Chemical constituents from the stem bark of Illicium burmanicum and their anti-inflammatory activity

Thirty-six compounds were isolated from extract of the stem bark of Illicium burmanicum, including twelve previously undescribed prenylated C6-C3 compounds and a norsesquiterpene lactone: illicidione D (1), illicidione E (2), illicidione F (3), illicidione G (4), (2R,4S,11R)-12-O-ethylillifunone C (5), (2R,4S,11R)-illifunone C-12-O-β-d-glucopyranoside (6), (2R,4S,11R)-2-hydroxyillifunone C (7), 4-epi-2,3-dehydroillifunone C (8), illiburmanone A (9), illiburmanone B (10), illiburmanlactone A (11), (2S,4S,5S,11R)-2,3-dihydroillicione E (12), and illiburmanolside A (13). Their structures were determined based on extensive spectroscopic data analyses, including MS, NMR, and ECD spectra. The anti-inflammatory activity of the isolated compounds (1-36) was evaluated, and compounds 7, 12, 14, and 18 exhibited inhibitory effects in RAW 264.7 cells induced by LPS.