Natural deep eutectic solvents and aqueous solutions as an alternative extraction media for propolis

Effect of honey, as a natural deep eutectic solvent, on the phytochemical stability and anti-inflammatory activity of Eurycoma longifolia Jack

The use of Eurycoma longifolia Jack (EL) in combination with honey is widely recognized in conventional medicine because of its aphrodisiac and pyretic properties. However, the effects of honey, a natural deep eutectic solvent (NADES), on the phytochemical stability and anti-inflammatory activity of EL remain unknown. This study aimed to investigate the effect of honey on phytochemical and anti-inflammatory effects of EL. The stabilities of bioactive compounds, including eurycomanone (EU), 9-hydroxycanthine-6-one (9HCO), and 9-methoxycanthine-6-one (9MCO), were evaluated after treating EL with honey. The anti-inflammatory activity was assessed by measuring the inhibition of NO production in lipopolysaccharide-induced RAW264.7 macrophages. The EL formulations treated with honey exhibited significantly higher yields of EU and 9HCO; however, a decrease in 9MCO was observed. After a 90 day infusion, the anti-inflammatory activities of honey-treated EL (9.19-68.73% NO inhibition) and simulated honey-NADES-treated EL (5.37-66.68% NO inhibition) were slightly lower than that of the non-treated EL extract (10.34-77.93% NO inhibition). Nonsugar honey constituents also exhibited anti-inflammatory effects. The combination of EL extract and honey resulted in a slightly lower anti-inflammatory activity (11.66-68.55% NO inhibition) compared with the EL extract. Honey and NADES enhanced the extraction and stabilization of bioactive compounds from EL. The anti-inflammatory properties of EL were preserved after honey treatment, indicating that honey-treated EL is a potential natural treatment for inflammatory conditions.

The Comparative Study of the Antioxidant and Antibacterial Effects of Propolis Extracts in Veterinary Medicine

Antimicrobial resistance (AMR) is one of the biggest threats to human and animal health. Efforts to combat AMR include the introduction of antimicrobial drugs as alternative treatment options. To contribute to an effective plan for the treatment of infectious diseases caused by bacteria, the development of new antimicrobial agents is increasingly being explored. Propolis has garnered significant attention from both scientists and industry due to its extensive spectrum of biological activity. The growing interest in polyphenols of natural origin and their plant sources further encourages the investigation of their chemical composition and biological effects. Propolis serves as a rich source of phenolic compounds. Baltic region propolis, classified as poplar-type propolis, was selected for this study, and extracts were prepared using raw propolis materials from various Baltic countries. The production of liquid extracts utilized a combination of 70 percent ethanol, a mixture of water and poloxamer P407, and DES (deep eutectic solvent). The research aims to produce liquid propolis extracts using different solvents and to assess their chemical composition, antioxidant, and antimicrobial activity against different veterinary pathogens. Antioxidant activity was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), revealing antioxidant activity in all extracts, with results correlating with the total phenolic compound content. It was found that p-coumaric acid predominated in the studied propolis extracts (in ethanol extracts 1155.90-1506.65 mg/g, in DES extracts 321.13-954.76 mg/g, and in polymeric extracts 5.34-30.80 mg/g), with smaller amounts of ferulic acid and vanillin detected. Clinical and reference bacterial strains were collected from the Lithuanian University of Health Sciences, the Academy of Veterinary Medicine, and the Institute of Microbiology and Virology. To effectively treat bacterial infections, the antimicrobial activity of propolis extracts was tested against six pathogenic bacterial species and one pathogenic fungus (S. aureus, S. agalactiae, B. cereus, E. faecalis, E. coli, P. aeruginosa, and C. albicans). Antimicrobial activity studies demonstrated that DES propolis extracts exhibited stronger antimicrobial activity compared to ethanolic propolis extracts. The minimum inhibitory concentration (MIC) values of DES propolis extracts against the tested strains ranged between 50 and 1000 μg/mL. Considering the study results, it can be concluded that propolis from the Baltic region is abundant in phenolic compounds exhibiting antioxidant and antibacterial activities.

