Anti-inflammatory components isolated from Atractylodes macrocephala in LPS-induced RAW264.7 macrophages and BV2 microglial cells

The phytochemical investigation on the methanol extract of the rhizomes of Atractylodes macrocephala resulted in the discovery of one new compound 9α-hydroxyatractylenolide (1) and 21 known compounds including atractylone (2), 3β-acetoxyatractylon (3), atractylenolide I (4), atractylenolide II (5), 8-epiasterolid (6), atractylenolide III (7), atractylenolide VII (8), 8-epiatractylenolide III (9), eudesm-4(15)-ene-7α,11-diol (10), linoleic acid (11), myristic acid (12), 3-O-caffeoyl-1-methyquinic acid (13), (2E,8E,10E)-tetradecatriene-4,6-diyne-1,14-diol (14), 14-aceroxy-12-senecioyloxytetradeca-2E,8Z,10E-trien-4,6-diyn-1-ol (15), isoscopoletin (16), caffeic acid (17), protocatechic acid (18), 3-O-caffeoylquinic acid (19), 4-O-caffeoylquinic acid (20), 1,5-di-O-caffeoylquinic acid (21), and nicotinic acid (22). Their structures were identified using nuclear magnetic resonance (NMR) and mass spectroscopy, and by comparison with previously published data. Compounds 4, 5, 6, 8, and 10–22 significantly inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages, and compounds 4, 5, 6, 16, and 17 showed those responses in BV2 microglial cells. Especially, compound 6 showed the second-best effect, and inhibited the LPS-induced production of prostaglandin E2 (PGE₂), the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and the production of cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in both cells. These inhibitory effects were mediated by the inactivation of nuclear factor kappa B (NF-κB) signaling pathway.