Deep Eutectic Solvent Extraction Research Articles

Back to the future with emerging iron technologies.

Here is a comprehensive overview of iron's potential in low-carbon energy technologies, exploring applications like metal fuel combustion, iron-based batteries, and energy-carrier cycles, as well as sustainable approaches for production and recycling with a focus on reducing environmental impact. Iron, with its abundance, safety, and electrochemical characteristics, is a promising material to contribute to a decarbonized future. This paper discusses the advancements and challenges in iron-based energy storage technologies and sustainable iron production methods. Various innovative approaches are explored as energy storage solutions based on iron, like advancements in thermochemical Fe-Cl cycles highlight the potential of iron chloride electrochemical cycles for long-term high-capacity energy storage technology. Additionally, the utilization of iron as a circular fuel in industrial processes demonstrates its potential in large-scale thermal energy generation. Sustainable iron production methods, such as electrolysis of iron chloride or oxide and deep eutectic solvent extraction, are investigated to reduce the carbon footprint in the iron and steel industry. These findings also show the importance of policy and technology improvements that are vital for the widespread use and recycling of iron-based tech, stressing the need for collaboration toward a sustainable future.

Phytochemical Study of <i>Butea superba</i> Roxb. and its Extraction by Successive Solvent and Direct Ethanolic Extraction

Herbal therapy is a widely accepted therapeutic method, where the use of medicinal herbs has great importance in traditional medicine. Butea superba L., often referred to as Ghandhali, Bakuchi, Khip, and Prasaran, is an indigenous green vegetable originating from India. The herb has been traditionally used to augment physical strength, potency, and male sexual prowess. An essential aspect of research is examining the bioactivity of each component, since it has a substantial impact on the regulation of biological processes and the treatment of numerous conditions such as diabetes, hypertension, asthma, hepatomas, psoriasis, and perhaps cancer. The current investigation centered on the extraction and phytochemical analysis of Butea superba Roxb, using both Successive Solvent Extraction (SSE) and Direct Ethanolic Extraction (DEE) techniques. The SSE technique included a methodical extraction procedure using solvents with progressively higher polarity, while DEE immediately employed ethanol. Phytochemical analysis was performed on the extracted components of Butea superba to determine the presence and amount of bioactive substances. Diverse analytical techniques, such as chromatography, were used to investigate the chemical makeup. This extensive study seeks to provide valuable insights into the efficacy of SSE (Solvent Extraction) and DEE (Deep Eutectic Solvent Extraction) techniques for extracting phytochemicals from Butea superba, as well as to clarify the range of bioactive substances found in this plant.

Citrus Peel Extracts: Effective Inhibitors of Heterocyclic Amines and Advanced Glycation End Products in Grilled Pork Meat Patties.

In the present study, citrus peels were extracted using various conventional and deep eutectic solvents (DESs). Compared to other citrus peel extracts, the DES extract based on choline chloride showed notably higher total phenolic and flavonoid content levels, along with superior antioxidant activity, among these extracts. Consequently, this study aimed to further investigate the inhibitory effects of the choline chloride based DES extract on the production of both free and bound heterocyclic amines (HAs) and advanced glycation end products (AGEs) in roast pork meat patties. The results indicated that the addition of choline chloride-based DES extracts, particularly the choline chloride-carbamide based DES extract, can effectively reduce the oxidation of lipids and proteins by quenching free radicals. This approach proves to be the most efficient in reducing the formation of both HAs and AGEs, leading to a significant reduction of 19.1-68.3% and 11.5-66.5% in free and protein-bound HAs, respectively. Moreover, the levels of free and protein-bound AGEs were reduced by 50.8-50.8% and 30.5-39.8%, respectively, compared to the control group. Furthermore, the major phenolics of citrus peel extract identified by UHPLC-MS were polymethoxylated flavonoids (PMFs) including hesperidin, isosinensetin, sinensetin, tetramethoxyflavone, tangeretin, and hexamethoxyflavone, which inferring that these compounds may be the main active ingredients responsible for the antioxidant activity and inhibition effects on the formation of HAs and AGEs. Further research is needed to explore the inhibitory effects and mechanisms of PMFs with different chemical structures on the formation of HAs and AGEs.

