Natural Deep Eutectic Solvents Research Articles

Biorefinery of flavonoid aglycones using acidic natural deep eutectic solvents: Role of Bronsted acids and application in valorization of Sophora japonica buds waste

Biorefinery of flavonoid aglycones by natural deep eutectic solvents (NADESs) is a green approach for the valorization of agro-food wastes. Using rutin/quercetin as a model system, this work studies the role of Bronsted acids in deglycosylation of flavonoid glycosides and the sustainable approach to producing aglycone-rich extracts by acidic NADESs. Different NADESs were tested, and the effects of Bronsted acids in catalysis and Hammett acidities were determined. The deglycosylation kinetics of rutin in the choline chloride-citric acid was measured and followed a first-order model with a half-life time (t1/2) of 0.16 h at 90 ℃ and an activation energy (Ea) of 140.3 kJ mol−1. A two-step one-pot approach was valid to produce quercetin-rich extracts from Sophora japonica buds waste. The quercetin-to-rutin ratio in the acidic NADES extracts was adjustable by changing the heating time. The acidic NADES of ChCl-Citric and quercetin-rich extracts showed low cytotoxicity to Caco-2 cells with EC50 greater than 2000 mg L−1, and the cytotoxicity was mainly determined by citric acid. The study provides a new perspective for the valorization of bioproducts into ready-to-use flavonoid aglycone-rich extracts using acidic NADES.

Study on the deacetylation and mechanism of chitin in natural deep eutectic solvent

A large number of hydrogen bonds is the main reason for hindering the dissolution and reaction of chitin, and a mild and green deacetylation method to prepare chitosan for a wider range of applications is urgent. As a non-toxic and degradable green solvent, the deep eutectic solvent can effectively interfere with the hydrogen bond network of chitin, making chitin more susceptible to other solvents. Therefore, a NADES system consisting of betaine and glycerol was proposed for application in the deacetylation reaction of chitin to facilitate further attack of N-acetyl groups by low concentrations of NaOH. After optimizing the reaction conditions, chitosan with 83.77 % deacetylation was prepared, requiring only a concentration of 25 wt% NaOH. The analysis of the product chitosan showed that NADES could not only effectively improve the degree of deacetylation, but also reduce the degree of damage to the molecular weight by alkali. In addition, the potential mechanisms involved in the deacetylation process by NADES were explored. The nature of the reaction was verified by FT-IR, XRD and theoretical calculations as the process of opening intra/intermolecular hydrogen bonds of chitin by NADES. More importantly, experimental and in-depth theoretical studies provide a reference for the green preparation of chitosan.

Improved Curcumin Recovery and In Vitro Biological Activity of Turmeric Extracts Using Nipa Palm Syrup– and Nipa Palm Vinegar–Based Natural Deep Eutectic Solvent (NADES) Hybridized with Microwave-Assisted Extraction

Improved Curcumin Recovery and In Vitro Biological Activity of Turmeric Extracts Using Nipa Palm Syrup– and Nipa Palm Vinegar–Based Natural Deep Eutectic Solvent (NADES) Hybridized with Microwave-Assisted Extraction

Ultrasound-assisted extraction with natural deep eutectic solvent for phenolic compounds recovery from Rosa damascene Mill.: Experimental design optimization using central composite design

