Lores Marta, Pájaro Marta, Álvarez-Casas Marta, Domínguez Jorge, García-Jares Carmen
Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química. Universidade de Santiago de Compostela, Avda. das Ciencias s/n, Campus Vida, E-15782 Santiago de Compostela, Spain.
Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química. Universidade de Santiago de Compostela, Avda. das Ciencias s/n, Campus Vida, E-15782 Santiago de Compostela, Spain.
Talanta. 2015 Aug 1;140:134-142. doi: 10.1016/j.talanta.2015.03.034. Epub 2015 Mar 27.
An important trend in the extraction of chemical compounds is the application of new environmentally friendly, food grade solvents. Ethyl lactate (ethyl 2-hydroxypropanoate), produced by fermentation of carbohydrates, is miscible with both hydrophilic and hydrophobic compounds being a potentially good solvent for bioactive compounds. Despite its relatively wide use as a general solvent, the utilization of ethyl lactate as an extraction solvent has only recently been considered. Here, we evaluate the possible use of ethyl lactate to extract phenolic compounds from wild plants belonging to Cytisus scoparius, and we compare the characteristics of the extracts obtained by Pressurized Solvent Extraction (the total phenolics content, the antioxidant activity and the concentration of the major polyphenols) with those of other extracts obtained with methanol. In order to explore the industrial production of the ethyl lactate Cytisus extract, we also evaluate medium scale ambient temperature setups. The whole plant and the different parts (flowers, branches, and seed pods) were evaluated separately as potential sources of polyphenols. All extracts were analyzed by LC-MS/MS for accurate identification of the major polyphenols. Similar phenolic profiles were obtained when using ethyl lactate or methanol. The main bioactives found in the Cytisus extract were the non-flavonoid phenolic compounds caffeic and protocatechuic acids and 3,4-dihydroxybenzaldehyde; the flavonoids rutin, kaempferol and quercetin; the flavones chrysin, orientin and apigenin; and the alkaloid lupanine. Regarding the comparison of the extraction systems, although the performance of the PLE was much better than that of the ambient-temperature columns, the energy consumption was also much higher. Ethyl lactate has resulted an efficient extraction solvent for polyphenols from C. scoparius, yielding extracts with high levels of plant phenolics and antioxidant activity. The antimicrobial activity of these extracts was also tested, showing antibacterial activity against Gram +ve bacteria. Qualitatively similar extracts were obtained either by using PLE or medium-scale-ambient-temperature systems, these last rendering larger volumes of extract with lower energy cost. Good results have been obtained with whole plant extracts; nevertheless, extracts enriched in a particular polyphenol can be obtained from different parts of the plant.
在化合物提取方面，一个重要趋势是应用新型环保型食品级溶剂。由碳水化合物发酵产生的乳酸乙酯（2 - 羟基丙酸乙酯），既能与亲水性化合物混溶，又能与疏水性化合物混溶，是一种对生物活性化合物而言潜在的优良溶剂。尽管乳酸乙酯作为一种通用溶剂已得到较为广泛的应用，但将其用作提取溶剂的研究只是最近才受到关注。在此，我们评估了乳酸乙酯从野生金雀花中提取酚类化合物的可能性，并将通过加压溶剂萃取法获得的提取物（总酚含量、抗氧化活性和主要多酚的浓度）的特性与用甲醇获得的其他提取物的特性进行了比较。为了探索乳酸乙酯金雀花提取物的工业化生产，我们还评估了中试规模的常温装置。分别对整株植物以及不同部位（花、枝和豆荚）作为多酚潜在来源进行了评估。所有提取物均通过液相色谱 - 串联质谱法进行分析，以准确鉴定主要多酚。使用乳酸乙酯或甲醇时获得了相似的酚类谱图。在金雀花提取物中发现的主要生物活性成分有非黄酮类酚类化合物咖啡酸、原儿茶酸和3,4 - 二羟基苯甲醛；黄酮类化合物芦丁、山奈酚和槲皮素；黄酮类化合物白杨素、异荭草素和芹菜素；以及生物碱金雀花碱。关于提取系统的比较，尽管加压液体萃取法的性能比常温柱法要好得多，但其能耗也高得多。乳酸乙酯已被证明是从金雀花中提取多酚的有效溶剂，所得到的提取物含有高水平的植物酚类和抗氧化活性。还测试了这些提取物的抗菌活性，结果表明其对革兰氏阳性菌具有抗菌活性。无论是通过加压液体萃取法还是中试规模的常温系统，都获得了定性相似的提取物，后者能以较低的能源成本得到更大体积的提取物。整株植物提取物取得了良好的结果；然而，从植物的不同部位可以获得富含特定多酚的提取物。
