title: Structures and structure-activity relationships of three mitogenic and complement fixing pectic arabinogalactans from the malian antiulcer plants Cochlospermum tinctorium A. Rich and Vernonia kotschyana Sch. Bip. ex Walp.
abstract: Structures of three pectic arabinogalactans, one from Vernonia kotschyana (Vk2a) and two from Cochlospermum tinctorium (Ct50A1 and Ct50A2), and their complement fixation and induction of B cell proliferation in vitro were compared. The polysaccharide Vk2a expressed potent biological activity in both assays compared with Ct50A1 and Ct50A2. Vk2a possessed a very high molecular weight (1150 +/- 20 kDa) compared with Ct50A1 and Ct50A2 which both showed a polydisperse nature with the highest molecular weight polymers in each fraction estimated at approximately 105 kDa (Ct1a) and 640 +/- 100 kDa (Ct2a), respectively. The HMW polymers showed complement fixation in the same range as the native fractions. The arabinogalactan II content was low in Vk2a (2%) compared with that in Ct50A1 (23%) and Ct50A2 (12%). The high molecular weight polymers were subjected to digestion with a beta-d-(1, 3)-galactanase-rich fraction from Driselase, oligomers were isolated by HPAEC, and their finer structures were determined by MALDI- and ES-qoToF-MS, linkage, and monosaccharide composition analyses. Vk2a consists of both a galacturonan core and a rhamnogalacturonan core rich in neutral side chains. The backbones of both Ct-polysaccharides consist mainly of RG-I regions with numerous neutral side chains dominated by galactosyl residues, whereas the homogalacturonan regions seem to be small. Differences in the chain lengths of the 6-linked galacto-oligosaccharides attached to the 3-linked galactan core could not be related to the differences in the potencies of the biological activities observed.
authors.affiliation: Department of Pharmacognosy, School of Pharmacy, University of Oslo, P.O. Box 1068, Blindern, 0316 Oslo, Norway.
authors.forename: Cecilie Sogn
authors.initials: CS
authors.lastname: Nergard
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kiyohara
authors.forename: James C
authors.initials: JC
authors.lastname: Reynolds
authors.forename: Jane E
authors.initials: JE
authors.lastname: Thomas-Oates
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Haruki
authors.initials: H
authors.lastname: Yamada
authors.forename: Trushar
authors.initials: T
authors.lastname: Patel
authors.forename: Dirk
authors.initials: D
authors.lastname: Petersen
authors.forename: Terje E
authors.initials: TE
authors.lastname: Michaelsen
authors.forename: Drissa
authors.initials: D
authors.lastname: Diallo
authors.forename: Berit Smestad
authors.initials: BS
authors.lastname: Paulsen
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D000897:Anti-Ulcer Agents / Q000737:chemistry / Q000494:pharmacology; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D031212:Bixaceae / Q000737:chemistry*; D002478:Cells, Cultured; D003168:Complement Fixation Tests; D003165:Complement System Proteins / Q000187:drug effects* / Q000276:immunology*; D005260:Female; D005685:Galactans / Q000737:chemistry* / Q000494:pharmacology*; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008934:Mitogens / Q000737:chemistry / Q000494:pharmacology*; D008938:Mitosis / Q000187:drug effects; D008970:Molecular Weight; D009005:Monosaccharides / Q000737:chemistry; D009792:Oceans and Seas; D010368:Pectins / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D035741:Vernonia / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D000897:Anti-Ulcer Agents; D005685:Galactans; D008934:Mitogens; D009005:Monosaccharides; D010368:Pectins; D003165:Complement System Proteins; C005653:arabinogalactan