High energy transition state complex increased anticancer activity: A case study on CuII-complexes.

The different anticancer activities of two Cu (II) -complexes are reported: 1) containing acetylacetonate (acac), NO 3 − and 2,9-dimethyl-1,10-phenanthroline (2,9-dmp), 2) containing acetylacetonate (acac), NO 3 − and 1,10-phenanthroline (phen). Cytotoxicity test shown that complex 1 has much higher inhibition rate than complex 2 especially, higher than the famous anticancer drug 5-Fu. In this paper, we associated the bond length of complexes with their anticancer activity, and demonstrated that (1) in water solution the bonds of L-Cu II (2,9-dmp) will neither stay coordinated nor break up completely, but change into a transition state with weaker linkage than those in a solid state; (2) the superior anticancer activates of complex 1 correspond to the increased flexibility between ligand and Cu II as the bond length was elongated in solution; (3) The high energy transition State of complex 1 in water solution is more effective in oxidizing O 2 − into O 2 than complex 2 . [ABSTRACT FROM AUTHOR]