茶叶EGCG调节机体内源活性氧的时空变化规律及作用机制研究

新食品原料EGCG是茶叶中含量最高的多酚类化合物。长期以来，人们认为抗氧化作用是茶多酚/EGCG具有多种生物活性的主要原因。申请者利用抗衰老模式生物秀丽线虫研究却发现：EGCG诱导机体生成的内源性活性氧先短暂升高后显著降低。因此，我们认为在活体生物中，EGCG不是静态地表现为具有抗氧化或者促氧化作用，而是诱导内源性活性氧动态变化。本项目拟采用新型比率荧光探针等方法对活性氧（超氧阴离子与过氧化氢）进行活体成像示踪，从时间进程与空间定位（不同组织与亚细胞结构）探索EGCG诱导机体内源性活性氧的动态变化规律；利用ICAT与UPLC-MS/MS等技术解析其造成的氧化还原稳态变化；并通过研究线粒体稳态与适应性应激响应来揭示其作用机制，旨在阐明EGCG诱导机体内源性活性氧的时空变化、机体反馈调控氧化还原动态平衡与抗衰老生物活性三者的内在联系，为新食品原料（特别是膳食多酚）抗氧化活性提供新的研究视角。

Tea polyphenol epigallocatechin gallate (EGCG) is regarded as a new-food-raw material approved by National Health Commission of the People's Republic of China. As one of the most abundant tea catechins, EGCG is generally accepted as an antioxidant, possessing various biological activities associated with antiaging. While recent investigations have revealed that it functions as a pro-oxidant. .To explore the controversial issue, we detected the endogenous ROS in C. elegans chronologically, employing 2, 7- dichlorofluorescin diacetate (DCF-DA), a small molecule sensor. The intriguing result showed that the hormesis effect was observed in model organism C. elegans after pretreatment with EGCG ranged from low to high concentration, the induced endogenous ROS levels, raised transiently in the earlier time then declined significantly with prolonging days. It is inconsistent with all other previous reports. .On base of the observation, we try to further dissect the ROS dynamics in living organism exposed to EGCG. To test this, the advance approaches in vivo for monitoring ROS, such as the targeted synthetic fluorescent probes and the genetically encoded ratiometric fluorescent protein sensors, will be used to track the spatial and temporal ROS levels in C. elegans from cellular compartments to the tissues. Furthermore, the dynamics of redox processes will be monitored by using the thiol trapping technique OxICAT coupled with UPLC-MS/MS. Then the feedback adjustment mechanism will be analysed to discover the internal causes for the interesting phenomenon. .The work will provide a new research perspective for the anti-oxidant function of the new-food-raw materials (especially for dietary polyphenols). It also will give us a new understand of the free radical theory of aging, and a beneficial guide for exploring the bioactivities of EGCG, such as the effect for extending healthy lifespan.