p-Terphenyls from the fruiting bodies of Paxillus curtisii and their antioxidant properties.

New p-terphenyls, curtisians R (1)-V (5), have been isolated together with known compounds, curtisians E, I-P, and kynapcin-12, from the methanolic extract of the fruiting bodies of Paxillus curtisii (Paxillaceace). Their structures were established by various spectroscopic analyses including 1D- and 2D-NMR experiments, as well as high-resolution FAB-mass analysis. They exhibited significant protective effects against oxidative damage of supercoiled DNA and 2-deoxyribose by hydroxyl radicals generated from the Fenton reaction.