Structure of Silenan, a Pectic Polysaccharide from Campion Silene vulgaris (Moench) Garcke

O. A. Bushneva¹, R. G. Ovodova¹, A. S. Shashkov², A. O. Chizhov², and Yu. S. Ovodov^1*

¹Institute of Physiology, Komi Science Center, The Ural Branch of the Russian Academy of Sciences, Pervomaiskaya ul. 50, Syktyvkar 167982, Russia; fax: (8212) 24-1001; E-mail: ovoys@physiol.komisc.ru or bushneva@physiol.komisc.ru

²Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky pr. 47, Moscow 119991, Russia; fax: (7-095) 135-5328; E-mail: shash@ioc.ac.ru or chizhov@ioc.ac.ru

^* To whom correspondence should be addressed.

Received February 11, 2003; Revision received April 25, 2003

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A pectic polysaccharide named silenan, [alpha]_D²⁰ +148.6° (c 0.1; H₂O), was isolated earlier from the aerial part of campion, Silene vulgaris (Moench) Garcke. Silenan has been shown to contain homogalacturonan segments as “smooth regions” and rhamnogalacturonan fragments as “hairy regions”. The present study reveals a generalization of structural features of silenan. Silenan was subjected to enzymic digestion with pectinase, to Smith degradation, and to lithium-degradation to determine the conforming poly- and oligosaccharide fragments of “hairy regions” of silenan. The NMR-spectral data and mass-spectrometry confirmed that the core of the ramified region of silenan consisted of residues of alpha-rhamnopyranose 2-O-glycosylated with the residues of alpha-1,4-D-galactopyranosyl uronic acid. The part of the alpha-rhamnopyranose residues of the backbone are branched at O-4. On the basis of the data, the hairy regions of silenan proved to contain mainly linear chains of beta-1,3-, beta-1,4-, and beta-1,6-galactopyranan and alpha-1,5-arabinofuranan. The side chains of the ramified region were shown to have branching points represented 2,3-, 3,6-, 4,6-di-O-substituted beta-galactopyranose residues.

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KEY WORDS: campion, Silene vulgaris, Oberna behen, pectin, silenan, structure, NMR spectroscopy, GLC-MS

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