title: Scirpusin A, a hydroxystilbene dimer from Xinjiang wine grape, acts as an effective singlet oxygen quencher and DNA damage protector.
abstract: BACKGROUND
  Grapes and red wines are rich sources of phenolic compounds such as anthocyanins, catechins, flavonols and stilbenes, most of which are potent antioxidants showing cardioprotective properties. We first isolated scirpusin A, a hydroxystilbene dimer, from a wine grape of Xinjiang, and studied its antioxidant activity.
  
  
  RESULTS
  Reactive oxygen species scavenging effects and the protection against reactive singlet oxygen-induced DNA damage of scirpusin A have been investigated in our experiments. The concentration of scirpusin A required to inhibit 50% of (1)O(2) generation was 17 micromol L(-1), while addition of scirpusin A at 140 micromol L(-1) caused complete inhibition. Further kinetic study revealed that the reaction of Scirpusin A with singlet oxygen has an extremely high rate constant (k(a) = 4.68 x 10(9) L mol(-1) s(-1)). Scirpusin A (140 micromol L(-1)) exhibited significant inhibition effects on pBR322 DNA breakage. However, scavenging effects of scirpusin A on superoxide anion O(2) (*-) and hydroxyl radical .OH were not potent as the inhibitor rates at a concentration of 1400 micromol L(-1) were 28.83% and 19.5%, respectively.
  
  
  CONCLUSIONS
  The present study shows that scirpusin A is a selective quencher of singlet oxygen and a protector against reactive singlet oxygen-induced pBR322 DNA damage at very low concentrations.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Kong
authors.forename: Xueyan
authors.initials: X
authors.lastname: Ren
authors.forename: Liyan
authors.initials: L
authors.lastname: Jiang
authors.forename: Yuanjiang
authors.initials: Y
authors.lastname: Pan
authors.forename: Cuirong
authors.initials: C
authors.lastname: Sun
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001572:Benzofurans / Q000737:chemistry* / Q000302:isolation & purification; D004249:DNA Damage / Q000187:drug effects*; D019281:Dimerization; D004578:Electron Spin Resonance Spectroscopy; D004587:Electrophoresis, Agar Gel; D016166:Free Radical Scavengers / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010957:Plasmids / Q000737:chemistry / Q000187:drug effects; D026082:Singlet Oxygen / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013267:Stilbenes / Q000737:chemistry* / Q000302:isolation & purification; D013481:Superoxides / Q000737:chemistry; D027843:Vitis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001572:Benzofurans; D016166:Free Radical Scavengers; D013267:Stilbenes; C550387:scirpusin A; D013481:Superoxides; D026082:Singlet Oxygen; D017665:Hydroxyl Radical