Itoh Nobuya, Kurokawa Junji, Isogai Yasuhiro, Ogasawara Masaru, Matsunaga Takayuki, Okubo Tsutomu, Katsube Yuji
Toyama Prefectural Institute for Pharmaceutical Research , 17-1 Nakataikouyama, Imizu, Toyama 939-0363, Japan.
Research Center, Taiyo Kagaku Co. Ltd. , 1-3 Takaramachi, Yokkaichi, Mie 512-1111, Japan.
J Agric Food Chem. 2017 Dec 6;65(48):10473-10481. doi: 10.1021/acs.jafc.7b04208. Epub 2017 Nov 27.
Epitheaflagallin (ETFG) and epitheaflagallin 3-O-gallate (ETFGg) are minor polyphenols in black tea extract that are enzymatically synthesized from epigallocatechin (EGC) and epigallocatechin gallate (EGCg), respectively, in green tea extract via laccase oxidation in the presence of gallic acid. The constituents of laccase-treated green tea extract in the presence of gallic acid are thus quite different from those of nonlaccase-treated green tea extract: EGC and EGCg are present in lower concentrations, and ETFG and ETFGg are present in higher concentrations. Additionally, laccase-treated green tea extract contains further polymerized catechin derivatives, comparable with naturally fermented teas such as oolong tea and black tea. We found that ETFGg and laccase-treated green tea extracts exhibit versatile physiological functions in vivo and in vitro, including antioxidative activity, pancreatic lipase inhibition, Streptococcus sorbinus glycosyltransferase inhibition, and an inhibiting effect on the activity of matrix metalloprotease-1 and -3 and their synthesis by human gingival fibroblasts. We confirmed that these inhibitory effects of ETFGg in vitro match well with the results obtained by docking simulations of the compounds with their target enzymes or noncatalytic protein. Thus, ETFGg and laccase-treated green tea extracts containing ETFGg are promising functional food materials with potential antiobesity and antiperiodontal disease activities.
表没食子儿茶素（ETFG）和表没食子儿茶素3 - O - 没食子酸酯（ETFGg）是红茶提取物中的微量多酚类物质，它们分别由绿茶提取物中的表没食子儿茶素（EGC）和表没食子儿茶素没食子酸酯（EGCg）在没食子酸存在下通过漆酶氧化酶促合成。因此，在没食子酸存在下经漆酶处理的绿茶提取物的成分与未经漆酶处理的绿茶提取物有很大不同：EGC和EGCg的浓度较低，而ETFG和ETFGg的浓度较高。此外, 经漆酶处理的绿茶提取物含有进一步聚合的儿茶素衍生物，与天然发酵茶如乌龙茶和红茶相当。我们发现，ETFGg和经漆酶处理的绿茶提取物在体内和体外均表现出多种生理功能，包括抗氧化活性、抑制胰腺脂肪酶、抑制嗜热栖热菌糖基转移酶，以及对基质金属蛋白酶 - 1和 - 3的活性及其由人牙龈成纤维细胞合成的抑制作用。我们证实，ETFGg在体外的这些抑制作用与通过化合物与其靶酶或非催化蛋白的对接模拟获得的结果非常吻合。因此，ETFGg和含有ETFGg的经漆酶处理的绿茶提取物是具有潜在抗肥胖和抗牙周病活性的有前景的功能性食品原料。
