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The Chemical Structure of Agar from Gracilaria compressa (C. Agardh) Greville, G. cervicornis (Turner) J. Agardh, G. damaecornis J. Agardh and G. domingensis Sonder ex Kützing (Gigartinales, Rhodophyta)

The Chemical Structure of Agar from Gracilaria compressa (C. Agardh) Greville, G. cervicornis... Abstract The chemical structure of agar fractions obtained from Gracilaria compressa, G. cervicornis, G. damaecornis and G. domingensis with a sequential solvent extraction has been determined by I3C-NMR spectroscopy. Gracilaria compressa agar consists of agarobiose, pyruvated agarobiose and a low concentration of 6-Omethylated agarobiose repeating units; G. cervicornis and G. domingensis agars are composed of 6-O-methylated agarobiose, agarobiose-6-sulfate, agarobiose, and a repeating unit with 4-O-methyl-a-L-galactose; finally, G. damaecornis agar is made of the same repeating units of the latter agars plus agarobiose-4-sulfate. From these four algae, a fraction enriched with pyruvated or sulfated repeating units was obtained in water at room temperature. An extract essentially composed of only 6-O-methylated,agarobiose repeating units was obtained from the Gracilaria species with boiling 80% ethanol. The concentration of the methylated repeating unit decreased in the subsequent boiling in 60% and 40% ethanol extracts and in the hot water extract (121 °C), whereas charged repeating units were present in these agar fractions. Floridean starch contaminated the hot water extract. The combination of sequential solvent extraction and 13C-NMR represents a convenient approach in determining the chemical heterogeneity of agar. Introduction Lahaye et al. 1986) and probably also the molecular . «. 1 1 weight. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Botanica Marina de Gruyter

The Chemical Structure of Agar from Gracilaria compressa (C. Agardh) Greville, G. cervicornis (Turner) J. Agardh, G. damaecornis J. Agardh and G. domingensis Sonder ex Kützing (Gigartinales, Rhodophyta)

Botanica Marina , Volume 32 (4) – Jan 1, 1989

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References (34)

Publisher
de Gruyter
Copyright
Copyright © 2009 Walter de Gruyter
ISSN
0006-8055
eISSN
1437-4323
DOI
10.1515/botm.1989.32.4.369
Publisher site
See Article on Publisher Site

Abstract

Abstract The chemical structure of agar fractions obtained from Gracilaria compressa, G. cervicornis, G. damaecornis and G. domingensis with a sequential solvent extraction has been determined by I3C-NMR spectroscopy. Gracilaria compressa agar consists of agarobiose, pyruvated agarobiose and a low concentration of 6-Omethylated agarobiose repeating units; G. cervicornis and G. domingensis agars are composed of 6-O-methylated agarobiose, agarobiose-6-sulfate, agarobiose, and a repeating unit with 4-O-methyl-a-L-galactose; finally, G. damaecornis agar is made of the same repeating units of the latter agars plus agarobiose-4-sulfate. From these four algae, a fraction enriched with pyruvated or sulfated repeating units was obtained in water at room temperature. An extract essentially composed of only 6-O-methylated,agarobiose repeating units was obtained from the Gracilaria species with boiling 80% ethanol. The concentration of the methylated repeating unit decreased in the subsequent boiling in 60% and 40% ethanol extracts and in the hot water extract (121 °C), whereas charged repeating units were present in these agar fractions. Floridean starch contaminated the hot water extract. The combination of sequential solvent extraction and 13C-NMR represents a convenient approach in determining the chemical heterogeneity of agar. Introduction Lahaye et al. 1986) and probably also the molecular . «. 1 1 weight.

Journal

Botanica Marinade Gruyter

Published: Jan 1, 1989

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