Combining natural deep eutectic solvents (NADES) and ultrasonic-assisted extraction (UAE) created a green extraction medium for important phenolic compounds recovery from Rosa damascene Mill. For this purpose, three different NADES based on lactic acid were designed and tested as green extraction solvents. Citric acid, glucose, mannitol, and glycerol were used as hydrogen bond donors (HBD), while lactic acid as a hydrogen bond acceptor (HBA). The best extraction efficiency was demonstrated by NADESLACAGLY, which contains lactic acid, citric acid, and glycerol (3:1:2) compare with two other NADES (NADESLAGLU and NADESLAMA) and conventional solvents (ethanol and methanol). These parameters included total phenolic compounds (TPC), total flavonoid compounds (TFC), and antioxidant activity (AA). Then the UAE procedure was optimized through response surface methodology (RSM) using central composite design (CCD). Quadratic models produced a satisfactory fitting of the experimental data with regard to total phenolic compounds (R2 = 0.9625, p < 0.0001 and p < 0.05), total flavonoid compounds (R2 = 0.9682, p < 0.0001 and p < 0.05), and antioxidant activity (R2 = 0.9940, p < 0.0001 and p<0.05). An extraction time of 60 min, a solvent volume of 35 mL, and an amount of water in NADES 30 % (v/v) were considered optimal conditions. The present study demonstrates the potential for creating eco-friendly solvents with enhanced extraction capabilities compared to organic solvents for the extraction of bioactive compounds from various natural sources that are used as natural food colorants and cosmetic dyes.

Natural deep eutectic solvent extraction of xanthorrhizol and curcuminoids from Curcuma xanthorrhiza Roxb and simultaneous determination by high-performance liquid chromatography

Context: Curcuma xanthorrhiza, a native to Indonesia, has been recognized as a potential medicinal plant. Xanthorrhizol (XTZ), curcumin (Cur), bisdemethoxycurcumin (BDMC), and demethoxycurcumin (DMC) are the main major metabolites with different bioactivities. Thus, the selective extraction of these markers is required. Aims: To characterize and use natural deep eutectic solvents (NADES) for the extraction of XTZ and curcuminoids (CURS) from C. xanthorrhiza. Methods: Four NADES, comprising of glucose:lactic acid (Glu:LA, 1:3), choline chloride: malic acid (ChCl:MA, 1:1), choline chloride: glycerol (ChCl:Gly, 1:1), and choline chloride: sucrose (ChCl:Suc, 3:1) were synthesized and subjected to FTIR. The physicochemical properties of NADES were characterized, including polarity, viscosity, and density. Their antioxidant profiles were evaluated. The toxicity of NADES was assessed towards Escherichia coli by real-time growth monitoring. Tested NADES were employed to extract marker compounds from the rhizome of C. xanthorrhiza. A validated high-performance liquid chromatography (HPLC) method was applied to simultaneously quantify XTZ and CURS in NADES extracts. Results: FTIR spectra confirmed the formation of hydrogen bonds between components. Using the DPPH and FRAP methods, all NADES and NADES extracts displayed antioxidative activity, suggesting the contribution of NADES to the activity. Of the tested NADES, Glu:LA (1:3) obtained the highest content of XTZ over Cur, BDMC, and DMC, comparable to that of ethanol maceration. All tested NADES were harmless to E. coli, except for ChCl:MA (1:1). However, NADES extracts of Glu:LA (1:3) and ChCl:MA (1:1) suppressed the growth of the bacterium. Scanning electron micrographs demonstrated the destruction of the surface structure of the rhizome powder by NADES-ultrasonication. Conclusions: The study recommended the use of Glu:LA (1:3) to selectively extract XTZ to promote environmentally friendly and sustainable extraction.

Development and characterization of sustainable active pectin films: The role of choline chloride/glycerol-based natural deep eutectic solvent and lavender extracts

This study aimed to evaluate the potential effects of choline chloride: glycerol-based natural deep eutectic solvent (NADES) as a plasticizer, NADES extract (NADESext) of lavender as both plasticizer and active ingredient, as well as the lyophilized extract (LE) of lavender at different concentrations (0.5 %, 1 %, and 2 %) on the physical, mechanical, optical, thermal, barrier, morphological, and antioxidant properties of pectin films. The properties of the films were compared to those of the neat pectin film and the film plasticized with glycerol. The addition of plasticizers and LE increased thickness, water vapor permeability, and elongation at break values of the films while decreasing tensile strength and young modulus. Pectin films plasticized with glycerol, NADES, and NADESext had a similar color property but a lower opacity. The use of LE decreased lightness and increased opacity compared to the films with plasticizers. The addition of plasticizers revealed a smoother surface than neat pectin film while LE triggered the formation of agglomerates on the films. Changes in the FTIR spectra of the films showed some interactions between pectin and polyphenols in LE. The plasticizers had an insignificant effect on the antioxidant capacity of films whereas LE improved antioxidant capacity depending on the concentration. In conclusion, the results suggested that pectin films with NADES and LE could be beneficially used to improve antioxidant packaging technology along with acceptable mechanical properties.

