Medicinal Chemistry - Volume 10, Issue 6, 2014

Due to the wide range of chemical structures and variety of mechanisms of action of antischizophrenic agents, it is difficult to identify and confirm a common pharmacophore. The present review summarizes various pharmacophore models for antischizophrenic activity including those based on the new targets, the kynurenine aminotransferase (KATs), which may facilitate the development of novel drugs. Some models illustrate the structural differences of compounds with mechanisms of action considered similar, and yet others demonstrate pharmacophore models for similar chemical classes of compounds for which the mechanism of antischizophrenic action is still not clear. In this study, we discuss the pharmacophore models for antipsychotics including phenothiazine, butyrophenone, thioxanthene, and atypical agents along with the novel antischizophrenic agents which are inhibitors of KATs isozymes.

In the last few decades, the pharmaceutical application of marine natural products has attracted much attention from both organic and medicinal chemists. Recently, significant interest is focused on the isolation, identification, and biological activities of compounds from the Red Sea organisms and many of these compounds show promising biological activities, particularly cytotoxic and antimicrobial effects. This review covers the natural products and their biological activities isolated from the Red Sea flora and fauna in the recent past years.

The available treatment for the prevention and cure of Chagas disease, caused by the protozoan Trypanosoma cruzi, is still unsatisfactory. Thus, there is an urgent need to develop new drugs. In the last few years, our research group has focused on finding a new chemical entity able to target the infectious bloodstream trypomastigotes. In this study, we assayed 16 β-lapachone analogous with modifications in the pyran and aromatic ring to find a new prototype with high trypanocidal activity. Interestingly, two ortho-naphthoquinones presented the best trypanocidal profile (8c and 8d with an IC50/24 h of 26.9 ± 1.3 and 23.5 ± 2.5 μM, respectively), which were 4 to 17 times more effective than β-lapachone (391.5 ± 16.5 μM) and the standard drug benznidazole (103.6 ± 0.6 μM). The introduction of a hydroxyl group on the compounds’ aromatic ring modulated their biological profile by increasing their activity not only for cancer cells (MDAMB435), as previously described in literature, but also against T. cruzi. The Structure-Activity Relationship (SAR) study indicated that this introduction modulated HOMO and MEP parameters, improving the trypanocidal activity.

A series of functionalized N-sulfonyl-piperidines and N-sulfonyl-tetrahydropyridines were evaluated for their antiproliferative activity against the representative panel of human solid tumor cells A2780 (ovarian), SW1573 (non-small cell lung) and WiDr (colon). The SAR study showed for WiDr cells a correlation between the biological activity and the length of the N-sulfonyl group, the nature of the substituents and the type of alkyl side chain. Further QSAR studies indicate that the size and nature of the N-sulfonyl group, the atomic polarizability (MP) and the partition coefficient are the most important descriptors for the activity. The major contribution is the size (F05C-S) of the N-sulfonyl group.

Special attention has been given to the mosquito Aedes aegypti Linn. (Diptera: Culicidae) owing to numerous dengue epidemic outbreaks worldwide. Failure to control vector spreading is accounted for unorganized urban growth and resistance to larvicides and insecticides. Therefore, researchers are currently searching for new and more efficient larvicides and insecticides to aid dengue control measures. Triptamine is known to affect insect behavior, development, and physiology. Expression of this compound in plants has reduced the growth rate of herbivore insects. In view of these facts, it was of our interest to synthesize triptamine amide derivatives as potential larvicides against Ae. aegypti, establishing a Structure-Activity Relationship. Eleven amide derivatives of triptamine were synthesized, characterized, and evaluated for their larvicidal activity against third-instar Ae. aegypti larvae. N-(2-(1H-indol-3-yl)ethyl)-2,2,2-trichloroacetamide exhibited the highest overall larvicidal potency, while N-(2-(1H-Indol-3-yl)ethyl) acetamide displayed the lowest larvicidal potency. A regression equation correlating the larvicidal activity with Log P was obtained. We have found a clear relationship between the larvicidal activity of non-chlorinated compounds and Log P. Analysis of the relationship between Log P and larvicidal activity against Ae. aegypti may be useful in the evaluation of potential larvicidal compounds.

