Natural Deep Eutectic Solvents Research Articles

Exploring the potential of lignin extracted with natural deep eutectic solvents for adsorption of carbon dioxide

Exploring the potential of lignin extracted with natural deep eutectic solvents for adsorption of carbon dioxide

The use of deep eutectic solvent-liquid phase microextraction as green analytical sample treatment for the analysis of drugs in urine

In this paper, a natural deep eutectic solvent (NADES)-based liquid phase microextraction (LPME) of 20 pharmaceuticals from urine, employing liquid chromatography tandem mass spectrometry (LC-MS/MS) for precise quantification, has been developed. The chromatographic gradient was accurately evaluated to ensure the effective separation of tramadol, an opioid receptor agonist, and o-desmethylvenlafaxine, one active metabolite of the antidepressant venlafaxine, both compounds sharing identical molecular mass for the precursor ion (Q1: 264.2 m/z) and fragmentation patterns (Quantifier ion: 58.2 m/z; qualifier ion: 246.0 m/z). NADES consisted of menthol-octanoic acid in a molar ratio of 1:2. Using the appropriate extraction conditions, the developed methodology provided appropriate LOQ values, ranging from 15 to 208 ng L–1, with reasonable RSD values (below 11 %), recoveries ranging from 64 to 120 % and preconcentration factors up to 66.6 folds. Application of the developed method to the analysis of urine samples served to highlight its usefulness. An AGREEprep score of 0.64 was obtained despite the demand for substantial sample volumes and the use of LC-MS/MS for analyte determination.

Protein and Polysaccharide Recovery from Shrimp Wastes by Natural Deep Eutectic Solvent Mediated Subcritical Water Hydrolysis for Biodegradable Film.

Environmental pollution is a significant problem due to the improper disposal of plastics and shrimp shells outdoors. Therefore, the synthesis of biodegradable film from waste materials is highly important. The novelty of this research lies in the extraction of protein hydrolysates and chitosan from shrimp shells, as well as the fabrication of biodegradable film from these materials. In this study, the composite films were produced using the solution casting method. Moreover, the combined effect of ultrasound pretreatments (UPT) and natural deep eutectic solvents (NADES) was investigated as extraction media, to determine their potential impact on shrimp waste subcritical water hydrolysis (SWH). Shrimp shells were submitted to UPT in NADES solution, followed by SWH at different temperatures ranging from 150 to 230°C under 3MPa for 20min. Then, the physiochemical properties and bioactivities of the hydrolysates were assessed to determine their suitability for use in biodegradable packaging films. Additionally, the physiochemical properties and bioactivities of the resulting hydrolysates were also analyzed. The highest amount of protein (391.96 ± 0.48mg BSA/g) was obtained at 190°C/UPT/NADES, and the average molecular size of the protein molecules was less than 1000Da with different kinds of peptide. Overall, combined UPT and SWH treatments yielded higher antioxidant activity levels than individual treatments. Finally, the application of composite films was evaluated by wrapping fish samples and assessing their lipid oxidation. The use of higher concentrations of protein hydrolysates significantly delayed changes in the samples, thereby demonstrating the film's applicability.

Reactive liquid-liquid extraction of lactic acid from microfiltered sweet sorghum silage press juice in an agitated extraction column using a hydrophobic natural deep eutectic solvent as modifier

Downstream processing of carboxylic acids from fermentation broths is cost-intensive and environmentally harmful, which makes methods such as reactive liquid-liquid extraction attractive separation technologies. To enhance the sustainability of liquid-liquid extraction processes, research focuses on sustainable solvents like hydrophobic natural deep eutectic solvents. However, the application of hydrophobic natural deep eutectic solvents in agitated extraction columns for continuous processing has never been investigated. This is essential to facilitate their use in industrial processes, promoting cleaner production. In this study, the application of a thymol-menthol-based deep eutectic solvent as a modifier (with the extractant tri-n-octylamine) in an agitated extraction column is evaluated for reactive liquid-liquid extraction of lactic acid from microfiltered sweet sorghum silage press juice. In addition, three-stage cross-current extractions were performed. The thymol-menthol-based deep eutectic solvent showed efficient phase separation, stable operation, and chemical stability in the agitated extraction column. In three-step cross-current operation, the extraction efficiency for lactic acid was increased from 37.0 ± 0.4 % without feed pH adjustment to 76.2 ± 0.9 % with continuously adjusting the pH value to 2.05 ± 0.02. The thymol-menthol-based deep eutectic solvent shows great potential for application in agitated extraction columns. This is highly promising because natural deep eutectic solvents can enhance the sustainability of extraction processes and reduce the reliance on fossil-based solvents.

