Efficient extraction of flavonoids from Polygonatum sibiricum using a deep eutectic solvent as a green extraction solvent

Green extraction of bioactive flavonoids in Scutellariae Radix using deep eutectic solvents-based ultrasound-assisted matrix solid phase dispersion combined with computer-aided analysis

An efficient and sustainable deep eutectic solvents-based ultrasound-assisted matrix solid phase dispersion (DES-UAMSPD) method was proposed for extracting the bioactive flavonoids in Scutellariae Radix (SR), with molecular sieve (ZSM-5) as dispersant and betaine-levulinic acid (Bet-Lea (1:2, 50 % water content)) as the effective extractant. The interaction mechanism of DES formation and extraction process was comprehensively elucidated by computer simulation techniques such as electrostatic potential (ESP) distributions, independent gradient model based on hirshfeld partition (IGMH) and frontier molecular orbitals theory. The response surface methodology experiments were conducted to optimize the extraction conditions. Under optimal extraction conditions, the total content of five analytes (baicalin, oroxyloside, wogonoside, baicalein and wogonin) reached 182.66 mg g-1, which was 1.50-2.19 folds higher than conventional extraction solvents. The greenness and environmental friendliness of the proposed method were evaluated through Green Analytical Procedure Index and Analytical Eco-Scale. Additionally, this quantitative method exhibited reliable linearity for the analytes (r2 > 0.9997) and excellent recovery (95.4 %-102 %, RSD < 2.72 %). The limits of detection ranged from 0.02 to 0.04 μg mL-1. Overall, these results highlighted the excellent extraction and quantification capability of the proposed approach, which offered an environmentally friendly strategy for effective extraction of bioactive compounds from natural products.

Deep eutectic solvents in food contaminants detection: Characteristics, interaction mechanism and application advances from extracting to other roles

Food safety is crucial for public health, yet it faces growing threats from environmental and anthropogenic pollutants. Deep eutectic solvents (DESs) have emerged as green and efficient alternative solvents for detecting trace pollutants. This review highlights the characteristics of DESs, their mechanisms for extracting target analytes and applications in food analysis. Subsequently, the challenges faced by DESs in the detection of food samples and future development trends are further discussed. DESs can selectively interact with various target analytes (including pesticides, veterinary drugs, food additives, heavy metals, toxins, and other residues) during the food safety testing process by forming hydrogen bond networks. Beyond serving as extraction solvents, DESs can act as adsorbents, eluents, and reaction media, thereby simplifying sample pretreatment and enhancing the detection performance of various contaminants. Overall, as customizable functional solvents, DESs hold great promise for advancing next-generation food analysis methods, though some technical barriers remain to be addressed.

Synergistic coupling of ultrasonic cavitation with tailored deep eutectic solvent systems for intensified extraction of Scutellaria Radix flavonoids: Modelling and optimization by genetic algorithm

Deep eutectic solvents (DESs) are increasingly recognized as viable environmentally friendly alternatives to traditional organic solvents because of their low toxicity and exceptional dissolving capabilities. In this research, 12 DESs were synthesized and systematically integrated with ultrasonic-assisted extraction (UAE) to extract flavonoids from Scutellaria Radix. Comprehensive screening revealed that the optimal DES outperformed conventional solvents (water and 70 % ethanol) in extraction efficiency. Through statistical optimization, including single-factor experiments, response surface methodology, and an artificial neural network-genetic algorithm, we achieved remarkable extraction yields for six target flavonoids: scutellarin (3.88 ± 0.37), baicalin (137.67 ± 8.61), wogonoside (13.40 ± 0.58), baicalein (27.95 ± 1.12), wogonin (15.95 ± 1.48), and chrysin (1.81 ± 0.21 mg/g). These values represented significant improvements over conventional extraction methods. Subsequent enrichment processes yielded flavonoid recovery rates of 76.80-85.13 %, and demonstrated excellent DES recyclability over four consecutive extraction cycles. In sum, this work establishes a sustainable, high-efficiency platform for phytochemical extraction, offering substantial advances in sustainable natural product processing through intelligent solvent design and process optimization.

