Comparative Study On Anti-free Radical Effects Of Tea Polyphenols And Vitamin C

Backgroud and purposePresently, research and development of anti-free radical drugs have become very active hot point in biochemical fields. This article is designed to investigate anti-free radical effects of Tea polyphenol (Tea polyphenol, TP) in comparison with Vitamin C (VitC), using in vitro chemical reaction models, anoxia/hypoglycemia injury cell model and in vivo mouse liver injury models in order to provide further preclinical pharmacological basis for its development and clinical uses. Methods1. In vitro free radical models: (1) Preparation of models: Hydroxyl free radical (·OH) was generated using H₂O_/Fe²⁺ system via Fenton reaction, superoxide anion ((O₂^·)^- ) using pyrogallol auto-oxidation method. The inhibitory effect of TP on lipid peroxidation was examined by use of ?OH-caused hepatic homogenate lipid peroxidation. The protective effect of TP on RBC membrane was investigated utilizing ?OH-caused rupture of RBC membrane. (2) Examination and determination of index: Absorbence was measured with UV-754 spectrophotometer, and free radical scavenging percent- tage, SC50 and IC50 of TP and VitC were calculated.2. Anoxia/hypoglycemia injury cell model: (1) Preparation of models: Cultured human embryonic kidney cells were incubated in Earle's salt solution deprived of glucose and oxygen via Na₂S₂O₄ for 24 hours so as to get anoxia/hypoglycemia injury cells. (2) Examination and determination of index: The cell survival percentage, lactate dehydrogenase (LDH), superoxide dismutase (SOD) and total antioxidant capacity (TAC) were examined and IC50 was calculated.