Deep eutectic solvents as efficient extractants of caffeoylquinic acids from Blumea aromatica: A comparative analysis of content and antioxidant potential

This study conducted a comparative analysis of the extraction efficiency and antioxidant potential of caffeoylquinic acids (CQAs) from Blumea aromatica using deep eutectic solvents (DESs) and traditional solvents. Utilizing UPLC-Q-Orbitrap HRMS, the quantification of seven CQAs revealed concentrations ranging from 0.46 to 7.60 mg/g, with 1,5-diCQA identified as the most abundant. DESs demonstrated significant advantages (P < 0.05) over traditional solvents. The optimal extraction occurred with DES-6 (choline chloride / 1,4-butanediol) for 3-CQA (4.71 ± 0.31 mg/g) and 4,5-diCQA (2.28 ± 0.19 mg/g), DES-7 (choline chloride / oxalic acid) for 4-CQA (2.05 ± 0.05 mg/g), and DES-5 (choline chloride / glycerol) for 5-CQA (1.70 ± 0.14 mg/g). Antioxidant activity assessment through DPPH, ABTS, and reducing power assays indicated that DES extracts outperformed conventional solvents. Notably, DES-3 (choline chloride / ethylene glycol) displayed remarkable activity, with IC50 values of 197.36 ± 1.05 and 14.86 ± 3.33 μg/mL for DPPH and ABTS radicals, respectively. DES-6 exhibited the highest reducing power. Correlation analysis established positive relationships between phenolic acid content and antioxidant activity, notably for 3-CQA and 5-CQA (p < 0.001 and p < 0.05). Additionally, 4-CQA, 1,3-diCQA, 3,4-diCQA, and 4,5-diCQA displayed specific and correlated antioxidant activities. Crucially, the environmentally friendly DESs extraction method proposed in this study offers a sustainable approach for obtaining CQAs from B. aromatica, concurrently ensuring their antioxidant potential is fully realized. This research not only advances our understanding of B. aromatica but also highlights a green and efficient method for extracting bioactive compounds with potential applications in the pharmaceutical and nutraceutical industries.

Deep eutectic solvent extraction combined with magnetic bead ligand fishing for identification of α-glucosidase inhibitors from Pueraria lobata.

In this study, a deep eutectic solvent (DES) extraction combined with a magnetic bead ligand affinity analytical method was developed and used for α-glucosidase inhibitor identification from Pueraria lobata. Several critical parameters affecting the analysis performance, including the type of DES, molar ratio, water amount, pH, salt concentration, and volume of DES, were investigated. The selected analytical sample preparation conditions were as follows. The composition of DES is choline chloride-1,4-butanediol (1:3), the water content is 40%, pH is 7.0 and the volume of extraction solution is 2 mL. The obtained sample extraction solution was analyzed directly using α-glucosidase immobilized magnetic beads (GMBs). Three α-glucosidase inhibitors in Pueraria lobata, including puerarin, daidzin, and daidzein, were identified. Luteolin was used as a positive control to evaluate the method's selectivity. Results showed it could selectively bond to the GMBs in the DES. As the affinity analysis was performed directly in a DES, the solution-removing process could be avoided. The intra-day and inter-day precisions of the method are 5.21% and 6.38%, respectively. The solvent amount was 1/50-1/2000 of that used in traditional methods.

Efficient extraction of pectic polysaccharides from thinned unripe kiwifruits by deep eutectic solvent-based methods: Chemical structures and bioactivities

To promote the potentially industrial applications of thinned unripe kiwifruits, two deep eutectic solvent-based methods, including deep eutectic solvent-assisted extraction (DAE) and microwave-assisted deep eutectic solvent extraction (MDE), were optimized for the extraction of polysaccharides from thinned unripe kiwifruits (YKP). Results showed that the yields of YKP-D prepared by DAE and YKP-DM prepared by MDE were extremely higher than YKP-H prepared by hot water extraction. Furthermore, YKP-H, YKP-D, and YKP-DM were mainly composed of pectic polysaccharides, including homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. Besides, both YKP-D and YKP-DM exhibited stronger antioxidant, anti-glycosylation, and immunomodulatory effects than those of YKP-H, and their higher contents of uronic acids and bound polyphenols as well as lower molecular weights could partially contribute to their bioactivities. Overall, these results revealed that the developed MDE method could be utilized as a promising method for highly efficient extraction of YKP with superior beneficial effects.

