SERS of a Series of New Substituted Ellipticinium Derivatives and their Complexes to DNA

The natural plant alkaloid ellipticine and some of its quaternarized derivatives are used as antitumor agents in the treatment of various human cancers. These molecules are planar conjugated aromatic systems and bind strongly to DNA by intercalation.1 It has been postulated that their oxidative activation at C(9) leads to a quinone imine intermediate (ie. NMOE; scheme 1) which reacts with biological molecules such as amino acids, proteins or nucleic acids, that contain suitable nucleophilic groups, to give covalent adducts through a Michael addition at C(10). In the case of primary amines, recyclization process occurs during coupling leading to oxazolopyridocarbazole (OPC) adducts.2