Department of Analytical Chemistry, Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
Department of Horticulture, Faculty of Biotechnology and Horticulture, Hugo Kołłątaj University of Agriculture, 29 Listopada 54, 31-425 Kraków, Poland.
Int J Mol Sci. 2020 Nov 22;21(22):8834. doi: 10.3390/ijms21228834.
Herein, the generation of decarboxylated derivatives of gomphrenin pigments exhibiting potential health-promoting properties and the kinetics of their extraction during tea brewing from the purple flowers of L. in aqueous and aqueous citric acid solutions were investigated. Time-dependent concentration monitoring of natural gomphrenins and their tentative identification was carried out by LC-DAD-ESI-MS/MS. The high content of acylated gomphrenins and their principal decarboxylation products, 2-, 15-, 17-decarboxy-gomphrenins, along with minor levels of their bidecarboxylated derivatives, were reported in the infusions. The identification was supported by the determination of molecular formulas of the extracted pigments by liquid chromatography coupled with high-resolution mass spectrometry (LCMS-IT-TOF). The influence of plant matrix on gomphrenins' stability and generation of their derivatives, including the extraction kinetics, was determined by studying the concentration profiles in the primary and diluted infusions. Isolated and purified acylated gomphrenins from the same plant material were used for the preliminary determination of their decarboxylated derivatives. The acylated gomphrenins were found to be more stable than nonacylated ones. Citric acid addition had a degradative influence on natural gomphrenins mainly during the longer tea brewing process (above 15 min); however, the presence of plant matrix significantly increased the stability for betacyanins' identification.
本研究旨在探讨从紫花 L. 的花瓣中提取具有潜在保健功能的去羧基化糖苷酮色素衍生物的方法，并考察其在茶水中的提取动力学。通过 LC-DAD-ESI-MS/MS 对天然糖苷酮及其潜在结构进行了时变浓度监测和鉴定。研究结果表明，在茶汤中检测到了高含量的酰化糖苷酮及其主要的去羧基化产物 2-、15-和 17-去羧基糖苷酮，以及少量的双去羧基化衍生物。通过液相色谱-高分辨质谱联用（LCMS-IT-TOF）测定提取色素的分子式，为鉴定结果提供了支持。通过研究原始和稀释茶汤中糖苷酮的浓度变化，确定了植物基质对糖苷酮稳定性和衍生物生成的影响，包括提取动力学。从同一植物材料中分离和纯化的酰化糖苷酮用于初步确定其去羧基化衍生物。研究结果表明，酰化糖苷酮比非酰化糖苷酮更稳定。柠檬酸的加入主要在较长的泡茶过程中（超过 15 分钟）对天然糖苷酮有降解作用；然而，植物基质的存在显著提高了 betacyanins 的鉴定稳定性。
