Chemical component analysis of the root parts of P. odoratissimus led to the isolation of two phenolic compounds, four lignan type compounds plus a new benzofuran derivative. Among them, pinoresinol and 3,4-bis(4-hydroxy-3-methoxybenzyl) tetrahydrofuran showed strong antioxidative activities when BHA was used as a standard in the thiocyanate method. The new compounds were identified as 4hydroxy-3-(2’,3’-dihydroxy-3’-methylbutyl)-benzoic acid methyl ester and 3-hydroxy-2-isopropenyl-dihydrobenzofuran-5-carboxylic acid methyl ester, by spectroscopic analysis.