Cryoprotective effect of water-tailored trehalose-based natural deep eutectic solvents on frozen-thawed mirror carp (Cyprinus carpio L.) surimi.

The inhibitory effect of water-tailored natural deep eutectic solvents (NADES) constructed from citric acid and trehalose with different amounts on the quality deterioration and oxidation of frozen-thawed (F-T) mirror carp (Cyprinus carpio L.) surimi was studied. NADES was obtained by citric acid to trehalose and the effect of moisture addition (v/v) on the structure, physicochemical, and anti-freezing capacity of NADES was assessed. NADES+10% H2O has relatively low viscosity (25%) and strong freezing resistance. However, a 50% H2O addition leads to the disappearance of the hydrogen bond. The addition of NADES effectively inhibits water loss, migration, and mechanical damage on F-T surimi. An inhibitory effect of 4% (w/w) NADES on oxidation was verified by a decrease in carbonyl contents (17.4%, 8.63%) and TBARS (37.9%, 15.2%) of surimi compared with control (P<0.05) and sucrose+sorbitol after 5F-T cycles, suggesting the potential of NADES as a cryoprotectant for the food industry.

Denitrogenation of Light Hydrocarbon Fractions with Natural Deep Eutectic Solvents Using Commercial Extraction Equipment

Denitrogenation of Light Hydrocarbon Fractions with Natural Deep Eutectic Solvents Using Commercial Extraction Equipment

Lycopene in hydrophobic deep eutectic solvent with natural catalysts: A promising strategy to simultaneously promote lycopene Z-isomerization and extraction.

Lycopene Z-isomerization and degradation in a series of hydrophobic natural deep eutectic solvents (HNDES) was firstly studied. The highest lycopene retention (about 84.6%) was found in HNDES composed of thymol and menthol (TM), and fatty acid-basedHNDES promoted lycopene Z-isomerization (about 70% for total Z-isomers) and degradation. The addition of allyl isothiocyanate (AITC), diallyl disulfide (DADS) and capric acid into TM promoted Z-isomerization of lycopene (80% for total Z-isomers), especially 5Z-isomer (>30%), while lycopene remaining rate in TM/-capric acid was below 20%. During lycopene extraction from tomato power and watermelon juice by TM, the ratios of Z-isomer significantly (p<0.05) increased especially with AITC and DADS (up to about 80%), and extraction yields increased even>100% with capric acid. Lycopene in TM/-capric acid extracts showed low degradation with Z-isomers increasing during storage. TM with capric acid could simultaneously promote lycopene Z-isomerization and extraction.

Chitosan-based supramolecular aerogel with “skeletal structure” constructed in natural deep eutectic solvents for medical dressings

Bacterial infection of wounds remains one of the major clinical challenges, calling for the urgent development of novel multifunctional biological dressings. In this study, we developed a chitosan-based supramolecular aerogel NADES/PVA/CS, constructed by hydrogen bonding between chitosan, a natural deep eutectic solvents and polyvinyl alcohol, as a novel wound dressing against bacterial infections. The effect of polyvinyl alcohol content and its incorporation within chitosan-based supramolecular aerogels were investigated. The results of antibacterial test and MTT assay showed that it has obvious inhibitory effect on Staphylococcus aureus and Escherichia coli, showing excellent biocompatibility and effectively promotes wound healing. The microstructure of chitosan-based supramolecular aerogel showed that by adjusting the addition amount of polyvinyl alcohol, it could exhibit a perfect skeleton-type 3D network structure, which also made it possess smaller density and larger porosity and exhibit excellent water absorption property, contributing to the wetting of wound surface. More importantly, chitosan-based supramolecular aerogel is an environment-friendly biomaterial, which has been verified by degradability experiment. In a word, these unique advantages provide a broad prospect for the medical application of chitosan-based supramolecular aerogel NADES/PVA/CS, and provide a new strategy for the construction of green polysaccharide medical materials.

