Mehlika Dilek Altıntop

Synthesis and biological evaluation of some hydrazone derivatives as new anticandidal and anticancer agents

New hydrazone derivatives were synthesized via the nucleophilic addition-elimination reaction of 2-[(1-methyl-1H-tetrazol-5-yl)thio)]acetohydrazide with aromatic aldehydes/ketones. The compounds were tested in vitro against various Candida species and compared with ketoconazole. Genotoxicity of the most effective anticandidal compounds was evaluated by umuC and Ames assays. All compounds were also investigated for their cytotoxic effects on NIH3T3 and A549 cell lines. Compound 8 was the most effective antifungal derivative against C. albicans (ATCC-90028) with a MIC value of 0.05 mg/mL. Compound 5 can be identified as the most promising anticancer agent against A549 cancer cell lines due to its inhibitory effect on A549 cell lines and low toxicity to NIH3T3 cells.

New pyrazoline derivatives and their antidepressant activity

Some triazolo-pyrazoline derivatives were synthesized to investigate their potential antidepressant activities. The chemical structures of the compounds were elucidated by IR, NMR and FAB(+)-MS spectral data and elemental analyses. Antidepressant-like activities of the test compounds (100 mg/kg) were screened using both modified forced swimming and tail suspension tests. Rota-Rod test was performed for the examination of probable neurological deficits due to the test compounds, which may interfere with the test results. The test compounds in the series exhibited different levels of antidepressant activities when compared to reference drug fluoxetine. None of the test compounds changed motor coordination of animals when assessed in the Rota-Rod test. Therefore, experimental results in this study were not interfered with motor abnormalities.

Synthesis and Biological Evaluation of Some Hydrazone Derivatives as Anti-inflammatory Agents

In the present study, some hydrazone derivatives were synthesized via the reaction of 3-cyclohexylpropionic acid hydrazide with various benzaldehydes. The chemical structures of the compounds were elucidated by spectroscopic techniques such as IR, 1 H-NMR and FAB-MS and elemental analyses. The compounds were evaluated for their anti- inflammatory and cytotoxic activities. Anti-inflammatory activity was determined in terms of inhibition of NF-! B, ROS generation and iNOS activity. Several derivatives inhibited NF-! B and iNOS, but no effect was observed on intracellular ROS generation. Furthermore no cytoxicity was observed. Biological activity compared with the chemical structural information suggests that different functional groups on the phenyl ring influence the physicochemical properties and thus modulate biological activity.

Synthesis of Thiadiazole Derivatives Bearing Hydrazone Moieties and Evaluation of Their Pharmacological Effects on Anxiety, Depression, and Nociception Parameters in Mice

Novel thiadiazole derivatives bearing hydrazone moieties were synthesized through the reaction of 2-[(5-methyl-1,3,4-thiadiazol-2-yl)thio)]acetohydrazide with aldehydes/ketones. The chemical structures of the compounds were elucidated by 1H-NMR, 13C-NMR, MS-FAB spectral data, and elemental analyses. Behavioral effects of the test compounds in mice were examined by hole-board, activity cage, tail suspension and modified forced swimming tests (MFST). Antinociceptive activities were evaluated using the hot-plate and tail-clip methods. Results of the experiments indicated that the test compounds did not significantly change the exploratory behaviors or locomotor activities of animals in the hole-board and activity cage tests, respectively. Administration of the reference drug fluoxetine (10 mg/kg) and compounds 3a, 3b, 3c, 3j, 3k, and 3l significantly shortened the immobility times of animals in the tail suspension and MFST tests, indicating the antidepressant-like effects of these derivatives. Morphine (10 mg/kg) and compounds 3a, 3b, 3c, 3d, 3e, 3j, 3k, and 3l increased the reaction times of mice in both the hot-plate and tail-clip tests, indicating the antinociceptive effects of these compounds. To the best of our knowledge, this is the first study of central nervous system activities of chemical compounds carrying thiadiazole and hydrazone moieties together on their structures.

Synthesis and Evaluation of New 1,5-Diaryl-3-(4-(methyl- sulfonyl)phenyl)-4,5-dihydro-1H-pyrazole Derivatives as Potential Antidepressant Agents

In an effort to develop potent antidepressant agents, new pyrazoline derivatives 2a–s were synthesized and evaluated for their antidepressant-like activity by tail suspension test (TST) and modified forced swimming test (MFST). The effects of the compounds on spontaneous locomotor activity were also investigated using an activity cage apparatus. Among these derivatives, compounds 2b, 2d, 2f, 2o, and 2r decreased both horizontal and vertical activity number of the mice. On the other hand, compounds 2a, 2h, 2j, 2k, 2l, 2m, and 2n, which did not induce any significant change in the locomotor activity, significantly shortened the immobility time of mice in TST and MFST, representing the presence of the antidepressant-like effect. Additionally, the same compounds increased the swimming time of mice in MFST without any change in climbing duration, similar to the reference drug fluoxetine (10 mg/kg). In the light of previous papers examining the effects of pyrazolines on central nervous system, this study, once more, pointed out remarkable antidepressant activity potential of pyrazoline derivatives.

