Tailor-made Deep Eutectic Solvents Research Articles

Corrosion inhibition activity of a natural polysaccharide from Dysosma versipellis using tailor-made deep eutectic solvents

In this work, a total of 18 types of choline chloride, betaine, and L-proline-based deep eutectic solvents (DESs) were synthesized to determine the extraction yield of a natural polysaccharide (PSA) from Dysosma versipellis using an ultrasound-assisted extraction method. Results indicate that the choline-oxalic acid-based DES has the best extraction yield for PSA due to the proper physical-chemical properties between PSA and DES. To evaluate the optimal extraction conditions, a response surface methodology was carried out. Under the optimal conditions, the extraction yield of PSA reaches 10.37 % (± 0.03 %), higher than the conventional extraction methods. Findings from FT-IR and NMR suggest that the extracted PSA belongs to a neutral polysaccharide with (1 → 6)-linked α-d-glucopyranose in the main chain. Interestingly, results from various electrochemical measurements show the extracted PSA exhibits excellent corrosion inhibition performance for mild steel (MS) in a 0.5 M HCl solution, with 90.8 % of maximum corrosion inhibition efficiency at 210 mg L−1. SEM and XPS measurements reveal the formation of a protective layer on the MS surface. The adsorption behaviour of extracted PSA well obeys the Langmuir adsorption isotherm containing the chemisorption and physisorption. Additionally, theoretical calculations validate the experimental findings.

Ultrasonic-Assisted Extraction of Antioxidants from Perilla frutescens Leaves Based on Tailor-Made Deep Eutectic Solvents: Optimization and Antioxidant Activity.

The development of natural antioxidants to replace synthetic compounds is attractive. Perilla frutescens leaves were proven to be rich in antioxidants. The extraction of antioxidants from Perilla leaves via ultrasonic-assisted extraction (UAE) based on choline chloride-based deep eutectic solvents (DESs) was studied. Firstly, several DESs were prepared, and their extraction effects were compared. Secondly, the extraction process was optimized by single-factor experiments and response surface methodology (RSM). Finally, the optimization results were verified and compared with the results of traditional solvent-based UAE. The effects of solvents on the surface cell morphology of Perilla frutescens leaves were characterized by scanning electron microscopy (SEM). Choline chloride-acetic acid-based DES (ChCl-AcA) extract showed a relatively high ferric-reducing antioxidant activity (FRAP) and 2,2-diphenyl-1-picrylhyldrazyl radical scavenging rate (DPPH). Under the optimal operating conditions (temperature 41 °C, liquid-solid ratio 33:1, ultrasonic time 30 min, water content 25%, ultrasonic power 219 W), the experimental results are as follows: DPPH64.40% and FRAP0.40 mM Fe(II)SE/g DW. The experimental and predicted results were highly consistent with a low error (<3.38%). The values of the DPPH and FRAP were significantly higher than that for the water, ethanol, and butanol-based UAE. SEM analysis confirmed that ChCl-AcA enhanced the destruction of the cell wall, so that more antioxidants were released. This study provides an eco-friendly technology for the efficient extraction of antioxidants from Perilla frutescens leaves. The cytotoxicity and biodegradability of the extract will be further verified in a future work.

Tailor-Made Deep Eutectic Solvents for the Extraction of Natural Podophyllotoxin Product from Dysosma Versipellis and its Anti-Corrosion and Anti-Tumor Performances

Tailor-Made Deep Eutectic Solvents for the Extraction of Natural Podophyllotoxin Product from Dysosma Versipellis and its Anti-Corrosion and Anti-Tumor Performances

Tailor-made deep eutectic solvents extraction combined with UPLC-MS/MS determination of icarrin and icarisid II in rat plasma and its comparative pharmacokinetic application

Using green and high efficient solvents to extract and trace active ingredients of traditional Chinese medicine (TCM) in the complex biological samples was still challenging. In this paper, a co-friendly, fast pretreatment method with high extraction efficiency, based on the tailor-made deep eutectic solvent (DES) system, combined with ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination of icarrin and icarisid II in rat plasma samples, which can be further applied to comparative pharmacokinetic studies after oral administration of Herba Epimedii and icarrin monomer in rats, respectively. PrE (l-proline: ethylene glycol = 1:4 mol/mol) and acetonitrile were optimized and combined as the tailor-made DES at the volumetric ratio of 3:7 to extract icarrin and icarisid II, and to precipitate the protein in rat plasma in one step simultaneously. The extraction efficiency of the tailor-made DES was about 1.7 times of DES (PrE). The extraction recovery of icarrin and icarisid II in rat plasma samples by this method were within the range of 90–110 %, and the lower limits of quantification (LLOQ) were 0.32 ng mL−1 (icarrin) and 0.43 ng mL−1 (icarisid II). There was a linear relationship between 0.32−80.16 ng mL−1 (icarrin) and 0.43−107.4 ng mL−1 (icarisid II), which effectively reduced the detection limit. In this comparative pharmacokinetic study, the maximum plasma concentration (Cmax) and the area under plasma concentration-time curve (AUC0-∞) of two analytes in rat plasma of Herba Epimedii group were both much higher than those in the icarrin monomer group, which suggested that other ingredients in Herba Epimedii may contribute to the in vivo absorption of icarrin and icarisid II. This simple, rapid, relatively green and high effeicient method would provide a new approach for the extraction of active ingredients from complex biological samples.

