Electron Spin Resonance Spectroscopic Studies on the Radical Scavenging Capacities of Catechin and Pyrogallol

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• 作者：Shaolin Mu ; Chong Chen
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：February 2, 2012
• 年：2012
• 卷：116
• 期：4
• 页码：3065-3070
• 全文大小：280K
• 年卷期：v.116,no.4(February 2, 2012)
• ISSN：1932-7455

文摘

The antioxidant activities and free radical scavenging capacities of (+)-catechin, pyrogallol, and red wine are investigated using the electrochemical method and electron spin resonance (ESR) technique. Poly(aniline-co-o-aminophenol) (PAoA) is used as a source of the free radical. On the basis of the electrochemical measurements, among the samples used, the antioxidant activity is the strongest for pyrogallol and is weakest for red wine. However, the ESR measurements reveal the fact that (+)-catechin can effectively scavenge the free radical of PAoA; however, pyrogallol not only cannot scavenge the free radical but also makes the ESR signal intensity of PAoA pronouncedly increase. This result is just contrary to the previous reports based on the determination of the scavenging free radical of DPPH using the UV鈥搗isible spectral method, in which the maximum absorbance is related only to the reducing power of an antioxidant. This difference is due to the formation of the new free radical during the oxidation process of pyrogallol. It is found that the red wine used can scavenge the free radical, but its scavenging capacity is lower than that of (+)-catechin.