Simultaneous extraction of crocin and geniposide from gardenia fruits (Gardenia jasminoides Ellis) by probe-type ultrasound-assisted natural deep eutectic solvents and their inhibition effects on low density lipoprotein oxidation

The simultaneous extraction of crocin and geniposide from gardenia fruits (Gardenia jasminoides Ellis) was performed by integrating natural deep eutectic solvents (NADES) and ultrasound-assisted extraction (UAE). Among the eight kinds of NADES screened, choline chloride-1,2-propylene glycol was the most suitable extractant. The probe-type ultrasound-assisted NADES extraction system (pr-UAE-NADES) demonstrated higher extraction efficiency compared with plate-type ultrasound-assisted NADES extraction system (pl-UAE-NADES). Orthogonal experimental design and a modified multi-index synthetic weighted scoring method were adopted to optimize pr-UAE-NADES extraction process. The optimal extraction conditions that had a maximum synthetic weighted score of 29.46 were determined to be 25 °C for extraction temperature, 600 W for ultrasonic power, 20 min for extraction time, and 25% (w/w) for water content in NADES, leading to the maximum yields (7.39 ± 0.20 mg/g and 57.99 ± 0.91 mg/g, respectively) of crocin and geniposide. Thirty-three compounds including iridoids, carotenoids, phenolic acids, flavonoids, and triterpenes in the NADES extract were identified by LC-Q-TOF-MS2 coupled with a feature-based molecular networking workflow. The kinetics evaluation of the conjugated dienes generation on Cu2+-induced low density lipoprotein (LDL) oxidation via the four-parameter logistic regression model showed that crocin increased the lag time of LDL oxidation in a concentration-dependent manner (15 μg/mL, 30 μg/mL, 45 μg/mL) by 12.66%, 35.44%, and 73.42%, respectively. The quantitative determination for fluorescence properties alteration of the apolipoprotein B-100 exhibited that crocin effectively inhibited the fluorescence quenching of tryptophan residues and the modification of lysine residues caused by reactive aldehydes and malondialdehydes. The pr-UAE-NADES showed significant efficiency toward the simultaneous extraction of crocin and geniposide from gardenia fruits. And this study demonstrates the potential utility of gardenia fruits in developing anti-atherogenic functional food.

Chemical profiling of botanical extracts obtained in NADES systems using centrifugal partition chromatography combined with 13 C NMR dereplication-Hypericum perforatum as a case study.

Natural deep eutectic solvents (NADES) have emerged as interesting extractants to develop botanical ingredients. They are nontoxic and biodegradable, nonflammable, easy to prepare, and able to solubilize a wide range of molecules. However, NADES extracts remain difficult to analyze because the metabolites of interest stay highly diluted in the nonvolatile viscous NADES matrix. This study presents a robust analytical workflow for the chemical profiling of NADES extracts. It is applied to Hypericum perforatum aerial parts extracted with the neutral mixture fructose/glycerol/water (3/1/1, w/w/w), and compared to the chemical profiling of a classical dry methanol extract. Exploiting polarity differences between metabolites, the H. perforatum NADES extract was partitioned in a liquid-liquid solvent system to trap the hydrophilic NADES constituents in the lower phase. The upper phase, containing a diversity of secondary metabolites from H. perforatum, was fractionated by centrifugal partition chromatography. All fractions were chemically investigated using a 13 C NMR dereplication method which involves hierarchical clustering analysis of the whole NMR dataset, a natural metabolite database for metabolite identification, and 2D NMR analyses for validation. Liquid chromatography-mass spectrometry (LC-MS) analyses were also performed to complete the identification process. A range of 21 metabolites were unambiguously identified, including glycosylated flavonols, lactones, catechins, phenolic acids, lipids, and simple sugars, and 15 additional minor extract constituents were annotated by LC-MS based on exact mass measurements. The proposed identification process is rapid and nondestructive and provides good prospects to deeply characterize botanical extracts obtained in nonvolatile and viscous NADES systems.

