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-hydroxyc oumarin sodium salt in water. The complexes were characterized and identifi ed by elemental analysis, conductivities, IR, H-1 and C-13 NMR spectroscopi es and mass spectral data. DTA and TGA have been applied to study the compo sitions of the compounds. The newly synthesized compounds were assayed for acute intraperitoneal and per oral toxicity, influence on blood clotting ti me and the most active complex was investigated for spasmolytic activity. T he complexes of cerium(III) and neodymium(III) showed marginal cytotoxic ac tivity against transformed leukemic cell lines (P3HR1 and THP-1) as compare d to the inorganic salts. (C) 2001 Editions scientifiques et medicales Else vier SAS.