The water-soluble fullerene derivative "Radical Sponge" exerts cytoprotective action against UVA irradiation but not visible-light-catalyzed cytotoxicity in human skin keratinocytes

Bioorg Med Chem Lett. 2006 Mar 15;16(6):1590-5. doi: 10.1016/j.bmcl.2005.12.011. Epub 2006 Jan 24.


Fullerene was entrapped in polyvinylpyrrolidone of 60-80 kDa at a molar ratio range of 0.42-0.67:1, resulting in a water-soluble derivative with a mean particle diameter of about 688 nm, named "Radical Sponge" because of its ROS-scavenging ability as previously demonstrated, and examined in the present study for its photo-biological actions toward human skin keratinocytes HaCaT. The keratinocytes were repeatedly irradiated with a visible light of wavelengths of 400-2000 nm (approximately 19,800 lux) in the presence or absence of Radical Sponge of 25-75 microM and did not exhibit any photo-cytotoxicity due to coexistent Radical Sponge as compared with the sham-irradiation control. Radical Sponge exerted a more marked cytoprotection at doses of 10-40 microM against UVA irradiation of 30 J/cm(2) when it was pre-irradiationally administered and rinsed out immediately before the irradiation, than when administered only during or after the irradiation, indicating the preventive rather than therapeutic or ray-sheltering effect of Radical Sponge on UVA injuries. Cytoprotection by Radical Sponge against UVA was achieved at the advisable range doses of 10-40 microM in contrast to no effect of polyvinylpyrrolidone alone; its dose-dependency was advantageous over that of VC-IP, a tetra-alkyl-esterized provitamin C, which became less cytoprotective above 20 microM. Thus, Radical Sponge is expected as an anti-UVA-preventive agent without visible-light-catalyzed cytotoxicity toward human skin keratinocytes.

MeSH terms

  • Cytoprotection / drug effects*
  • Cytoprotection / radiation effects*
  • Fullerenes / pharmacology*
  • Humans
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Keratinocytes / radiation effects*
  • Light
  • Skin / cytology
  • Skin / drug effects
  • Skin / radiation effects
  • Solubility
  • Ultraviolet Rays
  • Water


  • Fullerenes
  • Water