Structure of Tanacetan, a Pectic Polysaccharide from Tansy Tanacetum vulgare L.

A. Ya. Polle¹, R. G. Ovodova¹, A. O. Chizhov², A. S. Shashkov², and Yu. S. Ovodov^1*

¹Institute of Physiology, Komi Science Center, Ural Branch of the Russian Academy of Sciences, ul. Pervomaiskaya 50, Syktyvkar, 167982 Russia; fax: (8212) 241-001; E-mail: ovoys@physiol.komisc.ru; polle@physiol.komisc.ru

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

^* To whom correspondence should be addressed.

Received June 21, 2002; Revision received August 9, 2002

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Tanacetan TVF was found to have a branched structure with a backbone of linear alpha-1,4-D-galacturonan. The ramified regions consist of linear alpha-1,2-L-rhamno-alpha-1,4-D-galacturonan as the core. The side chains appear to attach to the 4-position of the L-rhamnopyranose residues. They are present as single beta-galactopyranose residues or a branching beta-1,4-galactopyranan bearing 4,6-substituted beta-D-galactopyranose residues as branched points. In addition, the ramified regions contain side chains of a branched alpha-1,5-arabinofuranan possessing 2,5- and 3,5-substituted alpha-L-arabinofuranose residues as branching points. Some side chains of rhamnogalacturonan appear to be arabinogalactan which contains branched sugar chains of alpha-1,5-arabinofuranan attached to the linear chains of beta-1,4-galactopyranan by 1,3- and 1,6-linkages. The residues of alpha-L-arabinofuranose seem to occupy the terminal positions of the arabinogalactan side chains.

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KEY WORDS: Tanacetum vulgare L., pectins, tanacetan, structure of plant polysaccharides, NMR spectroscopy of polysaccharides, GLC-MS of methylated sugars

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