Asymmetric Additions Empowered by OrganoCatalysts, Metal Catalysts, and Deep Natural Eutectic Solvents (NADES).

This article is a history of an industrial-academic partnership that started almost two decades ago and details the evolution of a relationship between a small academic research group and a spin-out company located in Portugal. Their activities have ranged from the development of new metal-based catalytic systems for asymmetric epoxidations, allylic alkylations, and arylations to the development of novel cinchona-based organocatalysts for asymmetric hydrosilylations and Michael additions. Current common interests are centered on the development of novel chiral Natural Deep Eutectic Solvent systems, which they are investigating in different types of reaction systems.

Aquaporin expression in cryopreserved human sperm: exploring the capabilities of natural deep eutectic solvents (NADES)

BACKGROUND: Aquaporins (AQPs) are essential proteins that facilitate the rapid movement of water and cryoprotective agents (CPAs) during the cryopreservation process, and ensure the cryotolerance of sperm cells. OBJECTIVE: This study evaluated the preservation of aquaporin levels in human sperm after undergoing freezing using natural deep eutectic solvents (NADES) as CPAs for cryoprotection. MATERIALS AND METHODS: From June 2021 to October 2022, 35 semen samples with normal sperm parameters were acquired from the Mehr Infertility Treatment Institute in Rasht, Iran. The samples were divided into several groups for analysis: control group (not frozen), group frozen with SpermFreeze Solution, and groups frozen with different NADESs, including ChS, ChX, ChU, ChG, GlyP, and EtP. After thawing, various aspects for each group were assessed, including the integrity and condensation of sperm chromatin, viability, motility, integrity of acrosome, and the expression of AQP1, AQP3, AQP7, AQP8, and AQP9 genes. RESULTS: The analysis of gene expression revealed that freezing with ChS and GlyP preserved the expression of the AQP1 and AQP3 genes compared to the control group. Regarding AQP7 and AQP8, significant differences were not observed in expression levels between certain NADES groups (e.g., ChS, ChU, and GlyP) and the control group. Additionally, samples frozen with specific NADESs, such as ChS, ChG, EtP, and GlyP, exhibited preserved levels of AQP9 expression when compared to the control group. CONCLUSION: These findings emphasize the importance of NADES in preserving the expression of aquaporins in cryopreserved human sperm and their important fertility parameters.

Ultrasonic-Assisted Extraction of Xanthorrhizol from Curcuma xanthorrhiza Roxb. Rhizomes by Natural Deep Eutectic Solvents: Optimization, Antioxidant Activity, and Toxicity Profiles.

Xanthorrhizol, an important marker of Curcuma xanthorrhiza, has been recognized for its different pharmacological activities. A green strategy for selective xanthorrhizol extraction is required. Herein, natural deep eutectic solvents (NADESs) based on glucose and organic acids (lactic acid, malic acid, and citric acid) were screened for the extraction of xanthorrhizol from Curcuma xanthorrhiza. Ultrasound-assisted extraction using glucose/lactic acid (1:3) (GluLA) gave the best yield of xanthorrhizol. The response surface methodology with a Box-Behnken Design was used to optimize the interacting variables of water content, solid-to-liquid (S/L) ratio, and extraction to optimize the extraction. The optimum conditions of 30% water content in GluLA, 1/15 g/mL (S/L), and a 20 min extraction time yielded selective xanthorrhizol extraction (17.62 mg/g) over curcuminoids (6.64 mg/g). This study indicates the protective effect of GluLA and GluLA extracts against oxidation-induced DNA damage, which was comparable with those obtained for ethanol extract. In addition, the stability of the xanthorrhizol extract over 90 days was revealed when stored at -20 and 4 °C. The FTIR and NMR spectra confirmed the hydrogen bond formation in GluLA. Our study reported, for the first time, the feasibility of using glucose/lactic acid (1:3, 30% water v/v) for the sustainable extraction of xanthorrhizol.

