In Vitro Cytotoxicity Evaluation of Sixteen New N-Piperazinyl Quinolone Derivatives Against A Panel Of Tumor Cell Lines

Abstract

Introduction: Fluoroquinolones are potent inhibitors of bacterial topoisomerase II. They can also inhibit eukaryotic topoisomerase, and may confer antitumoral properties. Method: In this study the antitumoral activity of a new series of N-substituted piperazinylfluoroquinolones against a panel of human tumor cell lines was determined by MTT assays. Results: Among the tested compounds N-[2- (5-bromo-2-thienyl)-2-oxoethyl ] (C1,N1,E1), N-[ 2- (5-bromo-2-thienyl)-2-(hydroxyimino) ethyl]( C2,N2,E2) and N-[2-(5-bromo-2-thienyl)-2- (phenylmethoxyimino) ethyl] (C3,N3,E3) piperazinyl quinolones exhibited the most cytotoxic activities (mean IC50s = 2.5 to 3 µg/ml), comparable to that of the Etoposide (mean IC50= 1.7µg/ml). Replacement of the 5- bromo-2-thienyl with 4- fluorophenyl or 2,6- difluorophenyl rings leads to variable inhibition activity. The quinolone activity was enhanced by the presence of a chlorine and two fluorine atoms at the benzyl and phenyl groups, especially against ACHN renal adenocarcinoma cell line. Conclusion: These data suggest that these series of quinolones provide good models for the further design of potent antitumor compounds.