Curtisians A~D, new free radical scavengers from the mushroom Paxillus curtisii

In our continuous investigation for free radical scavengers from extracts of fruit body of basidiomycetes, we have isolated four new p-terphenyl compounds, designated as curtisians A~D, from the methanolic extract of the fruit body of Paxillus curtisii. These compounds were isolated by silica gel and Sephadex LH-20 column chromatographies, preparative-TLC and HPLC, consecutively. The structures of curtisians were assigned as p-terphanyls with substituents of acetyl, benzoyl, phenylbutyryl, 3-hydroxybutyryl and 3-acetoxybutyryl. Curtisians A, B, C and D exhibited inhibitory activity against lipid peroxidation with IC₅₀ values of 0.15, 0.17, 0.24 and 0.14 μg/ml, respectively.