Cytotoxicity of nitroheterocyclic compounds, Quinifuryl and Nitracrine, towards leukaemic and normal cells on the dark and under illumination with visible light

The cytotoxicity of two nitroheterocyclic compounds (NHCD), Nitracrine, 1-nitro-9(3-3dimethylaminopropylamino) acridine and Quinifuryl, 2-(5ʹ-nitro-2ʹ-furanyl) ethenyl-4-{N-[4-(N,N-diethylamino)-1ʹmethylbutyl] carbamoyl} quinoline, towards two lines of leukaemic cells and a line of non-transformed cells, was measured in comparison, on the dark and under illumination with visible light (350–450 nm). Both drugs showed highly elevated cytotoxicity when illuminated with LC50 values 7–35 times lower after 1 h illumination compared to 1 h incubation of cells incubation with drug on the dark. Cytotoxicity of Nitracrine toward all cell lines studied exceeded that of Quinifuryl, both on the dark and under illumination, so that (almost equal)10 times lower concentration of former drug was needed to reach the same toxicity as the latter. General toxic effect was calculated as a direct cell kill and a cell proliferation arrest. The effect >80% for both drugs was achieved after 1 h cell illumination with as low drug concentrations as 0.2 (mu)M for Quinifuryl and 0.02 (mu)M for Nitracrine.