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This paper explores the emerging subject of extracting tannins from various plant sources using deep eutectic solvents (DESs). Tannins are widely used in the food and feed industries as they have outstanding antioxidant qualities and greatly enhance the flavor and nutritional content of a wide range of food products. Organic solvents are frequently used in traditional extraction techniques, which raises questions about their safety for human health and the environment. DESs present a prospective substitute because of their low toxicity, adaptability, and environmental friendliness. The fundamental ideas supporting the application of DESs in the extraction of tannins from a range of plant-based materials frequently used in daily life are all well covered in this paper. Furthermore, this paper covers the impact of extraction parameters on the yield of extracted tannins, as well as possible obstacles and directions for future research in this emerging subject. This includes challenges such as high viscosity, intricated recovery of compounds, thermal degradation, and the occurrence of esterification. An extensive summary of the diversity, structure, biosynthesis, distribution, and roles of tannins in plants is given in this paper. Additionally, this paper thoroughly examines various bioactivities of tannins and their metabolites. [ABSTRACT FROM AUTHOR]

Saffron (Crocus sativus) floral by-products are a source of phenolic compounds that can be recovered and used in the nutraceutical, pharmaceutical, or cosmetic industries. This study aimed to evaluate the phenolic compounds' extraction using green extraction techniques (GETs) in saffron floral by-products and to explore the influence of selected extraction techniques on the phytochemical composition of the extracts. Specifically, ultrasound-assisted extraction (UAE), subcritical water extraction (SWE), and deep eutectic solvents extraction (DESE) were used. Phenolic compounds were identified with (HR) LC-ESI-QTOF MS/MS analysis, and the quantitative analysis was performed with HPLC-PDA. Concerning the extraction techniques, UAE showed the highest amount for both anthocyanins and flavonoids with 50:50% v/v ethanol/water as solvent (93.43 ± 4.67 mg/g of dry plant, dp). Among SWE, extraction with 96% ethanol and t = 125 °C gave the best quantitative results. The 16 different solvent mixtures used for the DESE showed the highest amount of flavonoids (110.95 ± 5.55–73.25 ± 3.66 mg/g dp), while anthocyanins were better extracted with choline chloride:butane-1,4-diol (16.0 ± 0.80 mg/g dp). Consequently, GETs can be employed to extract the bioactive compounds from saffron floral by-products, implementing recycling and reduction of waste and fitting into the broader circular economy discussion. [ABSTRACT FROM AUTHOR]

Global food waste has a huge impact on the environment, as it is a source of greenhouse gas emissions and wasted natural resources. Across the world, over 30% of food is lost or wasted each year. Aside from this, the food industry, as well, is one of the biggest sources of agro-industrial waste and by-products, which can be valorized and used for different purposes. Such waste is a good source of bioactive organic compounds that can be extracted without altering their properties, where deep eutectic solvents can serve as green solvents and as an excellent replacement for volatile organic solvents. Isolated compounds can be used in innovative food production, chemical production, cosmetics and other industries. Deep eutectic solvents have attracted extraordinary attention due to their advantages such as environmental friendliness, availability and easy preparation, easy handling and utilization of non-toxic components for their formation. Due to these properties, they are a greener alternative to classic organic solvents for many processes, including extractions. In this paper, we review the utilization of deep eutectic solvents as potential green media for the extraction of organic compounds such as polyphenols, carbohydrates, proteins and alkaloids from by-products of the food industry and from agro-industrial waste. [ABSTRACT FROM AUTHOR]

The development of an appropriate delivery system of active pharmaceutical ingredients (APIs) is an absolute necessity in the treatment of different diseases. Recently, DESs have been intensively studied for the purpose of improved API delivery. As a part of our continuous investigations in this particular field, we have prepared and characterized two new deep eutectic solvents with pharmaceutically active ingredients. Lidocaine (Lid), 7-hydroxy-4-methylcoumarin (Cou) and lactic (La) or levulinic (Le) acid were used for the preparation of the desired DESs. Both solvents were characterized by different methods in order to determine their physical and chemical properties. The water content determined by Karl–Fischer titration is 1.02% and 1.66%, respectively, while the polarity of both solvents is between the polarity of water and methanol. NMR and IR studies indicate the presence of Cou in the deprotonated (anionic) form, Lid in both neutral and protonated forms, and acids in the neutral form. Spectroscopic studies indicate the presence of strong O–H⋯O and C–O⋯H hydrogen bonds in both DESs. In silico methods provided a deeper insight into the complex intermolecular interaction patterns between the components of the prepared deep eutectic solvents. The thermal analysis indicates that these solvents can be considered as DESs with high thermal stability. [ABSTRACT FROM AUTHOR]

