Ibrahim M. Labouta

Synthesis of some substituted benzimidazoles with potential antimicrobial activity

SummaryThe synthesis andin vitro antimicrobial evaluation of several benzimidazole derivatives with different heterocyclic nuclei at position-2 are described.ZusammenfassungDie Synthese und antimikrobielle Prüfung einiger Benzimidazole mit verschiedenen heterozyklischen Substituenten in 2-Stellung wird beschrieben.

Design, synthesis, and biological evaluation of new 4-thiazolidinone derivatives substituted with benzimidazole ring as potential chemotherapeutic agents

In search of novel antiviral and anticancer agents with promising pharmacotoxicological profile, a study was initiated to synthesize new 2-thioxo-4-thiazolidinones as well as 2-phenylimino-4-thiazolidinones substituted with benzimidazole ring system. The compounds were screened primarily for their antiviral as well as anticancer activities. The synthesis of some novel 5-substituted thiazolidinones was also described. None of the tested compounds showed inhibitory activity against Hepatitis C virus replication. Two 2-phenylimino-4-thiazolidinone derivatives (9a and 10) exhibited significant antiproliferative activity against human colon carcinoma cell line HCT 116 and human hepatocellular carcinoma HEPG2 cell line, respectively. Results also indicated that six thiazolidinone derivatives (5a, 5d, 5e, 5f, 5h, and 9d) showed moderate antiproliferative activity against human breast adenocarcinoma cell line MCF7 in comparison to the standard drug Doxorubicin. Moreover, a docked pose of the most potent three cytotoxic compounds 5a, 5h, and 9d against MCF7 was obtained bound to Human N-acetyl transferase1 NAT1 binding pocket by molecular operating environment module.

Potential anti-microbial: syntheses and in vitro anti-microbial evaluation of some 5-arylazo-thiazolidones and related compounds

As a part of a research project on anti-microbial agents, a series of 5-arylazo-3-benzyl-4-thioxothiazolidin-2-ones 4 and some of their 4-oxo 5, 4-hydroximino 6 and 4-phenylhydrazono 7 derivatives were prepared and evaluated as potential anti-microbial agents. Some compounds were found to have significant activity against Staphylococcus aureus strains.

Target identification, lead optimization and antitumor evaluation of some new 1,2,4-triazines as c-Met kinase inhibitors.

In silico target fishing approach using PharmMapper server identified c-Met kinase as the selective target for our previously synthesized compound NCI 748494/1. This approach was validated by in vitro kinase assay which showed that NCI 748494/1 possessed promising inhibitory activity against c-Met kinase (IC50=31.70μM). Assessment of ADMET profiling, drug-likeness, drug score as well as docking simulation for the binding pose of that compound in the active site of c-Met kinase domain revealed that NCI 748494/1 could be considered as a promising drug lead. Based on target identification and validation, it was observed that there is structure similarity between NCI 748494/1 and the reported type II c-Met kinase inhibitor BMS-777607. Optimization of our lead NCI 748494/1 furnished newly synthesized 1,2,4-triazine derivatives based on well-established structure-activity relationships, whereas three compounds namely; 4d, 7a and 8c displayed excellent in vitro cytotoxicity against three c-Met addicted cancer cell lines; A549 (lung adenocarcinoma), HT-29 (colon cancer) and MKN-45 (gastric carcinoma); with IC50 values in the range 0.01-1.86µM. In vitro c-Met kinase assay showed 8c to possess the highest c-Met kinase inhibition profile (IC50=4.31µM). Docking of the active compounds in c-Met kinase active site revealed strong binding interactions comparable to the lead NCI 748494/1 and BMS-777607, suggesting that c-Met inhibition is very likely to be the mechanism of the antitumor effect of these derivatives.

Design, synthesis and evaluation of some pyrazolo[3,4-d]pyrimidines as anti-inflammatory agents

New pyrazolo[3,4-d]pyrimidines substituted with various functionalities or attached to a substituted pyrazole ring through different linkages were synthesized. The synthesized compounds were evaluated for their anti-inflammatory activity using in vitro COX-1/COX-2 inhibition assay and in vivo formalin induced paw edema and cotton pellet-induced granuloma assays. Results revealed that compounds 17b and 18 possessed COX-1/COX-2 selectivity indices higher than diclofenac sodium and celecoxib. However, compounds 16a,b exhibited selectivity indices higher than diclofenac sodium and nearly equivalent to celecoxib, whereas, 9b displayed selectivity index comparable to diclofenac sodium. In vivo anti-inflammatory data showed that compounds 9b, 16a, 18 displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, the pyrazolyl derivatives 9b, 16b and 17b displayed anti-inflammatory activity about 2-2.5-fold that of diclofenac sodium and nearly 8-10.5-fold that of celecoxib in the cotton pellet-induced granuloma assay. The ulcerogenic effect of the active compounds was also investigated and results revealed that compounds 16a, 17a,b and 18 showed good gastrointestinal safety profile. Based on this, compounds 16a and 18 were considered as safe and effective leads in managing acute inflammation, while, 17b was prominent in controlling chronic inflammation.

Design, synthesis and evaluation of some pyrazolo[3,4-d]pyrimidine derivatives bearing thiazolidinone moiety as anti-inflammatory agents

Two new series of pyrazolo[3,4-d]pyrimidine bearing thiazolidinone moiety were designed and synthesized. The newly synthesized compounds were evaluated for their in vitro (COX-1 and COX-2) inhibitory assay. Compounds that showed promising COX-2 selectivity were further subjected to in vivo anti-inflammatory screening applying formalin induced paw edema (acute model) and cotton-pellet induced granuloma (chronic model) assays using celecoxib and diclofenac sodium as reference drugs. The histopathological and ulcerogenic potential were also determined. In vivo anti-inflammatory data showed that compounds 2, 6, 7d displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, compounds 2, 3d, 3e, 7b and 7d displayed anti-inflammatory activity greater than or nearly equivalent to diclofenac sodium in the cotton pellet-induced granuloma assay. Moreover, most of the tested compounds revealed good gastrointestinal safety profile. Collectively, compounds 2 and 7d were considered as promising candidates in managing both acute and chronic inflammation with safe gastrointestinal margin.

Structure-based design of some isonicotinic acid hydrazide analogues as potential antitubercular agents

New pyridine derivatives were designed and synthesized as Isonicotinic acid hydrazide (INH) analogues. The synthesized compounds were evaluated for their antitubercular activity against Mycobacterium tuberculosis strain H37Rv. Ten compounds (3c, 3e-g, 5a-c, 6h, 10 and 11b) showed promising antitubercular activity with MIC range 7.30 µM-19.39 µM. Compounds 3e, 3g, 5b and 11b were the most potent analogues, with MIC 7.30-8.74 µM. They were equipotent to the standard drug Ethambutol (MIC 7.64 µM) and more active than the standard drug Pyrazinamide (MIC 50.77 µM). They were further examined for cytotoxicity in human embryonic kidney (HEK) cell line at the concentration of 50 µg/mL using MTT assay. Results declared that most compounds showed acceptable safety margin. Molecular Docking studies into 2-trans-enoyl-acyl carrier protein reductase, called InhA have been conducted for compounds 3e, 3g, 5b and 11b using Molecular Operating Enviroment software (MOE 2016.0802), where reasonable binding interactions have been identified and effective overall docking scores have been recorded. Their drug-likeness has been assessed using Molinspiration and Osiris software.