Isolation, characterization and structural determination of a unique type of arabinogalactan from an immunostimulatory extract of Chlorella pyrenoidosa

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• 作者：Su??rez ; Erick Reyes ; Kralovec ; Jaroslav A. ; Noseda ; Miguel D. ; Ewart ; H. Stephen ; Barrow ; Colin J. ; et. al.
• 关键词：Chlorella pyrenoidosa ; Immunomodulators ; NMR spectroscopy ; Polysaccharide structure determination ; Arabinogalactans
• 刊名：Carbohydrate Research
• 出版年：2005
• 出版时间：June 13, 2005
• 年：2005
• 卷：340
• 期：8
• 页码：1489-1498
• 全文大小：314 K

文摘

An arabinogalactan was isolated from a hot water extract of freeze-dried cells of the green microalga, Chlorella pyrenoidosa. This hot water extract is a proprietary immunomodulator, with the trademark Respondin™ (ONC-107). The arabinogalactan was recovered from the ethanol-soluble fraction of the supernatant resulting from a process that involved controlled ethanol precipitation followed by size exclusion chromatography on Sephadex G-100, then Cetavlon precipitation. Sugar analyses, GC–MS data for (S)-2-octyl glycosides, and 1D and 2D NMR experiments established unambiguously that the repeating unit was →2)-α-l-Araf-(1→3)-[α-l-Araf-(1→4)]-β-d-Galp-(1→. This structure does not fit into any of the known classes of arabinogalactans. SEC/MALS experiments gave a molecular mass for the arabinogalactan isolated as 47 ± 4 kDa but the original structure was probably larger.