Protein extraction from detoxified cassava leaves using various deep eutectic solvents: A sustainable strategy to enhance nutritional and functional properties

Cassava (Manihot esculenta) leaves, containing 20-30 % protein and essential amino acids (EAAs), present a promising source of sustainable plant-based protein alternatives. Deep eutectic solvent (DES) offers an eco-friendly, emerging solution for qualitative protein with great functionality, superior to the alkaline extraction-isoelectric precipitation (AE-IP). In this study, the protein extraction from detoxified cassava leaves using eight DESs composed of various HBAs and HBDs. Their physical properties, strong hydrogen bonds, and hydroxyl interactions were most effective for protein extraction. DES-8 (lactic acid: glycerol), emerged as optimal, providing higher protein content and recovery yield 22.16 ± 0.36 mg/g dm and 73.77 ± 1.05 %, respectively while slight reduction in extraction yield (16.85 ± 0.41 %) In addition, the extracted protein (DCPI-D8) exhibited superior EAAs (40.36 %) leading hydrophilic amino acids (60.16 %). Lactic acid's mild acidity and glycerol's stabilizing properties preserved DCPI-D8's nutritional properties, significantly reducing antinutrients while maintaining protein integrity and enhancing its structural and functional qualities compared to AE-IP.

Ionic Liquid-Based Polarity-Adjustable Deep Eutectic Solvent Extraction Followed by High-Performance Liquid Chromatography-Diode-Array Detection for the Determination of Liposoluble Anthraquinones in Salvia miltiorrhiza Bge. Root

A simple, green, and efficient ultrasound-assisted deep eutectic solvents (DESs) extraction followed by high-performance liquid chromatography-diode array detector was established to detect four liposoluble anthraquinones in Salvia miltiorrhiza Bge. root. In this study, a series of polarity-adjustable DESs were prepared using n-hexanol and tetrabutylammonium chloride, and their structure, density, viscosity, pH, and thermal stability were determined. The conditions for extraction were optimized through single-factor experiments and response surface methodology. The kinetic and thermodynamic properties associated with the ultrasound-assisted extraction of anthraquinones were investigated. The results showed that the standard curves for anthraquinones showed excellent linearity from 0.018 to 150 µg mL-1 (r > 0.9998). The detection and quantification limits varied from 5.04 to 5.60 ng mL-1 and 16.81 to 18.67 ng mL-1, respectively. The recoveries were measured as 84.1%-95.1%, and the relative standard deviations were not exceeded 4.6%.

Preparation, Structure, Function, and Application of Dietary Polysaccharides from Polygonatum sibiricum in the Food Industry: A Review

Polygonatum sibiricum is one of the most widely used plants in the Liliaceae family, renowned for its dual medicinal and edible properties. Polygonatum sibiricum polysaccharides, as the main pharmacological active ingredient of Polygonatum sibiricum, have various excellent physiological activities, such as antioxidant, immune enhancement, and hypoglycemic activities. Through extraction, purification, and structural analysis, the influence and mechanism of the molecular weight and glycosidic bonds of Polygonatum sibiricum polysaccharides on the pharmacological effects, as well as their structure-activity relationship, can be explored in more detail. With the increasing demand for Polygonatum sibiricum polysaccharide products, Polygonatum sibiricum has been widely used in the fields of medicine, food, and biochemistry, and various green and harmless products containing Polygonatum sibiricum polysaccharides have been developed for different populations. This study summarizes the extraction, structure, and function of Polygonatum sibiricum polysaccharides, and it further explores their applications in the food industry, including in beverages, health foods, additives, and food packaging. Overall, Polygonatum sibiricum polysaccharides have been proven to be a promising natural product and have been introduced into the food system. It is worth mentioning that further efforts and time are needed in the future to expand the deep processing of and feasibility research on Polygonatum sibiricum polysaccharides while exploring their bioactive molecular mechanisms in depth, laying the foundation for their product development and clinical applications.

