“绿茶是全世界很受欢迎的一种饮料”，来自中国重庆第三军医大学（Third Military Medical University）的白云教授说道，“一直以来，有大量的科学研究都在关注它在帮助预防心血管疾病方面的应用，但是目前有新的证据表明，它的化学性质可能会影响大脑中的细胞机制。”
Bai教授的团队重点关注了有机化学物质EGCG（表没食子儿茶素—3—没食子酸酯）——这是绿茶的一种重要成分。虽然EGCG是一种众所周知的抗氧化剂，但该团队认为它还能够对年龄相关的退行性疾病产生有利影响。
“我们认为，EGCG能够通过影响神经元细胞的生成来改善认知功能，这一生成过程被称为神经形成”，白教授说道，“我们将我们的研究聚焦在海马区，大脑的这个部位用来处理从短期到长期记忆的信息。”
该团队发现EGCG能够促进神经前体细胞的生成，像干细胞一样，这种细胞能够改变或分化成不同类型的细胞。随后，该团队利用实验室小鼠来观察这种增加的细胞生成能否有助于记忆力或空间学习。
“我们对两组小鼠进行了试验：一组已吸入了ECGC而另一组则作为对照组”，白教授说道，“首先，小鼠接受三天的训练以便于它们能够在迷宫中找到一个看得见的平台；随后，它们又接受了七天的训练，来找到一个隐蔽的平台。”
该团队发现，经过EGCG处理的小鼠能在更短的时间内找到隐蔽的平台。总的来说，研究结果表明EGCG能够通过改善物体识别与空间记忆来促进学习与记忆力。
“我们的研究表明，在玻璃试验和小鼠体内，有机化学物质EGCG能够直接促进神经前体细胞的生成”，白教授总结道，“这有助于我们理解绿茶所含有的成分EGCG在帮助防治退行性疾病与健忘方面的潜力。”
Green tea epigallocatechin-3-gallate (EGCG) promotes neural progenitor cell proliferation and sonic hedgehog pathway activation during adult hippocampal neurogenesis
Scope Adult hippocampal neurogenesis is a lifelong feature of brain plasticity that appears to be critically involved in adult brain function and neurological disease. Recent studies suggest that (–)-epigallocatechin-3-gallate (EGCG), which is the main polyphenolic constituent of green tea, may be used for the prevention and treatment of various neurodegenerative diseases. We hypothesized that EGCG promotes adult neurogenesis, which may be beneficial to hippocampus-dependent learning and memory.
Methods and results We show that EGCG treatment significantly increased the number of 5-bromo-2′-deoxyuridine (BrdU)-labeled cells in adult hippocampal neural progenitor cell (NPC) cultures and in the dentate gyrus of adult mice. Meanwhile, EGCG markedly improved spatial cognition in mice. These events are associated with the sonic hedgehog (Shh) signaling pathway. We observed that EGCG triggered a robust upregulation of Shh receptor (Patched) mRNA and protein expression in cultured NPCs as well as an upregulation of the downstream Shh transcriptional target Gli1. These changes were further confirmed in the hippocampus of mice administered EGCG. The blockage of the Shh signal with the pharmacological inhibitor cyclopamine attenuated EGCG-induced hippocampal neurogenesis.
Conclusion Our results provide strong evidence that EGCG enhances adult hippocampal neurogenesis.
