Beetroot betalain inhibits peroxynitrite-mediated tyrosine nitration and DNA strand cleavage

Free Radic Res. 2012 Jan;46(1):93-9. doi: 10.3109/10715762.2011.641157. Epub 2011 Dec 5.


Two major betalains, red-purple betacyanins and yellow betaxanthins, were isolated from red beetroots (Beta vulgaris L.), and their peroxynitrite (ONOO(-)) scavenging capacity was investigated. Apparent colours of the betalains were bleached by the addition of ONOO(-), and the absorbance decreases were suppressed in the presence of glutathione, a ONOO(-) scavenger. After bleaching, a new absorption maximum was observed at 350 nm in the spectrum of the resulting reaction mixture. New peaks were detected from HPLC analysis of the reaction products of betanin, a representative constituent of red beetroot betacyanins, treated with ONOO(-) monitoring at 350 nm, and the intensity of the major peak was positively correlated with ONOO(-) concentration. Betanin inhibited the ONOO(-) (0.5 mM)-dependent nitration of tyrosine (0.1 mM). Additionally, the IC(50) value of betanin (19.2 μM) was lower than that of ascorbate (79.6 μM). The presence of betanin (0.05-1.0 mM) also inhibited ONOO(-) (0.5 mM)-dependent DNA strand cleavage in a concentration-dependent manner. These results suggest that betalains can protect cells from nitrosative stress in addition to protecting them from oxidative stresses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Beta vulgaris / chemistry
  • Betalains / isolation & purification
  • Betalains / pharmacology*
  • DNA Breaks*
  • Free Radical Scavengers / isolation & purification
  • Free Radical Scavengers / pharmacology*
  • Nitrates / chemistry
  • Nitrates / metabolism
  • Peroxynitrous Acid / antagonists & inhibitors*
  • Peroxynitrous Acid / chemistry
  • Reactive Oxygen Species
  • Tyrosine / analogs & derivatives
  • Tyrosine / chemistry*
  • Tyrosine / metabolism


  • Free Radical Scavengers
  • Nitrates
  • Reactive Oxygen Species
  • Peroxynitrous Acid
  • Betalains
  • Tyrosine