[Scavenging action of green tea extracts on singlet oxygen and preventive effect on lipid peroxidation].

Singlet oxygen (1O2) produced by illuminated photosensitizer Rose Bengal was detected by its bleaching effect on N,N-dimethylnitrosoaniline(DMNA). The 1O2 could be scavenged by green tea extracts (GTE), with the scavenging action being obvious at the early stage of photosensitized oxidation. The higher the concentration of GTE in the photooxidation reaction system, the stronger the 1O2 scavenging action. The scavenging effect of the fresh GTE solution on singlet oxygen was better than that of old solution. The preventive effects of GTE on lipid peroxidation induced by 1O2 in ghosts and microsomal membranes were also observed. Malondialdehyde (MDA) production was found to be completely inhibited by a high concentration of GTE in the reaction system.