title: Structural studies of endopolygalacturonase-resistant fragments of an antiulcer pectin from the roots of Bupleurum falcatum L.
abstract: The endo-alpha-(1-->4)-polygalacturonase-resistant fractions (PG-1, PG-2, and PG-3) from an antiulcer pectin (Bupleuran 2IIc), isolated from the roots of Bupleurum falcatum L., were further analysed by lithium degradation. The results indicated that PG-1 contained a small proportion of long, branched arabinosyl chains and a large proportion of short, neutral oligosaccharide chains. GLC-MS analysis showed that, after methylation the short, neutral oligosaccharide fraction consisted of at least 22 kinds of di- to tetra-saccharide alditols, such as Gal-(1-->4)-Rha-ol (a major component), Ara-(1-->4)-Rha-ol, Glc-(1-->4)-Rha-ol, Ara-->Ara-->Ara-ol, and Ara-->Ara-->Ara-->Ara-ol (minor components) in addition to heteroglycosyl alditols. After deesterification, PG-2 and PG-3 were digested with endo-alpha-(1-->4)-polygalacturonase again, and the enzyme-resistant intermediate size fraction (PG-2') was purified. Component sugar analysis indicated that PG-2' contained 2-Me-Fuc, 2-Me-Xyl, apiose (Api), aceric acid (AceA), 3-deoxy-D-lyxo-heptulosaric acid (Dha), and 3-deoxy-D-manno-2-octulosonic acid (Kdo) in addition to Rha, Fuc, Ara, Xyl, Man, Gal, Glc, GalA, and GlcA. Lithium degradation of PG-2' gave mainly a pentosyl-->6-deoxyhexosyl-->6-deoxyhexosyl-->pentitol fragment, with some neutral di- and tri-saccharide alditols, including a pentosyl-->deoxyhexitol. Methylation analysis of these degradation products indicated that they contained terminal Rha, Araf, Fuc, Xyl, and Gal, 4-linked Rha, 3-linked Fuc, 3-linked Ara, and 3'-linked Api. Bupleuran 2IIc was eluted as essentially a single peak on gel filtration on Sepharose CL-6B. The neutral sugar content of the successive fractions increased with increasing molecular weight, but each fraction also contained, in addition to Rha, Ara, and Gal, 2-Me-Fuc, 2-Me-Xyl, and Api.
authors.affiliation: Oriental Medicine Research Center of the Kitasato Institute, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hirano
authors.forename: H
authors.initials: H
authors.lastname: Kiyohara
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Yamada
mesh_terms: D000818:Animals; D000897:Anti-Ulcer Agents / Q000737:chemistry* / Q000494:pharmacology; D029972:Bupleurum; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D004187:Disaccharides / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D008094:Lithium; D008745:Methylation; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry; D010368:Pectins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D011096:Polygalacturonase / Q000378:metabolism*; D013402:Sugar Alcohols / Q000737:chemistry; D014312:Trisaccharides / Q000737:chemistry
chemical_list: D000897:Anti-Ulcer Agents; C051274:Bupleurum root extract; D002241:Carbohydrates; D004187:Disaccharides; D009844:Oligosaccharides; D010936:Plant Extracts; D013402:Sugar Alcohols; D014312:Trisaccharides; C073829:Bupleuran 2IIc; D010368:Pectins; D008094:Lithium; D011096:Polygalacturonase