The interactions between the Sm(III) complex with all-trans retinoic acid [Sm(RA)2·Ac·4H2O] and calf thymus DNA have been studied by using fluorimetric, viscometric and CD (circular dichroism) methods. DNA has different viscosity, denatured temperature and spectral characteristics in the absence and presence of the complex. Increasing fluorescence is observed for the complex with DNA addition. Quenching fluorescence is also observed for EB-DNA system when the complex is added. The results suggested that the complex can bind to DNA mainly by intercalation, which may be the one of the reasons that the complex can inhibit the HL-60, EJ cancer cell.

Key words: SAMARIUM COMPLEX, RETINOIC ACID, THYMUS GLAND, DNA, ETHIDIUM BROMIDE, ANTITUMOR DRUGS