Viacava Gabriela E, Roura Sara I, Berrueta Luis A, Iriondo Carmen, Gallo Blanca, Alonso-Salces Rosa M
Grupo de Investigación en Ingeniería en Alimentos, CONICET, Departamento de Ingeniería Química y en Alimentos, Facultad de Ingeniería, Universidad Nacional de Mar del Plata, Juan B. Justo 4302, 7600, Mar del Plata, Argentina.
Grupo de Investigación de Química Analítica de Productos Naturales, Departamento de Química Analítica, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), P.O. Box 644, 48080, Bilbao, Spain.
J Mass Spectrom. 2017 Dec;52(12):873-902. doi: 10.1002/jms.4021.
Lettuce (Lactuca sativa) is one of the most popular leafy vegetables in the world and constitutes a major dietary source of phenolic compounds with health-promoting properties. In particular, the demand for green and red oak-leaf lettuces has considerably increased in the last years but few data on their polyphenol composition are available. Moreover, the usage of analytical edge technology can provide new structural information and allow the identification of unknown polyphenols. In the present study, the phenolic profiles of green and red oak-leaf lettuce cultivars were exhaustively characterized by ultrahigh-performance liquid chromatography (UHPLC) coupled online to diode array detection (DAD), electrospray ionization (ESI), and quadrupole time-of-flight mass spectrometry (QToF/MS), using the MS instrument acquisition mode for recording simultaneously exact masses of precursor and fragment ions. One hundred fifteen phenolic compounds were identified in the acidified hydromethanolic extract of freeze-dried lettuce leaves. Forty-eight of these compounds were tentatively identified for the first time in lettuce, and only 20 of them have been previously reported in oak-leaf lettuce cultivars in literature. Both oak-leaf lettuce cultivars presented similar phenolic composition, except for apigenin-glucuronide and dihydroxybenzoic acid, only detected in the green cultivar; and for luteolin-hydroxymalonylhexoside, an apigenin conjugate with molecular formula C H O (monoisotopic MW = 838.3259 u), cyanidin-3-O-glucoside, cyanidin-3-O-(3″-O-malonyl)glucoside, cyanidin-3-O-(6″-O-malonyl)glucoside, and cyanidin-3-O-(6″-O-acetyl)glucoside, only found in the red cultivar. The UHPLC-DAD-ESI-QToF/MS approach demonstrated to be a useful tool for the characterization of phenolic compounds in complex plant matrices.
生菜（Lactuca sativa）是世界上最受欢迎的叶菜类蔬菜之一，是具有促进健康特性的酚类化合物的主要饮食来源。特别是，近年来对绿色和红色橡叶生菜的需求大幅增加，但关于它们多酚成分的数据却很少。此外，使用先进的分析技术可以提供新的结构信息，并有助于鉴定未知的多酚。在本研究中，通过超高效液相色谱（UHPLC）在线连接二极管阵列检测（DAD）、电喷雾电离（ESI）和四极杆飞行时间质谱（QToF/MS），对绿色和红色橡叶生菜品种的酚类特征进行了详尽的表征，使用质谱仪采集模式同时记录前体离子和碎片离子的精确质量。在冻干生菜叶的酸化甲醇提取物中鉴定出115种酚类化合物。其中48种化合物首次在生菜中被初步鉴定，而其中只有20种先前在文献中的橡叶生菜品种中被报道过。除了仅在绿色品种中检测到的芹菜素 - 葡萄糖醛酸苷和二羟基苯甲酸，以及仅在红色品种中发现的木犀草素 - 羟基丙二酰己糖苷、一种分子式为C H O（单同位素分子量 = 838.3259 u）的芹菜素共轭物、花青素 - 3 - O - 葡萄糖苷、花青素 - 3 - O -（3″ - O - 丙二酰基）葡萄糖苷、花青素 - 3 - O -（6″ - O - 丙二酰基）葡萄糖苷和花青素 - 3 - O -（6″ - O - 乙酰基）葡萄糖苷外，两种橡叶生菜品种呈现出相似的酚类组成。UHPLC - DAD - ESI - QToF/MS方法被证明是表征复杂植物基质中酚类化合物的有用工具。
