This study investigated the chemical components from the florets of Carthamus tinctorius. Five compounds were isolated from C. tinctorius by column chromatography with silica gel and toyopearl HW-40 F, preparative thin-layer chromatography(TLC), and semi-preparative reverse phased high performance liquid chromatography(RP-HPLC). Their structures were identified by mass spectrometry(MS), one-dimension nuclear magnetic resonance(1 D-NMR), two-dimension nuclear magnetic resonance(2 D-NMR), and single-crystal X-ray diffraction as(-)-(2S,3S,5S,7S,10R)-eudesma-4(15)-en-2,3,11-triol(1 a),(+)-(2R,3R,5R,7R,10S)-eudesma-4(15)-en-2,3,11-triol(1 b), rosin(2),(+)-syringaresinol(3), and(E)-1-(4'-hydroxyphenyl)-but-1-en-3-one(4). Compounds 1 a and 1 b are a pair of enantiomeric sesquiterpenoids. Compound 1 a is a new eudesmene and is named(-)-plucheol A. Compound 1 a at 100 μmol·L~(-1) showed significant antioxidant activity against ABTS~(+·) and DPPH·, with the scavenging rates of 30.98%±4.17% and 27.52%±1.24%, respectively, while compound 1 b was inactive. In addition, compounds 1 a and 1 b showed no obvious anti-inflammatory activity.
Keywords: Carthamus tinctorius; absolute configuration; antioxidant activity; enantiomers; sesquiterpenoids.