First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa

Suarez, Erick Reyes, Bugden, Sarah M., Kai, Fui Boon, Kralovec, Jaroslav A., Noseda, Miguel D., Barrow, Colin J. and Grindley, T. Bruce 2008, First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa, Carbohydrate research, vol. 343, no. 15, pp. 2623-2633.

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Title First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa
Formatted title First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa
Author(s) Suarez, Erick Reyes
Bugden, Sarah M.
Kai, Fui Boon
Kralovec, Jaroslav A.
Noseda, Miguel D.
Barrow, Colin J.
Grindley, T. Bruce
Journal name Carbohydrate research
Volume number 343
Issue number 15
Start page 2623
End page 2633
Total pages 11
Publisher Elsevier Scientific
Place of publication Amsterdam, Netherlands
Publication date 2008-10-13
ISSN 0008-6215
1873-426X
Keyword(s) Chlorella pyrenoidosa
immunomodulators
glucans
starch
cyclic β-(1→2)-glucans
Summary The aqueous extract of the edible green microalgae Chlorella pyrenoidosa is of interest because of its immunostimulatory activity. Some components in the extract have been identified previously, namely a unique type of arabinogalactan and a galactofuran. Further fractionation of this extract was accomplished by treating the aqueous solution of the fraction precipitated by addition of 1.5vol of 95% ethanol with cetyltrimethylammonium bromide. The residue obtained by concentration of the supernatant was fractionated further by anion-exchange chromatography and size-exclusion chromatography on Sephadex G-100. Two fractions from the latter column were retained, of which one was a starch-like alpha-(1-->4)-linked d-glucan with some alpha-(1-->6) branches, and the other contained a starch plus a mixture of beta-(1-->2)-d-glucans. ESI mass spectrometry was used to show that the mixture contained both cyclic and linear beta-(1-->2)-d-glucans in a cyclic:linear ratio of 64:36, based on intensities of mass spectral peaks. For the cyclic beta-(1-->2)-d-glucans, ring sizes ranged from 18 to 35 monosaccharides with the ring containing 21 glucose units (54% of the cyclic glucans) being greater than three times more abundant than the next most abundant component, the ring containing 22 glucose units (15%). No rings containing 20 glucose units were present. This is the first observation of cyclic beta-(1-->2)-d-glucans in algae, as far as we are aware. For the linear beta-(1-->2)-d-glucans, the component containing 20 glucoses was most abundant (35% of the linear glucans), while the component containing 21 glucose units was the next most abundant (17%). These relatively low-molecular-weight glucans had low immunostimulatory activity.
Language eng
Field of Research 119999 Medical and Health Sciences not elsewhere classified
Socio Economic Objective 970111 Expanding Knowledge in the Medical and Health Sciences
HERDC Research category C1.1 Refereed article in a scholarly journal
Copyright notice ©2008, Elsevier
Persistent URL http://hdl.handle.net/10536/DRO/DU:30019570

Document type: Journal Article
Collection: School of Life and Environmental Sciences
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