Combination of Lactic Acid-Based Deep Eutectic Solvents (DES) with β-Cyclodextrin: Performance Screening Using Ultrasound-Assisted Extraction of Polyphenols from Selected Native Greek Medicinal Plants

Abstract

Abstract:A series of novel L-lactic acid-based deep eutectic solvents (DES) were tested for polyphenol extraction performance, using organically grown, native Greek medicinal plants. The extractions were ultrasonically-assisted and the effect of the addition of β-cyclodextrin (β-CD) as extraction booster was also tested, at a concentration of 1.5% (w/v). The estimation of total polyphenol yield (Y TP ) suggested that DES composed of L-lactic acid and nicotinamide and L-lactic acid and L-alanine, both at a molar ratio of 7:1, are promising solvents giving significantly higher yields compared with 60% (v/v) aqueous ethanol and water. However, when β-CD was combined with DES comprised of L-lactic acid and ammonium acetate (molar ratio 7:1), the extraction yields obtained in some instances were equal of even higher. The pattern was not consistent when the yield in total flavonoids (Y TFn ) was considered, indicating water, 60% (v/v) aqueous ethanol and L-lactic acid:sodium acetate (molar ratio 7:1) to be the most efficient solvents. In this case, the effect of β-CD was of rather lower magnitude. The examination of the antioxidant activity of the extracts generated showed that there is a close correlation mainly with their concentration in total polyphenols.

Assessment of Ultrasound Assisted Extraction as an Alternative Method for the Extraction of Anthocyanins and Total Phenolic Compounds from Maqui Berries (Aristotelia chilensis (Mol.) Stuntz)

“…When the above-mentioned optimal conditions were applied, the total average concentrations of anthocyanins and phenolic compounds were 33.02 mg g −1 and 50.26 mg g −1 , respectively. Similar results were reported by other authors in some vegetable matrices [8,56]. It can be observed that the main phenolic compounds that are present in maqui berries are anthocyanins, unlike many other berries that have less anthocyanin content in comparison with the total phenolic compounds.…”

The Effect of Ultrasonication Pretreatment on the Production of Polyphenol-Enriched Extracts from Moringa oleifera L. (Drumstick Tree) Using a Novel Bio-Based Deep Eutectic Solvent

“…mol ) The use of nicotinamide as HBA in L-lactic acid-based DES has been recently reported for the first time [24]; however, the use of glycerol as HBD in combination with nicotinamide as HBA, to the best of the authors' knowledge, is heretofore unreported. When designing a DES, the role of R D/A mol in the polyphenol extraction performance is salient [19,25], and therefore, an initial screening of DES with varying R D/A mol was deemed essential in identifying the highest-performing combination.…”

Deep Eutectic Solvents as Extraction Media for Valuable Flavonoids from Natural Sources

“…Other additives can be added to assist the extraction of a substance or any other action, however, similarly to the ternary systems, any addition may promote or hamper an extraction, depending on the target. An example by Georgantzi et al [47] shows that the addition of β-cyclodextrin alters the extractability of select flavonoids depending on the selected DES, benefiting one but worsening the other, with varying levels of significance based on the miscellaneous parameters of the extraction.…”