New tetrahydrofuran-type sesquilignans of Saururus chinensis root

Three new tetrahydrofuran-type sesquilignans, called saucerneol A, saucerneol B and saucerneol C were isolated from the underground parts of Saururus chinensis (Saururaceae), together with known lignans, di-O-methyltetrahydrofuriguaiacin B, machilin D and machilin D 4-methyl ether. Their structures were established from several spectral data.