Structural and immunological studies of a pectin and a pectic arabinogalactan from Vernonia kotschyana Sch. Bip. ex Walp. (Asteraceae).
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.
Nergard
Cecilie Sogn
CS
Department of Pharmacognosy, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway. c.s.nergard@farmasi.uio.no
Matsumoto
Tsukasa
T
Inngjerdingen
Marit
M
Inngjerdingen
Kari
K
Hokputsa
Sanya
S
Harding
Stephen E
SE
Michaelsen
Terje E
TE
Diallo
Drissa
D
Kiyohara
Hiroaki
H
Paulsen
Berit Smestad
BS
Yamada
Haruki
H
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*
D005685:Galactans; D009569:Nitric Oxide; D010368:Pectins; D003165:Complement System Proteins; C005653:arabinogalactan