Browsing by Author "Sayiner H."

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Ceftriaxone and phenylalanine combination as broad spectrum antimicrobials therapy
(2017-08-01) Sayiner H.; Ganim M.; Altunoglu Y.; Baloglu M.; Kandemirli F.
Background: Ceftriaxone belongs to the third-generation β-lactam antibiotics and it is useful for the treatment of a number of infectious diseases caused by both aerobic and anaerobic Gram-positive and Gram-negative bacteria. Phenylalanine is an essential aromatic amino acid of human being, from which dopamine and norepinephrine neurotransmitters are being synthesized. In the present study, we examined their combined efficacy against different types of pathogenic bacterial strains. Objective: The aim of the study was designed to investigate the effects of ceftriaxone combination with phenylalanine on antimicrobial activity Method: Gram positive-bacteria and Gram negative- including Klebsiella pneumoniae, - ATCC 25923, Proteus vulgaris, Escherichia coli, Serratia marcrescens, Staphylococcus epidermis, Alpha haemolyticus streptococcus, Enterococcus faecium, Pseudomonas aeruginosa, Listeria monocytogenes ATCC 7644, Enterococcus durans, Salmonella kentucky, Enterobacter aerogenes ATCC 13048 and Candida albicans ATCC 26555 were exposed to ceftriaxone and phenylalanine based on disk-diffusion method, and Minimum inhibition concentration (MIC) was determined with ceftriaxone. Results: 0.3 mol/L ceftriaxone and 0.3 mol/L phenylalanine solutions were mixed and observed greater zone of inhibition than ceftriaxone or phenylalanine alone against above mentioned bacterial strains. These results might open up a new avenue for using phenylalanine in combination with ceftriaxone to lower MIC level for better antibacterial effect, to reduce side effects of antibiotics, and to reduce emerging threats of antibiotic resistance bacteria. Conclusion: In this study, combined use of phenylalanine and ceftriaxone has revealed increased antimicrobial sensitivity against some selected both Gram positive and Gram negative bacteria in vitro.
ETM and ANN study for polysubstituted 2H-pyran-2-ones
(2013-09-01) Saracoglu M.; Basaran M.A.; Thul P.; Sayiner H.; Kandemirli S.G.; Gupta V.P.; Kandemirli F.
The structure glutamate pyruvate transaminase (GPT), glutamate oxaloacetate transaminase (GOT), acid phosphatase (ACP), alkaline phosphatase (ALP) and glutamate dehydrogenase (GlDH) activity relationships of 2H-pyran-2-ones polysubstitutes being a new class of hepatoprotective agents have been investigated by means of the Electronic-Topological Method (ETM) and two Statistical Analysis. Molecular fragments specific for active compounds were calculated for 2H-pyran-2-ones polysubstitutes by applying the ETM. QSAR descriptors such as molecular weight, EHOMO, ELUMO, ΔE, chemical potential, softness, electrophilicity index, dipole moment, etc were calculated. In order to examine the relationship between independent and dependent variables, both Partial Least Squares Regression and ANNs are employed to determine the relationship since the data set consists of highly nonlinearity and multicolinearity. It is observed that ANN has surpassed both PLS2 and PLS1 in terms of better modeling and validation. © 2013 Bentham Science Publishers.
Experimental and theoretical investigation of antioxidant activity and capacity of thiosemicarbazones based on isatin derivatives
(2018-08-03) Bakır T.; Sayiner H.; Kandemirli F.
The peroxidation of linoleic acid (LA) in the presence of copper (II) ions alone and with butylhydroxytoluene (BHT), gallic acid (GA), a BHT/GA pair, 5-methoxyisatin-3-(N-4-chlorophenyl) thiosemicarbazone (H25MI3ClPT), and 5-methoxyisatin-3-(N-phenyl) thiosemicarbazone (H25MI3PT) was investigated in aerated and incubated emulsions at 37°C and pH 7. Cu(II)-induced LA peroxidation followed pseudo-first-order kinetics with respect to the primary oxidation products (hydroperoxides), which were determined by the ferric thiocyanate (Fe(III)-SCN) method. It was observed that (H25MI3ClPT) and (H25MI3PT) showed antioxidant properties, but the percentage inhibition decreased as the concentration increased, contrary to the behavior of GA and BHT. In addition, they were investigated by the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. The IC50 values were 69.60, 11.87, 88.71, 73.62, and 430.11 µM for the standard antioxidants BHT, GA, H25MI3ClPT, H25MI3PT, and bis(isatin-3-(4-iodophenyl)thiosemicarbazonato) zinc(II) (BI3ITZn), respectively. The bond dissociation enthalpy (BDE), adiabatic ionization potential (AIP), proton dissociation enthalpy (PDE), proton affinity (PA), electron transfer enthalpy (ETE), ΔHacidity, ΔGacidity descriptors and DPPH radical scavenging mechanisms of thiosemicarbazone were also determined with the B3LYP method. Furthermore, the energy values in the transition state form for the reactions of H25MI3PT and H25MI3ClPT with DPPH were calculated as 0.022278 and 0.021953 au, respectively.
Synergistic and Antagonistic Effects of Phenylalanine and Various Antibiotics on the Growth of Pathogenic Bacteria
(2019-06-15) Sen F.; Ganim M.; Baloglu M.; Aygun A.; Sayiner H.; Altunoglu Y.; Kandemirli F.; Demirkan B.; Kuyuldar E.; Bulut E.
Broad-spectrum antibiotics have been widely used in the treatment of many systemic and local infections in humans and animals. Herein, we aimed to determine the synergistic and antagonistic effects of phenylalanine with antibiotics cefoxitin, amoxicillin, vancomycin, lincomycin, and bacitracin against 14 pathogenic bacteria. The effect of antibiotics, either alone or in combination with this biomolecular liquid, was tested using the disk diffusion method against different bacteria. The addition of phenylalanine to antibiotic disks directly affected their antimicrobial activity. All the antibiotics used did not show any antimicrobial activity against Staphylococcus haemolyticus when used alone. However, in combination with phenylalanine, each antibiotic inhibited the growth of S. haemolyticus. The use of this biomolecular liquid together with amoxicillin and vancomycin also increased the antimicrobial activity against Enterococcus durans. The use of phenylalanine in combination with antibiotics also resulted in antagonistic effects on some pathogens. Further, the effects of antibiotics in combination with phenylalanine on different bacterial pathogens were investigated in vitro. Results provide valuable information to further our understanding of the molecular mechanism of action of antibiotics and to improve their efficacy against bacterial pathogens.