Inhibition on LDL-oxidation by phenolic compounds from the fruit body of phellinus linteus

The fruit body of Pheiinus linteus was extracted with 80% aqueous MeOH, and the concentrated extract was successively partitioned using EtOAc, n-BuOH and H20. From the EtOAc and nBuOH fractions, three phenolic compounds were isolated through repeated silica gel and ODS column chromatography. The chemical structures of these compounds were determined as 2-(3',4'- dihydroxyphenyl)-1,3- benzodioxole-5-aldehyde (1), 4-(3,4-dihydroxyphenyl)-3-buten-2-one (2), and protocatechuic acid methyl ester (3) by spectroscopic data including NMR, MS and IR. Compounds 1̃3 exhibited low density lipoprotein (LDL) antioxidant activity with IC₅₀ values of 1.7, 0.7, and 2.4 μM, respectively.