A green chemistry method was applied in the synthesis of N2,N6-bis(6-iodo-2-methyl-4-oxoquinazolin-3(4H)-yl)pyridine-2,6-dicarboxamide. The desired compound was synthesized mechanochemically, using a choline chloride-based deep eutectic solvent as a catalyst. The synthesis took 20 min and the new compound was characterized using different spectral methods. [ABSTRACT FROM AUTHOR]

The Menshutkin reaction represents the alkylation of tertiary amines by alkyl halide where the reactants are neutral and the products, quaternary ammonium salts, are two ions with opposite signs. The most commonly used organic solvents in quaternization reactions are volatile organic solvents (VOSs), namely acetone, anhydrous benzene, dry dichloromethane (DCM), dimethylformamide (DMF) and acetonitrile (ACN). The purpose of this work was to examine eutectic solvents as a "greener" alternative to conventional solvents so that quaternization reactions take place in accordance with the principles of green chemistry. Herein, sixteen eutectic solvents were used as replacements for volatile organic ones in quaternization reactions of isonicotinamide with substituted phenacyl bromides. The reactions were carried out at 80 °C by three synthetic approaches: conventional (4–6 h), microwave (20 min) and ultrasound (3 h). Microwave-assisted organic reactions produced the highest yields, where in several reactions, the yield was almost quantitative. The most suitable eutectic solvents were based on choline chloride (ChCl) as the hydrogen bond acceptor (HBA) and glycerol, oxalic or levulinic acid as hydrogen bond donors (HBDs). The benefits of these three deep eutectic solvents (DESs) as a medium for quaternization reactions are the simplicity of their preparation for large-scale production, with inexpensive, available and nontoxic starting materials, as well as their biodegradability. [ABSTRACT FROM AUTHOR]

The article discusses study to investigate the influence of various deep eutectic solvents (DES) on yield, reaction time and temperature applied for N-acetylation of various amines and the influence of DES recycling on product yield.

In this study, deep eutectic solvents (DESs) were used as green and eco-friendly media for the synthesis of substituted 2-mercaptoquinazolin-4(3H)-ones from different anthranilic acids and aliphatic or aromatic isothiocyanates. A model reaction on anthranilic acid and phenyl isothiocyanate was performed in 20 choline chloride-based DESs at 80 °C to find the best solvent. Based on the product yield, choline chloride:urea (1:2) DES was found to be the most effective, while DESs acted both as solvents and catalysts. Desired compounds were prepared with moderate to good yields using stirring, microwave-assisted, and ultrasound-assisted synthesis. Significantly, higher yields were obtained with mixing and ultrasonication (16–76%), while microwave-induced synthesis showed lower effectiveness (13–49%). The specific contribution of this research is the use of DESs in combination with the above-mentioned green techniques for the synthesis of a wide range of derivatives. The structures of the synthesized compounds were confirmed by 1H and 13C NMR spectroscopy. [ABSTRACT FROM AUTHOR]

In this study, for the first time, the adsorption/desorption characteristics of carnosic acid and carnosol from deep eutectic solvent extract of Salvia officinalis on five macroporous resins (HP20, XAD7HP, XAD16N, HP21, HP2MG) were evaluated. The high adsorption and medium desorption capacities of carnosic acid and carnosol as well as antibacterial and antiradical activity from the extract obtained with choline chloride:lactic acid (1:2) on XAD7HP resin indicated that resin was appropriate. To get the optimal separation process, the influence of factors such as adsorption/desorption time and volume of desorbent was further investigated. The results showed that the extract with high antiradical and antibacterial activity was obtained via adsorption and desorption on XAD7HP resin. The extraction efficiencies of the deep eutectic solvents (DESs) recycled once, twice, and thrice were 97.64% (±0.03%), 93.10% (±0.66%), and 88.94% (±1.15%), respectively, for carnosic acid, and 96.63% (±0.04%), 94.38% (±0.27%), and 91.19% (±0.36%), respectively, for carnosol, relative to the initial solvent efficiency. Based on that, this method is a promising basis for the large-scale preparation of extracts from Salvia officinalis with further application in the pharmaceutical or food industry, especially for maintaining the "green" character of the whole process to obtain the appropriate extract. [ABSTRACT FROM AUTHOR]

