Scavenging effects of baicalin on free radicals and its protection on erythrocyte membrane from free radical injury.
Using electron spin resonance (ESR) spin trapping technique, we found that baicalin (B) could scavenge hydroxyl radicals generated from Fenton reaction. It also could scavenge superoxide radicals generated from the reaction system containing xanthine (X) and xanthine oxidase (XO), as was found by using chemiluminescence (CL) method. Kinetic studies on the competition between baicalin and a spin trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) in trapping OH showed that baicalin had a kinetic reactive rate constant of the order of 7.7 x 10(11) M-1 s-1 in its reaction with OH, and the studies on the competition between baicalin and ferricytochrome c (f.c.) in trapping O2- gave a kinetic reactive rate constant of 3.2 x 10(6) M-1 s-1 for baicalin in its reaction with O2-. Furthermore, we have investigated the protective effects of baicalin on erythrocyte membranes from hydroxyl free radical injuries. The results showed that baicalin could reduce hydrogen peroxide-induced hemolysis, protect the conformation of sulfhydryl groups (-SH) on membrane proteins and the membrane fluidity of erythrocytes incubated with hydrogen peroxide. The results indicated that baicalin could protect the membranes of erythrocytes from free radical injuries, and it was even more effective than alpha-tocopherol.
Shi
H
H
Institute of Biophysics, Academia Sincia, Chaoyang District, Beijing, China.
Zhao
B
B
Xin
W
W
D000838:Anions; D000890:Anti-Infective Agents; D000998:Antiviral Agents; D001665:Binding Sites; D004365:Drugs, Chinese Herbal; D004910:Erythrocyte Membrane / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005419:Flavonoids / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005609:Free Radicals; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D011487:Protein Conformation; D015427:Reperfusion Injury / Q000517:prevention & control*; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
D000838:Anions; D000890:Anti-Infective Agents; D000998:Antiviral Agents; D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D016166:Free Radical Scavengers; D005609:Free Radicals; D008565:Membrane Proteins; D013438:Sulfhydryl Compounds; D013481:Superoxides; D017665:Hydroxyl Radical; C038044:baicalin; D006861:Hydrogen Peroxide; D007501:Iron