Oxidative stress-induced diseases and tea polyphenols

// Xiangbing Mao 1, 2 , Changsong Gu 1, 2 , Daiwen Chen 1, 2 , Bing Yu 1, 2 and Jun He 1, 2 1 Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, People’s Republic of China 2 Key Laboratory of Animal Disease-Resistance Nutrition, Chinese Ministry of Education, Chengdu, 611130, People’s Republic of China Correspondence to: Xiangbing Mao, email: acatmxb2003@163.com Keywords: oxidative stress, tea polyphenols, antioxidant capacity, pro-oxidant capacity Received: June 20, 2017      Accepted: August 26, 2017      Published: September 14, 2017 ABSTRACT Reactive oxide species are the middle products of normal metabolism, and play a crucial role in cell signaling transduction. On the contrary, accumulation of excess reactive oxide species results in oxidative stress that often brings multifarious impairment to cells, including decrease of ATP level in cells, elevation of cytosolic Ca 2+ , DNA damage, dysfunction of biological function in lipid bilayer and so on. These effects will finally lead to all kinds of diseases. Tea polyphenols are widely considered as a kind of excellent antioxidant agents. It can be antioxidants by directly scavenging reactive oxide species or chelating transition metals, and indirectly upregulating the activity of antioxidant enzymes. In addition, tea polyphenols have also been observed a potent pro-oxidant capacity, which directly leads to the generation of reactive oxide species, and indirectly induces apoptosis and death of cancer cells. The underlying characters of its pro-oxidant activity in some diseases is not well understood. The present review we will discuss the dual character of tea polyphenols, both antioxidant and pro-oxidant properties, in some human diseases induced by oxidative stress.