Green Extraction of Antioxidant-Rich Flavonoids from Fagonia cretica Using Deep Eutectic Solvents

This study optimized the extraction of flavonoids from Fagonia cretica using deep eutectic solvents (DESs), focusing on key factors such as the type of DES used, molar ratio, water content, solid/liquid ratio, extraction temperature, and time. Among six DESs tested, the betaine-acetic acid combination exhibited the highest extraction efficiency, attributed to its low viscosity (4.98 mPa·s). Optimal extraction conditions were determined to be a 1:4 molar ratio of betaine to acetic acid, a 25% water content, a solid/liquid ratio of 1:60 g/mL, an extraction temperature of 50 °C, and an extraction time of 30 min. Under these conditions, the flavonoid yield was maximized while preserving bioactivity. Antioxidant assays revealed that flavonoids extracted with DESs exhibited superior scavenging activity against DPPH and hydroxyl radical compared to ethanol-extracted flavonoids, highlighting DESs' potential to enhance antioxidant properties. The recyclability of DESs was demonstrated using ultracapacitor porous activated carbon, achieving an 89.78% recovery efficiency. The reused DES maintained a high flavonoid extraction yield, retaining 92% efficiency after six cycles, emphasizing its sustainability and cost-effectiveness. This study establishes DES-based extraction as an environmentally friendly and efficient approach for isolating flavonoids with strong antioxidant properties, offering significant advantages in green chemistry and bioactive compound recovery.

Deep Eutectic Solvent-Based Ultrasound-Assisted Extraction of Flavonoids from Houttuynia cordata

Recently, deep eutectic solvents (DESs) have attracted much attention in the extraction and separation field because of their green characteristics, and they are widely used to extract various bioactive substances from plants. In this study, ten choline chloride (ChCl)-based mixtures were selected for extracting flavonoids from Houttuynia cordata. Then, the optimal conditions for the DES-based extraction of Houttuynia cordata flavonoids (HCFs) were determined through one-way experiments and response surface optimization (RSM). The optimal conditions were a 60 min extraction time, an extraction temperature of 40 °C, a water content of 30%, a solid-liquid ratio of 1:22 g·mL-1, a molar ratio of 1:2, and an ultrasound power of 420 W. The antioxidant capacities of HCFs in terms of ABTS radical, DPPH radical, and hydroxyl radical scavenging capacity and nitrite inhibition capacity were determined. DESs can be efficiently recycled after extraction. This study developed an effective and environmentally friendly method for HCF extraction, thereby also supporting the development and utilization of natural products.

Enhanced Extraction and Separation with HPLC-DAD of Phenolic and Flavonoid Antioxidants from Portulaca oleracea L. Leaves Using Tailored Terpenoid-Based NADES: Comparative Assessment of Antiradical and Antimicrobial Activities

This study evaluates Natural Deep Eutectic Solvents (NADES) for extracting antioxidant compounds from Portulaca oleracea dried leaves, compared to traditional ethanol extraction. NADES were synthesized using terpenoids (menthol and β-citronellol) and organic acids (lactic and capric acid), characterized by favorable viscosity, density, and pH, ensuring liquid stability at ambient temperature. NADES extraction outperformed ethanol, with NADES 1 yielding the highest bioactive contents: 83.66 Eq GA/mg, 786.55 Eq Q/mg, and 0.78 Eq C/mg versus ethanol's 58.49 Eq GA/mg, 363.23 Eq Q/mg, and 0.44 Eq C/mg. HPLC-DAD analysis identified higher levels of phenolic acids (caffeic and syringic acid) and flavonoids (rutin and quercetin) in NADES extracts, compounds absent in ethanol. Antioxidant potential, assessed via IC50 values, confirmed superior activity for NADES extracts (NADES 1-Ext: IC50 28.10 ± 1.73 µg/µL) compared to ethanol (IC50 1615.97 ± 5.34 µg/µL), and the Trolox method has confirmed extensively this superiority. Additionally, NADES demonstrated improved antimicrobial effects, varying with microorganisms. Despite their high viscosity potentially limiting extraction efficiency, adjusting temperature offers a promising approach to enhance mass transfer. These findings emphasize NADES as a sustainable alternative for bioactive compound extraction, paving the way for optimizing extraction techniques through viscosity reduction strategies.