Propolis as a functional food and promising agent for oral health and microbiota balance: A review study

Bee Propolis has been used for its therapeutic properties, including anti-inflammatory, antibacterial, antifungal, and immune-stimulating properties, for centuries as a functional food. This study reviewed the effectiveness of propolis as a functional food on oral-related diseases as a rich bioflavonoid produced by honey bees. A literature search was conducted to identify studies published that investigated the effects of propolis on oral health and its ability to treat related diseases. The search was performed in electronic databases using relevant keywords. Initially, 3429 studies were identified through database searching, and based on the inclusion and exclusion criteria, 22 articles were eligible to be included. Reviewing the articles, propolis was recognized as a functional food and promising agent to balance oral microbiota and prevent oral diseases due to its effectiveness on related bacteria, its anti-inflammatory properties, and its activity against Porphyromonas gingivalis and Actinomyces Oris allowed it to be an effective substance to prevent periodontal diseases. Based on our findings, Propolis is a desirable preventive option for various oral health conditions, including dental caries and periodontal diseases. Therefore, it is recommended to be consumed as a functional food in our daily diet, which can reduce the risk of oral disease and improve oral health.

Investigation of antifungal and antibacterial potential of green extracts of propolis

Propolis extracts have been used in traditional medicines since ages due to its advantageous complex chemical composition. However, the antibacterial and antifungal activity of poplar propolis extracts prepared in Natural Deep Eutectic Solvent (NADES) are seldom studied. This study investigates suitable alternate for ethanol as a solvent for extraction for Polish poplar propolis. It also attempts to identify suitable extraction condition for the efficient transfer of compounds from propolis to the solvents. The extraction efficiency of NADES extracts was assessed in terms of total phenolic content, antioxidant activity and antimicrobial activity. The chemical composition of the extracts was analysed using UHPLC-DAD-QqTOF-MS. Four extracts, prepared in Propylene Glycol, Choline Chloride:Propylene Glycol (1:3), Choline Chloride:Propylene Glycol (1:4) and Choline Chloride:Glycerol (1:2), demonstrated activity and properties similar to ethanolic extract and extraction at 50 °C was found the most suitable for propolis. HPLC analysis confirmed that the chemical cocktail extracted by these solvents from propolis were identical with minor variations in their concentration as compared to its ethanolic extract. Thus, extracts of propolis at 50 °C in Propylene Glycol, Choline Chloride:Propylene Glycol (1:3) and Choline Chloride:Propylene Glycol (1:4) can be alternates for ethanolic extracts.

Insight into the influence of natural deep eutectic solvents on the extraction of phenolic compounds from poplar type propolis: Composition and in vitro biological activity

Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.

Exploring the Functional Properties of Propolis, Geopropolis, and Cerumen, with a Special Emphasis on Their Antimicrobial Effects

Bee propolis has been touted as a natural antimicrobial agent with the potential to replace antibiotics. Numerous reports and reviews have highlighted the functionalities and applications of the natural compound. Despite much clamor for the downstream application of propolis, there remain many grounds to cover, especially in the upstream production, and factors affecting the quality of the propolis. Moreover, geopropolis and cerumen, akin to propolis, hold promise for diverse human applications, yet their benefits and intricate manufacturing processes remain subjects of intensive research. Specialized cement bees are pivotal in gathering and transporting plant resins from suitable sources to their nests. Contrary to common belief, these resins are directly applied within the hive, smoothed out by cement bees, and blended with beeswax and trace components to create raw propolis. Beekeepers subsequently harvest and perform the extraction of the raw propolis to form the final propolis extract that is sold on the market. As a result of the production process, intrinsic and extrinsic factors, such as botanical origins, bee species, and the extraction process, have a direct impact on the quality of the final propolis extract. Towards the end of this paper, a section is dedicated to highlighting the antimicrobial potency of propolis extract.

