Green tea polyphenols react with 1,1-diphenyl-2-picrylhydrazyl free radicals in the bilayer of liposomes: Direct evidence from electron spin resonance studies
C. Chen et al., Green tea polyphenols react with 1,1-diphenyl-2-picrylhydrazyl free radicals in the bilayer of liposomes: Direct evidence from electron spin resonance studies, J AGR FOOD, 48(11), 2000, pp. 5710-5714
Free radical scavenging reactions of green tea polyphenols (GTP) were inves
tigated with electron spin resonance (ESR) spectroscopy in the phospholipid
bilayer of liposomes, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical a
s a model. The results showed that (1) GTP reacts with DPPH radicals in the
bilayer of liposomes of both 1-hexadecanoyl-2- [(cis,cis,cis,cis,cis,cis)-
4,7,10,13,16,19-docosahexaenoyl] -sn-glycero-3-phosphocholine (DHAPC) and 1
,2-di[cis-9-hexadecenoyl]-sn-glycero-3-phosphocholine) (DPPC); and (2) GTP
protects DHAPC liposomes effectively from the oxidation initiated by DPPH r
adicals. These results provide direct evidence that GTP reacts with free ra
dicals in the model membrane and support the hypothesis that GTP protects u
nsaturated phospholipids from oxidation by reacting directly with the radic
als.