College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China.
School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, China.
Molecules. 2019 Aug 5;24(15):2842. doi: 10.3390/molecules24152842.
The leaf (AL) has been used as a traditional medicine and food supplement in China and other Asian countries for hundreds of years. Phytochemical studies disclosed that AL contains various bioactive constituents. Among bioactive constituents, phenolic acids have been recognized as the main active compounds in AL. To the best of our knowledge, no research has been focused on extraction method for the bioactive phenolic acids from AL. Nowadays, deep eutectic solvents (DESs) are emerging as a new type of green and sustainable solvent for efficient extraction of bioactive compounds from natural products. In the present study, an environmentally friendly extraction method based on DESs was established to extract bioactive phenolic acids from ALs. Diverse tailor-made solvents, including binary and ternary DESs, were explored for simultaneous extraction of four phenolic acids (3-caffeoylquinic acid, 3,4-di--caffeoylquinic acid, 3,5-di--caffeoylquinic acid, and 4,5-di--caffeoylquinic acid) from AL. The results indicated that the ternary DES composed of a 2:1:2 molar ratio of choline chloride, malic acid, and urea showed enhanced extraction yields for phenolic acids compared with conventional organic solvents and other DESs. Subsequently, the extraction parameters for the four phenolic acids by selected tailor-made DESs, including liquid-solid ratios, water content (%) in the DESs, and extraction time, were optimized using response surface methodology and the optimal extraction conditions were: extraction time, 23.5 min; liquid-solid ratio, 57.5 mL/g (mL of DES/g dry weight of plant material); water content, 54%. The research indicated that DESs were efficient and sustainable green extraction solvents for extraction of bioactive phenolic acids from natural products. Compared to the conventional organic solvents, the DESs have a great potential as possible alternatives to those organic solvents in health-related areas such as food and pharmaceuticals.
该叶（AL）已在中国和其他亚洲国家被用作传统药物和食品补充剂数百年。植物化学研究表明，AL 含有各种生物活性成分。在这些生物活性成分中，酚酸已被认为是 AL 的主要活性化合物。据我们所知，目前还没有研究专注于从 AL 中提取生物活性酚酸的方法。如今，深共晶溶剂（DESs）作为一种新型的绿色可持续溶剂，正被用于从天然产物中高效提取生物活性化合物。在本研究中，建立了一种基于 DESs 的环保提取方法，用于从 AL 中提取生物活性酚酸。探索了多种定制的溶剂，包括二元和三元 DESs，用于同时从 AL 中提取四种酚酸（3-咖啡酰奎宁酸、3,4-二咖啡酰奎宁酸、3,5-二咖啡酰奎宁酸和 4,5-二咖啡酰奎宁酸）。结果表明，与传统有机溶剂和其他 DESs 相比，由氯化胆碱、苹果酸和尿素以 2:1:2 摩尔比组成的三元 DES 对酚酸的提取收率更高。随后，使用响应面法优化了所选定制 DES 提取四种酚酸的提取参数，包括液固比、DES 中的含水量（%）和提取时间，最佳提取条件为：提取时间 23.5 分钟；液固比 57.5 mL/g（DES 体积/mL 干重植物材料）；含水量 54%。研究表明，DES 是从天然产物中提取生物活性酚酸的高效、可持续的绿色提取溶剂。与传统有机溶剂相比，DES 作为食品和制药等健康相关领域替代有机溶剂具有很大的潜力。
