Structural studies of the pectic polysaccharide from Siberian fir (Abies sibirica Ledeb.)

• Published in: Carbohydrate polymers 2013-02, Vol.92 (2), p.1817-1826
• Main Authors: Makarova, Elena N., Patova, Olga A., Shakhmatov, Evgeny G., Kuznetsov, Sergey P., Ovodov, Yury S.
• Format: Article
• Language: English
• Subjects: Abies - chemistry; Abies sibirica; acid hydrolysis; Arabinan; Chromatography, Ion Exchange; esters; Galactan; hydrochloric acid; Hydrochloric Acid - chemistry; Hydrolysis; ion exchange chromatography; Magnetic Resonance Spectroscopy; NMR; nuclear magnetic resonance spectroscopy; Pectins - chemistry; Pectins - isolation & purification; polysaccharides; Rhamnogalacturonan I; sugars; wood; Wood greenery
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2012.11.038

► Pectin material was isolated from the wood greenery of Abies sibirica under acidic conditions. Its structure was established by chemical and NMR studies. ► Pectin contains regions of galacturonan, rhamnogalacturonan and RG-I. ► The side chains of RG-I have blocks of 1,4-β-galactan and branched 1,5-α-arabinan. The pectic polysaccharide named abienan AS-A was isolated from the wood greenery of Abies sibirica using dilute hydrochloric acid (pH 4.0) at 70°C. The structure of abienan AS-A was elucidated using sugar composition analysis, ion-exchange chromatography and partial acid hydrolysis followed by NMR spectroscopy. The linear region of abienan AS-A was shown to contain linear 1,4-α-d-galactopyranosyluronan partially substituted with methyl esters or 3-O-acetyl groups and rhamnogalacturonan blocks consisting of 1,4-α-d-galacturonan partially substituted with methyl ester groups and connected by 2-O-substituted α-rhamnopyranose residues. The branched region of abienan AS-A was found to be made of RG-I. The side chains of RG-I were shown to contain 1,4-β-galactan and branched arabinan. Some 4-O-substituted β-galactopyranose residues were shown to be attached to the 4-position of the 2-O-substituted α-rhamnopyranose residues of the RG-I backbone. The arabinan groups were made up of a 1,5-linked α-l-arabinofuranan backbone that was 3-O-, 2-O-, and 2,3-di-O-substituted with the terminal and 1,3-linked α-l-arabinofuranose residues.