Yağmur Tunalı

Antimicrobial activity and a SAR study of some novel benzimidazole derivatives bearing hydrazone moiety

In this study 12 novel benzimidazole compounds bearing hydrazone moiety were synthesized in order to investigate their possible antibacterial and antifungal activity. Structures of the synthesized compounds were elucidated by spectral data. Six different gram-negative and four different gram-positive bacterial strains were used in antibacterial activity tests. Antifungal activity tests were also performed against three different fungal strains. Most of the test compounds found to be significantly effective against Proteus vulgaris, Staphylococcus typhimurium, Klebsiella pneumoniae and Pseudomonas aeruginosa gram-negative bacterial strains. A structure-activity relationship (SAR) study including some electronic parameters was carried out and a connection between antibacterial activity and electronic properties of the target compounds was determined. Toxicity of the most effective compounds was established by performing Brine-Shrimp lethality assay.

Biosorption of phenol and 2-chlorophenol by Funalia trogii pellets.

The removal of phenol (Ph) and 2-chlorophenol (2-CPh) from aqueous solution by native and heat inactivated fungus Funalia trogii pellets were investigated. The effects of contact time, solid/liquid ratio, optimum pH and temperature on the phenols removal capacity by the pellets were established. The removal efficiency of phenols increased significantly with increasing biomass dose. The optimum pH was detected to be 8.0. The second-order equations are described and evaluated on the basis of a comparative estimation of the corresponding coefficients. The phenol removal equilibrium isotherm was modeled by the Langmuir equations. The enthalpy change values were obtained between -7.62 and -10.64 kJ/mol. This indicated that the uptake of phenols either on native or heat inactivated fungal pellets was based on a physical adsorption process.

Synthesis, antibacterial and antifungal activities of 3-(1,2,4-triazol-3-yl)-4-thiazolidinones

A new series of 3-(1,2,4-triazol-3-yl)-4-thiazolidinone derivatives has been synthesized by the reaction of Schiff bases of 3-amino-1,2,4-triazoles with mercaptoacetic acid and 2-mercaptopropionic acid. Their antibacterial and antifungal activities were evaluated against S. aureus, S. epidermidis, C. albicans and C. glabrata

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.

Synthesis and biological activities of new hydrazide derivatives

The synthesis of a new series of imidazo[1,2-a]pyrazine-2-carboxylic acid arylidene-hydrazides is described. The chemical structures of the compounds were elucidated by IR, 1H-NMR, FAB+-MS spectral data. Their biological activity against various bacteria, fungi species, and Mycobacterium tuberculosis was investigated. Antibacterial activity was measured against Escherichia coli (NRRL B-3704), Staphylococcus aureus (NRRL B-767), Salmonella typhimurium (NRRL B-4420), Proteus vulgaris (NRLL B-123), Enterococcus faecalis (isolated obtained from Faculty of Medicine Osmangazi University, Eskisehir, Turkey), Pseudomonas aeruginosa (NRRL B-23 27853), Klebsiella spp. (isolated obtained from Faculty of Medicine Osmangazi University, Eskisehir, Turkey), while antifungal activity was evaluated against Candida albicans (isolates obtained from Osmangazi Uni. Fac.of Medicine), Candida glabrata (isolates obtained from Osmangazi Uni. Fac.of Medicine). Compounds were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. The compounds showed moderate inhibitor effects against human pathogenic microorganisms., whereas the preliminary results indicated that all of the tested compounds were inactive against Mycobacterium tuberculosis H37Rv.

Antimicrobial Activity of a New Combination System of Benzimidazole and Various Azoles

In the present study a new series of benzimidazole derivatives bearing various (benz)azolylthio moieties were synthesized so as to investigate their antimicrobial activity. Structures of the target compounds (5a–5i) were confirmed by their IR, 1H‐NMR, ES‐MS spectral data, and elemental analyses. The synthesized compounds (5a–5i) exhibited poor activity against bacterial strains. On the other hand, antifungal activity of the compounds against Candida species was very significant. Brine‐Shrimp lethality assay was performed for determination of toxicity of the compounds. Compounds 5a, 5c, and 5d were evaluated as non‐toxic in addition to their attractive antifungal activity. However, the other compounds (5b, e–i) in the series showed toxicity to different extents.

