| Summary: | 碩士 === 臺灣大學 === 化學研究所 === 96 === Water-soluble O-acetylglucomannan was isolated from Dendrobium huoshanense by cold water extraction. This mucilaginous polysaccharide was purified by chromatography on DEAE-cellulose and SEC columns. These mucilage fractions of Dendrobium huoshanense were characterized by NMR, Mass, HPAEC-PAD and analysis to have a backbone of β-D-(1→4)-mannopyranosyl units and β-D-(1→4)-glucopyranosyl units in a ratio of 10:1. Its molecular weight was estimated to be 1.0×104 by HPLC and NMR, using pullulan of known molecular weight as standards. The mannopyranosyl residues were partially acetylated at C-2 and C-3 with approximately 34% degree of acetylation appeared randomly from water extracted fractions as shown by the NMR analysis. The extract of O-acetylglucomannans of D. houshanense can induce several cytokines in mice splenocytes and PBMC models, including IL-6, IL-10, IFN-γ, G-CSF, M-CSF and GM-CSF. Among these cytokines, the G-CSF is the most obvious biomarker this mucilage fraction. In contrast, the mucilage after deacetylation shows no cytokines induction in mice.
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