Salvia officinalis L. is a good source of antioxidant compounds such as phenolic diterpenes carnosic acid and carnosol. From 17 deep eutectic solvents (DESs) used, choline chloride: lactic acid (1:2 molar ratio) was found to be the most suitable for the extraction of targeted compounds. The influence of H2O content, extraction time, and temperature (for stirring and heating and for ultrasound-assisted extraction (UAE)), H2O content, extraction time, and vibration speed for mechanochemical extraction on the content of targeted compounds were investigated. Carnosic acid content obtained by the extraction assisted by stirring and heating was from 2.55 ± 0.04 to 14.43 ± 0.28 µg mg−1, for UAE it was from 1.62 ± 0.29 to 14.00 ± 0.02 µg mg−1, and for mechanochemical extraction the yield was from 1.80 ± 0.02 to 8.26 ± 0.45 µg mg−1. Determined carnosol content was in the range 0.81 ± 0.01 to 4.83 ± 0.09 µg mg−1 for the extraction with stirring and for UAE it was from 0.56 ± 0.02 to 4.18 ± 0.05 µg mg−1, and for mechanochemical extraction the yield was from 0.57 ± 0.11 to 2.01 ± 0.16 µg mg−1. Optimal extraction conditions determined by response surface methodology (RSM) were in accordance with experimentally demonstrated values. In comparison with previously published or own results using conventional solvents or supercritical CO2, used DES provided more efficient extraction of both targeted compounds. [ABSTRACT FROM AUTHOR]

Rue (R. graveolens) has been an extensively studied medicinal plant due to its rich phytochemicals content, such as furanocoumarins and flavonoids. The aim of this study was to determine the effects of varying extraction conditions on the total phenolic content, the antioxidant and antibacterial property of rue leaves crude extracts using deep eutectic solvents with different water content. These extraction conditions include the temperature and the extraction time. The extract obtained at 30 °C, with 20% water and at 90 min, with 13.3 µg mL−1 concentration, was found to possess the highest total phenolic content (38.24 ± 0.11 mg of GAE g−1 of DM) and the highest antioxidant activity (72.53 ± 0.31%). In this study, the same extract showed the best antibacterial efficiency against all the tested strains, especially gram-negative P. aeruginosa. [ABSTRACT FROM AUTHOR]

A series of rhodanine derivatives was synthesized in the Knoevenagel condensation of rhodanine and different aldehydes using choline chloride:urea (1:2) deep eutectic solvent. This environmentally friendly and catalyst free approach was very effective in the condensation of rhodanine with commercially available aldehydes, as well as the ones synthesized in our laboratory. All rhodanine derivatives were subjected to 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity investigation and quantitative structure-activity relationship (QSAR) studies were performed to elucidate their structure-activity relationship. The best multiple linear QSAR model demonstrate a stability in the internal validation and Y-randomization (R2 = 0.81; F = 24.225; Q2loo = 0.72; R2Yscr = 0.148). Sphericity of the molecule, ratio of symmetric atoms enhanced atomic mass along the principle axes in regard to total number of atoms in molecule, and 3D distribution of the atoms higher electronegativity (O, N, and S) in molecules are important characteristic for antioxidant ability of rhodanine derivatives. Molecular docking studies were carried out in order to explain in silico antioxidant studies, a specific protein tyrosine kinase (2HCK). The binding interactions of the most active compound have shown strong hydrogen bonding and van der Waals interactions with the target protein. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) are multipurpose media for polysaccharide treatment. Thus, the DESs are also used as a plasticizers in preparation of thermoplastic films from natural polymers. Since attempts are being made to reduce the production of petroleum-based polymer materials, DESs are a good alternative in the production of biopolymers. DESs have desirable properties such as low costs, biodegradability and non- or low toxicity. This review summarizes research that are dealing with preparation of biopolymer-based materials with DESs in the role of plasticizer. [ABSTRACT FROM AUTHOR]

In this work, natural deep eutectic solvents (NADESs) were used as a worthy alternative to organic solvents in combination with microwave-assisted, ultrasound-assisted, and mechanochemical synthesis for the preparation of substituted quinazolin-4(3 H)-one derivatives 1–29. Choline chloride-based (ChCl) NADESs were tested in the condensation of 2-methylbenzoxazin-4-ones (f–j) and amines or hydrazides to obtain substituted quinazolin-4(3 H)-one derivatives. The reaction conditions were optimized for each method using 2-methylbenzoxazin-4-one and 4-chloroaniline as model substrates. Their structures were also confirmed by 1H- and 13C NMR and mass spectrometry. Prediction of biological activities and drug-like properties of the compounds was performed by in silico methods. Among 20 tested NADESs, choline chloride/urea was proven to be the best solvent and catalyst system for the synthesis of target compounds. Synthesized quinazolin-4(3 H)-ones were obtained conventionally with 17–73% yields, by microwave-assisted synthesis (10–41%), ultrasound-assisted synthesis (15–56%), and mechanochemical synthesis (45–87%), respectively. Synthesized quinazolin-4(3 H)-ones have the potential to be anticonvulsants, skeletal muscle relaxants, and antifungal drugs. These green procedures provide better methods for the synthesis of substituted quinazolin-4(3 H)-ones, because mechanochemical synthesis, among others, shown the best efficiency. Leading compounds for the design of future drugs were pointed out. [Display omitted] [ABSTRACT FROM AUTHOR]