New lanthanide complexes of 4-methyl-7-hydroxycoumarin and their pharmacological activity.

Complexes of cerium(III), lanthanum(III) and neodymium(III) with 4-methyl-7-hydroxycoumarin (Mendiaxon, Hymecromone) were synthesized by the mixing of equimolar amounts of the respective metal nitrates and 4-methyl-7-hydroxycoumarin sodium salt in water. The complexes were characterized and identified by elemental analysis, conductivities, IR, (1)H and (13)C NMR spectroscopies and mass spectral data. DTA and TGA have been applied to study the compositions of the compounds. The newly synthesized compounds were assayed for acute intraperitoneal and per oral toxicity, influence on blood clotting time and the most active complex was investigated for spasmolytic activity. The complexes of cerium(III) and neodymium(III) showed marginal cytotoxic activity against transformed leukemic cell lines (P3HR1 and THP-1) as compared to the inorganic salts.