scholarly journals Green Valorization of Olive Leaves to Produce Polyphenol-Enriched Extracts Using an Environmentally Benign Deep Eutectic Solvent

2020 ◽  
Vol 2 (2) ◽  
pp. 226-239 ◽  
Author(s):  
Olga Kaltsa ◽  
Spyros Grigorakis ◽  
Achillia Lakka ◽  
Eleni Bozinou ◽  
Stavros Lalas ◽  
...  

Olive leaves (OLL) are considered to be a highly appreciated bioresource of bioactive polyphenolic phytochemicals, embracing several different structures. However, extraction processes based on deep eutectic solvents (DES) are very limited despite the wide range of techniques developed for the efficient recovery of polyphenols. This study had as objective the development of a simple, green, high-performance extraction methodology for OLL polyphenols, using a recently reported effective DES, composed of L-lactic acid and glycine. Initially, a screening was performed to select the most appropriate L-lactic/glycine molar ratio and process optimization was then carried out with response surface methodology. The optimized process variable values were DES/water (78% w/v), liquid-to-solid ratio of 36 mL g−1, and stirring speed of 500 rounds per minute, and the total polyphenol yield amounted to 97.53 ± 3.54 mg gallic acid equivalents per g dry matter. Extraction with DES at 80 °C did not significantly increase the total polyphenol yield, but it did enhance the total flavonoid yield and antioxidant activity. High-performance liquid chromatography analyses revealed that extraction with the DES resulted in extended oleuropein hydrolysis, to the favor of hydroxytyrosol formation. This finding might have a prospect in using properly tuned DES for polyphenol modification with improved bioactivities.

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1924 ◽  
Author(s):  
Yan-Yan Gao ◽  
Yue Jiang ◽  
Guo-Chao Chen ◽  
Shuang-Shuang Li ◽  
Fei Yang ◽  
...  

Background: Allergic disease is a common clinical disease. Natural products provide an important source for a wide range of potential anti-allergic agents. This study was designed to evaluate the anti-allergic activities of the water-soluble polysaccharides extracted and purified from Saposhnikoviae Radix (SRPS). The composition and content of monosaccharides were determined to provide a material basis. Methods: An ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established to determine the composition and content of SRPS. 2,4-dinitrofluorobenzene (DNFB) induced a delayed-type hypersensitivity (DTH) mouse model orally administrated SRPS for seven consecutive days. Ear swelling, organ index, and serum IgE levels were observed to evaluate the anti-allergic activities. Results: The UPLC-MS/MS analysis showed that SRPS was consisted of eight monosaccharides including galacturonic acid, mannose, glucose, galactose, rhamnose, fucose, ribose, and arabinose with a relative molar ratio of 4.42%, 7.86%, 23.69%, 12.06%, 3.10%, 0.45%, 0.71%, and 47.70%, respectively. SRPS could effectively reduce ear swelling, a thymus index, and a serum IgE levels. Conclusions: The method was simple, rapid, sensitive, and reproducible, which could be used to analyze and determine the monosaccharide composition of SRPS. The vivo experiments demonstrated that SRPS may effectively inhibit development of DNFB-induced DTH. SRPS is a novel potential resource for natural anti-allergic drugs.


2017 ◽  
Author(s):  
Xifeng Zhang ◽  
Ji Zhang

Deep eutectic solvents (DESs) are new green solvents that have attracted the attention of the scientific community mainly due to their unique properties and special characteristics, which are different from those of traditional solvents.A method based on ultrasonically assisted deep eutectic solvent aqueous two-phase systems( UAE-DES-ATPS) was developed for extracting ursolic acid (UA) from Cynomorium songaricum Rupr. Four different types of choline chloride-based DESs were prepared.Choline chloride-glucose (ChCl-Glu) exhibited good selective extraction ability. An optimum DES-ATPS of 36% (w/w) ChCl-Glu and 25% (w/w) K2HPO4 was considered to be a satisfactory system for extracting UA. Response surface methodology (RSM) method was used to optimize the extraction of UA using UAE-DES-ATPS. The optimum ultrasound-assisted conditions were as follows: solvent to solid ratio of 15:1 (g/g), ultrasound power of 470 W, and extraction time of 54 min. Compared with the conventional UAE method, the yields were basically the same, but the presented method had higher purity. The structure of UA did not change between pure UA and UA in the upper phase by UV–vis and FT-IR. This approach using ChCl-based DES-ATPS as a novel extraction system and ultrasound as a source of energy provided better choice for the separation of active components from other natural products.


Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1706
Author(s):  
Fang Bai ◽  
Chao Hua ◽  
Yongzhi Bai ◽  
Mengying Ma

Deep eutectic solvents (DESs) have properties that make them suitable candidates to be used as entrainers for extractive distillation. In the previous work, it was proven that DES(1:2) (tetrabutylammonium bromide: levulinic acid, 1:2, molar ratio) can break the cyclohexane-benzene azeotrope. In the present work, the HBA and HBD ratio and molar concentration of DES were optimized to obtain a better constitute and condition of DES to be utilized in cyclohexane and benzene extractive distillation. The physical properties and structure of the prepared DESs were characterized. Vapor–liquid equilibrium data of the ternary system (benzene + cyclohexane + DESs) were also measured at atmospheric pressure. All experimental equilibrium data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models, from which the coefficient of determination (R2) of the three pseudo-ternary systems fitting was calculated. From the obtained results, the best HBA and HBD ratio in the DESs is elucidated as 1:2, the best molar concentration of DES is 0.1, and the NRTL model predicts the experimental data more accurately than the Wilson and UNIQUAC models. From the derived mechanism, the formation of stronger hydrogen bond and π–π bond interactions between DES and benzene is obtained when HBA and HBD ratio in DES is 1:2. In other conditions, the azeotrope cannot be broken, or the efficiency is low. The present work provides an environmentally friendly method to separate aromatic/aliphatic mixtures and act as a guide for further study of DESs in extractive distillation.


2020 ◽  
Vol 58 (9) ◽  
pp. 880-886
Author(s):  
Xiao Li ◽  
Tao Yuan ◽  
Ting Zhao ◽  
Xiaomei Wu ◽  
Yaling Yang

Abstract An environmentally friendly method for the determination of testosterone and methyltestosterone by acid–base-induced deep eutectic solvents liquid–liquid microextraction (DES-ABLLME) combining with high-performance liquid chromatography was established. The deep eutectic solvent (DES) consisting of menthol:lauric acid:decanoic acid (3:1:1) can act as both hydrogen bond donor and hydrogen bond acceptor. In this approach, ammonia solution (NH3•H2O) is used as an emulsifier to react with DESs in the extraction process to generate salt and form milky white solution, achieving high extraction efficiency. Hydrochloric acid was used as a phase separator to change the emulsification state and promote the separation of extraction agent from water phase. A series of parameters were optimized including the volume of DES and the emulsifying agent, glucose concentration as well as hydrochloric acid volume. The method was linear in the range 0.5–100 μg mL−1 with a correlation coefficient (R) of 0.9999, and the limits of detection were 0.067 and 0.2 μg mL−1 for testosterone and methyltestosterone, respectively. This method was applied to analyze testosterone and methyltestosterone in milk samples, and the recoveries were between 89.2 and 108.2%.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5093 ◽  
Author(s):  
Ainul F. Kamarudin ◽  
Hanee F. Hizaddin ◽  
Lahssen El-blidi ◽  
Emad Ali ◽  
Mohd A. Hashim ◽  
...  

Deep eutectic solvents (DESs) are green solvents developed as an alternative to conventional organic solvents and ionic liquids to extract nitrogen compounds from fuel oil. DESs based on p-toluenesulfonic acid (PTSA) are a new solvent class still under investigation for extraction/separation. This study investigated a new DES formed from a combination of tetrabutylphosphonium bromide (TBPBr) and PTSA at a 1:1 molar ratio. Two sets of ternary liquid–liquid equilibrium experiments were performed with different feed concentrations of nitrogen compounds ranging up to 20 mol% in gasoline and diesel model fuel oils. More than 99% of quinoline was extracted from heptane and pentadecane using the DES, leaving the minutest amount of the contaminant. Selectivity was up to 11,000 for the heptane system and up to 24,000 for the pentadecane system at room temperature. The raffinate phase’s proton nuclear magnetic resonance (1H-NMR) spectroscopy and GC analysis identified a significantly small amount of quinoline. The selectivity toward quinoline was significantly high at low solute concentrations. The root-mean-square deviation between experimental data and the non-random two-liquid (NRTL) model was 1.12% and 0.31% with heptane and pentadecane, respectively. The results showed that the TBPBr/PTSADES is considerably efficient in eliminating nitrogen compounds from fuel oil.


