Deep Eutectic Solvents Based on Carboxylic Acids and Glycerol or Propylene Glycol as Green Media for Extraction of Bioactive Substances from Chamaenerion angustifolium (L.) Scop.

Chamaenerion angustifolium (L.) Scop. is one of the promising sources of biologically active compounds and a valuable industrial crop. Recently, green extraction methods have become more topical. One of them is the application of deep eutectic solvents (DESs). The aim of this work was the synthesis and characterization of DES consisting of glycerin or propylene glycol with malonic, malic, or citric acids, evaluation of their effectiveness for extracting useful substances from C. angustifolium during ultrasonic extraction, description of kinetics, and optimization of extraction conditions. DESs were obtained and characterized with FTIR. Their effectiveness in the process of ultrasound-assisted extraction of biologically active substances from C. angustifolium was estimated. Kinetic parameters describing the dependence of the total phenolic, flavonoids, and antioxidant content, free radical scavenging of DPPH, and concentration of flavonoid aglycons (myricetin, quercetin, and kaempferol) via time in the range of 5-60 min at 45 °C are obtained. Extraction conditions were optimized with the Box-Behnken design of experiment. The results of this work make it possible to expand the scope of DES applications and serve the development of C. angustifolium processing methods.

Application of Natural Deep Eutectic Solvents for Extraction of Bioactive Components from Rhodiola rosea (L.).

Rhodiola rosea (L.) is a valuable source of nutrients. Nutrients have adaptogenic, immunostimulating, nootropic, anti-inflammatory and anti-cancer properties. Natural deep eutectic solvents (NADES) consisting of choline chloride and malonic, malic, tartaric or citric acids have been first used to extract biologically active substances from R. rosea. The total content of polyphenols has been determined by the Folin-Ciocalteu method for all extracts. Antioxidant activity has been determined by the phosphomolybdate method, and antiradical activity has been determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Rosavin concentration has been determined by high-performance liquid chromatography (HPLC). Extraction kinetics has been evaluated regarding the effectiveness of NADES with each other and with reference solvents (water and 50% ethanol) has been made. Extraction conditions have been optimized according to the Box-Behnken design of the experiment. The optimal parameters of the extraction process have been established. The antibacterial activity of NADES-based extracts against bacterial cultures of Micrococcus luteus, Pseudomonas fluorescens, and Bacillus subtilis has been studied.

Extraction of Bioactive Components from Chamaenerion angustifolium (L.) Scop. with Choline Chloride and Organic Acids Natural Deep Eutectic Solvents.

Chamaenerion angustifolium (L.) Scop. (fireweed) is a perennial herbaceous plant of the Onagraceae family widely used in folk and scientific medicine. It is a promising source of bioactive components. One of the modern trends in extraction is the use of natural deep eutectic solvents (NADESs) combined with ultrasound-assisted extraction (UAE). However, works devoted to the extraction of biologically active substances from C. angustifolium using NADESs are scarce. The aim of this work is a comprehensive study of UAE of bioactive components from C. angustifolium using NADESs based on choline chloride and malonic, malic, tartaric, and citric acids. The antioxidative properties, total phenols, and flavonoids content were estimated for NADES-based extracts. The reference solvents were water and 90% v/v ethanol. Volatile extracted components were identified using GC-MS. The kinetics of the UAE were studied at 45 °C for 20-180 min with water added to 30 wt% NADES. The power of the ultrasound was 120 W, and the frequency was 40 kHz. It was found that NADES choline chloride + citric acid is more effective for the extraction of bioactive components. For this, NADES UAE conditions were optimized following a Box-Behnken design of the experiment and a response surface methodology. The temperature ranged from 30 to 60 °C, the time of extraction ranged from 20 to 60, and the addition of water ranged from 30 to 70 wt%. We established the optimal extraction conditions: temperature 58 °C, time of extraction 35 min, and 70 wt% water. The obtained results expand the knowledge about the use of NADES for the extraction of biologically active compounds from cheap and available plant raw materials.

Catalytic Activity of Thermolyzed [Co(NH3)6][Fe(CN)6] in CO Hydrogenation Reaction.

Currently, the processes of obtaining synthetic liquid hydrocarbons and oxygenates are very relevant. Fischer-Tropsch synthesis (FTS) is the most important step in these processes. The products of thermal destruction in argon of the mixture [Co(NH3)6][Fe(CN)6] and Al(OH)3 were used as catalysts for CO hydrogenation. The resulting compositions were studied using powder X-ray diffraction, IR spectroscopy, elemental analysis, SEM micrographs. The specific surface area, pore and particle size distributions were determined. It was determined that the DCS-based catalysts were active in the high-temperature Fischer-Tropsch synthesis. The effect of aluminum in the catalyst composition on the distribution of reaction products was revealed.