Correlation of redox potentials and inhibitory effects on Epstein–Barr virus activation of naphthoquinones

As a continuation of our studies using natural and synthetic products as cancer chemopreventive agents, we examined the standard redox potentials of some naphthoquinones in phosphate buffer at pH 7.2 by means of cyclic voltammetry. A definite correlation has been found between the redox potentials and the inhibitory effects of the naphthoquinones on Epstein–Barr virus early antigen activation. It has been further shown that the correlation can be enhanced by introducing an electronic property, i.e. the atomic charges at the C4 and O10 atoms in the quinone skeleton ring as additional parameters.