[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 1ß(IL-1ß) 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.

Dendrobine inhibits dopaminergic neuron apoptosis via MANF-mediated ER stress suppression in MPTP/MPP+-induced Parkinson's disease models.

BACKGROUND: Parkinson's disease (PD) is an age-related neurodegenerative disorder without effective treatments. Mesencephalic astrocyte-derived neurotrophic factor (MANF) has been suggested to be capable of protecting against PD by inhibiting endoplasmic reticulum (ER) stress-mediated neuronal apoptosis. PURPOSE: This study was aimed to evaluate the antiparkinsonian effect of dendrobine and reveal its underlying mechanisms from the perspective of MANF-mediated ER stress suppression. METHODS: Behavioral assessments of PD mice as well as LDH/CCK-8 assay in SH-SY5Y cells and primary midbrain neurons were carried out to detect the antiparkinsonian effect of dendrobine. Immunofluorescence, western blot, flow cytometry and shRNA-mediated MANF knockdown were used to determine the apoptosis of dopaminergic neurons and the expressions of ER stress-related proteins for investigating the underlying mechanism of dendrobine. RESULTS: Dendrobine significantly ameliorated the motor performance of PD mice and attenuated the injuries of dopaminergic neurons. Dendrobine could also relieve neuronal apoptosis, up-regulate MANF expression and inhibit ER stress, which were largely abolished by shRNA-mediated MANF knockdown in PD model. CONCLUSION: Dendrobine might protect against PD by inhibiting dopaminergic neuron apoptosis, which was achieved by facilitating MANF-mediated ER stress suppression. Our study suggested that dendrobine could act as a MANF up-regulator to protect against PD, and provided a potential candidate for exploring etiological agents of PD.