Potato starch plasticization by natural deep eutectic solvent

A natural deep eutectic solvent (NADES) based on choline chloride and malic acid was used to plasticize potato starch. The influence of starch gelatinization temperature, NADAES content and the method of its incorporation (before and after gelatinization) on starch plasticization was investigated. Polymer-plasticizer interactions were studied using MDSC, DMTA, XRD and FTIR-ATR methods. The viscosity of starch solutions as well as the mechanical properties and water absorption of the obtained films were determined. Gelatinization conditions had a significant impact on the viscosity of starch solutions and the physicochemical properties of the obtained films. The cross-linking reaction between starch and malic acid was confirmed by MDSC, DMTA, and mechanical properties. Slight recrystallization of starch was observed after 12 months of storage.

An innovative and environmentally friendly approach for resveratrol solubilization and bioaccessibility enhancement by using natural deep eutectic solvents

The goal of this investigation is the experimental and COSMO-RS theoretical determination of resveratrol (RSV) solubility in five choline chloride-based and five menthol-based natural deep eutectic solvents NADES. Choline chloride (ChCl) and menthol (ME) served as hydrogen bond acceptors (HBA). In contrast, as hydrogen bond donors (HBD), various natural organic compounds were used (urea, 1,2-propanediol, sorbitol, lactic acid, and ascorbic acid). By comparing experimental and theoretical results, it was proved that both results are in exceptional agreement. Obtained results show that the ChCl:1,2-propanediol system showed the highest solubilization potential at 211.05 ± 0.12 mg/mL. It was found that the RSV and NADES formulations show a high antioxidative effect, which is directly related to the solubility of RSV in NADES. Enhanced RSV solubility in NADES and consequently increased antioxidant activity and stability promote RSV formulations in NADES as functional food ingredients for design added value products.

NADES-based selective extraction of bioactive molecules: A case study with commercially important Himalayan medicinal plant Aconitum heterophyllum

Natural deep eutectic solvents (NADESs) are recognized as sustainable green media for extracting bioactive compounds from biomass. Herein, NADES-based green media was employed to extract bioactives from the Himalayan medicinal herb Aconitum heterophyllum Wall. Bioactive compounds such as aconitic acid (insecticidal, anti-bacterial, anti-fungal), atisinium (anti-plasmodial, anti-cancer, insecticidal), lappaconitine (analgesic, anti-cancer, anti-inflammatory), and 2-O-cinnamoyl hetisine (anti-plasmodial) were extracted by ultrasound-assisted methodology from the roots of A. heterophyllum. Twenty NADES-based solvent systems and four conventional solvents were screened to extract targeted bioactives. After performing the initial small-scale extraction, NADES-15 [lactic acid: glycerol (1:1)] was found to be the most effective extraction media compared to conventional solvents. The extraction efficiency of NADES-15 was further optimized by varying different parameters such as S: L (solid: liquid) ratio, extraction time, extraction temperature, and water content. The large-scale extraction was performed to validate the best-optimized parameters, and finally, solid-liquid extraction was utilized to recover NADES-15. Approximately 77.5% of NADES-15 was successfully recovered and reused. The extraction efficiency of recovered NADES-15 was found to be relatively lower than that of its fresh counterpart. DFT-based molecular mechanism studies revealed that higher exergonic stability and the presence of more hydrogen bond donor/acceptor species (which contributes to intermolecular hydrogen bond interactions) might be responsible for enhanced extraction efficiency of NADESs compared to conventional solvents.

