| Abstract
| - The scavenging effects of grape seed extract (GSE) on free radicals formed in an H2O2/NaOH/DMSOsystem were examined using a spin-trapping electron spin resonance (ESR) method and comparedwith other natural antioxidants, ascorbic acid, dl-α-tocopherol, and β-carotene. GSE reduced greatlythe ESR signal intensity of superoxide radical−5,5-dimethyl-1-pyrroline-N-oxide (DMPO) adducts.GSE also exhibited weak scavenging activity on hydroxyl radical and a little scavenging activity onmethyl radical. Ascorbic acid exhibited strong superoxide and hydroxyl radical scavenging activities,but it increased the amount of methyl radical at high concentration. dl-α-Tocopherol reduced theamount of superoxide anion, especially the amount of methyl radical. However, it slightly reducedthe amount of hydroxyl radical. β-Carotene reduced the amount of hydroxyl radical and methylradical, but it also slightly reduced superoxide anion. In the case of combination use of β-caroteneand dl-α-tocopherol, all radical species were suppressed. Combination of GSE and dl-α-tocopherolalso could reduce all radical species. β-Carotene and dl-α-tocopherol could reduce the methyl radicalformation induced by ascorbic acid. Keywords: Electron spin resonance; reactive oxygen species; superoxide anion; hydroxyl radical;methyl radical; grape seed extract
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