Green and efficient extraction of phenolic compounds from Neem leaves using deep eutectic solvents based ultrasonic-assisted extraction

Deep eutectic solvent (DES) combined with ultrasonic-assisted extraction was employed as an environmentally friendly technique for extracting antioxidant phenolic compounds from Neem leaves in place of organic solvents. Choline chloride-Ethylene glycol (1:2) with 40% V/V water content (DES-1) was investigated as a potential total phenolic content extractant (38.2 ± 1.2 mg GAE/g DW, where GAE: gallic acid equivalent, DW: dry weight). The optimal operational parameters assessed using single-factor experiments to maximize the total phenolic compounds content were as follows: extraction time of 30 min, 40% V/V water content, liquid-solid ratio of 15:1, and room temperature. Additionally, the in-vitro antioxidant experiments (2,2-diphenyl-1- picrylhydrazyl radical scavenging assay and ferric reducing antioxidant power assay) demonstrated the DES-1-based extract of Neem leaves as a potent antioxidant agent, compared to traditional solvents. Moreover, microscopic morphological analysis supported the effectiveness of DES-1 for the noticeable alteration in the fiber surface structure of Neem leaves after extraction which benefited in the release of polyphenols from these leaves. Eventually, the mass analysis of the extract disclosed the presence of eleven polyphenols in the extract. The Green Analytical Procedure Index revealed the greenness of the extraction method.

The Most Potent Natural Pharmaceuticals, Cosmetics, and Food Ingredients Isolated from Plants with Deep Eutectic Solvents

There is growing interest in reducing the number of synthetic products or additives and replacing them with natural ones. The pharmaceutical, cosmetic, and food industries are especially focused on natural and bioactive chemicals isolated from plants or microorganisms. The main challenge here is to develop efficient and ecological methods for their isolation. According to the strategies and rules of sustainable development and green chemistry, green solvents and environmentally friendly technologies must be used. The application of deep eutectic solvents as efficient and biodegradable solvents seems to be a promising alternative to traditional methods. They are classified as being green and ecological but, most importantly, very efficient extraction media compared to organic solvents. The aim of this review is to present the recent findings on green extraction, as well as the biological activities and the possible applications of natural plant ingredients, namely, phenolics, flavonoids, terpenes, saponins, and some others. This paper thoroughly reviews modern, ecological, and efficient extraction methods with the use of deep eutectic solvents (DESs). The newest findings, as well as the factors influencing the efficiency of extraction, such as water content, and hydrogen bond donor and acceptor types, as well as the extraction systems, are also discussed. New solutions to the major problem of separating DESs from the extract and for solvent recycling are also presented.

Determination of volatile components in cumin by microwave-assisted PDMS/GO/DES headspace solid phase extraction combined with GC-MS

A novel approach based on polydimethylsiloxane/graphene oxide/deep eutectic solvent (PDMS/GO/DES) sponge headspace solid phase extraction followed by GC-MS was successfully developed to determine the volatile components in cumin. The PDMS/GO/DES exhibits outstanding properties with high adsorption capacity and good chemical stability, and has shown its potentiality as an ideal adsorbent for the extraction of volatile compounds. The influence factors of the extraction process were investigated. Excellent analytical performances were achieved, including wide linearity (0.60-107.72 ng) with high correlation coefficients (R² ≥ 0.9951), low LODs (0.23-9.23 ng) and LOQs (0.54-18.47 ng), satisfactory precision (intra-day RSDs ≤ 2.85% and inter-day RSDs ≤ 3.92%). Under the optimal extraction conditions, the volatile components in 17 cumin samples from four origins in Xinjiang were analyzed and 31 compounds were identified. PCA was used to establish the relationship between the origins and the volatile compounds for further discriminant analysis. The results showed that the PDMS/GO/DES method was a rapid, simple and sensitive technique for the analysis of volatile components in spices.

