Interaction of anticancer drug methotrexate with nucleic acids analyzed by multi-spectroscopic method

Methotrexate (MTX) as an antifolate, which is widely used as chemotherapeutic drugs. A high-dose MTX therapy has a direct toxicity influence on the non-germinal cells, especially the liver cells. It is known that the inject dose for adults is 10–30 mg and is half for children for routine use, while our experiments showed that the optimum dosage of MTX which enhanced the RLS intensities to the maximum is 4.54 ng ml−1. The interaction of methotrexate (MTX) with nucleic acids in aqueous solution in the presence of cetyltrimethylammonium bromide (CTMAB), a kind of cationic surfactant similar to the Human cells, were investigated based on the measurements of resonance light scattering (RLS), UV–vis, fluorescence and NMR spectra, etc. The interaction has been proved to give a ternary complex of MTX–CTMAB–DNA in BR buffer (pH 9.30), which exhibits strong enhanced RLS signals at 339.5 nm.