College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, Ministry of Science and Technology, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China.
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, Ministry of Science and Technology, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing 100083, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China.
Food Res Int. 2021 Jan;139:109941. doi: 10.1016/j.foodres.2020.109941. Epub 2020 Dec 3.
Chlorophyll can be obtained from a variety of green vegetables. In this study, chlorophyll-rich spinach (Spinacia oleracea L.) extracts were subjected to early-life and adult-life gastrointestinal digestion and colonic fermentation in a murine model in vitro to investigate the biological transformation of the chlorophyll. Chlorophylls a and b were the main compounds present in the extracts. Furthermore, some other compounds were also confirmed, such as 15-hydroxy-lactone chlorophyll a, 13-hydroxy chlorophyll a, and 15-hydroxy-lactone chlorophyll b. Chlorophylls favored pheophytinization and oxidative reactions under in vitro early-life and adult-life gastrointestinal digestion, leading to the formation of pheophytin a, pheophytin b, 13-hydroxy pheophytin a, and 15-hydroxy-lactone pheophytin a. 16S rRNA gene sequencing conveyed that pheophytins modulated the gut microbiota composition during in vitro colonic fermentation. Notably, Blautia in the gut microbiota of 3-week-old mice (early life) and unclassified Lachnospiraceae in 8-week-old mice (adult life) were advantageous for transforming the pheophytins to pheophorbide a, pheophorbide b, 15-hydroxy-lactone pheophorbide a, and 13-hydroxy pheophorbide a, thereby demonstrating the loss of the phytol chain in the pheophytins. Meanwhile, total short-chain fatty acids, as well as acetic, propionic, and butyric acids, were increased by the process of microbial fermentation in the presence of pheophytins. Our study provides fundamental insight into the contribution of diverse gut microbiota functions toward the biological transformation of pheophytins.
叶绿素可从各种绿色蔬菜中获得。在这项研究中，采用体外鼠模型对富含叶绿素的菠菜（Spinacia oleracea L.）提取物进行了生命早期和成年期胃肠道消化和结肠发酵，以研究叶绿素的生物转化。提取物中主要存在叶绿素 a 和 b 两种化合物。此外，还确认了一些其他化合物，如 15-羟基内酯叶绿素 a、13-羟基叶绿素 a 和 15-羟基内酯叶绿素 b。叶绿素在体外生命早期和成年期胃肠道消化过程中容易发生脱镁反应和氧化反应，导致形成脱镁叶绿素 a、脱镁叶绿素 b、13-羟基脱镁叶绿素 a 和 15-羟基内酯脱镁叶绿素 a。16S rRNA 基因测序表明，脱镁叶绿素调节了体外结肠发酵过程中的肠道微生物群落组成。值得注意的是，3 周龄（生命早期）小鼠肠道微生物群中的布劳特氏菌（Blautia）和 8 周龄（成年期）小鼠肠道微生物群中的未分类lachnospiraceae 有利于将脱镁叶绿素转化为粪卟啉原 a、粪卟啉原 b、15-羟基内酯粪卟啉原 a 和 13-羟基粪卟啉原 a，从而证明脱镁叶绿素中的植醇链丢失。同时，在脱镁叶绿素存在的情况下，微生物发酵过程中总短链脂肪酸以及乙酸、丙酸和丁酸的含量增加。本研究为深入了解不同肠道微生物功能对脱镁叶绿素生物转化的贡献提供了基础。
