Letters in Drug Design & Discovery - Volume 12, Issue 5, 2015

A series of di-substituted cinnamic hydroxamic derivatives was designed, synthesized and evaluated as HDAC inhibitors. Compound 5f (HS270) demonstrated potent HDAC inhibitory and antiproliferative activities. In xenograft model, 5f showed significant antitumor efficacy in tumorbearing mice.

Structure and ligand based approaches are effectively employed for the accurate design of ligands. The main objective of this study was to find out the correlation between structure and biological activity using structure and ligand based methodology. Azetidin-2-ones have been recognized as effective tubulin polymerization inhibitors that bind to the colchicine site on β-tubulin. Molecular docking (structure based method) was performed on a series of azetidin-2-ones using colchicines binding β tubulin. The docking studies indicate the important interactions of trimethoxy benzene with Cys241 and Val318 for anticancer activity. Energetic based pharmacophore mapping (hybrid structure and ligand based method) explain how the energy parameter from the Glide XP scoring function are plotted onto pharmacophore sites from the docked fragments so as to rank their implication for binding. Pharmacophore and atom based 3D QSAR modeling (ligand based method) was performed on 71 compounds of azetidin-2-ones derivatives as tubulin-binding agents for antitumor activity. Five-point common pharmacophore hypothesis was selected for alignment of all compounds. The 3D-QSAR models were developed using training set of 51 compounds and test set of 20 compounds. The generated common pharmacophore hypothesis (CPHs) and 3D-QSAR models were confirmed further externally by estimating the activity of database of compounds and comparing it with actual activity. We have established structure activity correlation using docking, energetic based pharmacophore mapping, pharmacophore and atom based 3D QSAR model. The results of these studies would be beneficial to refine the pharmacophore for design of novel potential compounds for antitumor activity.

A series of 7,8-dihydroxy-4-arylcoumarins, the derivatives related to DW532 that was an anti-tumor agent targeting both kinase and tubulin, was prepared by Suzuki coupling reaction. Among them, compounds 6a, 6b, and 6c were found to exhibit anti-proliferation activities against human breast carcinoma MDA-MB-468 cells with IC50 values of 0.64, 0.69, and 1.33 μM, respectively and human epidermoid carcinoma A431 cells with IC50 values of 2.56, 1.78, and 2.29 μM, respectively. Further evaluation of the selected molecules revealed that they displayed broad-spectrum inhibitory activities against a panel of kinases including Flt-1, VEGFR2, RET, EGFR, etc. In vitro tubulin polymerization assay and molecular docking indicated that the substitution of 3’-OH and 4’-OCH3 on the 4-phenyl ring was essential to achieve potent tubulin inhibition.

Naphthalimide-benzimidazole conjugates were prepared using two different types of spacer units; either a simple alkane chain or a substituted piperazine moiety with variable alkyl side chains. Each set of conjugates was evaluated for their in vitro anticancer activity, and compounds 14a, 14b and 20c were found to exhibit significant activity against a number of cancer cell lines. In particular, compound 14a showed remarkable anticancer activity with GI50 values of 0.02 μM and 0.49 μM against central nervous system (SNB-75) and leukemia (K-562) cell lines, respectively. Compound 14b showed noticeable activity against melanoma (MAME-3M) cell line with GI50 value 0.09 μM. Compound 20c also displayed selectivity against leukemia cell lines with GI50 values up to 0.21 μM as well as appreciable broad-spectrum cytotoxicity.

18 chromone derivatives were designed and synthesized from paeonol. All synthetic compounds were evaluated for their anti-proliferative activity towards eight human cancer cell lines including HepG2, HL-60, KB, LLC, LNCaP, LU-1, MCF7, and SW480. Compounds 3g and 3h presented the best cytotoxic effects towards tested cancer cell lines except HepG2. Their IC50 values were ranging from 7.9±0.4 to 18.9±1.3 μg/mL. Meanwhile, compound 3l showed selective cytotoxicity against MCF7 and KB with IC50 of 13.7±0.6 and 15.5±0.9 μg/mL, respectively.

A series of novel fluorinated heterocyclic hybrid molecules based on triazole & quinoxaline scaffold were designed, synthesized and evaluated for inhibition of Plasmodium falciparum, a virulent human malaria parasite. Mono and bis triazole tagged quinoxaline analogs were synthesized by propargylation of 6-amino quinoxaline followed by click reaction with various substituted aromatic azides under uncertain reaction conditions. The newly synthesized molecules were assessed for antimalarial activity and three of the analogs were identified as promising leads which killed parasites with IC50 values <10 μM and showed 27-70 selective indices.

Thirteen α-aminophosphonate derivatives with artesunate were synthesized by introducing bioactive α-aminophosphonate combination with artesunate in this work. The reaction were easily carried out at normal pressure, low temperature and without any catalyst. Four strains of microbials, namely Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, were used for the evaluation of the antimicrobial activities of these target compounds. Experimental results indicated that most of the compounds had good inhibitory effects. Compound 7k showed obvious antimicrobial activities with the MICs of 64 μg/ml against Staphylococcus aureus and 32 μg/ml against Candida albicans. Furthermore, when combined with roxithromycin, the synthesized compounds showed overlapping enhanced activities and proved potential antimicrobial synergists of roxithromycin.

The heterocyclic system is a promising core nucleus in many bioactive compounds. This work describes our effort to synthesize and characterize a set of new biphenyl, benzofuran and benzothiophene carboxamide derivatives. Our biological studies showed that compounds 10 and 17 have antifungal activity against C. galabrate more potent than fluconazole compounds 9, 10, and 17 exerted cytotoxic activities in immortalized embryonic mouse fibroblast cells (3T3) and a human cervical cancer cell line (HeLa); in particular, the cyclic amidine derivative 17 showed selective toxicity against HeLa. This study showed that the tested compounds have the potential to be useful as antitumor drugs after further optimization.

The present study involved the design and synthesis of new substituted 4-[2-(4- alkoxybenzylamino) ethyl]-2H-1,2,4-triazol-3(4H)-one derivatives (8a-w) starting from 1,2- ethanediamine. The final compounds were screened for their in vivo anticonvulsant activities and neurotoxicities by maximal electroshock (MES) and rotarod tests, respectively. Among the compounds studied, 4-[2-(4-butoxybenzylamino)ethyl]-2H-1,2,4-triazol-3(4H)-one hydrochloride (8b) was found by intraperitoneal administration in mice to be the most potent compound with a median effective dose (ED50) value of 33.2 mg/kg and a high protective index (PI) value of 11.4. Compound 8b showed significant oral activity against MES-induced seizures in mice with an ED50 value of 83.1 mg/kg and a PI of 18.1. The results demonstrated that compound 8b possessed better anticonvulsant activity and higher safety than the marketed drug carbamazepine.

Neonicotinoids are the most widely used insecticides currently, but their nematicidal activity was seldom reported. A series of spiro or bridged heterocyclic neonicotinoid analoges was prepared and their nematicidal activity was evaluated. Most of the synthesized compounds showed moderate to good nematicidal activity against Meloidogyne incognita. The investigations here provide the novel nematicidal chemotypes which can be used as leads for further structured modifications.