The extraction of valuable phytochemicals from natural sources is an important and constantly evolving research area. Zingiber officinale Roscoe (ginger) contains high amounts of bioactive phytochemicals, which are desirable due to their significant properties. In this work, the ability of different natural deep eutectic solvents (NaDESs) to serve as green solvents for the preparation of high added value extracts from ginger is explored, in combination with ultrasound assisted extraction. The method was optimized by applying a response surface methodology using the NaDES Bet/La/W (1:2:2.5). Three independent variables, namely the extraction time, ultrasound power and NaDES-to-dry-ginger ratio, were investigated by employing a 17-run three-level Box–Behnken Design (BBD) in order to study the correlation between the extraction conditions and the quality of the obtained extracts. The optimum conditions (in order to achieve simultaneously maximum total phenolic content and antioxidant activity), were found to be 23.8 min extraction time, 60 Watt and NaDES/ginger 25:1 w/w. In the optimum conditions the DPPH radical scavenging ability of the extracts was found to reach IC50 = 18.16 mg/mL after 120 min, whereas the TPC was 20.10 ± 0.26 mg GAE/g of dry ginger. The green methodology was also compared with the extraction using conventional solvents. All the obtained extracts were evaluated for their antioxidant activity and their total phenolic content, while the extract derived by the optimum extraction conditions was further investigated for its ability to bind to calf thymus DNA (ctDNA).

Biocompatible Ionic Liquids (Bio-ILs) are a new class of ILs that are task-specifically designed to derive from naturally occurring compounds and/or derivatives thereof, as well as molecules well known for their biocompatibility (e.g., active pharmaceutical ingredients or non-toxic bioactive compounds) in terms of sustainability and biocompatibility. Owing to their remarkable physicochemical properties that can be tailor made to comply with the requirements of each application, Bio-ILs have emerged as novel, efficient and green technology, appropriate for a vast variety of scientific fields. Herein, this review describes the state-of-the-art scientific research regarding the synthesis, characterization and applications of Bio-ILs reported in the literature for the period between 2020 and 2022.