Challenging DESs and ILs in the valorization of food waste: a case study.

In this study, the efficacy of two of the best performing green solvents for the fractionation of lignocellulosic biomass, cholinium arginate (ChArg) as biobased ionic liquid (Bio-IL) and ChCl:lactic acid (ChCl:LA, 1:10) as natural deep eutectic solvent (NADES), was investigated and compared in the pretreatment of an agri-food industry waste, apple fibers (90°C for 1h). For the sake of comparison, 1-butyl-3-methylimidazolium acetate (BMIM OAc) as one of the best IL able to dissolve cellulose was also used. After the pretreatment, two fractions were obtained in each case. The results gathered through FTIR and TG analyses of the two materials and the subsequent DNS assay performed after enzymatic treatment led to identify ChArg as the best medium to delignify and remove waxes, present on the starting apple fibers, thus producing a material substantially enriched in cellulose (CRM). Conversely, ChCl:LA did not provide satisfactorily results using these mild conditions, while BMIM OAc showed intermediate performance probably on account of the reduced crystallinity of cellulose after the dissolution-regeneration process. To corroborate the obtained data, FTIR and TG analyses were also performed on the residues collected after the enzymatic hydrolysis. At the end of the pretreatment, ChArg was also quantitatively recovered without significant alterations.

Screening of Natural Deep Eutectic Solvents for the Recovery of Valuable Phenolics From Waste of Shalgam Juice Process

Shalgam juice is one of the most popular non-alcoholic beverages in Türkiye and also in many countries. The high amount of production, regarding the high amount of consumption leads to an inevitable amount of solid waste. This amount reaches to almost 12 million kg of fermented black carrot annually. The accumulation of this waste causes fatal environmental pollution. The waste of shalgam juice process, fermented black carrot, retains significant amount of valuable components, such as phenolics, flavonoids, and anthocyanins. In this study new generation green solvents, Natural Deep Eutectic Solvents (NADESs) were screened for the extraction of valuable phenolics from fermented black carrot using ultrasound assisted extraction. The NADESs used were selected from four different groups such as acidic, sugar-based, choline chloride-sugar based and polyol-based. According to the results, the members of polyol and choline chloride sugar NADESs showed up. Choline chloride-glycerol (polyol group), extracted the highest total phenol amount (16.04 mg/g) and also provided the highest antioxidant activity (81.77%). On the other hand, NADESs belonging to choline chloride-sugar group were effective for the extraction of flavonoids and monomeric anthocyanins. Namely, choline chloride-fructose-water extract contained 21.45 mg/g of total flavonoids, while choline chloride-sucrose-water extract contained 1680.51 mg/kg of total monomeric anthocyanins. The performances of NADESs tested were found to be higher than that of water and ethanol showing the high yield recovery of valuable phenolics with NADESs. The results exhibited the significance of the components inside the waste. The remaining valuable content could be easily and efficiently extracted using NADESs and these extracts –as a mixture or after purification- can furtherly be used for different purposes in different fields, such as cosmetics, antioxidant preparations, etc, using a zero-cost waste as the input of the processes.