Development and Characterization of New Green Propolis Extract Formulations as Promising Candidates to Substitute for Green Propolis Hydroalcoholic Extract

The technologies used to produce the different dosage forms of propolis can selectively affect the original propolis compounds and their biological activities. The most common type of propolis extract is hydroethanolic. However, there is considerable demand for ethanol-free propolis presentations, including stable powder forms. Three propolis extract formulations were developed and investigated for chemical composition and antioxidant and antimicrobial activity: polar propolis fraction (PPF), soluble propolis dry extract (PSDE), and microencapsulated propolis extract (MPE). The different technologies used to produce the extracts affected their physical appearance, chemical profile, and biological activity. PPF was found to contain mainly caffeic and p-Coumaric acid, while PSDE and MPE showed a chemical fingerprint closer to the original green propolis hydroalcoholic extract used. MPE, a fine powder (40% propolis in gum Arabic), was readily dispersible in water, and had less intense flavor, taste, and color than PSDE. PSDE, a fine powder (80% propolis) in maltodextrin as a carrier, was perfectly water-soluble and could be used in liquid formulations; it is transparent and has a strong bitter taste. PPF, a purified solid with large amounts of caffeic and p-Coumaric acids, had the highest antioxidant and antimicrobial activity, and therefore merits further study. PSDE and MPE had antioxidant and antimicrobial properties and could be used in products tailored to specific needs.

Reaction of the Phytochemistry Community to Green Chemistry: Insights Obtained Since 1990

This review article aims to study how phytochemists have reacted to green chemistry insights since 1990, the year when the U.S. Environmental Protection Agency launched the "Pollution Prevention Act". For each year in the period 1990 to 2019, three highly cited phytochemistry papers that provided enough information about the experimental procedures utilized were sampled. The "greenness" of these procedures was assessed, particularly for the use of solvents. The highly hazardous diethyl ether, benzene, and carbon tetrachloride did not appear in the papers sampled after 2010. Advances in terms of sustainability were observed mainly in the extraction stage. Similar progress was not observed in purification procedures, where chloroform, dichloromethane, and hexane regularly have been employed. Since replacing such solvents in purification procedures should be a major goal, potential alternative approaches are discussed. Moreover, some current initiatives toward a more sustainable phytochemical research considering aspects other than only solvents are highlighted. Although some advances have been achieved, it is believed that natural products chemists can play a major role in developing a novel ecological paradigm in chemistry. To contribute to this objective, six principles for performing natural products chemistry consistent with the guidelines of green chemistry are proposed.

Natural Deep Eutectic Solvents (NADESs) Combined with Sustainable Extraction Techniques: A Review of the Green Chemistry Approach in Food Analysis

Usual extraction processes for analyzing foods, supplements, and nutraceutical products involve massive amounts of organic solvents contributing to a negative impact on the environment and human health. In recent years, a new class of green solvents called natural deep eutectic solvents (NADES) have been considered a valid alternative to conventional solvents. Compared with conventional organic solvents, NADES have attracted considerable attention since they are sustainable, biodegradable, and non-toxic but also are easy to prepare, and have low production costs. Here we summarize the major aspects of NADEs such as the classification, preparation method physicochemical properties, and toxicity. Moreover, we provide an overview of novel extraction techniques using NADES as potential extractants of bioactive compounds from foods and food by-products, and application of NADEs in food analysis. This review aims to be useful for the further development of NAES and for broadening the knowledge of these new green solvents in order to increase their use for the extraction of bioactive compounds and in food analysis.

Deep Eutectic Liquids as Tailorable Extraction Solvents: A Review of Opportunities and Challenges

Deep Eutectic Liquids (DELs) fall among the rapidly evolving discoveries of the 21st century, and these liquids are considered as alternative solvents to toxic and volatile organic liquids. Nevertheless, the emerging trend regarding the use of DELs in every field of physical and biological sciences, a lot of ambiguities and misconceptions exist about their formation, mechanism, and efficiencies observed or projected. A review of available technical data makes it obvious that these liquids have the potential to revolutionize the underdeveloped areas of analytical chemistry particularly the extraction/enrichment of analytes. To ensure the green and sustainable use of DELs, the researchers need to have a thorough understanding of DELs, their classification, chemistry, the nature and strength of molecular entanglements, and their tailorable features. Many researchers have declared these liquids recyclable but more attentive trials are needed to develop an authentic and straightforward DELs recycling methodology. The present review covers sound background knowledge and expert opinions about the technical definition of DELs, their classification, formation, recyclability, and tailorable features for their application as extraction solvent/sorbent in analytical chemistry.

