Ciardi Matteo, Ianni Federica, Sardella Roccaldo, Di Bona Stefano, Cossignani Lina, Germani Raimondo, Tiecco Matteo, Clementi Catia
Department of Chemistry, Biology and Biotecnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
Department of Pharmaceutical Sciences, University of Perugia, Via Fabretti 48, 06123 Perugia, Italy.
Materials (Basel). 2021 Oct 28;14(21):6465. doi: 10.3390/ma14216465.
Deep Eutectic Solvents (DESs) are experiencing growing interest as substitutes of polluting organic solvents for their low or absent toxicity and volatility. Moreover, they can be formed with natural bioavailable and biodegradable molecules; they are synthesized in absence of hazardous solvents. DESs are, inter alia, successfully used for the extraction/preconcentration of biofunctional molecules from complex vegetal matrices. Onion skin is a highly abundant waste material which represents a reservoir of molecules endowed with valuable biological properties such as quercetin and its glycosylated forms. An efficient extraction of these molecules from dry onion skin from "Dorata di Parma" cultivar was obtained with water dilution of acid-based DESs. Glycolic acid (with betaine 2/1 molar ratio and L-Proline 3/1 molar ratio as counterparts) and of -toluensulphonic acid (with benzyltrimethylammonium methanesulfonate 1/1 molar ratio)-based DESs exhibited more than 3-fold higher extraction efficiency than methanol (14.79 µg/mL, 18.56 µg/mL, 14.83 µg/mL vs. 5.84 µg/mL, respectively). The extracted quercetin was also recovered efficaciously (81% of recovery) from the original extraction mixture. The proposed extraction protocol revealed to be green, efficacious and selective for the extraction of quercetin from onion skin and it could be useful for the development of other extraction procedures from other biological matrixes.
低共熔溶剂（DESs）因其低毒性或无毒性以及低挥发性，作为污染性有机溶剂的替代品正受到越来越多的关注。此外，它们可以由天然可生物利用和可生物降解的分子形成；它们是在无有害溶剂的情况下合成的。DESs尤其成功地用于从复杂的植物基质中提取/预浓缩生物功能分子。洋葱皮是一种非常丰富的废料，它是具有宝贵生物学特性的分子的储存库，如槲皮素及其糖基化形式。用酸基DESs的水稀释液从“多拉塔迪帕尔马”品种的干洋葱皮中高效提取了这些分子。基于乙醇酸（与甜菜碱的摩尔比为2/1，与L-脯氨酸的摩尔比为3/1）和对甲苯磺酸（与甲磺酸苄基三甲基铵的摩尔比为1/1）的DESs的提取效率比甲醇高出3倍以上（分别为14.79μg/mL、18.56μg/mL、14.83μg/mL对5.84μg/mL）。从原始提取混合物中也能有效地回收提取的槲皮素（回收率为81%）。所提出的提取方案被证明是绿色、有效且具有选择性的，可用于从洋葱皮中提取槲皮素，并且可能有助于开发从其他生物基质中提取的其他方法。
