In order to comprehensively elucidate the chemical biosynthesis process of the beige-scape Gastrodia elata Blume (Wutianma) as a traditional herbal medicines, the untargeted analysis–based UHPLC-PDA-ESI-Q-TOF-MS reveals the metabolites ranging from the skeletons to novel dimers of citric acids in fresh and dried immature/mature stem tubers. Interestingly, two novel types of dimers for citric acids with the anhydride groups at sn-1 and/or sn-5 were discovered in fresh samples. Moreover, the classical mono- versus novel di-mers, and the aglycons versus the glycosides could be easily discriminated by signature fragmentation patterns and some novel adduct ions. The heat map of contents demonstrated more p-hydroxybenzyl metabolites than gastroxyl ones were determined in fresh Wutianma revealing a significant specificity with the lack of the sufficient gastrodin and gastroxyl products in biosynthetic pathway.
... in fresh samples. 2. Experimental. 2.1. Chemicals and reagents. Standard compounds of PA, PB, PC, and parishin E (PE) were purchased from Chengdu Biopurify Phytochemicals Co., Ltd. (Chengdu, China). Rutin (internal standard ...
