Padilla-González Guillermo F, Sadgrove Nicholas J, Ccana-Ccapatinta Gari V, Leuner Olga, Fernandez-Cusimamani Eloy
Jodrell Laboratory, Royal Botanic Gardens, Kew, Kew Road, London TW9 3AB, UK.
AsterBioChem Research Team, Laboratory of Pharmacognosy, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av do café s/n, Ribeirão Preto 14040-903, SP, Brazil.
Metabolites. 2020 Oct 13;10(10):407. doi: 10.3390/metabo10100407.
(yacon) is an edible tuberous Andean shrub that has been included in the diet of indigenous people since before recorded history. The nutraceutical and medicinal properties of yacon are widely recognized, especially for the improvement of hyperglycemic disorders. However, the chemical diversity of the main bioactive series of caffeic acid esters has not been explored in detail. In this metabolomics study, we applied the latest tools to facilitate the targeted isolation of new caffeic acid esters. Using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), we analyzed extracts from different organs (roots, vascular tissues of the stems, stem epidermis, leaves, bracts, and ray flowers) and followed a feature-based molecular networking approach to characterize the structural diversity of caffeic acid esters and recognize new compounds. The analysis identified three potentially new metabolites, one of them confirmed by isolation and full spectroscopic/spectrometric assignment using nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), and MS/MS. This metabolite (5--caffeoyl-2,7-anhydro-d-glycero-β-d-galacto-oct-2-ulopyranosonic acid), along with eight known caffeic acid esters, was isolated from the roots and stems. Furthermore, based on detailed tandem MS analyses, we suggest that the two isomeric monocaffeoyl-2,7-anhydro-2-octulopyranosonic acids found in yacon can be reliably distinguished based on their characteristic MS and MS spectra. The outcome of the current study confirms the utility of feature-based molecular networking as a tool for targeted isolation of previously undescribed metabolites and reveals the full diversity of potentially bioactive metabolites from .
雪莲果是一种可食用的块茎类安第斯灌木，自有历史记载之前就已被纳入当地居民的饮食中。雪莲果的营养保健和药用特性已得到广泛认可，尤其在改善高血糖病症方面。然而，咖啡酸酯主要生物活性系列的化学多样性尚未得到详细探究。在这项代谢组学研究中，我们应用了最新工具来促进新型咖啡酸酯的靶向分离。通过液相色谱-串联质谱联用技术（LC-MS/MS），我们分析了不同器官（根、茎的维管组织、茎表皮、叶、苞片和舌状花）的提取物，并采用基于特征的分子网络方法来表征咖啡酸酯的结构多样性并识别新化合物。分析鉴定出三种潜在的新代谢物，其中一种通过使用核磁共振（NMR）、高分辨率质谱（HRMS）和MS/MS进行分离及全光谱/光谱归属得以确认。这种代谢物（5-咖啡酰-2,7-脱水-D-甘油-β-D-半乳糖-辛-2-酮吡喃糖酸）与八种已知的咖啡酸酯一起从根和茎中分离出来。此外，基于详细的串联质谱分析，我们认为雪莲果中发现的两种异构单咖啡酰-2,7-脱水-2-辛酮吡喃糖酸可根据其特征性的质谱和质谱图可靠地区分。本研究结果证实了基于特征的分子网络作为一种靶向分离先前未描述代谢物的工具的实用性，并揭示了雪莲果潜在生物活性代谢物的全部多样性。
