Comparison of antioxidant abilities of magnolol and honokiol to scavenge radicals and to protect DNA

Biochimie. 2011 Oct;93(10):1755-60. doi: 10.1016/j.biochi.2011.06.012. Epub 2011 Jun 23.


The antioxidant properties of magnolol and honokiol were evaluated in the experimental systems of reducing ONOO(-) and (1)O(2), bleaching β-carotene in linoleic acid (LH) emulsion, and trapping 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+)*) and 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and then were applied to inhibit the oxidation of DNA induced by Cu(2+)/glutathione (GSH) and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH). Magnolol and honokiol were active to reduce ONOO(-) and (1)O(2). Honokiol showed a little higher activity to protect LH and to inhibit Cu(2+)/GSH-induced oxidation of DNA than magnolol. In addition, honokiol exhibited higher activities to trap ABTS(+)* and DPPH than magnolol. In particular, honokiol trapped 2.5 radicals while magnolol only trapped 1.8 radicals in protecting DNA against AAPH-induced oxidation. The obtained results suggested that low antioxidant ability of magnolol may be related to the intramolecular hydrogen bond formed between di-ortho-hydroxyl groups, which hindered the hydrogen atom in hydroxyl group to be abstracted by radicals. Therefore, the antioxidant capacity of magnolol was lower than that of honokiol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antioxidants / chemistry*
  • Biphenyl Compounds / chemistry*
  • DNA / chemistry*
  • Free Radical Scavengers / chemistry*
  • Lignans / chemistry*


  • Antioxidants
  • Biphenyl Compounds
  • Free Radical Scavengers
  • Lignans
  • magnolol
  • honokiol
  • DNA