Characterisation of carotenoid radical cations in liposomal environments: interaction with vitamin C

J Photochem Photobiol B. 2001 Apr;60(1):1-6. doi: 10.1016/s1011-1344(01)00111-7.


Pulse radiolysis was used to generate the radical cations of beta-carotene and two xanthophylls, zeaxanthin and lutein, in unilamellar vesicles of dipalmitoylphosphatidyl choline. The rate constants for the reaction (repair) of these carotenoid radical cations with the water-soluble vitamin C were found to be similar (approximately 1x10(7) M(-1) s(-1)) for beta-carotene and zeaxanthin and somewhat lower (approximately 0.5x10(7) M(-1) s(-1)) for lutein. The results are discussed in terms of the microenvironment of the carotenoids and suggest that for beta-carotene, a hydrocarbon carotenoid, the radical cation is able to interact with a water-soluble species even though the parent hydrocarbon carotenoid is probably entirely in the non-polar region of the liposome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dipalmitoylphosphatidylcholine / chemistry*
  • Ascorbic Acid / chemistry*
  • Cations
  • Free Radicals / chemistry
  • Liposomes / chemistry
  • Lutein / chemistry*
  • Molecular Structure
  • Spectrophotometry, Ultraviolet
  • Xanthophylls
  • Zeaxanthins
  • beta Carotene / analogs & derivatives
  • beta Carotene / chemistry*


  • Cations
  • Free Radicals
  • Liposomes
  • Xanthophylls
  • Zeaxanthins
  • beta Carotene
  • 1,2-Dipalmitoylphosphatidylcholine
  • Ascorbic Acid
  • Lutein