Differential proteome and functional analysis of NSCLC cell lines in response to Tualang honey treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Honey's therapeutic and nutrition effects have been discovered for centuries. Traditionally, it is applied as a health supplement as well as an alternative treatment for a variety of medical issues ranging from wound healing to anticancer therapy. Tualang honey (TH) is a natural sweet substance produced by Apis dorsata, naturally has a dark brown appearance from its high polyphenolic compounds. TH has been reported to show anticancer effects on various types of cancers including breast, oral, leukemia, cervical and lung cancer through several pathways. The detailed molecular mechanism of anticancer activity of TH as a chemopreventive and therapeutic agent is an interesting endeavor to understand.

AIM OF THE STUDY

Despite the anticancer effects of Tualang honey (TH) on various types of cancer have been widely reported, the exact molecular mechanism underlying its' anticancer action remains unpublished. Thus, this study aimed to investigate changes that occur on the proteome profile and the functional analysis of proteins with differential abundances within non-small cell lung cancer (NSCLC) cells that were treated with TH and discover the plausible molecular mechanism governing its' anticancer action.

MATERIALS AND METHODS

NSCLC cell lines (H23 and A549) were treated with 3.6% and 3.1% v/v of TH for 24 h, respectively. Protein extracts were obtained from control NSCLC cells and TH-treated NSCLC cells. Label-free quantitative proteomic analysis was subsequently performed in nanoACQUITY UPLC with quadrupole-time of flight (Q-TOF) Synapt G2 HDMS mass spectrometer system to identify and quantify proteins of TH-treated NSCLC cells. The gene ontology (GO) PANTHER classification system was performed to categorize the identified proteins based on their protein class, biological processes, and pathway. Meanwhile, the STRING functional protein association network database was used to analyze the functional protein-protein interaction and associated pathways of significantly different proteins of NSCLC cells.

RESULTS

A total of 634 and 554 proteins were identified from H23 and A549 cell lines where 88 differential proteins were upregulated and 103 were downregulated in TH-treated H23 cells, whilst 66 differential proteins were upregulated and 61 were downregulated in TH-treated A549 cells. Differently expressed proteins of NSCLC were observed to be associated with the cell cycle, apoptosis, and VEGFA-VEGFR signaling pathway. TH modulated these signaling pathways through downregulation of ELAVL1, H3F3A and PCNA proteins. Three potential protein markers were significantly downregulated in NSCLC cells such as HRAS, HSPB1, and TUBA1C when treated with TH.

CONCLUSIONS

Our findings suggested the anticancer activity of TH on NSCLC cells through modulation of pertinent cancer-related proteins that are associated with cell proliferation, apoptosis inhibition, and induction of angiogenesis.

Influence of choline chloride-based NADES on the composition of Myristica fragrans Houtt. essential oil

Natural deep eutectic solvents (NADES) have emerged as green extracting solvents in recent years. In this study, a variety of choline chloride (ChCl)-based natural deep eutectic solvents (NADES) were used as co-solvents for the hydrodistillation of nutmeg with the aim to obtain M. fragrans essential oil (EO) in higher yield and with a lower content of toxic phenylpropenoids (e.g. myristicin and safrole). The influence of ChCl-based NADES as additives in the hydrodistillation process was studied. The results showed that NADES additives improved the yield of the extracted essential oil and influenced its composition leading to a decrease in toxic phenylpropenoids. Best results were achieved by using ChCl-CA NADES ultrasound-assisted pretreatment coupled with traditional 2 ​h Clevenger hydrodistillation that increased the yield of the EO from 0.98% (traditional) to 1.41% and a decrease of the phenylpropenoids amount in the essential oil.

