The green extraction of bioactive compounds from date seeds was investigated using seven natural deep eutectic solvents (NADES) coupled with ultrasound-assisted extraction (UAE). The seven NADESs mainly consisted of choline chloride as hydrogen bond acceptors (HBA) and four sugars, two organic acids, and one polyalcohol as hydrogen bond donors (HBD) were utilized in this study. When the extraction efficiency of the NADESs was compared to that of the conventional solvents, all the NADESs showed superior bioactive compounds recovery efficacy. The lactic acid-based NADES had the highest extraction efficiency and was further optimized using the response surface method and Box-Behnken design. A four-factors including extraction time (10, 20, and 30 min), ultrasound amplitude (70, 80, and 90 %), % NADES content (30 %, 50 %, and 70 %) and solid-to-solvent ratio (1:30, 1.5:30, and 2:30 g/ml) each at three levels (−1, 0 and 1) using Box-Behnken design was applied. The % NADES content and the solid-to-solvent ratio were the major factors influencing the extraction efficiency of the total phenolic content (TPC) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The optimum extraction conditions included an extraction time of 15 min, ultrasound amplitude of 90 %, % NADES content of 70 % and solid-to-liquid ratio of 1:30 g/ml. The experimental values for TPC and DPPH at optimum extraction conditions were 145.54 ± 1.54 (mg GAE/g powder) and 719.19 ± 2.09 (mmol TE/g powder), respectively. The major phenolic compounds observed in the date seeds extracted using ChCl-LA were 3,4-dihydroxybenzoic acid, catechin and caffeic acid. This study reveals that the extraction of date seeds with NADES in combination with UAE technique was able to recover significantly higher amounts of phenolic compounds which could find useful applications in the food, pharmaceutical, and cosmetics industries.

使用七种天然低共熔溶剂 (NADES) 结合超声辅助提取 (UAE) 研究了从枣子中绿色提取生物活性化合物。七种 NADES 主要由作为氢键受体 (HBA) 的氯化胆碱和四种糖、两种有机酸和一种多元醇作为氢键供体 (HBD) 组成，用于本研究。当将 NADES 的提取效率与传统溶剂的提取效率进行比较时，所有 NADES 都显示出优异的生物活性化合物回收效率。基于乳酸的 NADES 具有最高的提取效率，并使用响应面法和 Box-Behnken 设计进一步优化。提取时间（10、20 和 30 分钟）、超声振幅（70、80 和 90 %）、NADES 含量百分比（30 %、50 %、使用 Box-Behnken 设计在三个水平（-1、0 和 1）下分别应用 70 % 和固溶剂比（1:30、1.5:30 和 2:30 g/ml）。% NADES 含量和固溶剂比是影响总酚含量 (TPC) 提取效率和 1,1-二苯基-2-苦基肼 (DPPH) 自由基清除活性的主要因素。最佳提取条件包括提取时间为 15 分钟，超声振幅为 90%，% NADES 含量为 70%，固液比为 1:30 g/ml。在最佳提取条件下，TPC 和 DPPH 的实验值分别为 145.54 ± 1.54（mg GAE/g 粉末）和 719.19 ± 2.09（mmol TE/g 粉末）。在使用 ChCl-LA 提取的枣子中观察到的主要酚类化合物是 3,4-二羟基苯甲酸、儿茶素和咖啡酸。