Synthesis and Biological Evaluation of New Cholinesterase Inhibitors for Alzheimer's Disease.

Alzheimer's disease (AD) is a neurodegenerative disorder mostly influencing the elderly, and causes death due to dementia. The main pathogenic feature connected with the progression of this multifactorial disease is the weakening of the cholinergic system in the brain. Cholinesterase (ChE) inhibitors are recognized as one of the choices in the treatment of AD. The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were approved as a therapeutic strategy to reduce the symptoms of AD and prevent its progression. The capacity of BChE is not completely known yet; rather, it is accepted to assume a part in a few disorders such as AD. Thus, BChE inhibitors may have a greater role for the treatment of AD in the future. In the present study, 2-(9-acridinylamino)-2-oxoethyl piperazine/piperidine/morpholinecarbodithioate derivatives were synthesized in order to investigate anticholinesterase activity. Eight derivatives demonstrated a specific and promising action against BChE. Furthermore, compound 4n showed inhibitory activity against both enzymes. It was found that the active compounds were well tolerated in the cytotoxicity test. Possible interactions between the lead compound, 4n, and the BChE enzyme were determined through a docking study. The findings obtained within this paper will contribute to the development of new and effective synthetic anti-Alzheimer compounds, and will ideally encourage future screening against AD.

Design, Synthesis and Biological Evaluation of Novel N-Pyridyl-Hydrazone Derivatives as Potential Monoamine Oxidase (MAO) Inhibitors.

A new series of N-pyridyl-hydrazone derivatives was synthesized by using a simple and efficient method. The final compounds obtained were screened for their inhibitory potency against monoamine oxidase (MAO) A and B. The newly synthesized compounds 2a-2n specifically inhibited monoamine oxidases, displaying notably low IC50 values. Compounds 2i and 2j, with a CF3 and OH group on the 4-position of the phenyl ring, respectively, showed considerable MAO-A and MAO-B inhibitory activities. Compounds 2k, 2l and 2n, with N-methylpyrrole, furan and pyridine moieties instead of the phenyl ring, were the most powerful and specific inhibitors of MAO-A, with IC50 values of 6.12 µM, 10.64 µM and 9.52 µM, respectively. Moreover, these active compounds were found to be non-cytotoxic to NIH/3T3 cells. This study supports future studies aimed at designing MAO inhibitors to obtain more viable medications for neurodegenerative disorders, such as Parkinson's disease.

Design, synthesis and biological assessment of new thiazolylhydrazine derivatives as selective and reversible hMAO-A inhibitors.

In the recent works, it was shown that numerous thiazolylhydrazine derivatives display hMAO inhibitory activity in the range of micromolar concentration. Hence, in the present study a new series of new thiazole-hydrazines (3a-3n) were designed, synthesized, characterized and screened for their hMAO-A and hMAO-B inhibitory activity by an in vitro flurometric method. The enzyme inhibition assay revealed that most of the synthesized compounds have selective inhibition potency against hMAO-A. The compounds 3f and 3h showed promising hMAO-A inhibition with an IC50 values of 0.012 µM and 0.011 µM and significant selectivity indexes of 1214 and 1601 towards hMAO-A, respectively. The mechanism of hMAO-A inhibition of compounds 3f and 3h was investigated by Lineweaver-Burk graphics and reversible-competitive inhibition of hMAO-A was determined. Cytotoxicity and genotoxicity studies were carried out and the compound 3h was found as non-cytotoxic and non-genotoxic. Theoretical calculation of ADME properties suggested that synthesized compounds may have a good pharmacokinetic profile. The docking study of compound 3f and 3h revealed that there is a strong interaction between the active sites of hMAO-A and analyzed compound.

Citalopram Induces Reproductive Toxicity in Male Rats.

BACKGROUND: Citalopram hydrobromide (CTL) has been shown to cause sexual dysfunction; however, its reproductive toxicity potential has not been sufficiently elucidated in men. Therefore, we aimed to clarify the toxic effects of CTL on the reproductive system of male rats. METHODS: For this purpose, CTL was administered at 5, 10, and 20 mg/kg/day to rats orally for 28 days. Sperm concentration, motility, and morphology were investigated using a computer-assisted sperm analysis system, and sperm DNA damage was detected using a Comet assay. The testes were histopathologically examined. Serum follicle-stimulating hormone, luteinizing hormone, and testosterone levels were measured and the oxidative status of testes was investigated. RESULTS: Our results showed that sperm concentration was reduced, and abnormal sperm morphology and sperm DNA damage were increased in CTL-administered groups. Additionally, histopathological changes were observed in the testes of CTL-administered rats. Luteinizing hormone levels were increased in CTL-administered groups, while testosterone levels were increased in the 5 and 10 mg/kg CTL-administered groups. Decreased glutathione signaled enhanced oxidative stress in the 10 and 20 mg/kg CTL-administered groups. CONCLUSION: Thus, we concluded that CT induced testicular damage in male rats; this testicular damage was accompanied by oxidative stress and hormonal changes, which are considered as the important causes of reproductive disorders. Birth Defects Research 109:475-485, 2017. © 2017 Wiley Periodicals, Inc.

New Benzimidazole-1,2,4-Triazole Hybrid Compounds: Synthesis, Anticandidal Activity and Cytotoxicity Evaluation.

Owing to the growing need for antifungal agents, we synthesized a new series 2-((5-(4-(5-substituted-1H-benzimidazol-2-yl)phenyl)-4-substituted-4H-1,2,4-triazol-3-yl)thio)-1-(substitutedphenyl)ethan-1-one derivatives, which were tested against Candida species. The synthesized compounds were characterized and elucidated by FT-IR, ¹H-NMR, 13C-NMR and HR-MS spectroscopies. The synthesized compounds were screened in vitro anticandidal activity against Candida species by broth microdiluation methods. In vitro cytotoxic effects of the final compounds were determined by MTT assay. Microbiological studies revealed that compounds 5m, 5o, 5r, 5t, 5y, 5ab, and 5ad possess a good antifungal profile. Compounds 5w was the most active derivative and showed comparable antifungal activity to those of reference drugs ketoconazole and fluconazole. Cytotoxicity evaluation of compounds 5m, 5o, 5r, 5w, 5y, 5ab and 5ad showed that compounds 5w and 5ad were the least cytotoxic agents. Effects of these two compounds against ergosterol biosynthesis were observed by LC-MS-MS method, which is based on quantification of ergosterol level in C. albicans. Compounds 5w and 5d inhibited ergosterol biosynthesis concentration dependently. A fluorescence microscopy study was performed to visualize effect of compound 5w against C. albicans at cellular level. It was determined that compound 5w has a membrane damaging effect, which may be related with inhibition of biosynthesis of ergosterol.