Glucomannan isolation from porang (Amorphophallus muelleri Blume) flour using natural deep eutectic solvents and ethanol: A comparative study

Ethanol is a common solvent to isolate glucomannan from porang (Amorphophallus muelleri Blume) flour (NPF). This study investigated the use of natural deep eutectic solvents (NADESs) in glucomannan isolation from NPF. NADESs formed by the hydrogen bond acceptors (choline chloride and betaine) and the hydrogen bond donors (glycerol, 1,2-propanediol, formic acid, and acetic acid) in varying molar ratios of 1:2, 1:3, and 1:4 were characterized to optimize glucomannan isolation. The results showed that higher molar ratios of NADES tended to yield porang glucomannan flour (PGF) with higher glucomannan content and viscosity. The gel of PGF exhibited pseudoplastic behavior. The FTIR spectra indicated that betaine-based NADES removed the acetyl groups from glucomannan chains. The PGF obtained from NADESs with a molar ratio of 1:4 was comparable to those obtained from ethanol with a glucomannan content of 87.34 %–93.28 % and a weight-average molecular weight of 9.12 × 105–1.20 × 106 g/mol.

Natural deep eutectic solvent-supported exfoliated graphite nanoplatelet-based electrochemical sensor for the determination of tyramine in fermented beverages

A novel electrochemical sensor was developed for the determination of tyramine. The sensor was constructed by modifying the surface of a glassy carbon electrode (GCE) with a film composed of exfoliated graphite nanoplatelets (xGnPs) dispersed in a natural deep eutectic solvent (NADES). The NADES was prepared by simply mixing equimolar amounts of caprylic acid and menthol and heating at 80 °C for 30minutes. Characterization studies confirmed the formation of a NADES through the attenuated total reflectance-Fourier transform infrared spectroscopy technique, while transmission electron microscopy demonstrated the ability of the NADES to disperse the xGnPs. Electrochemical impedance spectroscopy data showed that the modified sensor exhibited lower resistivity than the unmodified electrode. By optimizing the parameters of square wave voltammetry and experimental conditions to obtain the highest peak current values for tyramine oxidation, a calibration curve was constructed in a 0.1molL−1 phosphate buffer (pH 7.0), obtaining detection and quantification limits of 0.06 and 0.20mgL−1, respectively. Finally, the sensor was successfully applied to the determination of tyramine in fermented milk, beer, and non-alcoholic beer samples, with satisfactory recovery data.

Nanodiamonds and natural deep eutectic solvents as potential carriers for lipase

This study investigates the use of nanodiamonds (ND) as a promising carrier for enzyme immobilization and compares the effectiveness of immobilized and native enzymes. Three different enzyme types were tested, of which Rhizopus niveus lipase (RNL) exhibited the highest relative activity, up to 350 %. Under optimized conditions (1 h, pH 7.0, 40 °C), the immobilized ND-RNL showed a maximum specific activity of 0.765 U mg−1, significantly higher than native RNL (0.505 U mg−1). This study highlights a notable enhancement in immobilized lipase; furthermore, the enzyme can be recycled in the presence of a natural deep eutectic solvent (NADES), retaining 76 % of its initial activity. This aids in preserving the native conformation of the protein throughout the reusability process. A test on brine shrimp revealed that even at low concentrations, ND-RNL had minimal toxicity, indicating its low cytotoxicity. The in silico molecular dynamics simulations performed in this study offer valuable insights into the mechanism of interactions between RNL and ND, demonstrating that RNL immobilization onto NDs enhances its efficiency and stability. All told, these findings highlight the immense potential of ND-immobilized RNL as an excellent candidate for biological applications and showcase the promise of further research in this field.

Investigation of use of hydrophilic/hydrophobic NADESs for selective extraction of As(III) and Sb(III) ions in vegetable samples: Air assisted liquid phase microextraction and chemometric optimization

In this paper, a green, cost-effective sample preparation method based on air assisted liquid phase microextraction (AA-LPME) was developed for the simultaneous extraction of As(III) and Sb(III) ions from vegetable samples using hydrophilic/hydrophobic natural deep eutectic solvents (NADESs). Central composite design was used for the optimization of extraction factors including NADES volume, extraction cycle, pH, and curcumin concentration. Limits of detection for As(III) and Sb(III) were 1.5 ng L−1 and 0.06 ng L−1, respectively. Working ranges for As(III) and Sb(III) were 0.2–300 ng L−1 (coefficient of determination (R2 = 0.9978) and 5–400 ng L−1 (R2 = 0.9996), respectively. Relative standard deviations for As(III) and Sb(III) were 2.2–2.8% and 2.9–3.2%, respectively. Enrichment factor of the method was 184 for As(III) and 172 for Sb(III). The accuracy and precision of the AA-NADES-LPME method were investigated by intraday/interday studies and standard reference material analysis, respectively. Finally, the AA-NADES-LPME method was successfully applied to microwave digested vegetable samples using the standard addition approach and acceptable recoveries were achieved.