Optimization of ultrasound-assisted deep eutectic solvent extraction of polyphenols from Rhamnus alaternus for their antioxidant activity

Optimization of ultrasound-assisted deep eutectic solvent extraction of polyphenols from Rhamnus alaternus for their antioxidant activity

Gastrointestinal delivery of codfish Skin-Derived collagen Hydrolysates: Deep eutectic solvent extraction and bioactivity analysis

The fishing industry produces substantial by-products, such as heads, skins, bones, and scales, rich in collagen—a prevalent protein in these materials. However, further application of deep eutectic solvent-based extraction remains unexplored. In this study, we extracted collagen with urea: propanoic acid mixture (U:PA; 1:2) with a 2.2 % yield, followed by enzymatic hydrolysis with alcalase for 120 min. The resulting bioactive peptides demonstrated notable antioxidant activity (961 µmol TE) and antihypertensive properties (39.3 % ACE inhibition). Subsequently, we encapsulated 39.3 % of these hydrolysates in chitosan-TPP capsules, which released about 58 % of their content, primarily in the intestine, as mimicked in the in vitro model of the gastrointestinal tract. Although the digestion process did not significantly alter the size of the non-encapsulated collagen peptides, it did influence their health benefits. The promising results suggest that further research could optimize the use of collagen from fish by-products, potentially offering a sustainable source for health products.

Ultrasound-assisted deep eutectic solvent extraction of bioactive compounds from persimmon calyx.

This study aimed to investigate the ultrasound-assisted extraction of bioactive compounds from persimmon (Diospyros kaki) calyx by deep eutectic solvents (DES) with different molar ratios. For this reason, the prepared DES extracts' total phenolic-flavonoid compounds and antioxidant activities (1,1-diphenyl-2-picrilhydrazyl radical scavenging activity [DPPH•], Cupric Reducing Antioxidant Capacity (CUPRAC), and ferric reducing antioxidant power [FRAP]) were investigated as a result of the experimental design and optimization study conducted for this purpose. A sonication time of 20min was determined as the optimal condition. Under these conditions, a molar ratio of 1.9:1 (lactic acid:choline chloride) and a water ratio of 70% provided the highest phenolic/flavonoid compounds and antioxidative activity. Correlations among water ratio, molar ratio, and sonication time were determined using principal component analysis (PCA). In conditions where total flavonoid compound, FRAP, and DPPH• are high due to PCA, it can be concluded that the sonication time is at high level; on the contrary, the water and molar ratios are at low level. In conclusion, ultrasound-assisted extraction using DES proved effective in persimmon calyx. Therefore, it can be recommended to use these environmentally friendly green solvents as an alternative to organic solvents in preparing extracts in various fields. PRACTICAL APPLICATION: This study shows the effectiveness of the ultrasound-assisted green extraction method using persimmon calyx specified as waste. These findings are compelling in the food industry in terms of consumers being now aware of green technology and the discovery that calyx is a good source of bioactive compounds.

Molecularly imprinted solid-phase extraction combined with non-ionic hydrophobic deep eutectic solvents dispersed liquid-liquid microextraction for efficient enrichment and determination of the estrogens in serum samples

Hormonal drugs in biological samples are usually in low concentration and highly intrusive. It is of great significance to enhance the sensitivity and specificity of the detection process of hormone drugs in biological samples by utilizing appropriate sample pretreatment methods for the detection of hormone drugs. In this study, a sample pretreatment method was developed to effectively enrich estrogens in serum samples by combining molecularly imprinted solid-phase extraction, which has high specificity, and non-ionic hydrophobic deep eutectic solvent-dispersive liquid-liquid microextraction, which has a high enrichment ability. The theoretical basis for the effective enrichment of estrogens by non-ionic hydrophobic deep eutectic solvent was also computed by simulation. The results showed that the combination of molecularly imprinted solid-phase extraction and deep eutectic solvent-dispersive liquid-liquid microextraction could improve the sensitivity of HPLC by 33∼125 folds, and at the same time effectively reduce the interference. In addition, the non-ionic hydrophobic deep eutectic solvent has a relatively low solvation energy for estrogen and possesses a surface charge similar to that of estrogen, and thus can effectively enrich estrogen. The study provides ideas and methods for the extraction and determination of low-concentration drugs in biological samples and also provides a theoretical basis for the application of non-ionic hydrophobic deep eutectic solvent extraction.