The search for novel lead from the group of various substituted N-piperazine ether derivatives was performed. Acyl- and pyridylpiperazine ethyl/propyl ethers were obtained via three different synthetic pathways. Affinity to histamine H3 receptor was established, as well as, for selected compounds, selectivity towards histamine H4R. Docking studies to the histamine H3R homology model strengthened the position of (4-(3-(4-(3-chlorobenzoyl)piperazin-1- yl)propoxy)phenyl)(cyclopropyl)methanone (compound 26) as a novel lead for further studies on histamine H3 receptor antagonist/inverse agonist.

Synthesis, characterization and investigation of antibacterial and antifungal activities of twelve camphor based 2,4-disubstituted 1,3-thiazoles is presented. Their structures were determined using NMR, IR, FAB MS and HRMS analyses. Among the derivatives, 3i and 5 were found to exhibit antifungal and antibacterial activities comparable to that of fluconazole and ciprofloxacin against yeast belonging to Candida spp., MIC 0.12-0.98 μg/ml and Gram-positive bacteria including both pathogenic S. aureus and opportunistic S. epidermidis, MIC 0.98-7.81 μg/ml, B. subtilis and B. cereus, MIC 3.91-31.25 μg/ml, and M. luteus, MIC 0.98 μg/ml species, respectively. Molecular docking studies of all compounds into the active sites of microbial enzymes indicated a possible targets SAP and NMT, thiazoles 3a-j, 4, 5 showed more favourable affinity than the native ligand.

We have previously reported the discovery of cytotoxic and pro-apoptotic hit compound 1,1-dimethylethyl (S)- 2,2-dimethyl-4-[(3-nitrophenoxy)methyl]-3-oxazolidinecarboxylate 1 against leukemia cells. In the present work we describe the synthesis of 25 derivatives of this hit varying the substituent at ring or stereochemistry of the oxazolidine ring and evaluated them against human cancer cells lines. Six compounds exerted significant activity against HL60 promyelocytic leukemia cells with IC50 in low micromolar range (4-18 μM) and three compounds displayed activity against MDA-MB231 breast cancer cells (25-37 μM). In vitro cytotoxicity on normal cells PBMC (human peripheral blood mononuclear cells) was also evaluated. Compounds 7e (p-NO2, S) and 7m (p-COOCH3, S) showed good antiproliferative activity against HL60 (4 and 5 μM) and MDA-MB231 (37 and 25 μM) without affecting lymphocyte proliferation in PBMC, indicating low toxicity to normal cells. Besides, compound 7e induced DNA fragmentation on about 100% of HL60 cells at 50 μM. In this case, it was more potent than 7m and lead 1. This indicated that compound 7e has a great pro-apoptotic potential.

A number of new aminosubstituted benzofuran analogues have been prepared and their cytotoxic/cytostatic activity was investigated against five human tumor cell lines (MCF-7, SKBR3, SKOV3, HCT-116 and HeLa). Certain compounds showed noticeable tumor cell growth inhibition, indicative of possible structure-activity relationships.

Protein kinase CK2, a serine/threonine kinase, is an attractive therapeutic target for many diseases. Here we described an application of cross-docking based drug design to discover novel and potent CK2 leads. Glide SP was chosen as the most suitable docking approach by comparing four docking protocols through native-docking. Then twenty-four CK2 crystal structures were compared by recovering known active ligands from a decoy database to select the optimal ensemble of CK2 structures, 2PVN, 2ZJW, 3AMY, 3FL5 and 3KXH were severed as the assemble, which were used in the virtual screening of compiled SPECS database for small molecules inhibiting CK2. Seven compounds were selected and purchased to test the biological activity. Compound g (AQ-390/42425635) showed the best inhibition rate and the lowest IC50, which can be used as a lead for our subsequent optimization.