Synthesis, characterization and biological evaluation of new derivatives of ciprofloxacin and norfloxacin of interesting biological activities

Abstract

Synthesis of new derivatives of ciprofloxacin 2 and norfloxacin 3 containing a tryptophan moiety linked to their NH of piperazine moiety forming amides was achieved by reaction of the carboxyl group of L-tryptophan. The chemical structures of these new compounds were confirmed by elemental (CHN) and spectral (IR, ¹H NMR) analyses. The minimum inhibitory concentrations (MICs) of these derivatives (2 and 3) were determined by a serial dilution method using B. Subtilus and E. coli and the results were comparable and promising, when compared with the parent compounds. The cell viability of these derivatives was also determined and the antitumor activity against three types of human cancer cell lines (Breast, Skin and Colorectal) was evaluated. Compound 2 has significant antiproliferative activity against breast and skin cancer cells, although slightly less active than ciprofloxacin. This result indicated that the new derivative of tryptophan-ciprofloxacin has selective antitumor activity against cancer cells and worth further investigation.