title: Green tea polyphenols react with 1,1-diphenyl-2-picrylhydrazyl free radicals in the bilayer of liposomes: direct evidence from electron spin resonance studies.
abstract: Free radical scavenging reactions of green tea polyphenols (GTP) were investigated with electron spin resonance (ESR) spectroscopy in the phospholipid bilayer of liposomes, using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical as 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 radicals. These results provide direct evidence that GTP reacts with free radicals in the model membrane and support the hypothesis that GTP protects unsaturated phospholipids from oxidation by reacting directly with the radicals.
authors.affiliation: Institute of Biophysics, Academia Sinica, Beijing 100101, People's Republic of China.
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: H R
authors.initials: HR
authors.lastname: Tang
authors.forename: L H
authors.initials: LH
authors.lastname: Sutcliffe
authors.forename: P S
authors.initials: PS
authors.lastname: Belton
mesh_terms: D015764:Bepridil / Q000031:analogs & derivatives* / Q000737:chemistry; D001713:Biphenyl Compounds; D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids; D005609:Free Radicals; D008051:Lipid Bilayers; D010636:Phenols / Q000737:chemistry*; D010851:Picrates; D011108:Polymers / Q000737:chemistry*; D059808:Polyphenols; D013662:Tea
chemical_list: D001713:Biphenyl Compounds; D005419:Flavonoids; D005609:Free Radicals; D008051:Lipid Bilayers; D010636:Phenols; D010851:Picrates; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D015764:Bepridil; C004931:1,1-diphenyl-2-picrylhydrazyl