Radical Scavenging Activity of Ribonuclease Inhibitor from Cow Placenta

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Shuo Wang^1* and Haiping Li^1,2

¹Tianjin Key Laboratory of Food Nutrition and Safety, Faculty of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300222, P. R. China; fax: (86) 226-060-1456; E-mail: s.wang@tust.edu.cn

²Faculty of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin 300134, P. R. China; fax: (86) 226-060-1456; E-mail: hhppli@163.com

^* To whom correspondence should be addressed.

Received September 11, 2005; Revision received December 2, 2005

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Cow placenta ribonuclease inhibitor (CPRI) has been purified 5062-fold by affinity chromatography, the product being homogeneous by sodium dodecyl sulfate-gel electrophoresis. The chemiluminescence technique was used to determine the radical scavenging activities of CPRI toward different reactive oxygen species (ROS) including superoxide anion (O₂^-*), hydroxyl radical (OH^*), lipid-derived radicals (R^*), and singlet oxygen (¹O₂). CPRI could effectively scavenge O₂^-*, OH^*, R^*, and ¹O₂ at EC₅₀ of 0.12, 0.008, 0.009, and 0.006 mg/ml, respectively. In addition, the radical scavenging activities of CPRI were higher than those of tea polyphenols, indicating that CPRI is a powerful antioxidant.

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KEY WORDS: ribonuclease inhibitor, cow placenta, antioxidant, purification, chemiluminescence

DOI: 10.1134/S0006297906050087

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