Eco-friendly and high-efficient extraction of natural antioxidants from Polygonum aviculare leaves using tailor-made deep eutectic solvents as extractants

Herein, an eco-friendly deep eutectic solvents-based ultrasonic-assisted extraction (DES-based UAE) procedure was exploited for high efficient extraction of natural antioxidants from Polygonum aviculare leaves (PALs). Choline chloride-levulinic acid (ChCl-Lev) was adopted for the first time as extractants for further optimization. Based on the results of single-factor experiments, the optimal extraction conditions for simultaneously maximizing the TPC, TFC and antioxidant activities were obtained by response surface methodology (RSM). RSM results indicated that four independent variables had evident effects on all responses, while ultrasonic temperature and liquid to solid ratio (L/S) showed significant interaction effects on the TFC and FRAP. Under the optimal conditions (L/S of 85:1, ultrasonic time of 60 min, ultrasonic temperature of 70 °C and water content in DES of 38%), the corresponding responses resulted in: TPC-102.07 ± 2.51 mg GAE/g DW, TFC-69.43 ± 9.37 mg RE/g DW, DPPH•-315.26 ± 7.52 μmol TE/g DW, and FRAP-496.79 ± 6.38 mM Fe(Ⅱ)SE/g DW. The measured results were consistent with the predicted values. Moreover, a comparative study showed that the ChCl-Lev-based UAE resulted in higher TPC, TFC and antioxidant activities than other available extraction methods. HPLC-DAD analysis results showed that ChCl-Lev-based UAE yielded high levels of antioxidants including gallic acid (39.80 mg/g DW), 5-caffeoylquinic acid (11.83 mg/g DW), myricitrin (10.47 mg/g DW), 3′′-O-galloylmyricitrin (7.91 mg/g DW), 3-chlorogenic acid (7.16 mg/g DW), quercitrin (4.26 mg/g DW), and avicularin (3.02 mg/g DW). This study develops an eco-friendly and high-efficient ChCl-Lev-based UAE method to obtain extracts rich in natural antioxidants from medicinal plants, which can be well applied in food, cosmetic and pharmaceutical industries.

Selective extraction of quinolizidine alkaloids from Sophora flavescens Aiton root using tailor-made deep eutectic solvents and magnetic molecularly imprinted polymers

In this study, an eco-friendly extraction method that used tailor-made deep eutectic solvents (DESs) for the extraction of oxymatrine and matrine from Sophora flavescens Aiton root was implemented for the first time. The extraction parameters, including the DES type, DES water content, solid-to-liquid ratio, extraction time, and extraction temperature, which affected the extraction efficiencies of oxymatrine and matrine were optimised. High-performance liquid chromatography with a diode-array detector and quantitative analysis of the DES components was conducted. The highest oxymatrine and matrine extraction yields (21.04 and 1.53 mg·g−1, respectively) were obtained using DES-2 (comprising choline chloride and malonic acid; molar ratio of 1:2) with 50% water and DES-8 (comprising choline chloride and ethylene glycol; molar ratio of 1:2) with 30% water as the extraction solvents, respectively. Furthermore, magnetic molecularly imprinted polymers (MMIPs) were successfully synthesised using oxymatrine, acrylic acid, ethylene glycol dimethylacrylate, azobisisobutyronitrile, and acetonitrile–methylbenzene (3:1, v/v) as the template, functional monomer, cross-linker, initiator, and porogen, respectively. The MMIPs were characterised using transmission electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction analyses, and the results demonstrated the successful preparation of MMIPs. The adsorption properties of MMIPs were further analysed using static and dynamic adsorption experiments, and the results indicated that MMIPs presented good adsorption capacities for oxymatrine and matrine (110.8 and 63.4 mg·g−1, respectively). Lastly, MMIPs were used as sorbents for the extraction and enrichment of oxymatrine and matrine from DES extracts of S. flavescens roots. The extraction efficiencies of oxymatrine and matrine (80.21–89.15% and 85.33–95.28%, respectively) were satisfactory. The proposed DES-based extraction followed by MMIPs secondary enrichment appeared to be an effective method for the selective extraction of specific components from complex samples.

