Laboratory for Functional Foods and Human Health, Center for Excellence in Post-Harvest Technologies, North Carolina Agricultural and Technical State University, North Carolina Research Campus, 500 Laureate Way, Kannapolis, NC, 28081, USA.
Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, 32611, USA.
Mol Nutr Food Res. 2021 Feb;65(4):e2000887. doi: 10.1002/mnfr.202000887. Epub 2021 Jan 12.
This study is to determine the in vivo efficacy of black tea theaflavin (TF) to detoxify two metabolic toxins, ammonia and methylglyoxal (MGO), in mice METHODS AND RESULTS: Under in vitro conditions, TF is able to react with ammonia, MGO, and hydrogen peroxide to produce its aminated, MGO conjugated, and oxidized products, respectively. In TF-treated mice, the aminated TF, the MGO conjugates of TF and aminated TF, and the oxidized TF are searched using LC-MS/MS. The results provide the first in vivo evidence that the unabsorbed TF is able to trap ammonia to form the aminated TF; furthermore, both TF and the aminated TF have the capacity to trap MGO to generate the corresponding mono-MGO conjugates. Moreover, TF is oxidized to dehydrotheaflavin, which underwent further amination in the gut. By exposing TF to germ-free (GF) mice and conventionalized mice (GF mice colonized with specific-pathogen-free microbiota), the gut microbiota is demonstrated to facilitate the amination and MGO conjugation of TF.
TF has the capacity to remove the endogenous metabolic toxins through oxidation, amination, and MGO conjugation in the intestinal tract, which can potentially explain why TF still generates in vivo efficacy while showing a poor systematic bioavailability.
本研究旨在确定红茶茶黄素 (TF) 在体内对两种代谢毒素氨和甲基乙二醛 (MGO) 的解毒功效。
在体外条件下，TF 能够与氨、MGO 和过氧化氢反应，分别产生其氨基化、MGO 缀合和氧化产物。在 TF 处理的小鼠中，使用 LC-MS/MS 搜索氨基化 TF、TF 和氨基化 TF 的 MGO 缀合物以及氧化 TF。结果提供了体内第一个证据，即未被吸收的 TF 能够捕获氨形成氨基化 TF；此外，TF 和氨基化 TF 都具有捕获 MGO 生成相应单 MGO 缀合物的能力。此外，TF 被氧化为脱没食子儿茶素，其在肠道中进一步发生氨基化。通过将 TF 暴露于无菌 (GF) 小鼠和常规化 (GF 小鼠定植无特定病原体微生物群) 小鼠，证实肠道微生物群有助于 TF 的氨基化和 MGO 缀合。
TF 具有通过氧化、氨基化和 MGO 缀合在肠道中去除内源性代谢毒素的能力，这可以解释为什么 TF 仍然具有体内功效，而显示出较差的系统生物利用度。
