Spectroscopic evidence for the interaction of tingenone with DNA

Tingenone (fig.1) is a quinonoid triterpene [ 1,2], isolated from the bark and roots of various plants of the Celastraceae and Hyppocrateaceae families as a red orange pigment, showing antineoplastic activity [3--S]. This compound, practically insoluble in water, is preva~in~y apolar. However, the solub~ization of tingenone can be favoured owing to the interactions occurring with more polar compounds, such as sodium deoxycholate or DNA, thus reducing the apolar surface of tingenone in contact with the aqueous environment. Its solubilizatjon in water may be important for a better pharmacological application and, therefore, its binding to sodium deoxycholate in aqueous solution was studied [6]. We have tried to bind tingenone to some DNA species in order to gain information on the possible types of interaction, since the antitumour activity of tingenone could depend on this binding. To clarify the role of the DNA’s base composition, which affects the macromolecular order and stability, three double-helical DNA species (from calf thymus, Clostridium perfringens and Micrococcus lysodeikticus) were investigated. Here we present the results of spectroscopic investigations which support the interaction between tingenone and DNA. No evidence could be gained about a relationship between the binding mode and the base composition.