STRUCTURAL STUDIES OF THE PECTIC POLYSACCHARIDE FROM FRUITS OF PUNICA GRANATUM

E.G. Shakhmatova, Ph.V. Toukachb,c, E.N. Makarovaa

aInstitute of Chemistry, Komi Science Centre, The Urals Branch of the Russian Academy of Sciences, Syktyvkar, Russia
bN.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia

cNational Research University Higher School of Economics, Moscow, Russia

KEYWORDS: Punica granatum; Pectic polysaccharides; Arabinan; Arabinogalactan; Structure; NMR

Carbohydrate Polymers, 2020, т. 235, ID 115978

PMID: 32122509, DOI: 10.1016/j.carbpol.2020.115978


The polysaccharide PGO containing 76% of uronic acids, was obtained from peels and membranes of Punica granatum fruits by extraction to the aqueous solution of (NH4)2C2O4. The chemical structure of PGO was characterized by enzymatic and partial acid hydrolyses, Smith degradation and 1D/2D NMR spectroscopy. It has been found that PGO consisted mainly of highly methyl-esterified and lowly acetylated pectin. Backbone of the macromolecule was represented by 1,4-α-D-GalpA, 1,4-α-D-GalpA(OMe), 1,4-α-D-GalpA(OAc). The branched region PGO contained minor segments of partially acetylated rhamnogalacturonan-I (RG-I). RG-I side chains were comprised of highly branched 1,5-α-L-arabinan and segments of arabinogalactan type I. In addition to pectins, PGO contained the glucuronoxylans and xyloglucans, indicating a close interaction of these polysaccharides with each other in the cell wall. It was concluded that P. granatum fruit could be a promising source of pectic polysaccharides.


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