Cellulose ◽  
2020 ◽  
Vol 27 (12) ◽  
pp. 6831-6848
Author(s):  
L. A. Soto-Salcido ◽  
I. Anugwom ◽  
L. Ballinas-Casarrubias ◽  
M. Mänttäri ◽  
M. Kallioinen

Abstract Waste biomass (agave bagasse) and native birch wood were used as raw materials for a novel fractionation and derivation process to produce cellulose acetates (CAs). During the first stage of the fractionation process, a significant amount of hemicelluloses and lignin were dissolved from the biomass using a natural deep eutectic solvent (NADES) that consisted of a mixture of choline chloride and lactic acid with the molar ratio of 1:9. Then, the residual solid material was delignified by bleaching it with a mixture of acetic acid and sodium chlorite. The fractionation process generated differently purified pulps (celluloses) which were converted to CAs. The crystallinity index, polymerization degree, chemical composition, and thermal properties of the differently purified pulps and CAs were analyzed to evaluate the efficacy of the acetylation process and to characterize the CAs. The chemical derivation of the differently purified cellulose samples generated CAs with different degrees of substitution (DSs). The more purified the cellulose sample was, the higher its DS was. Moreover, some differences were observed between the acetylation efficiencies of birch and agave bagasse. Typically, cellulose purified from birch by treating it with NADES followed by bleaching was acetylated more completely (DS = 2.94) than that derived from agave bagasse (DS = 2.45). These results revealed that using green solvents, such as NADES, to treat both agave bagasse (waste biomass) and birch wood, allowed pure fractions to be obtained from biomass, and thus, biomass could be valorized into products such as CAs, which present a wide range of applications.


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 617 ◽  
Author(s):  
Wim Wouter Oomen ◽  
Paloma Begines ◽  
Natali Rianika Mustafa ◽  
Erica G. Wilson ◽  
Robert Verpoorte ◽  
...  

Natural deep eutectic solvents (NADES) are a type of ionic liquid (IL) or deep eutectic solvent (DES), the ingredients of which are exclusively natural products (non-toxic and environmentally friendly). Here, we explore the potential of NADES as an alternative to conventional organic solvents (e.g., aqueous methanol or ethanol) for the extraction of flavonoids from Scutellaria baicalensis stem bark to investigate their extractability depending on structural variation. Four NADES, each containing citric acid in combination with β-alanine, glucose, xylitol, or proline (at a molar ratio of 1:1), and a variable amount of water, were used to extract the flavonoid aglycones: baicalein (1), scutellarein (3), wogonin (5), and oroxylin A (7), and their glycosides, baicalin (2), scutellarin (4), wogonoside (6) and oroxyloside (8) from the powdered bark of S. baicalensis. The chemical profile and yield of the extracts were determined using HPTLC and HPLC. The extractability of individual flavonoids was found to be influenced by the concentration of water (20–60%, w/w) in the NADES. Among the tested flavonoids, the extraction yield of baicalein (1), scutellarein (3), wogonin (5), oroxylin A (7) with NADES was 2 to 6 times that of aqueous methanol. However, the amount of their corresponding glycosides (baicalin (2), wogonoside (6) and oroxyloside (8)) extracted with NADES was only 1.5–1.8 times higher than with aqueous methanol. Interestingly, the more hydrophilic glycosides were less extracted than their corresponding aglycones despite the high hydrophilicity of the NADES. These results prove that NADES may be used for extraction of compounds with a wide range of hydrophilicity.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2079
Author(s):  
Gui-Ya Yang ◽  
Jun-Na Song ◽  
Ya-Qing Chang ◽  
Lei Wang ◽  
Yu-Guang Zheng ◽  
...  