A novel deep eutectic solvent as an extractant for the determination of bisphenol compounds in edible oils by high-performance liquid-phase fluorescence detection

In this study, an efficient, low-cost and environmentally friendly deep eutectic solvent (DES) was prepared using methanol and betaine, which was then employed as an extractant to detect BPA and BPF in several edible oils by high performance liquid chromatography-fluorescence detection (HPLC-FLD) with good results. The electrostatic potentials of methanol, betaine, water and BPs were analyzed by quantum chemical computational techniques to explain the mechanism of DES extraction. Several important parameters affecting the extraction efficiency, composition, volume and extraction time of DES were optimized. The optimum conditions for the use of DES were the molar ratio of 1:30 (betaine: methanol), the volume of DES of 200 μL and the extraction time of 1.5 min. The results of the method evaluation showed a wide linear range (0.01–0.8 μg g−1) and a high linear correlation coefficient (R2 ≥0.994). The limit of detection (LOD) and limit of quantification (LOQ) values ranged from 1.65 to 2.92 ng g−1 and 5.45–9.64 ng g−1, respectively. The greenness of the assay was evaluated by applying the green analytical procedure index method, and the results showed that the experimental method has the advantages of simple sample pre-treatment and low amount of waste generated during the assay. The experimental method has potential applications in the field of the detection of bisphenol compounds in edible oils.

Novel reusable and switchable deep eutectic solvent for extraction and determination of curcumin in water and food samples

For the first time, a fast and easy extraction method based on a unique reusable and switchable deep eutectic solvent (made of octylamine, succinic acid, and water as precursors) was presented and utilized for the microextraction and determination of curcumin as a model analyte. The main factors used to induce a phase transition in the as-prepared deep eutectic solvent were solutions of NaOH and HCl. Among the standout characteristics of the suggested deep eutectic solvent are the removal of toxic organic solvents like THF, the lack of a need for centrifugation, and the ability to be reused in subsequent extractions. The influence of effective parameters (i.e., proportions of deep eutectic solvent structure components, volume of prepared deep eutectic solvent, volume and concertation of NaOH, volume of HCl, and salt effect) on the extraction procedure were investigated. The calibration curve also was linear in the range of 35–500 μg L−1 with coefficients of determination (R2) of 0.9976. Limit of detection (S/N = 3) 10.0 μg L−1, the limit of quantification (LOQ) of 35.0 μg L−1, the relative standard deviations (RSDs %) composed of intra-day RSD (4.7) and inter-day RSD (6.4), preconcentration factor of 40.0, enrichment factor of 38.68, and relative recovery of 92.6%–100.3 % were achieved. The reusable and switchable deep eutectic solvent based-dispersive liquid-liquid microextraction technique was proficiently employed to expedite easy and fast extraction of curcumin from water and food samples.

A green method to extract rutin from Sophora japonica L.

Sophora japonica L. contains high levels of rutin, which has great potential for use in pharmaceutical products for the treatment of diseases related to the cardiovascular and circulatory systems. We proposed a method of extracting rutin from S. japonica by using a green solvent.•Green deep eutectic solvents (DESs) of choline chloride and ethylene glycol (ChCl-Eth) showed the highest extraction efficiency of rutin from S. japonica.•Under optimal conditions, the extraction yield of ChCl-Eth was 1.34 times higher than that of methanol as solvent.•Rutin was recovered from the DES extracts using water as the antisolvent with a high recovery yield, and the DESs of ChCl-Eth could be productively recovered and reused at least 3 times.

Extraction optimization of tea saponins from Camellia oleifera seed meal with deep eutectic solvents: Composition identification and properties evaluation.

Traditional organic solvent extractions of tea saponins have many drawbacks. This study aimed to establish an environment-friendly and efficient technology based on deep eutectic solvents (DESs) to extract tea saponins from Camellia oleifera seed meal. The solvent consisting of choline chloride and methylurea was screened as optimal DES. Under the optimal extraction conditions obtained by response surface methodology, the extraction yield of tea saponins reached 94.36mg/g, which increased by 27% compared with ethanol extraction, while the extraction time was reduced by 50%. Analysis of UV, FT-IR, and UPLC-Q/TOF-MS indicated tea saponins did not alter during DES extraction. Surface activity and emulsification evaluation showed that extracted tea saponins could reduce interfacial tension at the oil-water interface with excellent foamability and foam stability, and they could form nanoemulsions (d32<200nm) with excellent stability. This study provides a suitable approach for the efficient extraction of tea saponins.

