Hofmann Tamás, Nebehaj Esztella, Albert Levente
University of West-Hungary, Faculty of Forestry, Institute of Chemistry, Bajcsy-Zsilinszky u. 4, 9400 Sopron, Hungary.
University of West-Hungary, Faculty of Forestry, Institute of Chemistry, Bajcsy-Zsilinszky u. 4, 9400 Sopron, Hungary.
J Chromatogr A. 2015 May 8;1393:96-105. doi: 10.1016/j.chroma.2015.03.030. Epub 2015 Mar 19.
The aim of the present work was the high-performance liquid chromatographic separation and multistage mass spectrometric characterization of the polyphenolic compounds of beech bark, as well as the extraction optimization of the identified compounds. Beech is a common and widely used material in the wood industry, yet its bark is regarded as a by-product. Using appropriate extraction methods these compounds could be extracted and utilized in the future. Different extraction methods (stirring, sonication, microwave assisted extraction) using different solvents (water, methanol:water 80:20 v/v, ethanol:water 80:20 v/v) and time/temperature schedules have been compared basing on total phenol contents (Folin-Ciocâlteu) and MRM peak areas of the identified compounds to investigate optimum extraction efficiency. Altogether 37 compounds, including (+)-catechin, (-)-epicatechin, quercetin-O-hexoside, taxifolin-O-hexosides (3), taxifolin-O-pentosides (4), B-type (6) and C-type (6) procyanidins, syringic acid- and coumaric acid-di-O-glycosides, coniferyl alcohol- and sinapyl alcohol-glycosides, as well as other unknown compounds with defined M-H m/z values and MS/MS spectra have been tentatively identified. The choice of the method, solvent system and time/temperature parameters favors the extraction of different types of compounds. Pure water can extract compounds as efficiently as mixtures containing organic solvents under high-pressure and high temperature conditions. This supports the implementation of green extraction methods in the future. Extraction times that are too long and high temperatures can result in the decrease of the concentrations. Future investigations will focus on the evaluation of the antioxidant capacity and utilization possibilities of the prepared extracts.
本研究的目的是对山毛榉树皮中的多酚类化合物进行高效液相色谱分离和多级质谱表征，并对鉴定出的化合物进行提取优化。山毛榉是木材工业中常用的一种常见材料，但其树皮被视为副产品。使用适当的提取方法，这些化合物将来可以被提取和利用。基于总酚含量（福林-西奥尔特法）和鉴定出的化合物的多反应监测（MRM）峰面积，比较了使用不同溶剂（水、甲醇:水80:20 v/v、乙醇:水80:20 v/v）以及不同时间/温度方案的不同提取方法（搅拌、超声、微波辅助提取），以研究最佳提取效率。总共初步鉴定出37种化合物，包括（+）-儿茶素、（-）-表儿茶素、槲皮素-O-己糖苷、花旗松素-O-己糖苷（3种）、花旗松素-O-戊糖苷（4种）、B型（6种）和C型（6种）原花青素、丁香酸和香豆酸二-O-糖苷、松柏醇和芥子醇糖苷，以及其他具有确定的M-H m/z值和MS/MS光谱的未知化合物。方法、溶剂体系和时间/温度参数的选择有利于不同类型化合物的提取。在高压和高温条件下，纯水能够与含有有机溶剂的混合物一样高效地提取化合物。这支持了未来绿色提取方法的实施。提取时间过长和温度过高会导致浓度降低。未来的研究将集中于对所制备提取物的抗氧化能力和利用可能性的评估。
