Curtisians W and X, two new p-terphenyls from the fruiting bodies of Pseudomerulius curtisii, and their neuraminidase inhibitory activity.

Two new p-terphenyl derivatives, curtisians W (1) and X (2), were isolated from the methanolic extract of the fruiting bodies of Pseudomerulius curtisii (formerly Paxillus curtisii). The structures of 1 and 2 were elucidated by high-resolution mass and 1D- and 2D-NMR measurements. Compounds 1 and 2 inhibited the H5N1 neuraminidase in a dose-dependent manner, with IC50 values of 15.4 and 9.3 µM, respectively, and acted as non-competitive inhibitors with Ki values of 31.8 and 15.6 µM, respectively.