title: Structural and immunological studies of a pectin and a pectic arabinogalactan from Vernonia kotschyana Sch. Bip. ex Walp. (Asteraceae).
abstract: Two polysaccharides, a pectin (Vk100A2b) and a pectic arabinogalactan (Vk100A2a) with mean Mw 2 x 10(4) and 1.15 x 10(6)Da, respectively, were isolated from the dried powdered roots of Vernonia kotschyana Sch. Bip. ex Walp. by hot water extraction followed by fractionation on DEAE-Sepharose fast flow and Sephacryl S-400 HR. The pectin showed low-complement fixation activity and no influence on proliferation of B or T cells, while the pectic arabinogalactan showed a potent, dose-dependent complement fixation activity and a T cell independent induction of B-cell proliferation. Both polysaccharides induced chemotaxis of human macrophages, T cells and NK cells. exo-alpha-L-arabinofuranosidase and exo-beta-D-galactosidase digestion followed by component sugar and methylation analysis indicated that Vk100A2a consisted of a highly branched rhamnogalacturonan core with approximately 50% of the rhamnose 1,2,4-substituted, side chains rich in terminal-, 1,5-linked and 1,3,5-branched arabinose and terminal-, 1,4-, 1,6-linked and 1,3,6-branched galactose. The enzyme resistant part of Vk100A2a still showed strong complement fixating activity, suggesting that this activity may at least in part be expressed by carbohydrate structures present in the enzyme resistant, inner portion of the polymer.
authors.affiliation: Department of Pharmacognosy, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway. c.s.nergard@farmasi.uio.no
authors.forename: Cecilie Sogn
authors.initials: CS
authors.lastname: Nergard
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Marit
authors.initials: M
authors.lastname: Inngjerdingen
authors.forename: Kari
authors.initials: K
authors.lastname: Inngjerdingen
authors.forename: Sanya
authors.initials: S
authors.lastname: Hokputsa
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Harding
authors.forename: Terje E
authors.initials: TE
authors.lastname: Michaelsen
authors.forename: Drissa
authors.initials: D
authors.lastname: Diallo
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kiyohara
authors.forename: Berit Smestad
authors.initials: BS
authors.lastname: Paulsen
authors.forename: Haruki
authors.initials: H
authors.lastname: Yamada
mesh_terms: D002633:Chemotaxis; D003168:Complement Fixation Tests; D003165:Complement System Proteins / Q000276:immunology; D005434:Flow Cytometry; D005685:Galactans / Q000737:chemistry* / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007109:Immunity / Q000276:immunology*; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D009569:Nitric Oxide / Q000032:analysis; D010368:Pectins / Q000737:chemistry* / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D018517:Plant Roots; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D035741:Vernonia / Q000737:chemistry* / Q000145:classification*
chemical_list: D005685:Galactans; D009569:Nitric Oxide; D010368:Pectins; D003165:Complement System Proteins; C005653:arabinogalactan