Efficient Plutonium Extraction and Electrochemical Insights in a Hydrophobic Deep Eutectic Solvent for Radioactive Waste Management

In this study, we explore the extraction and electrochemical characteristics of Plutonium using a hydrophobic deep eutectic solvent (DES) consisting of tetra-Butyl Ammonium Bromide(TBABr) as the hydrogen bond acceptor and Decanoic acid (DA) as the hydrogen bond donor in a 1:2 ratio composition. Hydrophobic DES possesses unique attributes, such as low volatility and a high affinity for metal ions, making it a promising choice for Plutonium extraction. We systematically investigate the influence of various parameters, including DES composition, acid concentration, and extraction duration. Our extraction experiments reveal that the hydrophobic DES exhibits its maximum Plutonium extraction efficiency (95%) at a 4 M HNO3 concentration, with a distribution coefficient (D) reaching nearly 71. To gain insights into the electrochemical behavior of Plutonium within the hydrophobic DES, we conduct cyclic voltammetry experiments. The resulting voltammograms offer valuable insights into the redox properties and stability of Plutonium species within the DES. Furthermore, we analyze the impact of potential scan rate on the electrochemical response, shedding light on the kinetics and mechanisms underlying Plutonium electrochemistry within the hydrophobic DES. These findings underscore the considerable potential of hydrophobic DES for efficient Plutonium extraction and electrochemical separation. This research contributes to the development of sustainable and environmentally friendly approaches for managing Plutonium, particularly in the context of nuclear waste disposal

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.

The Bioactivity Potential of Acmella Paniculata Plant Extract in Antioxidant Activity by Two Different Extraction Methods

Widely used synthetic chemicals like heavy metals act as active compounds in personal care products such as shampoo, soap and cosmetics. These hazardous chemicals cause harmful threats to the environment and unintentionally lead to dangerous exposure towards human health. Thus, demands on natural organic compounds have increased nowadays. Bioactive compounds from plant extracts are well known to have intrinsic biological values that are relevant in promoting human health. There are numerous ways to extract these unique and important compounds involving techniques that are simple, environmentally friendly and efficient. The aim of this study is to highlight the biological potential of compounds from the local plant, Acmella paniculata in antioxidant activity. This small flowering shrub species is also known locally as Subang nenek. The first phase of this study involved the leaf extraction of A. paniculata performed by a common method known as Soxhlet extraction using methanol solvent and a simple centrifuged method using deep eutectic solvent (DES) which is a green solvent. Soxhlet method is a conventional procedure that takes longer time and involves specific equipments. However, this method has been used for many years as standard method due to its consistent results. Meanwhile, DES based centrifugation method is a new, innovative method for plant extraction with a fast procedure and minimal used of equipment. The second phase involved phytochemical screening and antioxidant activity testing. The phytochemical screening for A. paniculata leaf extract showed noticeable secondary metabolites such as alkaloids, tannins, terpenoids and steroids. This plant showed good pharmacological values in antioxidant activity using DPPH free radical scavenging assay. The antioxidant percentage of DES extract showed higher potential results (56.11±3.54) compared to the Soxhlet extract (39.15±23.99) in leaf. Overall, the DES extraction is promising method in increasing the yield of antioxidant compounds as well as provided a simple and rapid technique in plant extraction.