Deep eutectic solvents as green media for flavonoids extraction from the rhizomes of Polygonatum odoratum

Recent years have witnessed the growing popularity of deep eutectic solvents (DESs) in the extraction of functional components. As a novel green alternative to organic reagents, DESs are environmentally friendly, non-toxic, inexpensive, and biodegradable. In the present study, tailor-made DESs were prepared and applied for the first time to extract flavonoids from rhizomes of Polygonatum odoratum. We also investigated the extraction process, extraction efficiency, and solvent recovery efficiency. The response surface methodology (RSM) was adopted to optimise total flavonoid extraction, and the DES was recovered through macroporous resin adsorption. The results show that the DES synthesised by choline chloride and lactic acid at a molar ratio of 1:2 was the most suitable extraction medium. Extraction conditions were optimised as follows: extraction temperature of 51 °C, DES water content of 27%, liquid–solid ratio of 22 mL/g, and extraction time of 21 min. Under these conditions, the extraction rate of total flavonoids reached 11.47 mg/g, close to that of the heat reflux extraction (HRE) with organic solvents. The adsorption and desorption experiments of flavonoids on three types of macroporous resins (HPD826, D101, and AB8) were carried out, and D101 showed higher adsorption/desorption capacities, successively followed by AB8 and HPD826. The extraction rate of the recycled DES reached 10.78 mg/g, putting the reuse rate at 93.98%. In conclusion, the developed DES combined with macroporous resin enrichment can be an alternative method for green and efficient extraction of bioactive flavonoids from plant materials.

A green and integrated strategy for enhanced phenolic compounds extraction from mulberry (Morus alba L.) leaves by deep eutectic solvent

Green and tailor-made deep eutectic solvents (DESs) coupled with microwave-assisted extraction (MAE) were performed to extract phenolic compounds from mulberry leaves. Among the twelve DESs prepared, Choline chloride/Glycerol (1:2) with 20% water content was more efficient to get high extraction yields of phenolics. Then, several essential parameters of microwave-assisted deep eutectic solvents extraction (DES-MAE) were optimized by single-factor and Box-Behnken design (BBD) experiments. According to the result of optimization, the total extraction yield of target phenolic compounds reached 8.352 mg/g at microwave temperature 66 oC for extracting 18 min with the liquid/solid ratio of 20 mL/g, which was obviously superior to conventional solvent extraction. In addition, the extraction kinetic models confirmed that microwave-assisted extraction was a more efficient extraction technique than ultrasound-assisted extraction and heat-refluxing extraction. Meanwhile, the macroporous resin was utilized to enrich and separate target compounds from DES extracts, and the recovered DES still exhibited a good solvent effect to be applied for re-extraction. Therefore, DES-MAE followed by macroporous resin column chromatography was a green and integrated strategy for the extraction and preparative separation of active ingredients from plant materials.

Green Extraction of Phenolic Acids from Artemisia argyi Leaves by Tailor-Made Ternary Deep Eutectic Solvents.

The Artemisia argyi leaf (AL) has been used as a traditional medicine and food supplement in China and other Asian countries for hundreds of years. Phytochemical studies disclosed that AL contains various bioactive constituents. Among bioactive constituents, phenolic acids have been recognized as the main active compounds in AL. To the best of our knowledge, no research has been focused on extraction method for the bioactive phenolic acids from AL. Nowadays, deep eutectic solvents (DESs) are emerging as a new type of green and sustainable solvent for efficient extraction of bioactive compounds from natural products. In the present study, an environmentally friendly extraction method based on DESs was established to extract bioactive phenolic acids from ALs. Diverse tailor-made solvents, including binary and ternary DESs, were explored for simultaneous extraction of four phenolic acids (3-caffeoylquinic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid) from AL. The results indicated that the ternary DES composed of a 2:1:2 molar ratio of choline chloride, malic acid, and urea showed enhanced extraction yields for phenolic acids compared with conventional organic solvents and other DESs. Subsequently, the extraction parameters for the four phenolic acids by selected tailor-made DESs, including liquid–solid ratios, water content (%) in the DESs, and extraction time, were optimized using response surface methodology and the optimal extraction conditions were: extraction time, 23.5 min; liquid–solid ratio, 57.5 mL/g (mL of DES/g dry weight of plant material); water content, 54%. The research indicated that DESs were efficient and sustainable green extraction solvents for extraction of bioactive phenolic acids from natural products. Compared to the conventional organic solvents, the DESs have a great potential as possible alternatives to those organic solvents in health-related areas such as food and pharmaceuticals.

Polarity-dependent extraction of flavonoids from citrus peel waste using a tailor-made deep eutectic solvent

Choline chloride-based deep eutectic solvents (DESs) were used as green alternatives to conventional organic solvents for extracting valuable flavonoids from citrus peel waste. The effects of viscosity, pH, and polarity of DESs on the extraction efficiency were investigated. Results revealed linear dependence of extraction yield of citrus flavonoids on the polarity of the hydrogen bond donor (HBD). To simultaneously and effectively extract polymethoxylated flavonoids (PMFs) and glycosides of flavonoids (GoFs) with different polarities, five ternary DESs were designed and prepared by combining the effective HBD components. Among the tailor-made DESs studied, choline chloride–levulinic acid–N-methyl urea showed the highest extraction yield of total flavonoids. Under optimized extraction conditions, 18.75 mg/g PMFs and 47.07 mg/g GoFs were extracted from citrus peel with recoveries of 95.87% and 86.32%, respectively. This study presents a useful strategy based on tailor-made DESs to selectively extracted value-added flavonoids from waste peels in the citrus-processing industry.

Enhanced extraction of bioactive natural products using tailor-made deep eutectic solvents: application to flavonoid extraction from Flos sophorae

Green and efficient extraction of natural products from biomass is considered an important area of interest in the pharmaceutical and biochemical industries.