Medicinal Chemistry - Volume 10, Issue 8, 2014

A series of twelve analogs carrying fluoro, chloro, bromo and iodo halogens on the ortho, meta and para positions of a benzoyloxytropane skeleton were synthesized by a simple acylation of 8-methyl-8-aza-bicyclo[3.2.1]octan- 3α-ol by halogenobenzoyl chlorides. The compounds were evaluated in vitro against Plasmodium falciparum (P. f.), Trypanosoma brucei brucei (T. b. b.), Trypanosoma cruzi (T. c.) and Leishmania infantum (L. i.). This study shows that the presence of a halogenated atom and its position on the aromatic ring are important for in vitro activity. Compounds 4 (IC50 = 3.6 µM), 8 (IC50 = 6.7 µM), 5 (IC50 = 8.1 µM) and 7 (IC50 = 9.5 µM) were found the most active against P. f., whereas compounds 12 (IC50 = 5.1 µM), 11 (IC50 = 5.6 µM) and 9 (IC50 = 5.8 µM) exhibited the most pronounced activity against T. b. b. This series of compounds can be considered as non-toxic to the human cell line MRC-5.

The synthesis and chemical characterization of the novel 2,6-diacetylpyridine-bis(selenosemicarbazone) metal complexes of Zn(II), Cd(II) and Ni(II) were published previously. Here we report first evidence on anti-proliferative activity of the complexes and molecular patterns that underlie it. The complexes and the corresponding ligand are shown to be cytotoxic on the panel of nine, malignant and non-malignant cell lines, with the exception of Ni(II) complex that did not achieve IC50 value on any of the cell lines tested. Further experiments on the selected cell lines including A 549, MRC-5, EA.hy 926 and HeLa, have shown that the complexes posses unambiguous property of inducing necrosis in the cells treated for 6 hours, with the ligand and Zn(II) complex being the most active on all cell lines. On the contrary, only small portion of early apoptotic events was detected, under the same experimental condition. This was in complete concordance with the results obtained from Western blot analysis of the treated cells that showed no or slight increase of the protein amounts of two crucial apoptotic mediators: Cytochrome C and Caspase III. We propose the model, under which tested complexes induce necroptosis in treated cells, a recently described type of cell death with necrotic morphological features and acting via caspase independent pathway, and without elevated amounts of intracellular ROS. Endothelial EA.hy 926 cells have proven to be extremely sensitive on the necrosis-inducing effect of the complexes, which could indicate potential anti-angiogenic effect of the novel complexes that is to be investigated.

We have synthesized a series of anthrapyrazoles derivatives. The biological results indicated that these derivatives exhibited potent in vitro cytotoxicity against different cancer cell lines (human hepatocellular carcinoma HepG2 and BEL-7402, human colonic carcinoma HCT-116 and HT-29) and drug-resistant human hepatoma cell line (SMMC-7721). Among them, the polyamine-based anthrapyrazole derivatives 4c and 4f-g showed superior cytotoxicity than that of Mitoxantrone both on cancer cell lines and the drug-resistant subline. However, the DNA relaxation assay revealed that they had insignificant topoisomerase II inhibition. These results clearly indicate that polyamine side chains will have a profound effect on the cytotoxicity of anthrapyrazoles derivatives.

Twenty-three (23) derivatives of coumarin (5-27) were synthesized and screened for their in vitro β- glucuronidase (E. coli) inhibitory activities. Only three compounds, 7,8-dihydroxy-4-methyl-2H-chromen-2-one (9) (IC50 = 52.39 ± 1.85 µM), 3-chloro-6-hexyl-7-hydroxy-4-methyl-2H-chromen-2-one (18) (IC50 = 60.50 ± 0.87 µM), and 3,6- dichloro-7-hydroxy-4-methyl-2H-chromen-2-one (15) (IC50 = 380.26 ± 0.92 µM) displayed activities against β- glucuronidase as compared to standard D-saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 µM). The results indicated that the activity of the synthetic coumarins depends upon the substituents present on the coumarin skeleton.

To explore apolipoprotein E gene variants distribution among the patients of Alzheimer’s disease and vascular dementia for the elderly community population in Nanking, the polymerase chain reaction and restriction fragment length polymorphism techniques were employed to analyze the gene frequency of apolipoprotein E (ApoE) for 113 cases with Alzheimer’s disease (AD), 85 cases with vascular dementia (VaD), 147 cases with questionable dementia (QD), and 396 dementia-free controls. It was found that ApoE ε4 gene container (37.17%) and allele frequency (21.24±2.72) of ApoE ε4 in AD group were significantly higher than those in both control and VaD group (p<0.05). With the increment of ε4 gene dose, the incidence of the AD was significantly increased. Compared with the control group, ApoE ε4 had risk ratio (RR) of 1.82 to develop AD (p =4e-4), and attributable risk percentage (ARP) of 45%. These results suggest that ApoE ε4 gene may be responsible for up to 45% of the genetic component of Alzheimer’s disease, and may act as a discriminator between AD and VaD as well.

A series of 2´-hydroxy-4´-isoprenyloxychalcone derivatives was synthesized and evaluated for its antidepressant- like activity using the FST and TST. All compounds exhibited the potential antidepressant-like activity in the FST and the TST through intraperitoneal injection. Among them, compounds 4i, 4l and 4n exhibited more potent antidepressant- like activity at a dose of 10 mg/kg. And, compounds 4i, 4l and 4n were also adequately absorbed in mice after oral administration at a dose of 30 mg/kg. In the 5-HT induced head-twitch test and yohimbine induced mortality test, compound 4i could increase the head-twitch and rise mortality in mice. The results suggested that the antidepressant effects of compound 4i may be related to via the serotonergic and noradrenergic system.

