[Chemical constituents from stem bark of Aquilaria yunnanensis and their anti-inflammatory activities].

The stem bark of Aquilaria yunnanensis(Thymelaeaceae) is traditionally used to treat cough and asthma in folk medicine. However, its active components have not been reported. In the present study, the chemical constituents of A. yunnanensis stem bark were isolated and identified, and their inhibitory activities against nitric oxide(NO) production in RAW264.7 cells induced by lipopolysaccharide(LPS) were evaluated to clarify the anti-inflammatory components in the stem bark of A. yunnanensis. A total of 22 compounds, including a new norlignan [(±)-1], were isolated from the ethanolic extract of A. yunnanensis stem bark by column chromatography, high-performance liquid chromatography(HPLC), recrystallization, etc. Through chiral separation of(±)-1,(-)-1 and(+)-1 were obtained. Based on electronic circular dichroism(ECD) calculations, the absolute configurations of(-)-1 and(+)-1 were determined to be(-)-(7R,8S,8'S)-4-O-(1,3-dihydroxypropan-2-yl)zhebeiresinol and(+)-(7S,8R,8'R)-4-O-(1,3-dihydroxypropan-2-yl)zhebeiresinol. The known compounds included(±)-zhebeiresinol(2),(+)-syringaresinol(3),(+)-episyringaresinol(4), orcinol(5), orsellinic acid(6), methyl orsellinate(7), 3,4-dihydroxybenzoic acid(8), lecanoric acid(9), barbatic acid(10), 7β-hydroxy-β-sitosterol(11), β-sitosterol(12), stigmasterol(13), ergosterol peroxide(14), genkwanin(15), pilloin(16), 5-hydroxy-3',4',7-trimethoxyflavone(17),(-)-epicatechin(18),(-)-epicatechin gallate(19), tectorigenin 2-O-α-L-rhamnopyranoside(20), 2,3-dihydroxypropyl docosanoate(21), and 1-O-linolenoylglycerol(22). According to the bioassay testing results, compounds 4 and 22 which inhibited NO production with IC_(50) values of(32.82±1.04) and(18.50±0.95) μmol·L~(-1), respectively, exhibited anti-inflammatory activities.