Extraction of triterpene acids from loquat leaves via a novel hydrophobic deep eutectic solvent screened by COSMO-SAC model

Triterpene acids (TTAs) have promising applications in functional food, medicine and other fields. Here, ultrasonic-assisted hydrophobic deep eutectic solvent (HDES) extraction was employed to gain TTAs from loquat leaves. Combining COSMO-SAC model prediction with experimental verification，the HDES, composed of thymol and benzyl alcohol (molar ratio 2:1), was proved to have the highest extraction ability for TTAs. The preliminarily optimized extraction conditions were solid to solvent ratio 1:10 (g/g), temperature 60 °C and extraction time 60 min. Under these conditions, the extraction yield of ursolic acid (the main component of loquat leaf TTAs) was 17.769 ± 0.799 mg/g dry loquat leaf. HDES and TTAs were recovered from HDES extracting solution via gradient elution (60% and 80% ethanol aqueous solution, respectively) based on C18 reverse-phase silica gel column chromatography under low pressure (0.5 MPa). Recovered HDES could be reused for extracting TTAs from loquat leaves directly and had a similar extraction performance compared to fresh HDES. The purity of the obtained crude TTAs sample was 81.18% based on the total contents of maslinic acid (MA), corosolic acid (CA), oleanolic acid (OA) and ursolic acid (UA), with a mass ratio of 11:26:10:53. Crude TTAs sample was further separated by C18 reverse-phase silica gel column chromatography using 80% ethanol aqueous solution as mobile phase under high pressure (15 Mpa). By this mean, CA sample with 69.30% purity (MA to CA mass ratio 7:18) and UA sample with 93.94% purity (OA to UA mass ratio 4:21) were obtained. The in vitro antioxidant ability order of the attained TTAs samples was CA sample > crude TTAs sample > UA sample. This study laid a good scientific basis for applying HDES and C18 reverse-phase silica gel column chromatography in the bioactive component extraction and separation fields. It also provided theoretical basis and technical support for obtainment and utilization of high-purity loquat leaf TTAs in the fields of medicine, functional food, cosmetics and so on.

A green hydrophobic deep eutectic solvent for extraction of phenol from aqueous phase

Deep eutectic solvents (DESs), have been recognized as effective materials for the extraction of different compounds. In this study, the performance of a novel hydrophobic DES was evaluated for the extraction of phenol from aqueous solutions. Octanoic and dodecanoic fatty acid precursors with a definite molar ratio of 3:1, respectively, were used for the DES having a low melting point of 8.3 °C. The purity and stability of the product were confirmed via characterizing by FTIR, 1H and 13C NMR methods. The liquid–liquid equilibrium of the water + phenol + DES ternary system at different temperatures of 293.2, 298.2 and 308.2 K was accordingly studied through cloud point titration method and refractive index measurement. Interestingly, the important parameters of the solute distribution coefficient and the separation factor were, respectively, within the high levels of (6.8321–9.7787) and (895.76–2770.17), indicating the amazing capability of the DES. Reasonably, both of these parameters decreased with temperature. The NRTL and UNIQUAC thermodynamic models were employed to reproduce the obtained tie-lines and to determine the interaction parameters at each temperature. The low level root mean square deviations for the mentioned models were, respectively, within (0.0014–0.0027) and (0.0045–0.0063); confirming satisfactorily agreement with the experimental data.

Green ultrasound-assisted natural deep eutectic solvent extraction of phenolic compounds from waste broccoli leaves: Optimization, identification, biological activity, and structural characterization

In this study, an efficient natural deep eutectic solvent (NADES, 30 mL/100 mL water content) was identified and coupled with ultrasonication to extract phenolic compounds from broccoli leaves (BLs). A NADES prepared using choline chloride and 1,2-propylene glycol (ChCl-PG) at a molar ratio of 1:2 provided the highest extraction rate. Phenolic extraction conditions were optimized using single-factor experiments coupled with response surface methodology. The optimal parameters were as follows: solvent-to-solid ratio, 36.35 mL/g; extraction temperature, 49.5 °C; extraction time, 31.4 min; and ultrasonic power, 383 W. Under these parameters, the phenolic yield was 4.91 mg/g. Quantitative analysis revealed that neochlorogenic acid was the most abundant phenolic compound, followed by ferulic acid, erucic acid, quinic acid, chlorogenic acid, and caffeic acid. Furthermore, the isolation of broccoli leaf phenolics (BLPs) using ultrasonication-assisted extraction coupled with ChCl-PG (UAE + ChCl-PG) yielded a higher total phenolic content than other extraction methods. These BLPs also had greater antioxidant activity (DPPH, ABTS assay) and inhibitory effects against S. aureus, E. coli, and Salmonella. DSC, FT-IR, and SEM results further validated the synergistic efficiency of the new phenolic extraction process. Accordingly, this study offers an efficient and green alternative strategy for extracting phenolic compounds from plant by-products.