title: Structural characterization of a pectic polysaccharide from Nerium indicum flowers.
abstract: A polysaccharide fraction, J6, was isolated from the hot-water extract of flowers of oleander Nerium indicum Mill., using ethanol precipitation, cetyltrimethylammonium bromide (CTAB) complexing, anion-exchange chromatography and gel permeation chromatography. J6 was found to contain L-rhamnose, L-arabinose, D-galactose, and D-galacturonic acid, in the ratio of 10.1:49.8:30.1:10.0. Its structure was investigated by methylation analysis, periodate oxidation, Smith degradation, partial acid hydrolysis, electrospray ionization mass spectrometry and NMR spectroscopic methods. It was found that J6 is an RG-I type polysaccharide, which contains a rhamnogalacturonan backbone, with various branches attached to O-4 of L-rhamnose. The branches probably involve (1-->4)-beta-D-galactan, branched L-arabino-(1-->3)(1-->6)-beta-D-galactan, and (1-->5)-alpha-L-arabinan. J6 stimulated NO production of macrophage RAW264.7 cells in a preliminary test.
authors.affiliation: Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, 201203 Shanghai, China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Dong
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Yao
authors.forename: Xiaotang
authors.initials: X
authors.lastname: Dong
authors.forename: Chao
authors.initials: C
authors.lastname: Ma
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Xu
authors.forename: Jinian
authors.initials: J
authors.lastname: Fang
authors.forename: Kan
authors.initials: K
authors.lastname: Ding
mesh_terms: D000818:Animals; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D035264:Flowers / Q000737:chemistry; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D030007:Nerium / Q000737:chemistry*; D009569:Nitric Oxide / Q000096:biosynthesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D010368:Pectins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D004365:Drugs, Chinese Herbal; C552581:pectic polysaccharide J6; D009569:Nitric Oxide; D010368:Pectins