Background Secoisolariciresinol di glucoside (SDG) is a natural antioxidant generally extracted from flaxseed, which is one of the most important oil crops in China, the by-product of the flaxseed oil, i.e., flaxseed meal, still contains a lot of lignans. However, flaxseed meal is generally treated as waste, resulting in a huge waste of resources. Objective To establish an efficient and convenient method for extraction and purification of lignans from flaxseed meal. Methods First, we used response surface methodology (RSM) to optimize the extraction conditions of the ultrasonic-assisted aqueous two-phase system (UAATPS), and we obtained the purified extracts by macroporous resin purification (MRP). Second, the antioxidant ability of the extracts was studied in vitro. Results The best extraction conditions obtained were as follows: 9.0 wt% sodium hydroxide, 30.0 wt% isopropanol, extraction time 39 min, liquid-to-solid ratio of 52.0 mL/g, ultrasonic wave 560 W, and extraction temperature 40 °C. Under the optimal conditions, the purity of crude extracts (SDG-APTS-C) reached 21.5%. The desorption conditions of MRP were as follows: eluting 3 BV with ultrapure water, and then eluting with 25% ethanol at 2 BV/h to collect eluents. The purified extracts (SDG-ATPS-P) had a purity quotient of 73.9%, 52.4% higher than that of SDG-ATPS-C. Additionally, experiments conducted in this paper revealed that SDG-ATPS-C and SDG-ATPS-P could effectively remove DPPH, ABTS, and hydroxyl free radicals in vitro. Conclusions The method was validated for extracting SDG from flaxseed meal, thus achieving the reuse of flaxseed meal. Highlights This research provides some references for the application of UAATPS combined with MRP in natural products.

中文翻译：

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超声辅助水相两相萃取结合大孔树脂富集亚麻粕木脂素及其抗氧化活性

背景技术 Secoisolariciresinol di glucoside (SDG) 是一种天然抗氧化剂，一般从亚麻籽中提取，亚麻籽是我国最重要的油料作物之一，亚麻籽油的副产品亚麻籽粕中仍含有大量木脂素。然而，亚麻籽粉一般被当作废物处理，造成了巨大的资源浪费。目的建立一种高效、简便的亚麻粕中木脂素提取纯化方法。方法首先采用响应面法（RSM）优化超声辅助水相两相体系（UAATPS）的提取条件，通过大孔树脂纯化（MRP）得到纯化的提取物。其次，在体外研究了提取物的抗氧化能力。结果获得的最佳提取条件如下： 9. 0 wt%氢氧化钠，30.0 wt%异丙醇，提取时间39 min，液固比52.0 mL/g，超声波560 W，提取温度40 °C。在最佳条件下，粗提物（SDG-APTS-C）的纯度达到21.5%。MRP的解吸条件如下：用超纯水洗脱3 BV，然后用25%乙醇以2 BV/h的速度洗脱收集洗脱液。纯化的提取物（SDG-ATPS-P）的纯度商为73.9%，比SDG-ATPS-C高52.4%。此外，本文进行的实验表明，SDG-ATPS-C 和 SDG-ATPS-P 在体外可以有效去除 DPPH、ABTS 和羟基自由基。结论 该方法验证了从亚麻粕中提取SDG的方法，实现了亚麻粕的再利用。