Antioxidant effects of water-soluble fullerene derivatives against ultraviolet ray or peroxylipid through their action of scavenging the reactive oxygen species in human skin keratinocytes

Chemically generated hydroxyl radicals were scavenged by PEG-modified fullerene, hydroxy-fullerene and isostearate-mixed fullerene as efficiently as ascorbic acid (Asc) or its 2-O-phosphorylated derivative (A2P) as shown by the DMPO-spin trap/ESR method. Enzymatically generated superoxide anion radicals were also scavenged by PEG-modified or PVP-entrapped fullerene similarly as done by Asc or A2P. Some reactive oxygen species (ROS) such as hydroperoxides and hydrogen peroxides were generated preferably in the nuclei of UVB-irradiated human skin keratinocytes HaCaT, and repressed by PVP- or γ-cyclodextrin-fullerene. In contrast, the cytoplasm in the keratinocytes accumulated the ROS that were generated by the peroxylipid model compound t-BuOOH, and underwent the ROS repression by PVP-fullerene more markedly than by A2P. Thus several fullerene derivatives, especially PVP-fullerene, were shown to diminish the ROS amounts in terms of the molecular and cellular levels against either UVB or t-BuOOH, suggesting the expectation for development as rejuvenation cosmetics.