Antioxidant Constituents from Pinus massoniana (Pinaceae)

Twenty one known compounds were isolated from the twigs of Pinus massoniana. Their structures were elucidated as 7, 13, 15-abietatrien-18-oic acid (1), 12-methoxy-7, 13-abietadien-18-oic acid (2), 15-methoxy-7, 13-abietadien-18-oic acid methyl ester (3), 12-hydroxydehydroabietic acid (4), dehydroabietic acid (5), 15-hydroxydehydroabietic acid methyl ester (6), 3β-methoxyserrat-14-en-21-one (7), 3β-methoxy-30-hydroxyserrat-14-en-21-one (8), β-sitosterol (9), (±)-pinoresinol (10), (±)-matairesinol (11), (-)-nortrachelogenin (12), balanophonin (13), cedrusin (14), pinocembin (15), 5-methoxypinosylvin (16), pinosylvin (17), 1, 2-bis-(4-hydroxy-3-methoxyphenyl)-propane-1, 3-diol (18), cleistophostaudin (19), lignoceryl ferulate (20) and coniferaldehyde (21). Compounds 12, 14, 18 and 21 showed antioxidant activities on DPPH assay with EC50 values of 11.36, 6.76, 14.07, and 13.33 μg · mL-1, respectively. Compounds 2-4, 6-8, 10, 11, 13 and 15-21 were isolated from this plant for the first time.