Novel N3 aryl/heteroaryl substituted 2-((benzyloxy and phenylthio) methyl) 6,7-dimethoxyquinazolin-4(3H)- ones (8a-8l) were synthesized and evaluated for their anticonvulsant activity using various models of epilepsy, such as maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and intracerebroventricular AMPA (α-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid)-induced seizures in mice. The rotarod test has been used to determine the acute neurotoxicity. Further, the serum enzymatic activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assessed along with histopathological examination of liver. Among all the derivatives, compound 8f displayed significant activity profile based on the overall magnitude of activity and minimum neurotoxicity.

A new series of 3,4-disubstituted 1,2,4-triazol-5(4H)-one 5a-r, bearing various methoxyphenyl, fluorophenyl, tolyl and phenyl groups, was synthesized by the dehydrocyclization of hydrazinecarboxamides 4a-r by refluxing in a 2 N sodium hydroxide solution. Hydrazinecarboxamides 4a-r was synthesized via the condensation of the corresponding aralkanoic acid hydrazides, 3a-g, with fluoro-, tolyl- and methoxyphenylisocyanates. The newly synthesized compounds (5ar) were characterized by IR, 1H NMR and 13C NMR analyses. The structure of one compound 5a was determined by single crystal X-ray diffraction analysis. All of the synthesized compounds were screened for their anti-inflammatory and anti-diabetic (α-glucosidase and α-amylase inhibition) activity to identify new drugs that might be useful in preventing damage related to diabetes and inflammation. Compounds 5j, 5k and 5m decrease the expression of type II collagen in a dose dependent manner; similarly 5l decrease the COX-2 expression of rabbit articular chondrocytes in a dose dependent manner possessing potent anti-inflammatory potential while some of derivatives including 5c, 5e, 5g and 5h cause inflammation. Meanwhile, excellent α-glucosidase and moderate α-amylase inhibitory profiles against carbohydrate modulating enzymes were demonstrated by compounds 5b, 5f, 5k and 5q compared to the reference standard acarbose, and compounds 5g, 5h, 5i, 5j, 5l and 5o exhibited moderate to low enzyme inhibition potential among the series.

This manuscript describes the protein anti-glycation activity of thirty-three (33) benzothiazoles, out of which twenty-seven were the newly synthesized benzothiazoles. Compound 1 (IC50= 187 ± 2.6 µM) was found to be the most active, while compounds 2 (IC50= 219 ± 3.6 µM), 3 (IC50= 224 ± 1.9 µM), 4 (IC50= 223 ± 3.3 µM), 5 (IC50= 238 ± 2.2 µM), 7 (IC50= 266 ± 5.4 µM), 17 (IC50= 226 ± 1.6 µM) and 18 (IC50= 274 ± 2.4 µM) were significantly active, when compared with the standard rutin (IC50= 294 ± 1.5 µM). This study identified potential inhibitors of methylglyoxal mediated glycation of proteins, which is the pathophysiology of late diabetic complications.

Estrogen receptors (ERs) are members of a superfamily of ligand-modulated nuclear receptors, which have been associated with an increased risk of cardiovascular diseases and breast cancer. Based on molecular docking studies, 1,4-dihydrothieno[3’,2’:5,6]thiopyrano[4,3-c]pyrazole-3-carboxamide derivatives as estrogen receptor inhibitors with a new scaffold , have been synthesized and tested for the antitumor activity on the ER expressing (ER dependent) human MCF-7 breast cancer cell line. According to the biological activity evaluation, compound 6a demonstrated the most potent antiproliferative activity (relative inhibitory rate: 100%). Several of these compounds exhibited moderate antitumor activity and worthy of further modification to obtain more potent anticancer candidate drugs.

Selective uncompetitive antagonists of the phencyclidine (PCP) binding site of the N-methyl-D-aspartate receptor (NMDAR) are known to have therapeutic potential as anticonvulsants and neuroprotective agents. Several fluorinated molecules with each containing a cycloheptane ring were designed to probe the PCP pharmacophore and test the influence of fluorine substitution on NMDAR binding and in vivo efficacy. Syntheses and analyses of six novel compounds, 1-(4- fluorophenyl)cycloheptanamine (3), 1-(1-(4-fluorophenyl)cycloheptyl)piperidine (4), 1-(1-(4-fluorophenyl)cycloheptyl) pyrrolidine (5), 1-(3-fluorophenyl)cycloheptanamine (6), 1-(1-(3-fluorophenyl)cycloheptyl)piperidine (7), 1-(1-(3-fluorophenyl) cycloheptyl)pyrrolidine (8) and several related reference arylcyloalkylamines are described. Receptor binding was performed at the PCP site of NMDAR for each compound using [3H]-(+)-MK-801 displacement. Unexpectedly, the 3- fluoro- primary amine 6 had the greatest affinity of the series and these binding results support a different structure activity relationship (SAR) profile for arylcycloheptylamines when compared to arylcyclohexylamines like PCP. Five of the novel compounds have affinity (Ki) in the hundred nM (10-7) range. In addition, compounds 3, 5, 6, 7 and 8 were evaluated and found to exhibit neuroprotective effects from NMDA induced toxicity in vitro and compounds 6, 7 and 8 exhibited anticonvulsant activities in rats. An ED50 of 13.84 mg/kg was found for compound 6 in rat maximal electroshock (MES) test with a protective index (PI) of 3.66 against ataxia. These results support further investigation of the arylcycloheptylamine class.