Fluorescence of chromatin DNA induced by antitumoral naphthalimides.

Treatment of chicken blood smears and semithin sections from Epon-embedded mouse tissues with aqueous solutions of the 3-aminonaphthalimides FA-142, FA-2043, and FA-2143 induced a strong green-yellow fluorescence of chromatin under violet or violet-blue excitation. Chromatin emission was abolished by previous DNase or hot TCA treatment. The use of 3-methoxy (FA-655) and 3-nitro derivatives (M-4212 and M-12210) resulted in very weak fluorescence of chromatin. Absorption maxima at 346 and 408 nm and an emission peak at 570 nm were observed for the free compound FA-142. Fluorescence properties open new and interesting applications for some of these antitumoral and DNA-intercalating naphthalimides.