Greenhouse gases capture applying impregnated silica with ionic liquids, deep eutectic solvents, and natural deep eutectic solvents.

The development of technologies to capture greenhouse gases (GHGs) like carbon dioxide (CO2) and nitrous oxide (N2O) is vital for climate change mitigation. Ionic liquids (ILs), deep eutectic solvents (DES), and natural deep eutectic solvents (NADES) are promising absorbents to abate GHGs emissions. However, their high viscosity limits the gas-liquid contact, as consequence of the mass transfer. To overcome this, their impregnation onto porous silica gel has been carried out, increasing the gas-liquid contact area. The present study analyzes the effect of size particle of silica gel impregnated with ILs, DES, and NADES over the CO2 and N2O capture at atmospheric conditions. The degree of impregnation of silica particles was determined by thermogravimetric analysis (TGA). The identification of functional groups present on the surface of silica, ILs, DES, and NADES was performed using Fourier-transform infrared spectroscopy (FTIR), and their crystalline structure was determined by X-ray diffraction (XRD). The partition coefficient of CO2 and N2O between gas and ILs, DES, and NADES was determined by a static headspace method. Results show that the degree of solvent impregnation on silica gel ranged from 36.8 to 43.0% w/w, the partition coefficient of CO2 in the impregnated silica varied from 0.005 to 0.067, and for N2O, from 0.005 to 0.032. This suggests that impregnated particles have a greater affinity for N2O compared to CO2. Using impregnated particles requires only 40% of the bulk solvent to achieve a similar GHG capture capacity compared to using bulk solvents.

Phenolics from Polygonatum cyrtonema Hua extracted using natural deep eutectic solvents combined with auxiliary techniques: Composition, bioactivity, and mechanistic elucidation

This study investigated the natural extraction of polyphenolic compounds from Polygonatum cyrtonema Hua (P. cyrtonema). Employing the combination of natural deep eutectic solvents (NADESs) and auxiliary extraction techniques, we mainly focused on yield, total phenolics, total flavonoids, antioxidant capacity, and enzyme inhibition efficiency. Compared to hot reflux extraction (HRE), the NADES extract using a 1:2 ratio of choline chloride-lactic acid (ChCl-Lac) significantly increased the total phenolic content (TPC), total flavonoid content (TFC), and α-glucosidase inhibition (p < 0.05). The HPLC-MS-MS identified the five most abundant phenolic compounds. Quantitative analysis showed that these compounds had the highest leaching rates in the ultrasonic-assisted extraction (UAE) combined with lactic acid-based NADES system, followed by microwave-assisted extraction (MAE), requiring less than 4 min. Notably, rutin exhibited the highest extraction rate of 281.1 μg/g in the UAE-ChCl-Lac system, 9.82 times higher than conventional methods. The extraction mechanism was elucidated from the perspectives of surface charge density distribution and interaction energy. Therefore, ultrasound or microwave-assisted NADES extraction aligns with sustainable development principles, offering a green approach to enrich polyphenolic compounds in P. cyrtonema.

Green and efficient extraction of flavonoids from Perilla frutescens (L.) Britt. leaves based on natural deep eutectic solvents: Process optimization, component identification, and biological activity

In this study, an ultrasonic-assisted natural deep eutectic solvent (NaDES) was used to extract flavonoids from Perilla frutescens (L.) Britt. leaves. Of 10 tested NaDESs, that comprising D-(+)-glucose and glycerol exhibited the best total flavonoid extraction rate. Response surface methodology (RSM) was used for extraction modeling and optimization, and the total flavonoid content reached 87.48 ± 1.61 mg RE/g DW, which was a significant increase of 5.36% compared with that of 80% ethanol extraction. Morphological changes in P. frutescens leaves before and after extraction were analyzed by scanning electron microscopy (SEM), and the mechanism of NaDES formation was studied by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, 10 flavonoids were identified by UPLC-Q-TOF-MS. In addition, the NaDES extract had better biological activity according to five kinds of antioxidant capacity measurements, cyclooxygenase-2 (COX-2) and hyaluronidase (Hyal) inhibition experiments. Moreover, the stability test revealed that the total flavonoid loss rate of the NaDES extract after four weeks was 37.75% lower than that of the ethanol extract. These results indicate that the NaDES can effectively extract flavonoids from P. frutescens leaves and provide a reference for further applications in the food, medicine, health product and cosmetic industries.