DES: their effect on lignin and recycling performance

Lignocellulosic biomass raw materials are renewable resources with abundant reserves in nature, and have many advantages, such as being green, biodegradable and cheap. Lignin, one of the three significant components of lignocellulose, possesses a chemical structure rich in phenylpropane and is a primary aromatic resource for the bio-based economy. For the extraction and degradation of lignin, the most common method is the pretreatment of lignocellulose with deep eutectic solvents (DES), which have similar physicochemical properties to ionic liquids (ILs) but address the disadvantages associated with ILs (DES have the advantages of low cost, low toxicity, and non-flammability). In lignocellulose pretreatment, a large amount of solvent is generally required to achieve the desired effect. However, after treatment, a substantial volume of solvent will be wasted, and thus, the problem of the recovery and reuse of DES solution needs to be adequately solved. The methods and mechanisms of perfect DES regeneration will be discussed from the perspective of the elemental composition and features of DESs in this review, which will also outline the present DES recovery methods, such as rotary evaporation, membrane separation, freeze-drying, electrodialysis, etc. The detailed process and the advantages and disadvantages of each method since 2018 are introduced in detail. Future DES recovery methods have been prospected, and the optimization of the functional properties of DESs after recovery is discussed. It is expected to find a convenient and efficient application method for DES extraction or degradation of lignin with low energy and low cost.

Efficient Extraction of Flavonoids from Lotus Leaves by Ultrasonic-Assisted Deep Eutectic Solvent Extraction and Its Evaluation on Antioxidant Activities

The discovery of a green extraction solvent for natural plants could promote related research. In this study, deep eutectic solvents (DES) were used as green solvents coupled with an ultrasound-assisted extraction method (UAE) to extract flavonoids from lotus leaves. Thirty-four different DES were performed and choline chloride/urea with 40% water was chosen as the most promising one, and the related parameters in the procedures were optimized, resulting in the highest extraction amount of flavonoids in lotus leaves. D-101 was selected from four macroporous resins to separate the flavonoids from DES. Moreover, DES could be recycled and efficiently reused four times with satisfactory performances. In addition, the lotus leaf flavonoids from the DES extract exhibited antioxidant activities in five kinds of assays including DPPH, ABTS, Fe3+ reducing, FRAP, and Fe2+ chelating. It also showed antibacterial activities on Staphylococcus aureus and Escherichia coli bacterial strains with minimal inhibitory concentrations at 1666 μg/mL and 208 μg/mL, respectively. In the HPLC analysis, the three main components in the DES extract were identified as astragalin, hyperoside, and isoquercitrin. In conclusion, the developed UAE-DES followed by macroporous resin treatment could become an efficient and environmentally friendly extraction and enrichment method for flavonoids from lotus leaves and other natural products.

Main Bioactive Components and Their Biological Activities from Natural and Processed Rhizomes of Polygonum sibiricum

Polygonatum sibiricum (Asparagaceae) is often used as an herbal drug in the traditional medicine of Southeast Asia. Its rhizome, called “Huang Jing”, is used in traditional Chinese medicine as an immune system stimulant, hypolipidemic agent, anti-aging agent, anti-fatigue agent, and cardiovascular protectant. We investigated the antioxidant, anti-acetylcholinesterase (AChE), anti-inflammatory, and anti-α-glucosidase effects of various solvent extracts and major bioactive components of Polygonatum sibiricum (PS) and processed Polygonatum sibiricum (PPS). Dichloromethane extract of PS showed stronger antioxidant effects by DPPH, ABTS, and FRAP assays, and EtOAc extract displayed relatively high antioxidant activity by a superoxide radical scavenging test. Moreover, acetone, EtOAc, and dichloromethane extracts displayed a significant anti-α-glucosidase effect. EtOH and CH₂Cl₂ extracts showed effective AChE inhibitory activity. In addition, dichloromethane extract showed the best inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) accumulation in RAW264.7 macrophages. HPLC analysis was used to investigate and compare the content of major active components of various solvent extracts of PS and PPS. Rutin showed the most effective scavenging of DPPH and ABTS free radicals, while scopoletin and isoquercetin displayed the strongest anti-α-glucosidase and anti-AChE effect, respectively. Rutin showed the best inhibition against LPS-induced NO production and also inhibited inducible nitric oxide synthase (iNOS) expression in Western blot. The molecular docking of AChE and iNOS revealed that active components could have a better antagonistic effect than positive controls (common inhibitors). This study shows that the active extracts and components of Polygonatum sibiricum have the potential to be further developed as a natural anti-AChE, anti-α-glucosidase, antioxidant and anti-inflammatory agent.