title: Anti-influenza A virus effects of fructan from Welsh onion (Allium fistulosum L.).
abstract: A fructan that acts as an anti-influenza A virus substance was isolated from hot water extract of the green leafy part of a Welsh onion (Allium fistulosum L.). The structure of the fructan was characterised and elucidated by chemical and spectroscopic analyses. The fructan was composed of terminal (21.0%) and 2,1-linked β-D-Fruf residues (65.3%) with 1,6-linked β-D-Glcp residues (13.7%). The molecular weight of the polysaccharide and polydispersity was estimated to be 1.5×10(3) and 1.18, respectively. Although the fructan did not show anti-influenza A virus activity in vitro, it demonstrated an inhibitory effect on virus replication in vivo when it was orally administered to mice. In addition, the polysaccharide enhanced the production of neutralising antibodies against influenza A virus. Therefore, the antiviral mechanism of the polysaccharide seemed to be dependent on the host immune system, i.e., enhancement of the host immune function was achieved by the administration of the polysaccharide. From our observations, the fructan from Welsh onions is suggested to be one of the active principles which exert an anti-influenza virus effect.
authors: Graduate School of Medicine and Pharmaceutical Sciences for Research, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan. lee@pha.u-toyama.ac.jp
authors: Jung-Bum
authors: JB
authors: Lee
authors: Sachi
authors: S
authors: Miyake
authors: Ryo
authors: R
authors: Umetsu
authors: Kyoko
authors: K
authors: Hayashi
authors: Takeshi
authors: T
authors: Chijimatsu
authors: Toshimitsu
authors: T
authors: Hayashi
mesh_terms: D000490:Allium / Q000737:chemistry*; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects / Q000502:physiology; D007251:Influenza, Human / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000998:Antiviral Agents; D010936:Plant Extracts; D011134:Polysaccharides