Synthesis and anticandidal activity of new triazolothiadiazine derivatives

New triazolothiadiazine derivatives were synthesized via the ring closure reaction of 4-amino-5-substituted-2,4-dihydro-3H-1,2,4-triazol-3-thiones with phenacyl bromides. The compounds were tested in vitro against various Candida species and compared with ketoconazole. Among these compounds, the compound bearing cyclohexyl moiety and p-chlorophenyl substituent on triazolothiadiazine ring (2i) was found to be the most potent derivative against Candida albicans (ATCC 90028). It is clear that there is a positive correlation between anticandidal activity and two functional moieties, namely cycloaliphatic group and p-chlorophenyl substituent on triazolothiadiazine ring. The compounds were also investigated for their cytotoxic effects using MTT assay. Compound 2a exhibited the highest cytotoxic activity, whereas compound 2f possessed the lowest cytotoxic activity against NIH/3T3 cells.

Synthesis and in Vitro Evaluation of New Nitro-Substituted Thiazolyl Hydrazone Derivatives as Anticandidal and Anticancer Agents

Fourteen new thiazolyl hydrazone derivatives were synthesized and evaluated for their anticandidal activity using a broth microdilution assay. Among the synthesized compounds, 2-[2-((5-(4-chloro-2-nitrophenyl)furan-2-yl)methylene)hydrazinyl]-4-(4-fluorophenyl)thiazole and 2-[2-((5-(4-chloro-2-nitrophenyl)furan-2-yl)methylene) hydrazinyl]-4-(4-methoxyphenyl)thiazole were found to be the most effective antifungal compounds against Candida utilis, with a MIC value of 250 µg/mL, when compared with fluconazole (MIC = 2 µg/mL). Additionally, the synthesized compounds were evaluated for their in vitro cytotoxic effects on the MCF-7 and NIH/3T3 cell lines. As a result, 2-[2-((5-(4-chloro-2-nitrophenyl)furan-2-yl)methylene)hydrazinyl]-4-(4-chlorophenyl)thiazole was identified as the most promising anticancer compound against MCF-7 cancer cells due to its inhibitory effects (IC50 = 125 µg/mL) and relatively low toxicity towards the NIH/3T3 cell line (IC50 > 500 µg/mL).

Synthesis and Biological Evaluation of a Series of Dithiocarbamates as New Cholinesterase Inhibitors

In the present paper, a novel series of dithiocarbamates was synthesized via the treatment of 4‐(trifluoromethyl)benzyl chloride with appropriate sodium salts of N,N‐disubstituted dithiocarbamic acids. The chemical structures of the compounds were elucidated by 1H NMR, mass spectral data, and elemental analyses. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellmans spectrophotometric method. The most potent AChE inhibitor was found as compound 2g (IC50 = 0.53 ± 0.001 µM) followed by compounds 2f (IC50 = 0.74 ± 0.001 µM) and 2j (IC50 = 0.89 ± 0.002 µM) when compared with donepezil (IC50 = 0.048 ± 0.001 µM). Compounds 2f and 2g were more effective than donepezil (IC50 = 7.88 ± 0.52 µM) on BuChE inhibition. Compounds 2f and 2g exhibited the inhibitory effect on BuChE with IC50 values of 1.39 ± 0.041 and 3.64 ± 0.072 µM, respectively.

Synthesis and Evaluation of New Pyrazoline Derivatives as Potential Anticancer Agents

New pyrazoline derivatives were synthesized and evaluated for their cytotoxic effects on AsPC-1 human pancreatic adenocarcinoma, U87 and U251 human glioblastoma cell lines. 1-[((5-(4-Methylphenyl)-1,3,4-oxadiazol-2-yl)thio)acetyl]-3-(2-thienyl)-5-(4-chlorophenyl)-2-pyrazoline (11) was found to be the most effective anticancer agent against AsPC-1 and U251 cell lines, with IC50 values of 16.8 µM and 11.9 µM, respectively. Tumor selectivity of compound 11 was clearly seen between Jurkat human leukemic T-cell line and human peripheral blood mononuclear cells (PBMC). Due to its promising anticancer activity, compound 11 was chosen for apoptosis/necrosis evaluation and DNA-cleavage analysis in U251 cells. Compound 11-treated U251 cells exhibited apoptotic phenotype at low concentration (1.5 µM). DNA-cleaving efficiency of this ligand was more significant than cisplatin and was clearly enhanced by Fe(II)-H2O2-ascorbic acid systems. This result pointed out the relationship between the DNA cleavage and the cell death.

Synthesis and Biological Evaluation of Some Pyrazoline Derivatives Bearing a Dithiocarbamate Moiety as New Cholinesterase Inhibitors

In the present study, new pyrazoline derivatives were synthesized via the reaction of 1‐(chloroacetyl)‐3‐(2‐furyl)‐5‐aryl‐2‐pyrazolines with sodium salts of N,N‐disubstituted dithiocarbamic acids. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellmans spectrophotometric method. The compounds were also investigated for their cytotoxic properties using the MTT assay. The most potent AChE inhibitor was found as compound 7 followed by compounds 27 and 17, when compared with eserine. Compounds effective on AChE carry the 2‐dimethylaminoethyl moiety, which resembles the trimethylammonium group and the ethylene bridge of acetylcholine. Among all compounds, compound 7 bearing 2‐dimethylaminoethyl and 3,4‐methylenedioxyphenyl moieties was also found to be the most effective inhibitor of BuChE. The MTT assay indicated that the effective concentration of compound 7 was lower than its cytotoxic concentration.