Synthesis and initial biological evaluation of substituted 1-phenylamino-2-thio-4,5-dimethyl-1H-imidazole derivatives

In this work, some new 2-[(4,5-dimethyl-1-(arylamino)-1H-imidazol-2-yl)thio]-1-(aryl)ethanone derivatives were synthesized and investigated for their antibacterial, antifungal and anticancer activities. Toxicity of the most effective compounds was established by performing Brine-Shrimp lethality assay. Antifungal activity of the compounds was found to be higher than antibacterial and anticancer activities of the compounds.

Antimicrobial activity of a new series of benzimidazole derivatives

Due to antimicrobial importance of benzimidazoles and hydrazones, some benzimidazolehydrazone compounds were synthesized to screen their antimicrobial activity. Structures of the synthesized compounds were elucidated by 1H-NMR, IR and ES-MS spectral data and elemental analysis. The synthesized benzimidazole-hydrazones exhibited very weak antibacterial activity. However, antifungal activity of some of the synthesized compounds was very notable against Candida species. The compounds displaying important antifungal activity were screened for their toxicity. Artemia salina 96-well assay was used to determine cytotoxicity of the compounds. Tested compounds exhibited toxicity to different extents (LD50 = 126.33−368.72 μg/mL). Nevertheless, determination of 3–14 folds higher LD50 than minimum inhibitory concentration is a significant finding, which demonstrates that the compounds display antifungal activity at non-toxic concentration.

Synthesis and antimicrobial activity of some new hydrazone-bridged thiazole-pyrrole derivatives

In this work, we synthesized fourteen different compounds which contain hydrazone bridged thiazole and pyrrole rings. For this purpose, pyrrole-2-carboxaldehydes were reacted directly with thiosemicarbazide in ethanol and then obtained thiosemicarbazones were condensed with α-bromoacetophenone derivatives (Hantzsch reaction) to give 1-substituted pyrrole-2-carboxaldehyde [4-(4-substituted phenyl)-1,3-thiazol-2-yl] hydrazones. The structures of the obtained compounds were elucidated by using IR, 1H-NMR and FAB+-MS spectral data and elemental analyses results. All of the compounds were screened for their antibacterial and antifungal activities against twelve different microorganisms by using microbroth dilution method. Ketoconazole and chloramphenicol were used as standard drugs. All of the compounds showed good activity against Staphylococcus aureus and Enterococcus faecalis.

Investigation of the Apoptotic Effect of Curcumin in Human Leukemia HL-60 Cells by Using Flow Cytometry

Curcumin (diferuloylmethane), the major yellow pigment isolated from the turmeric (Curcuma longa), has received much attention due to several biological properties. Curcumin exhibits a variety of pharmacological effects including antitumor, anti-inflammatory, and anti-infectious activities. In the present study, the effects of curcumin on apoptosis in the acute promyelocytic human leukemia (HL-60) cells was evaluated. Cytotoxic effects of curcumin on HL-60 cells were determined by MTT. HL-60 cells underwent apoptosis on treatment with curcumin, as indicated by increased annexin V-binding capacity and caspase-3 activation with flow cytometric analysis. Concentrations of 15, 20, and 40 μM curcumin significantly reduced cell proliferations. When HL-60 cells were treated with 10, 15, 20, and 40 μM concentration of curcumin, apoptotic rates were determined as 1.2, 81.1, 84.5, and 88.6%, respectively. On the incubations with the concentrations of curcumin, caspase-3 expressions (+) were found to be elevated by 8.5, 18.6, 91.2, and 92.4%, respectively. It was shown that curcumin had significant cytotoxic and apoptotic effects on HL-60 cells. It was suggested that curcumin may have a potential therapeutic role for human leukemia.