Abstract Lots of minor constituents in herbal medicines have shown great potential to devolve into lead compounds, and their extraction is attracting more and more attention in pharmaceutical industry. This study provided an example that showed efficient and selective extraction of minor bioactive natural products (prenylated flavonoids with anti-cancer activities) from an herbal medicine (licorice) using pure ionic liquids as green solvents. After investigation of a variety of hydrophobic ionic liquids with ultrasonic-assisted extraction, we found that [C8MIM]BF4 (1-octyl-3-methylimidazolium tetrafluoroborate) was the most effective one for extraction of five representative compounds (isoangustone A, glycycoumarin, licoisoflavanone, licoricidin and glabridin), and solvent to solid ratio, extraction time, extraction temperature and soaking time were then optimized through single-factor experiments and response surface methodology. As a result, the established method had significantly higher extraction selectivity than conventional organic solvents, which could be attributed to significant physical change of licorice microstructures after extraction, as well as strong interactions (especially hydrogen bond interactions) between [C8MIM]BF4 and prenylated flavonoids by mechanism study. In addition, 78.92% of the extracted prenylated flavonoids could be readily recovered from [C8MIM]BF4 by using reversed-phase solid phase extraction, and the recyclability of [C8MIM]BF4 was also confirmed.

中文翻译：

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使用纯离子液体高效选择性提取微量生物活性天然产物：在甘草中异戊二烯化黄酮的应用

摘要 中药材中的大量微量成分具有转化为先导化合物的巨大潜力，其提取方法越来越受到制药行业的重视。本研究提供了一个示例，该示例展示了使用纯离子液体作为绿色溶剂从草药（甘草）中高效和选择性地提取少量生物活性天然产物（具有抗癌活性的异戊二烯化黄酮）。通过超声辅助萃取对多种疏水性离子液体进行研究后，我们发现 [C8MIM]BF4（1-octyl-3-methylimidazolium四氟硼酸盐）是萃取五种代表性化合物（异黄酮 A、甘草豆素、甘草异黄酮）最有效的一种。 、甘草苷和光甘草定），以及溶剂固体比、提取时间、然后通过单因素实验和响应面方法优化提取温度和浸泡时间。因此，所建立的方法比常规有机溶剂具有显着更高的提取选择性，这可能归因于提取后甘草微观结构的显着物理变化，以及 [C8MIM]BF4 与异戊二烯化黄酮之间的强相互作用（尤其是氢键相互作用）通过机理研究。此外，78.92% 的异戊二烯化黄酮类化合物可以通过反相固相萃取从 [C8MIM]BF4 中轻松回收，并且 [C8MIM]BF4 的可回收性也得到证实。所建立的方法比常规有机溶剂具有显着更高的提取选择性，这可能归因于提取后甘草微观结构的显着物理变化，以及 [C8MIM]BF4 与异戊二烯化黄酮之间的强相互作用（尤其是氢键相互作用）机制研究。此外，78.92% 的异戊二烯化黄酮类化合物可以通过反相固相萃取从 [C8MIM]BF4 中轻松回收，并且 [C8MIM]BF4 的可回收性也得到证实。所建立的方法比常规有机溶剂具有显着更高的提取选择性，这可能归因于提取后甘草微观结构的显着物理变化，以及 [C8MIM]BF4 与异戊二烯化黄酮之间的强相互作用（尤其是氢键相互作用）机制研究。此外，78.92% 的异戊二烯化黄酮类化合物可以通过反相固相萃取从 [C8MIM]BF4 中轻松回收，并且 [C8MIM]BF4 的可回收性也得到证实。