MEDICINAL SIGNIFICANCE OF BENZIMIDAZOLE ANALOGUES: A REVIEW

Benzimidazoles are well known biologically active N-containing heterocycles, widely used as drugs such as antifungal, antibacterial, antiparasitic, and antihelmintic. In addition, N₁ and C₂-substituted benzimidazoles and their derivatives have been found to be potent biologically active compounds as well. Further, N₁-substituted benzimidazoles have exhibited anti-microbial, antihelmintic activities and also antiviral activity against human cytomegalovirus and herpes simplex virus type-1. Specifically, N₁-substituted benzimidazole like 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole is known for inhibition of transcription elongation by RNA polymerase II. Another N₁-substituted benzimidazole derivative called enviroxime [2-amino-1- (isopropyl-sulphonyl)-6-benzimidazole phenyl ketone oxime] was reported to be a potent inhibitor of rhinovirus replication in human embryonic nasal organ cultures. The biological activities of these compounds depend upon the substitution on the benzimidazole at the N-1 or C-2 position. Since the benzimidazole heterocyclic ring system mimics the purine bases like adenine and guanine of nucleic acids, the N₁-substituted benzimidazole may incorporate into viral nucleic acid by enzymatic process and subsequently can alter the structure and/ or function of viral growth.