Structural characteristics of carrageenans of red alga Mastocarpus pacificus from sea of Japan

Anna O Kravchenko; Stanislav D Anastyuk; Valery P Glazunov; Ekaterina V Sokolova; Vladimir V Isakov; Irina M Yermak

doi:10.1016/j.carbpol.2019.115518

Structural characteristics of carrageenans of red alga Mastocarpus pacificus from sea of Japan

Carbohydr Polym. 2020 Feb 1:229:115518. doi: 10.1016/j.carbpol.2019.115518. Epub 2019 Nov 1.

Authors

Anna O Kravchenko¹, Stanislav D Anastyuk², Valery P Glazunov², Ekaterina V Sokolova², Vladimir V Isakov², Irina M Yermak²

Affiliations

¹ G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, 690022, Vladivostok, Russian Federation. Electronic address: kravchenko_25.89@mail.ru.
² G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, 100 Let Vladivostoku Prosp., 159, 690022, Vladivostok, Russian Federation.

PMID: 31826457
DOI: 10.1016/j.carbpol.2019.115518

Abstract

The sulfated polysaccharide from sterile alga Mastocarpus pacificus was investigated. Partial reductive hydrolysis and NMR spectroscopy showed that the extracted polysaccharides were only carrageenans. According to FT-IR- and NMR spectroscopy this polysaccharide was a hybrid kappa/iota-carrageenan with a predominance of kappa-type units. According to MALDI-TOFMS, oligosaccharide fragments obtained by mild acid hydrolysis had a polymerization degree of 1-9, while chains built up of galactose residues were up to 3. Tandem ESI mass spectrometry together with innovative ¹⁸O-labelling method showed that the polymer chain of the carrageenan included kappa-carrabiose, kappa-carratetraose, iota-carrabiose, hybrid kappa/iota oligosaccharide units and contained minor insertions of mu-carrageenan (the precursor of kappa-carrageenan). Parallel artificial membrane permeability assay shown that the studied carrageenan inhibited bile salts permeation through an artificial membrane imitating the gastrointestinal barrier by 50 % on average compared to negative control independent of incubation time. However, its action was less pronounced than the hindering ability of cholestyramine.

Keywords: (18)O-labeled; Carrageenan; Carrageenan oligosaccharide; ESIMS/MS; Kappa/iota-hybrid; MALDI-TOFMS.