Cancer is one of the deadliest diseases nowadays and is a great topic for research as the challenging task is to develop new entities with selectivity towards cancerous cells. Heterocyclic compounds are of great importance in medicinal chemistry as they possess an extensive range of therapeutic applications. Benzimidazole is one such important heterocyclic organic compound having structural analogy to nucleotides found in human body and hence is an important pharmacophore in medicinal chemistry. A variety of marketed drugs containing benzimidazole are thiabendazole, flubendazole (anthelmintic), astmizole (antihistaminic), lansoprazole and omeprazole (antiulcerative). In the light of the above facts, this review is an attempt to summarize the collective contributions from the authors around the world in the field of anticancer agents. This review highlights synthetic schemes and anticancer activity results of the research done in the past years.

A series of benzimidazole derivatives (1-20) was synthesized and evaluated for its in vitro antimicrobial, antitubercular and anticancer activities. Compound 10 was found to be the most active antibacterial agent. The compounds active in in vitro evaluation against M. tuberculosis were further assessed for their in vivo activity in mice and for their capacity to inhibit the vital mycobacterial enzymes viz., isocitrate lyase, pantothenate synthetase and chorismate mutase. The dose of the compounds in antitubercular evaluation that proved fatal and highly toxic to mice was 5.67 mg/kg while lethal dose varied from 1.82 mg/kg to 3.23 mg/kg body weight of the mice. A dose of 1.34 mg/kg was found to be safe for each of the compounds. All compounds inhibited the mycobacterial enzymes but to a lesser extent than streptomycin sulphate used as positive control. Compound 19, exhibiting inhibition of 67.56%, 53.45%, and 47.56% against isocitrate lyase, pantothenate synthetase and chorismate mutase, respectively is the most potent antitubercular compound among the synthesized benzimidazole derivatives. Further, compound 19 also emerged as a potent anticancer agent (IC 50 = 0.0013 mM) than 5-flourouracil against breast cancer cell line (MCF 7).

Shikonin and its derivatives, isolated from traditional medicinal plant species of the genus Lithospermum, Alkanna, Arnebia, Anchusa, Onosma, and Echium belonging to the Boraginaceae family, have numerous applications in foods, cosmetics, and textiles. Shikonin, a potent bioactive red pigment, has been used in traditional medicinal systems to cure various ailments and is well known for its diverse pharmacological potential such as anticancer, antithrombotic, neuroprotective, antidiabetic, antiviral, anti-inflammatory, anti-gonadotropic, antioxidants, antimicrobial and insecticidal. Herein, updated research on the natural sources, pharmacology, toxicity studies, and various patents filed worldwide related to shikonin and approaches to shikonin’s biogenic and chemical synthesis are reviewed. Furthermore, recent studies to establish reliable production systems to meet market demand, functional identification, and future clinical development of shikonin and its derivatives against various diseases are presented.

Intramolecular C–N heterocyclization and C–C bond formation under visible light irradiation at room temperature was accomplished with a metal-free photoredox catalyst.

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

A series of 4-[1-(substituted aryl/alkyl carbonyl)-benzoimidazol-2-yl]-benzene sulphonic acids (1-20) was synthesized and evaluated, in vitro, for their antimicrobial activity and the results indicated that compounds 4-[1-(4-Nitrobenzoyl)-1H-benzoimidazol-2-yl]-benzenesulfonic acid (9) and 4-(1-octadec-9-enoyl-1H-benzoimidazol-2-yl)-benzenesulfonic acid (18) were found to be the most active ones. QSAR investigations indicated that the multi-target QSAR model was effective in describing the antimicrobial activity over the one-target QSAR models. Further the mt-QSAR model indicated the importance of the topological parameter, Balaban index (J) followed by the electronic parameter, LUMO and topological parameter, valence second order molecular connectivity index (2χv) in describing the antimicrobial activity of synthesized compounds (1-20).

A catalyst free visible light assisted synthesis of thiazoles and imidazo[2,1-b]thiazoles in EtOH : H2O green medium.

BackgroundA series of 2-(1H-benzo[d]imidazol-2-ylthio)-N-(substituted 4-oxothiazolidin-3-yl) acetamides was synthesized and characterized by physicochemical and spectral means. The synthesized compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans and Aspergillus niger by tube dilution method. The in vitro cytotoxicity study of the compounds was carried out against human colorectal (HCT116) cell line. The most promising anticancer derivatives (5l, 5k, 5i and 5p) were further docked to study their binding efficacy to the active site of the cyclin-dependent kinase-8.ResultsAll the compounds possessed significant antimicrobial activity with MIC in the range of 0.007 and 0.061 µM/ml. The cytotoxicity study revealed that almost all the derivatives were potent in inhibiting the growth of HCT116 cell line in comparison to the standard drug 5-fluorouracil. Compounds 5l and 5k (IC50 = 0.00005 and 0.00012 µM/ml, respectively) were highly cytotoxic towards HCT116 cell line in comparison to 5-fluorouracil (IC50 = 0.00615 µM/ml) taken as standard drug.ConclusionThe molecular docking studies of potent anticancer compounds 5l, 5k, 5i and 5p showed their putative binding mode and significant interactions with cyclin-dependent kinase-8 as prospective agents for treating colon cancer.