Natural Deep Eutectic Solvents (NADES): Phytochemical Extraction Performance Enhancer for Pharmaceutical and Nutraceutical Product Development

Natural products from plants were extracted and widely studied for their activities against many disease conditions. The selection of the extracting solvent is crucial to develop selective and effective methods for the extraction and isolation of target compounds in the plant matrices. Pharmacological properties of plant extracts and their bioactive principles are related to their excellent solubility, stability, and bioavailability when administered by different routes. This review aims to critically analyze natural deep eutectic solvents (NADES) as green solvents in their application to improve the extraction performance of plant metabolites in terms of their extractability besides the stability, bioactivity, solubility, and bioavailability. Herein, the opportunities for NADES to be used in pharmaceutical formulations development including plant metabolites-based nutraceuticals are discussed.

Red Propolis as a Source of Antimicrobial Phytochemicals: Extraction Using High-Performance Alternative Solvents

Propolis is a resinous material rich in flavonoids and involved in several biological activities such as antimicrobial, fungicide, and antiparasitic functions. Conventionally, ethanolic solutions are used to obtain propolis phytochemicals, which restrict their use in some cultures. Given this, we developed an alcohol-free high-performance extractive approach to recover antibacterial and antioxidants phytochemicals from red propolis. Thus, aqueous-solutions of ionic liquids (IL) and eutectic solvents were used and then tested for their total flavonoids, antioxidant, and antimicrobial activities. The surface-responsive technique was applied regarding some variables, namely, the time of extraction, the number of extractions, and cavitation power (W), to optimize the process (in terms of higher yields of flavonoids and better antioxidant activity). After that, four extractions with the same biomass (repetitions) using 1-hexyl-3-methylimidazolium chloride [C6mim]Cl, under the operational conditions fixed at 3.3 min and 300 W, were able to recover 394.39 ± 36.30 mg RuE. g-1 of total flavonoids, with total antioxidant capacity evaluated up to 7595.77 ± 5.48 μmol TE. g-1 dried biomass, besides inhibiting the growth of Staphylococcus aureus and Salmonella enteritidis bacteria (inhibition halo of 23.0 ± 1.0 and 15.7 ± 2.1, respectively). Aiming at the development of new technologies, the antimicrobial effect also presented by [C6mim]Cl may be appealing, and future studies are required to understand possible synergistic actions with propolis phytochemicals. Thereby, we successfully applied a completely alcohol-free method to obtain antimicrobials phytochemicals and highly antioxidants from red propolis, representing an optimized process to replace the conventional extracts produced until now.

Propolis Extract and Its Bioactive Compounds-From Traditional to Modern Extraction Technologies

Propolis is a honeybee product known for its antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. It is rich in bioactive molecules whose content varies depending on the botanical and geographical origin of propolis. These bioactive molecules have been studied individually and as a part of propolis extracts, as they can be used as representative markers for propolis standardization. Here, we compare the pharmacological effects of representative polyphenols and whole propolis extracts. Based on the literature data, polyphenols and extracts act by suppressing similar targets, from pro-inflammatory TNF/NF-κB to the pro-proliferative MAPK/ERK pathway. In addition, they activate similar antioxidant mechanisms of action, like Nrf2-ARE intracellular antioxidant pathway, and they all have antimicrobial activity. These similarities do not imply that we should attribute the action of propolis solely to the most representative compounds. Moreover, its pharmacological effects will depend on the efficacy of these compounds’ extraction. Thus, we also give an overview of different propolis extraction technologies, from traditional to modern ones, which are environmentally friendlier. These technologies belong to an open research area that needs further effective solutions in terms of well-standardized liquid and solid extracts, which would be reliable in their pharmacological effects, environmentally friendly, and sustainable for production.

NADES-based surfactant-free microemulsions for solubilization and extraction of curcumin from Curcuma Longa

A choline chloride + lactic acid (1:1) natural deep eutectic solvent (NADES) is used as an adjuvant to ethanol/triacetin mixtures to solubilize and extract curcumin from Curcuma Longa. The obtained NADES/ethanol/triacetin mixtures are homogeneous, transparent and of low viscosity even in the absence of water. Dynamic light scattering revealed significant nanostructures, typical of surfactant-free microemulsions. A twofold increase of curcumin solubility and remarkable extraction power (yield of ~90%) can be achieved in the ternary system including the NADES, although curcumin is hydrophobic and the used NADES are very polar. Due to the elevated solubility of curcumin, more extraction cycles can be made than in the previously published aqueous systems with the same amount of solution. As a result, less solvent is required to achieve the same extraction yield.

