[Study on chemical constituents of Dendrobium huoshanense stems and their anti-inflammatory activity]

Three bibenzyls 1-3 and six other compounds 4-9 were firstly isolated from Dendrobium huoshanense stems. They were identified as 3',4-dihydroxy-3,5'-dimethoxybibenzyl(1), batatasin Ⅲ(2), 3,4'-dihydroxy-5-methoxy bibenzyl(3), dihydroconiferyl dihydro-p-coumarate(4), syringaresinol(5), 3-(4-hydroxyphenyl)-propionic acid ethyl ester(6),(3-ethylphenyl)-1,2-ethanediol(7),(S)-5-hydroxy-3,4-dimethyl-5-pentylfuran-2(5H)-one(8) and loliolide(9). Anti-inflammation assay showed that bibenzyls 1-3 could significantly inhibit the production of nitric oxide(NO) and the expression of tumor necrosis factor α(TNF-α) and interleukin 1β(IL-1β) mRNA in LPS-induced RAW264.7 macrophages. Mechanism study exhibited that the phosphorylation of nuclear factor kappa B(NF-κB) p65, inhibitor of κB(IκB), extracellular regulatedprotein kinase(ERK), c-Jun N-terminalkinase(JNK), p38 and Akt of LPS-induced RAW264.7 macrophages could be remarkably reduced by 1. These results suggested that the inflammatory response of LPS-induced RAW264.7 macrophages could be significantly inhibited by 1-3. Additionally, the anti-inflammatory effect of 1 might be contributed to its ability on the regulation of NF-κB, MAPKs and Akt signaling pathways.