Determination of remdesivir in human plasma using (deep eutectic solvent-ionic liquid) ferrofluid microextraction combined with liquid chromatography

A microextraction technique based on ferrofluids was developed for the preconcentration and quantification of Remdesivir in human plasma samples. This method utilized a new type of magnetic colloids created by combining silica-coated magnetic particles with modified ionic liquid and natural hydrophobic deep eutectic solvent as the carrier liquid. The efficiency of the sorption and desorption steps was optimized using a chemometrics approach. Under the optimized conditions, the calibration curve exhibited linearity in the concentration range of 0.5 to 500.0 μg L−1, with a limit of detection and quantification of 0.2 and 0.5 μg L−1, respectively. The method precision was evaluated by assessing intra- and interday precision at three different analyte concentrations, yielding values of 8.9% and 16.8%, respectively. Moreover, the method accuracy fell within the range of 90.9% to 107.5%. This proposed method offers a green and environmentally friendly sample preparation technique for conducting pharmacodynamic, pharmacokinetic, and therapeutic drug monitoring studies of Remdesivir in biological fluids. Importantly, this technique eliminates the need for external energy sources or the use of dispersive solvents, providing a more efficient and sustainable approach.

Synergistic combination of natural deep eutectic solvents and green extraction techniques for the valorization of date palm leaves: Optimization of the solvent-biomass interaction

This study was designed to explore date palm leaves as natural polyphenolics potential source using appropriate green Natural Deep Eutectic Solvent (NADES) and emerging green extraction technologies. Among the studied NADES, Glycerol-based NADES showed higher phenolics yield compared to saccharide and organic acid-based NADES. Experimental conditions for microwave (MAE)-NADES and ultrasonication (UAE)-NADES couplings were optimized using a 23-factorial design. Interestingly, it was found the UAE-NADES was not effective enough to enhance phenolics recovery, while MAE-NADES was significantly effective. Furthermore, MAE-NADES-based extracts portrayed higher bioactive properties compared to UAE-NADES-based extracts. Accordingly, MAE-NADES extraction parameters were further optimized using a Box-Behnken design of Response Surface Methodology (RSM). RSM predicted that MAE-NADES extraction can be maximized at a NADES concentration of 49 %, and power of 800 W for 0.84 min. The current study concludes that the application of MAE-NADES green extraction technology can be an effective approach for bioactive compounds recovery from date palm leaves.Industrial relevance:There are more than 120 million date palm trees in the world producing around 20–35 kg of leaves per palm tree annually. This is a huge burden on the environment and if explored as a potential source of polyphenols and other components may turn out to be a viable economic source for desert regions. During the last few decades, a special focus has been raised on ensuring that the extraction process is monitored in an economical and eco-friendly manner without downgrading the biological functionality of the resulting extracts. Recently, Natural Deep Eutectic Solvents (NADES) have been applied for the extraction of polyphenolic compounds. Moreover, the utilization of green extraction techniques, such as ultrasonication and microwave, have been extensively investigated for the extraction of bioactive compounds from plant-based matrices with promising future prospectus, in terms of the reduction in extraction time and higher recovery yields.

Development of an electrochemical sensor using carbon nanotubes and hydrophobic natural deep eutectic solvents for the detection of α-glucosidase activity in extracts of autochthonous medicinal plants

The present work describes for the first time the use of a hydrophobic natural deep eutectic solvent (H-NADES) as a dispersant for carboxylated nanotubes for the design and construction of an electrochemical sensor for the assay of α-glucosidase and its inhibitors. In this work, we used as the electrochemical probe the product of the enzymatic reaction, which consists of two redox groups and generates the analytical signal. The combination of de carboxylic multi-walled carbon nanotubes (MWCNTc) and the H-NADES of thymol and lactic acid (TLa) increases the electroactive surface area and promotes electron transfer of the electrode modified with carbon nanotubes. The electrochemical sensor enabled the detection of α-glucosidase in a range of 0.004–0.1 U mL−1 with a detection limit of 0.0013 U mL−1, which is lower than most existing methods. In addition, two α-glucosidase inhibitors, acarbose and quercetin, and two plant extracts, Schinus molle and Eugenia uniflora, were evaluated to assess the feasibility of screening potential antidiabetic drugs, and the IC50 values were 5.37 μg mL−1 and 5.28 μg mL−1. Thus, this sensing strategy represents the beginning of the incorporation of NADES in the development and design of novel sensors and their application in electrochemistry and medical analysis.