Two new cryptoporic acid derivatives from the fruiting bodies of Cryptoporus volvatus

Abstract Two new cryptoporic acid derivatives, cryptoporic acid R ( 1 ) and 6′,6‴-cryptoporic acid G dimethyl ester ( 2 ), together with two known compounds, cryptoporic acid E ( 3 ) and cryptoporic acid E pentamethyl ester ( 4 ), were isolated from a 90% alcohol extract of the fruiting bodies of Cryptoporus volvatus . Their structures were established on the basis of NMR spectroscopic and mass spectrometry data. Cryptoporic acid E ( 3 ) and cryptoporic acid E pentamethyl ester ( 4 ) exhibited antiviral activity against porcine reproductive and respiratory syndrome virus.