Inhibition of the superoxide anion release and hydrogen peroxide formation in PMNLs by flavonolignans

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The mixture of flavonolignans [LegalonR: silybin (2a), isosilybin (3), silydianin (4) and silychristin (5)] and derivatives of silybin (2b-d) were assessed for their inhibitory activity on the oxidative burst of PMA-stimulated human PMNLs. The inhibitory effect of flavonolignans on O2- release were compared with that of vitamin E (1). The flavonolignans tested exhibited the following order in inhibition of O2- release by PMA-stimulated PMNLs: 5,7,4″- trimethylsilybin (2c) ≅ vitamin E (1) > LegalonR ≥ peracetylsilybin (2b) ≥ silybin (2a) ≥ peracetyl-5,7,4″-trimethylsilybin (2d). The flavonolignans inhibited not only the O2- release, but also the H2O2 formation in PMA-stimulated PMNLs. The inhibitory capacity of flavonolignans on H2O2 formation was similar to their inhibitory capacity on O2- release. These data suggest that the flavonolignans have antioxidant properties on the PMNL oxidative burst. The fact that the trimethyl derivative of silybin (2c) has a greater inhibitory effect than silybin itself suggests that the efficacy of the antioxidant properties is dependent on the lipophilicity of the molecules. This is underlined by the fact that peracetylation of all of the hydroxyl groups in silybin resulted in a total loss of the anti-oxidant activity of the molecule. In summary, flavonolignans inhibit the oxidative burst of PMNLs, and this inhibitory effect depends on the chemical structure of the flavonolignans.

Original languageEnglish
Pages (from-to)608-612
Number of pages5
JournalPhytotherapy Research
Issue number7
Publication statusPublished - Nov 12 2001



  • Flavonolignans
  • Legalon
  • O release
  • Oxidative burst
  • PMNL
  • Silybin

ASJC Scopus subject areas

  • Pharmacology

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