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

journal contribution
posted on 2005-06-01, 00:00 authored by E Suárez, J Kralovec, M Noseda, H Ewart, Colin BarrowColin Barrow, M Lumsden, T Grindley
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.

History

Journal

Carbohydrate research

Volume

340

Issue

8

Pagination

1489 - 1498

Publisher

Pergamon

Location

Oxford, England

ISSN

0008-6215

eISSN

1873-426X

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2005, Elsevier