Synthesis of the novel cage amides and imides and evaluation of their antibacterial and antifungal activity

Cage amides and imides bearing bicyclo[2.2.1]- and bicyclo[2.2.2]-subunits were synthesized and evaluated both for antimicrobial activity toward five key ESKAPE pathogenic bacteria: one Gram‐positive bacteria methicillin‐resistant Staphylococcus aureus (ATCC 43300), four Gram‐negative bacteria Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 700603), Acinetobacter baumannii (ATCC 19606) and Pseudomonas aeruginosa (ATCC 27853) and for antifungal activity towards pathogenic fungal strains Candida albicans (ATCC 90028) and Cryptococcus neoformans var. Grubii (H99; ATCC 208821). Compound VP-4539 with bicyclo[2.2.2]octene motif demonstrated the highest cytotoxic activity towards C. neoformans, while human keratinocytes of HaCaT line, murine fibroblasts of Balb/c 3T3 line and mitogen-activated lymphocytes of peripheral human blood were found to be tolerant to its action. VP-4539 compound did not intercalate into salmon sperm DNA indicating that its cytotoxicity is not related to intercalation into nucleic acid. Keywords: antifungal, antimicrobial, bicyclo[2.2.1]heptane, bicyclo[2.2.2]octene, cytotoxicity, DNA intercalation, human keratinocytes, lymphocytes, сage compounds