Estrogenic/antiestrogenic activities of quinoid polycyclic aromatic hydrocarbons

Abstract

Estrogenic and antiestrogenic activities of 19 quinoid polycyclic aromatic hydrocarbons (PAHQs) and 9 ketone PAHs were evaluated by the yeast two-hybrid assay using yeast cells expressing estrogen receptor-α (ERα). Binding affinity of PAHQs to ERα was assayed by the polarized fluorescence method using Fluormone™ ES2. Ten PAHQs having 3-5 rings showed antiestrogenic activities. The most strongly antiestrogenic PAHQs were 1,4- chrysenequinone and 5,6-chrysenequinone. On the other hand, benzo[a]pyrene-3,6-quinone showed the strongest estrogenic activity. However, the other compounds tested did not show so strong estrogenic/antiestrogenic activities. Binding affinity to ER was required but not sufficient for estrogenic/antiestrogenic activities of PAHQs. The length-to-breadth ratios of the rectangular planes surrounding the ring molecules and the distances between the oxygen atom of the carbonyl group and farthest hydrogen atom of estrogenic/antiestrogenic PAHQs were in narrow ranges, suggesting a structure-activity relationship. As interactions between active PAHQ and ER, hydrogen bonding between carbonyl groups and amino acid residues and van derWaals forces were considered. © 2011 The Pharmaceutical Society of Japan.