrococcus luteus, Corynebavterium xenosis, Enterococcus faecalis, bacteria and Saccoramyces cerevisia, yeast. The keto-enol tautomeric equilibria of the ligands have been investigated in polar and non-polar solvents.

Use of Aspergillus wentii for biosorption of methylene blue from aqueous solution

In this study, Aspergillus wentii was used as a biosorbent for the adsorption of methylene blue from aqueous solution. The effects of contact time, initial dye concentration, solution pH and temperature on biosorption were investigated. The contact time required (that is, the equilibrium time) for maximum dye biosorption was found to be 120 min. The amount of the dye biosorbed increased with increasing initial dye concentrations and solution pH, while it was decreasing with an increase in temperature. Percent biosorption was changed between 14.86 and 85.04 under all conditions studied. Desorption studies were performed by changing of the value pH among 3 - 10. Desorption was considerably affected by lower pH. The maximum percentage of desorption was found to be 29.51 at pH 3. Biosorption isotherm from equilibrium values followed Freundlich model.

The synthesis, characterization, antimicrobial and antimutagenic activities of hydroxyphenylimino ligands and their metal complexes of usnic acid isolated from Usnea longissima

Novel multifunctional hydroxyphenylimino ligands (L1, L2 and L3) were synthesized by the condensation of 2-aminophenol, 3-aminophenol and 4-aminophenol with usnic acid, a lichen metabolite. The synthesized ligands and their Cu(II), Co(II), Ni(II) and Mn(II) complexes were characterized using FT-IR, UV-Vis, (1)H-NMR, (13)C-NMR, 1D- and 2D NMR (DEPT, COSY, HMQC and HMBC), LC-MS and TGA. In addition, the metal complexes of the novel ligands were prepared with high yields using Cu(II), Co(II), Ni(II) and Mn(II) salts and were characterized using the FT-MIR/FAR, UV-Vis, elemental analysis, ICP-OES and TG/DTA techniques. The ligands and their complexes were tested against ten important pathogen microorganisms using the disc diffusion method and the metal complexes of the ligands were more active against all of the microorganisms tested with a broad spectrum than the ligands exhibiting 11–32 mm inhibition zones. On the other hand, a broad spectrum of the strongest antimicrobial activity was determined for the Mn(II) and Cu(II) complexes of the hydroxyphenylimino ligand with usnic acid (L3). In addition, the antimutagenic activities of all of the ligands and their metal complexes were determined using the Ames-Salmonella and E. coli WP2 microbial assay systems and they showed varied and strong antimutagenic effects. In general, it has been found that the Co and Mn complexes of the ligands possess potent antimutagenic activity. In view of these results, it can be concluded that some metal complexes can be used as antimicrobial and anticancer agents.

Antibiotic Action of Seed Lipids from Five Tree Species Grown in Turkey

In this study, the seed lipids of Austrian pine (Pinus nigra Arnold.), Ehrami pine (Pinus nigra var. pyramidalis), Caucasian fir [Abies nordmanniana (Stev.) Spach], Eastern red (Thuja orientalis L.) and Scots pine (Pinus sylvestris L.) grown in Turkey were extracted with a mixture of methanol and chloroform. The bacterial and antifungal activities of the seed lipids were tested against various pathogenic bacteria and fungi by applying the disc-diffusion method. The seed lipids of A. nordmanniana were found to be most effective against the tested microorganisms, except for Pseudomonas aeruginosa and Micrococcus luteus bacteria, followed by T. orientalis and P. sylvestris, respectively. However, the seed lipids of P. nigra var. pyramidalis were not effective on the growth of any microorganism. Bacillus subtilis and Listeria monocytogenes bacteria were found as the most resistant bacteria in the study. Furthermore, the seed lipids of A. nordmanniana and, somewhat, T. orientalis, were generally comparable to two reference antibiotics.

Polydentate Schiff Base Ligands and Their La(III) Complexes: Synthesis, Characterization, Antibacterial, Thermal, and Electrochemical Properties

We synthesized the Schiff base ligands H2L1–H2L4 and their La(III) complexes and characterized them by the analytical and spectroscopic methods. We investigated their electrochemical and antimicrobial activity properties. The electrochemical properties of the ligands H2L1–H2L4 and their La(III) complexes were studied at the different scan rates (100 and 200 mV), different pH ranges (pH=2−12), and in the different solvents. The electrooxidation of the Schiff base ligands involves a reversible transfer of two electrons and two protons in solutions of pH up to 5.5, in agreement with the one-step two-electron mechanism. In solutions of pH higher than 5.5, the process of electrooxidation reaction of the Schiff base ligands and their La(III) complexes follows an ECi mechanism. The antimicrobial activities of the ligands and their complexes were studied. The thermal properties of the metal complexes were studied under nitrogen atmosphere in the range of temperature 20–1000°C.

Synthesis and characterization of some Schiff bases, their metal complexes and thermal, antimicrobial and catalytic features

Abstract Two pyridine carboxaldehyde-derived schiff bases and their copper, nickel and manganese complexes have been synthesized, characterized by spectroscopic and thermal analyses. For the antimicrobial activity experiments, the microorganisms B. megaterium, K. pneumoniae, E. coli, P. aeruginasa, S. aureus, B. subtilis and E. aerogenes have been used. Nickel and copper complex compounds of ligand L2 were recorded as the most effective coordination compounds as antimicrobial. Catalytic activity results revealed that the both manganese and nickel complexes were moderately more effective for the oxidation reactions of cyclohexene and styrene.

Antimicrobial activity of the essential oil of Origanum bargyli Mouterde from Turkey

Abstract Origanum bargyli Mouterde is a rare plant of this genus in Turkey. Essential oils from the aerial parts of O. bargyli were obtained by hydrodistillation. The chemical composition of the oils was analyzed by GC/MS. From the 24 identified constituents, p-cymene (19.6%), borneol (12.9%) and α-terpineol (11.0%) were found to be major components. Furthermore, the oil was tested against 11 bacteria and four fungi at different concentrations. The result showed that the oil exhibited significant antimicrobial activity.