Novel Biologically Active N-Substituted Benzimidazole Derived Schiff Bases: Design, Synthesis, and Biological Evaluation

Herein, we present the design and synthesis of novel N-substituted benzimidazole-derived Schiff bases, and the evaluation of their antiviral, antibacterial, and antiproliferative activity. The impact on the biological activity of substituents placed at the N atom of the benzimidazole nuclei and the type of substituents attached at the phenyl ring were examined. All of the synthesized Schiff bases were evaluated in vitro for their antiviral activity against different viruses, antibacterial activity against a panel of bacterial strains, and antiproliferative activity on several human cancer cell lines, thus enabling the study of the structure activity relationships. Some mild antiviral effects were noted, although at higher concentrations in comparison with the included reference drugs. Additionally, some derivatives showed a moderate antibacterial activity, with precursor 23 being broadly active against most of the tested bacterial strains. Lastly, Schiff base 40, a 4-N,N-diethylamino-2-hydroxy-substituted derivative bearing a phenyl ring at the N atom on the benzimidazole nuclei, displayed a strong antiproliferative activity against several cancer cell lines (IC50 1.1-4.4 mu M). The strongest antitumoral effect was observed towards acute myeloid leukemia (HL-60).

Automated summary

In this study, novel N-substituted benzimidazole-derived Schiff bases were designed and synthesized, and their antiviral, antibacterial, and antiproliferative activity were evaluated. The effects of substituents at the N atom of the benzimidazole nuclei and the type of substituents attached at the phenyl ring on the biological activity were investigated. The synthesized Schiff bases were tested for their antiviral activity against different viruses, antibacterial activity against various bacterial strains, and antiproliferative activity on human cancer cell lines, revealing the structure activity relationships. Several compounds showed mild antiviral effects, while some derivatives exhibited moderate antibacterial activity. One particular Schiff base, 4-N,N-diethylamino-2-hydroxy-substituted derivative with a phenyl ring at the N atom on the benzimidazole nuclei, displayed a strong antiproliferative activity against cancer cell lines, especially acute myeloid leukemia (HL-60).