Natural deep eutectic solvents: promising agents for extracting substances from plant materials

There is a growing trend to replace synthetic products or additives with natural alternatives. Historical experience and developments in human health science demonstrate the adverse effects of xenobiotics on human health and metabolism. The shift toward natural products is essential for enhancing vitality, social activity, and overall quality of life, while preventing adverse events and diseases. Industries such as pharmaceutical, cosmetic, and food are increasingly turning to natural and biologically active chemicals isolated from plants or microorganisms. However, the primary challenge lies in developing effective and eco-friendly methods for their isolation. Deep eutectic solvents are a mixture of two or more components with unique properties like low volatility, low melting points, ease of preparation, cost-effective starting materials, and minimal toxicity to humans. They have gained popularity as environmentally friendly agents for extracting biologically active substances from medicinal plants and as safe alternatives for various industries, including food and pharmaceuticals. Traditional organic solvent extraction methods have several drawbacks, including long extraction times, safety concerns, environmental damage, high cost, and the need for large solvent volumes. This review summarizes research progress on the benefits of using deep eutectic solvents for extracting bioactive compounds, including phenolic acid, flavonoids, isoflavones, catechins, polysaccharides, curcuminoids, proanthocyanidin, phycocyanin, gingerols, ginsenosides, anthocyanins, rutin, and chlorogenic acids. Additionally, it examines the biological activity of these extracts, including antioxidant, antibacterial, and antitumor properties.

Profiling and optimized extraction of bioactive polyphenolic compounds from young, red-fleshed apple using eco-friendly deep eutectic solvents

Red-fleshed apple cultivars with an enhanced content of polyphenolic compounds have attracted increasing interest due to their promising health benefits. Here, we have analysed the polyphenolic content of young, red-fleshed apples (RFA) and optimised extraction conditions of phenolics by utilising natural deep eutectic solvents (NDES). We also compare the antioxidant, neuroprotective and antimicrobial activities of NDES- and methanol-extracted phenolics from young RFA. High-performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC-HRMS) was used for phenolics identification and quantification. Besides young RFA, ripe red-fleshed, young and ripe white-fleshed apples were analysed, revealing that young RFA possess the highest phenolic content (2078.4 ± 4.0 mg gallic acid equivalent/100 g), and that ripe white-fleshed apples contain the least amount of phenolics (545.0 ± 32.0 mg gallic acid equivalent/100 g). The NDES choline chloride-glycerol containing 40 % w/w H2O gave similar yields at 40 °C as methanol. In addition, the polyphenolics profile, and bioactivities of the NDES extract from young RFA were comparable that of methanol extracts. Altogether, our data show that NDES extracts of young RFA are a promising source of bioactive polyphenolics with potential applications in diverse sectors, e.g., for functional food production, smart material engineering and natural therapies.

High-Temperature Hydrothermal Extraction of Phenolic Compounds from Brewer's Spent Grain and Malt Dust Biomass Using Natural Deep Eutectic Solvents.

Aligned with the EU Sustainable Development Goals 2030 (EU SDG2030), extensive research is dedicated to enhancing the sustainable use of biomass waste for the extraction of pharmaceutical and nutritional compounds, such as (poly-)phenolic compounds (PC). This study proposes an innovative one-step hydrothermal extraction (HTE) at a high temperature (120 °C), utilizing environmentally friendly acidic natural deep eutectic solvents (NADESs) to replace conventional harmful pre-treatment chemicals and organic solvents. Brewer's spent grain (BSG) and novel malt dust (MD) biomass sources, both obtained from beer production, were characterized and studied for their potential as PC sources. HTE, paired with mild acidic malic acid/choline chloride (MA) NADES, was compared against conventional (heated and stirred maceration) and modern (microwave-assisted extraction; MAE) state-of-the-art extraction methods. The quantification of key PC in BSG and MD using liquid chromatography (HPLC) indicated that the combination of elevated temperatures and acidic NADES could provide significant improvements in PC extraction yields ranging from 251% (MD-MAC-MA: 29.3 µg/g; MD-HTE-MA: 103 µg/g) to 381% (BSG-MAC-MA: 78 µg/g; BSG-HTE-MA: 375 µg/g). The superior extraction capacity of MA NADES over non-acidic NADES (glycerol/choline chloride) and a traditional organic solvent mixture (acetone/H2O) could be attributed to in situ acid-catalysed pre-treatment facilitating the release of bound PC from lignin-hemicellulose structures. Qualitative 13C-NMR and pyro-GC-MS analysis was used to verify lignin-hemicellulose breakdown during extraction and the impact of high-temperature MA NADES extraction on the lignin-hemicellulose structure. This in situ acid NADES-catalysed high-temperature pre-treatment during PC extraction offers a potential green pre-treatment for use in cascade valorisation strategies (e.g., lignin valorisation), enabling more intensive usage of available biomass waste stream resources.

