title: [A cyclotide against influenza A H1N1 virus from Viola yedoensis].
abstract: Three cyclotides were isolated from the whole plant of Viola yedoensis in this study. The two, vary peptide E and cycloviolacin Y5, were previously reported, and a novel cycloviolacin VY1 was characterized according to the interpretation of MS/MS fragmentation of peptides which were produced from the reduced and alkylated parent peptide with the digestion of Endo Lys-C, trypsin and chymotrypsin, separately. The stability of remarkable resistance to proteolytic degradation by trypsin and chymotrypsin, and that of thermal denaturation was confirmed again. Besides, the IC50 value of cycloviolacin VY1 against influenza A H1N1 virus was (2.27 +/- 0.20) microg x mL(-1). It is the first cyclotide reported with anti-influenza A H1N1 virus activity in vitro assay.
authors.forename: Min-Zhi
authors.initials: MZ
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.forename: Shu-Xiang
authors.initials: SX
authors.lastname: Zhang
authors.forename: Liang
authors.initials: L
authors.lastname: Tang
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Wang
authors.forename: Cheng-Juan
authors.initials: CJ
authors.lastname: Chen
authors.forename: Zhu-Fang
authors.initials: ZF
authors.lastname: Shen
authors.forename: Ke-Di
authors.initials: KD
authors.lastname: Cheng
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Kong
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000998:Antiviral Agents / Q000302:isolation & purification / Q000494:pharmacology*; D047169:Cyclotides / Q000494:pharmacology*; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects*; D053719:Tandem Mass Spectrometry; D032413:Viola / Q000737:chemistry*
chemical_list: D000998:Antiviral Agents; D047169:Cyclotides; C000604415:cycloviolacin VY1; C527609:cycloviolacin Y5