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), pinos、lvin (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 13.33μg·mL-1, respectively. Compounds 2-4, 6-8, 10, 11, 13 and 15-21 were isolated from this plant for the first time.
Key words: Pinus massoniana; Chemical constituents; Antioxidant activityPinus massoniana Lamb. belongs to the family of Pinaceae and is widely distributed in China. Its pollen and nodular branch are used as two traditional Chinese medicines, which can be used to treat traumatic hemorrhage, eczema, sprain and strain (Chinese Pharmacopoeia Commission, 2010). Previous investigations on P.massoniana led to the isolation of a series of lignans, flavones and diterpenoids (Feng et al., 2004; Bi et al., 2002; Shen and Theander, 1985; Wang et al., 2008; Yang et al., 2010), and the discovery of some antitumor diterpenes (Tanaka et al., 2008) and some antioxidant extracts (Pan et al., 2009). For the recent researches revealed that the occurrence of some chronic diseases such as cancer, cardiovascular disease and diabetes were main caused by oxidative stress, therefore antioxidant compounds might provide us some different insights for treating these severe diseases. In this paper, we report the isolation and structural elucidation of 21 known compounds from its twigs with the antioxidant activities.