Characterization of the Phytochemical Profile of Halophytes (Limonium Mill., Plumbaginaceae) with Natural Deep Eutectic Solvents Extraction

<i>Limonium</i> Mill. (Plumbaginaceae) is a genus comprising many species, some of which are reported to possess high bioactivity and are used as food, medicinal herbs, and fodder. Here we report the use of different deep eutectic solvents (DESs) and natural DESs (NADESs) to study the phytochemical composition of plants of the genus <i>Limonium</i> Mill. Most of the organic solvents commonly used for extracting phytochemicals from plants are hazardous to health and may harm the environment. Hence, their replacement with environmentally friendly solvents, particularly NADESs, is desirable. We performed ultrasound-assisted extractions of aerial parts of <i>Limonium</i> species using these solvents, followed by characterization of the phytochemicals with liquid chromatography with high-resolution mass spectrometry. Gallic acid and myricetin derivatives accounted for approximately 60 and 27% of all the compounds, respectively, therefore representing more than 80% of the characterized compounds in the analyzed plants. The best extraction yield for both flavonoids and organic acids was achieved using the NADES chloride choline/ethylene glycol (ratio 1:3), improving the recoveries by approximately 20% compared to the use of methanol and methanol/water mixtures. These results indicate the possibility of replacing conventional organic solvents with more environmentally friendly ones, reducing the use of toxic solvents and improving the sample treatment. In addition, possible new <i>Limonium</i> plant species were studied in the south of Spain with the optimized method.