Novel extraction of polyphenols from sour cherry pomace using natural deep eutectic solvents - Ultrafast microwave-assisted NADES preparation and extraction.

In this work, new approaches for the green extraction of polyphenols from sour cherry pomace were explored. Three Natural Deep Eutectic Solvents (NADES) systems based on choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and malic acid, urea, and fructose (MalA, Ur, and Fru) as hydrogen bond donors (HBD) were used. NADES systems were prepared by heating and stirring (H&S), ultrasound (US), and microwave (MW) methods. It was found that MW-assisted preparation was the fastest requiring less than 30 s. Polyphenol extraction from cherry pomace was performed also by three mentioned methods, and compared with conventional methods. MW extraction was the most rapid with less than 5 min necessary for the extract preparation. All three NADES systems were highly efficient for anthocyanin extraction, but the most efficient was ChCl:MalA system. Extract based on ChCl:MalA system was for 62.33% more efficient for anthocyanin extraction comparing with the conventional solvent.

Medicinal Plants Extracts Impact on Oxidative Stress in Mice Brain Under the Physiological Conditions: the Effects of Corn Silk, Parsley, and Bearberry.

This study was performed to examine the effects of medicinal plant extracts of corn silk (Stigma maydis), parsley leaf (Petroselini folium), and bearberry leaf (Uvae ursi folium) on antioxidant status of the brain of experimental animals (mice) under the physiological conditions. Biological properties of these plants are insufficiently investigated and the aim was to explore their possible antioxidant effects that can alleviate oxidative damage of the brain tissue. Corn silk extract showed positive effect on activities of antioxidant enzymes in mice brain tissue. Parsley extract induced the increase in glutathione content and decrease of lipid peroxidation. Bearberry leaf extract induced catalase activity and decrease of hydroxyl radical content, while malonyldialdehide accumulation was maintained at the control level. Results obtained in this study support the use of corn silk, parsley and bearberry leaves as natural antioxidant sources in the prevention and treatment of brain tissue damages and different diseases caused by oxidative stress.

The evaluation of phenolic content, in vitro antioxidant and antibacterial activity of Mentha piperita extracts obtained by natural deep eutectic solvents.

The focus of this study was to evaluate whether six choline chloride-based natural deep eutectic solvents (NADES) could serve as solvents for the extraction of bioactives from the leaves of Mentha piperita. NADES extracted significantly higher amounts of phenols from peppermint than 70% ethanol and may be useful in the extraction of targeted major compounds from peppermint, like rosmarinic acid, at a similar level as 70% ethanol. The microdilution method for in vitro antibacterial activity showed that all NADES exhibit bacterial growth inhibition at a lower concentration than 70% ethanol, especially NADESs containing organic acids. The majority of NADES extracts neutralize DPPH radical at a lower concentration than conventional solvent and showed similar ability to reduce Fe3+ to Fe2+ ions in FRAP assay. NADES can be useful in the isolation of phenolic compounds from plant sources and should be considered as novel, sustainable, and low-cost solvents with a variety of applications.