NADES extraction, UHPLC-ELSD-based quantification, and network pharmacology-guided target identification of fourteen specialised metabolites from Trillium govanianum Wall. ex D.Don.

Trillium govanianum Wall. ex D.Don is a folk medicinal herb rich in structurally diverse steroidal saponins. The annual demand for this herb in India is about 200-500 metric tons, highlighting the need for a thorough quality assessment. The objective of this study is to develop an easy and reliable ultrahigh-performance liquid chromatography-evaporative light scattering detector (UHPLC-ELSD)-based quality assessment method with 14 specialised metabolites of T. govanianum and identify the potential targets of this herb using network pharmacology. A UHPLC-ELSD method was developed and validated with 14 markers of T. govanianum. The developed method and natural deep eutectic solvent (NADES)-assisted extraction were utilised for the recovery enhancement study of targeted specialised metabolites from rhizome samples (collected from five geographically distinct areas). In addition, the network pharmacology approach was performed for these 14 markers to predict the plausible biological targets of T. govanianum. The developed method showed good linearity (r2: 0.940-0.998), limit of detection (LOD) (2.4-9.0μg), limit of quantification (LOQ) (7.92-29.7μg), precision (intra-day relative standard deviations [RSDs] 0.77%-1.96% and inter-day RSDs 2.19-4.97%), and accuracy (83.24%-118.90%). NADES sample TG-1* showed the highest recovery (yield: 167.66 ± 4.39 mg/g of dry weight) of total saponin content (TSC) as compared to its hydroethanolic extract (yield: 103.95 ± 5.36 mg/g of dry weight). Sample TG-1* was the most favourable (yield: 167.66 ± 4.39 mg/g) in terms of TSC as compared to other analysed samples (32.68 ± 1.04-88.22 ± 6.79 mg/g). Govanoside D (yield: 3.43-28.06 mg/g), 22β-hydroxyprotodioscin (yield: 3.22-114.79 mg/g), and dioscin (yield: 1.07-20.82 mg/g) were quantified as the major metabolites. Furthermore, network pharmacology analysis of targeted 14 markers indicated that these molecules could be possible therapeutic agents for managing neuralgia, diabetes mellitus, and hyperalgesia. The current study represents the first report for the simultaneous quantification and a network pharmacology-based analysis of 14 chemical marker compounds isolated from T. govanianum.

Effects of Hydrophilic Natural Deep Eutectic Solvents on the Rheological, Textural, and Sensory Properties of Carboxymethylcellulose-Based Cosmetic Hydrogels

Effects of Hydrophilic Natural Deep Eutectic Solvents on the Rheological, Textural, and Sensory Properties of Carboxymethylcellulose-Based Cosmetic Hydrogels

Ultrasound-assisted extraction of major anthocyanins in Korean black raspberries (Rubus coreanus Miquel) using natural deep eutectic solvents

This study investigated a methodology for the extraction of major anthocyanin from Korean black raspberries (KBR) using green chemistry. Ternary natural deep eutectic solvent (NADES) used in this study consisted of choline chloride, malic acid, and 1,4-butanediol (2:1:1; w/w/w) based on the viscosity and total anthocyanin contents. The interaction between the components of ternary NADES and their characteristic functional groups were confirmed from infrared spectroscopy. The optimized extraction conditions based on the Box–Behnken design and response surface methodology were as follows: extraction temperature of 26.6 °C, extraction time of 15.2 min, and NADESs water content of 23.3% (v/v). The extraction efficiency and storage stability of cyanidin-3-O-glucoside (C3G) in the ternary NADES were determined. The extraction efficiency of C3G from KBR was most influenced by the water content of the NADES. The storage stability of C3G extracted from KBR using the ultrasound-assisted method with optimized ternary NADES was higher than pure water and acidic water (0.1M HCl). C3G from KBR in the NADES remained stable at > 97% for nine days. The proposed methodology adheres to green chemistry principles, emphasizing on low energy consumption, mild conditions, biodegradability, and eco-friendliness.