Simple and Green Heat-Induced Deep Eutectic Solvent Microextraction for Determination of Lead and Cadmium in Vegetable Samples by Flame Atomic Absorption Spectrometry: a Multivariate Study

In this study, a simple, green, and cheap analytical procedure based on heat-induced deep eutectic solvent microextraction (HI-DES-ME) coupled with flame atomic absorption spectrometer (FAAS) was developed for the determination of Pb(II) and Cd(II) in vegetables. After the preliminary experiment, response surface methodology (RMS) based on central composite design (CCD) was used for the optimization of critical factors such as pH of sample solution, amount of extraction solvent, temperature, and amount of ligand. Microwave step was applied for the digestion of vegetable samples. Under optimum conditions obtained by the CCD, calibration graphs for Pb(II) and Cd(II) were linear in the concentration range of 0.5-250 and 1.0-300 ng mL^-1, respectively. Limits of detection (LODs) and sensitivity enhancement factor (SIFs) were found in the range of 0.17-0.35 ng mL^-1 and 93-67 ng mL^-1, respectively. Relative standard deviations (N = 10, RSDs%) for Pb(II) (10 ng mL^-1) and Cd(II) (50 ng mL^-1) were 3.7% and 2.3%, respectively. In order to validate the proposed method, certified reference material (CRM) and spiked samples were used. Experimental results showed that there was no significant difference between the obtained and certified values. Then, the proposed method was successfully applied for the preconcentration and determination of Pb(II) and Cd(II) in different vegetables.

A sensitive and visual molecularly imprinted fluorescent sensor incorporating CaF2 quantum dots and β-cyclodextrins for 5-hydroxymethylfurfural detection

Calcium fluoride (CaF₂) quantum dots have many applications in various fields. But there is no report on fluorescent characteristics of CaF₂ quantum dots (CaF₂ QDs). Here, a synthesis of multiple-color emission CaF₂ QDs by changing the temperature, time and raw ratio is reported, by which the CaF₂ QDs with purple, blue, green, and yellow emission can be obtained, respectively. They were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). On this basis, a novel molecular imprinting ratiometric fluorescence sensor (MIR sensor) had been constructed based on the prepared CaF₂ QDs and CdTe QDs, in which the yellow emission CaF₂ QDs was used as a responsive signal material and the red emission CdTe QDs was served as a reference signal material. And the β-CD and methylacrylic acid (MAA) as bifunctional monomers were used for constructing the specific molecularly imprinted polymers (MIPs) in MIR sensor. This MIR sensor was applied for highly selective and excellent sensitive detection of 5-hydroxymethylfurfural (HMF). Under optimum conditions, it exhibited an excellent linear relationship between the fluorescence intensity ratio (I₅₉₉/I₆₂₅) and the concentration of HMF in the range of 0.1-6.0 μg/mL with a detection limit of 0.043 μg/mL. Finally, the established HMF-MIR sensor was successfully utilized to detect HMF in honey with satisfactory results. This work provided a reference for the application of the CaF₂ QDs and the detection of the furfural substances.

Application of Deep Eutectic Solvents in Food Analysis: A Review

Deep eutectic solvents (DESs) have emerged recently as new and green solvents. DESs can be used for extraction and separation of both inorganic metallic components and organic compounds such as phenolic compounds, flavonoids, sugars, and aromatic amines from food samples. DESs possess a tunable property simply by adjusting the ratio of hydrogen bond acceptors to the hydrogen bond donors. As a green extraction medium, DESs have various applications in the pretreatment process and improve the efficiency of different food analyses. This review summarizes the findings of recent studies on the development, production, application, and efficacy of DESs in the pretreatment process of various food analyses.