Antioxidative properties of probucol estimated by the reactivity with superoxide and by electrochemical oxidation.
The reaction of probucol with superoxide (O2(*-)) was investigated in acetonitrile using both electron spin resonance (ESR) and electrochemical techniques. The formation of phenoxyl radical was observed during the reaction of probucol with O2(*-) by ESR spectroscopy. The reaction of probucol with O2(*-) in acetonitrile was followed by cyclic voltammetry. With the addition of probucol, the oxidation peak current of O2(*-) decreased concentration dependently. This suggests that probucol reacts with O2(*-), that is, probucol scavenges O2(*-) in acetonitrile. 2,6-Di-tert-butyl-p-benzoquinone was identified as the major product of the reaction of probucol with O2(*-) in acetonitrile. Electrochemical oxidation of probucol was also performed. Probucol gives an irreversible oxidation peak at ca. +1.4 V vs. the saturated calomel electrode in the cyclic voltammogram. Controlled-potential electrolysis was carried out at +1.2 V in a divided cell. 2,6-Di-tert-butyl-p-benzoquinone, 4,4'-dithiobis(2,6-di-tert-butylphenol), and 4,4'-trithiobis(2,6-di-tert-butylphenol) were identified as the products of anodic oxidation. These redox properties of probucol may correlate with the physiological activities.
Araki
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T
Drug Metabolism and Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan. araki45s@daiichipharm.co.jp
Kitaoka
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H
D000975:Antioxidants / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D010084:Oxidation-Reduction; D011341:Probucol / Q000737:chemistry*; D013481:Superoxides / Q000737:chemistry*
D000975:Antioxidants; D013481:Superoxides; D011341:Probucol