title: Pectic polysaccharide from immature onion stick (Allium cepa): structural and immunological investigation.
abstract: The structure of a water-soluble pectic polysaccharide (PS) isolated from immature onion stick (Allium cepa) was investigated using acid hydrolysis, methylation analysis, periodate oxidation study, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC). The results of the above experiments indicated that the PS contained d-galactose, 6-O-Me-D-galactose, 3-O-acetyl-D-methyl galacturonate and D-methyl galacturonate in a molar ratio of nearly 1:1:1:1 and possesses a backbone of [→4)-α-D-GalpA6Me-(1→4)-α-D-GalpA6Me-(1→] in which one methyl galacturonate was substituted at O-3 position by an acetyl group and the neighboring methyl galacturonate being substituted at O-2 with a side chain, α-D-Galp-(1→4)-6-O-Me-β-D-Galp-(1→. The probable structure of repeating unit of the pectic polysaccharide was established as: [formula in text] The pectic polysaccharide showed in vitro splenocyte, thymocyte as well as macrophage activations.
authors.affiliation: Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721102, West Bengal, India.
authors.forename: Pradip
authors.initials: P
authors.lastname: Patra
authors.forename: Ipsita K
authors.initials: IK
authors.lastname: Sen
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Bhanja
authors.forename: Ashis K
authors.initials: AK
authors.lastname: Nandi
authors.forename: Surajit
authors.initials: S
authors.lastname: Samanta
authors.forename: Debsankar
authors.initials: D
authors.lastname: Das
authors.forename: K Sanjana P
authors.initials: KS
authors.lastname: Devi
authors.forename: Tapas K
authors.initials: TK
authors.lastname: Maiti
authors.forename: Syed S
authors.initials: SS
authors.lastname: Islam
mesh_terms: D000818:Animals; D005690:Galactose / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D015394:Molecular Structure; D019697:Onions / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology; D060168:Thymocytes / Q000187:drug effects / Q000276:immunology; D014867:Water
chemical_list: D011134:Polysaccharides; D014867:Water; D010368:Pectins; D005690:Galactose