Quinic acid in its free form is broadly abundant in plants, and can accumulate in copious amounts in coffee, tea, and certain fruits. However, it has been mostly studied as chlorogenic acid, an ester of caffeic and quinic acids. When chlorogenic acid reaches the colon, it is hydrolyzed by microbial esterases releasing caffeic and quinic acids. While biotransformation of chlorogenic and caffeic acids have been elucidated by in vitro and in vivo studies, the gut metabolism of quinic acid has been so far overlooked.

中文翻译：

---

绿原酸的另一种水解产物[U-13C]-奎宁酸的体外肠道代谢

游离形式的奎宁酸在植物中广泛存在，并可以在咖啡，茶和某些水果中大量积累。但是，大多数研究以绿原酸的形式进行，绿原酸是咖啡酸和奎尼酸的酯。当绿原酸到达结肠时，它会被微生物酯酶水解，释放出咖啡酸和奎宁酸。尽管通过体外和体内研究已经阐明了绿原酸和咖啡酸的生物转化，但迄今为止，奎宁酸的肠道代谢一直被忽略。