In the present study, a simple and environmentally friendly extraction method based on natural deep eutectic solvents (NADESs) was established to extract four bioactive steroidal saponins from Dioscoreae Nipponicae Rhizoma (DNR). A total of twenty-one types of choline chloride, betaine, and L-proline based NADESs were tailored, and the NADES composed of 1:1 molar ratio of choline chloride and malonic acid showed the best extraction efficiency for the four steroidal saponins compared with other NADESs. Then, the extraction parameters for extraction of steroidal saponins by selected tailor-made NADES were optimized using response surface methodology and the optimal extraction conditions are extraction time, 23.5 min; liquid–solid ratio, 57.5 mL/g; and water content, 54%. The microstructure of the DNR powder before and after ultrasonic extraction by conventional solvents (water and methanol) and the selected NADES were observed using field emission scanning electron microscope. In addition, the four steroidal saponins were recovered from NADESs by D101 macroporous resin with a satisfactory recovery yield between 67.27% and 79.90%. The present research demonstrates that NADESs are a suitable green media for the extraction of the bioactive steroidal saponins from DNR, and have a great potential as possible alternatives to organic solvents for efficiently extracting bioactive compounds from natural products.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4271
Author(s):  
Rina Yasutomi ◽  
Riki Anzawa ◽  
Masamitsu Urakawa ◽  
Toyonobu Usuki

The essential oils of hinoki (Chamaecyparis obtusa) leaves have anti-bacterial, anti-fungal, and relaxation properties that are likely associated with the major components such as sabinene, α-terpinyl acetate, limonene, elemol, myrcene, and hibaene. The present study describes the use of a cellulose-dissolving ionic liquid (IL) [C2mim][(MeO)(H)PO2] and low-toxicity solvents called betaine-based deep eutectic solvents (DESs) for the efficient extraction of hinoki essential oils. As a control method, organic solvent extraction was performed using either hexane, ethyl acetate (EtOAc), or acetone at 30 °C for 1 h. Both the experimental and control methods were conducted under the same conditions, which relied on partial dissolution of the leaves using the IL and DESs before partitioning the hinoki oils into the organic solvent for analysis. Quantitative analysis was performed using gas chromatography–mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The results indicated that extraction using the [C2mim][(MeO)(H)PO2]/acetone bilayer system improved the yields of limonene and hibaene, 1.5- and 1.9-fold, respectively, when compared with the control method. In addition, extraction using betaine/l-lactic acid (molar ratio 1:1) gave the greatest yields for both limonene and hibaene, 1.3-fold and 1.5-fold greater, respectively, than when using an organic solvent. These results demonstrate the effective extraction of essential oils from plant leaves under conditions milder than those needed for the conventional method. The less toxic and environmentally begin DESs for the extraction are also applicable to the food and cosmetic industries.


2020 ◽  
Vol 9 (1) ◽  
pp. 7-10
Author(s):  
Axel Try Iddo Daely ◽  
Renita Manurung

Organophosphate insecticide is a type of pesticide that is commonly used, where this pesticide can be toxic to environmental organisms even to humans. Hydrophobic Deep Eutectic Solvent (DES) is a new generation nonpolar solvent of ionic liquids because it has better physical properties and chemical properties so that it can be used in the extraction process. DES was synthesized at 50 oC for 15 minutes with a stirring speed of 300 rpm and a molar ratio of Dl-menthol: lauric acid varied from 1: 1, 2: 1, and 3: 1. Pesticide removal is done by mixing 5 ml of DES with 200 ml of aquadest and then Tomatoes and Broccoli vegetables are washed with the solution. DES characteristics are done by analyzing the shape and measuring the freezing point, density and viscosity of DES. The concentration of pesticide residues was analyzed using Gas Chromatography-Mass Spectrometer (GC-MS). The highest elimination of pesticides obtained with DES hydrophobic which has a molar ratio of dl-menthol: lauric acid is 3: 1 where the highest elimination of pesticides in Tomatoe is 44.82% for Dimethoate pesticide, 84.1% for Chlorpyrifos pesticide, and 83.72% for Profenofos pesticide and Broccoli 35.19% for Dimetoat pesticide, 64.64% for Chlorpyrifos pesticide, and 55.28% for Profenofos pesticides.


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