Design, Synthesis, and Thrombin Inhibitory Activity Evaluation of Some Novel Benzimidazole Derivatives

A Comprehensive Account on Recent Progress in Pharmacological Activities of Benzimidazole Derivatives

Nowadays, nitrogenous heterocyclic molecules have attracted a great deal of interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole scaffolds are considerably prevalent. Due to their isostructural pharmacophore of naturally occurring active biomolecules, benzimidazole derivatives have significant importance as chemotherapeutic agents in diverse clinical conditions. Researchers have synthesized plenty of benzimidazole derivatives in the last decades, amidst a large share of these compounds exerted excellent bioactivity against many ailments with outstanding bioavailability, safety, and stability profiles. In this comprehensive review, we have summarized the bioactivity of the benzimidazole derivatives reported in recent literature (2012-2021) with their available structure-activity relationship. Compounds bearing benzimidazole nucleus possess broad-spectrum pharmacological properties ranging from common antibacterial effects to the world's most virulent diseases. Several promising therapeutic candidates are undergoing human trials, and some of these are going to be approved for clinical use. However, notable challenges, such as drug resistance, costly and tedious synthetic methods, little structural information of receptors, lack of advanced software, and so on, are still viable to be overcome for further research.

Identify thrombin inhibitor with novel skeleton based on virtual screening study

Virtual screening refers to the screening of active compounds based on a small-molecule database. This procedure can rapidly select active compounds with pharmaceutical properties from millions of molecules, thus considerably reducing the number of experimental screening compounds and cost of drug development and shortening the research cycle. In this paper, a pharmacophore screening method was used for virtual screening to determine new scaffold compounds with potential anticoagulant activities. The pharmacophore model (Model_01-20) was constructed in SYBYL-X 2.0 based on dabigatran derivatives (D1-D9) with micromolar to nanomolar activities and tested by decoy test method. Model_01 was selected to screen more than 1600 million compounds in the Zinc 12.0 database. Furtherly, molecular docking analysis and ADME prediction were conducted on more than 100,000 screened compounds. Finally, two compounds (Z-19 and Z-29) were selected for anticoagulant activity test in vitro, Compound Z-29 with tryptophan aurone structure was found possess anticoagulant effect and its IC₅₀ = 22.9 ± 6.88 μM. ADME prediction results show that compound Z-29 features a high intestinal absorption rate, which is valuable for further in-depth research. The research results of this paper can be used for further structural modification and optimisation to guide the design and provide new ideas and methods for the discovery of new thrombin inhibitors.Communicated by Ramaswamy H. Sarma.

Synthesis and evaluation of antimicrobial, antitubercular and anticancer activities of 2-(1-benzoyl-1H-benzo[d]imidazol-2-ylthio)-N-substituted acetamides

BACKGROUND

The study describes the synthesis, characterization, in vitro antimicrobial and anticancer evaluation of a series of 2-(1-benzoyl-1H-benzo[d]imidazol-2-ylthio)-N-substituted acetamide derivatives. The synthesized derivatives were also assessed for in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. The compounds found active in in vitro study were assessed for their in vivo antitubercular activity in mice models and for their inhibitory action on vital mycobacterial enzymes viz, isocitrate lyase, pantothenate synthetase and chorismate mutase.

RESULTS

Compounds 8, 9 and 11 emerged out as excellent antimicrobial agents in antimicrobial assays when compared to standard antibacterial and antifungal drugs. The results of anticancer activity displayed that majority of the derivatives were less cytotoxic than standard drugs (tamoxifen and 5-fluorouracil) towards MCF7 and HCT116 cell lines. However, compound 2 (IC₅₀ = 0.0047 µM/ml) and compound 10 (IC₅₀ = 0.0058 µM/ml) showed highest cytotoxicity against MCF7 and HCT116 cell lines, respectively. The results of in vivo antitubercular activity revealed that a dose of 1.34 mg/kg was found to be safe for the synthesized compounds. The toxic dose of the compounds was 5.67 mg/kg while lethal dose varied from 1.81 to 3.17 mg/kg body weight of the mice. Compound 18 inhibited all the three mycobacterial enzymes to the highest level in comparison to the other synthesized derivatives but showed lesser inhibition as compared to streptomycin sulphate.

CONCLUSIONS

A further research on most active synthesized compounds as lead molecules may result in discovery of novel anticancer and antitubercular agents.