Choline Chloride-glycerol Research Articles

Green and innovative extraction of polyphenols from Rhamnus alaternus using natural deep eutectic solvents and evaluation of their bioactivities

Phenolic compounds, naturally present in plants, are particularly relevant as nutraceutics for their antioxidant activities. Here, choline chloride-based natural deep eutectic solvents (NaDESs) were used for efficient extraction of total phenolic compounds (TPC) from leaves, pods and roots of Rhamnus alaternus plant. In each extract, the polyphenols content and their antioxidant activities were evaluated. More, their antibacterial activity was carried out against Gram-positive and Gram-negative bacteria. The investigated extracts presented antioxidant and antimicrobial activities. The leaves, pods and roots extracts obtained using the choline chloride-glycerol (ChCl-Gly) mixture exhibited a high value of TPC comprised within 437.7 and 317.0 mg GAE/100 g d.w. and showed the best antioxidant properties with ABTS radical scavenging capacity (IC50: from 44.55 to 53.56 µg/mL), DPPH assay (IC50: from 26.36 to 118.23 µg/mL), reducing activity (EC50: from 77.53 to 85.05 µg/mL) and iron chelation activity (EC50: from 91.73 to 108.7 µg/mL). In contrast, choline chloride-urea (ChCl-Ur) extracts showed a low antioxidant capacity. Lastly, the best bioactive extracts were characterized using HPLC-MS/MS to determine their bioactive compounds. The present study suggests that the DES-based method developed was selective, efficient and sustainable for extraction of polyphenols.

Green Extracts and UPLC-TQS-MS/MS Profiling of Flavonoids from Mexican Oregano (Lippia graveolens) Using Natural Deep Eutectic Solvents/Ultrasound-Assisted and Supercritical Fluids.

Mexican oregano (Lippia graveolens) is an important source of bioactive compounds, such as flavonoids. These have presented different therapeutic properties, including antioxidant and anti-inflammatory; however, their functionality is related to the quantity and type of compounds, and these characteristics depend on the extraction method used. This study aimed to compare different extraction procedures to identify and quantify flavonoids from oregano (Lippia graveolens). Emerging and conventional technologies include maceration with methanol and water, and ultrasound-assisted extraction (UAE) using deep eutectic solvents (DES) such as choline chloride-ethylene glycol, choline chloride-glycerol, and choline chloride-lactic acid. Supercritical fluid extraction using CO2 as a solvent was also studied. Six different extracts were obtained and the total reducing capacity, total flavonoid content, and antioxidant capacity by ABTS•+, DPPH•, FRAP, and ORAC were evaluated. In addition, flavonoids were identified and quantified by UPLC-TQS-MS/MS. Results showed that UAE-DES had the best extraction effect and antioxidant capacity using colorimetric methods. However, maceration-methanol was superior in compound content, and highlighting naringenin and phloridzin were the major compounds. In addition, this extract was microencapsulated by spray drying, which provided a protection feature of their antioxidant potential. Oregano extracts are rich in flavonoids and the microcapsules present promising results for future research.

Neutral natural deep eutectic solvents as anti-biofilm agents

Natural deep eutectic solvents (NADES) are a class of liquids with promising properties as components in pharmaceutical formulations, such as a low toxicity profile, biodegradability and versatility. Recently, their potential use as anti-biofilm agents has been proposed, due to their ability to solubilize and stabilize biological macromolecules. In the current work, the ability to break down biofilm matrix and the biofilm killing activity of three NADES of neutral pH were investigated against Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 9027 biofilms. The tested NADES were choline chloride:xylitol (ChX), choline chloride:glycerol (ChG) and betaine:sucrose (BS). Two of the NADES (ChX and ChG) significantly reduced the number of remaining viable cells of both bacterial species in pre-formed biofilm by 4–6 orders of magnitude, while the average biofilm biomass removal for all NADES was 27–67% (S. aureus) and 34–49% (P. aeruginosa). The tested NADES also inhibited biofilm formation of both bacterial species at concentrations at or below 0.5 x the minimal inhibitory concentration (MIC), possibly in part due to observed restrictions imposed by NADES on planktonic growth. These results demonstrate the potential value of neutral NADES as anti-biofilm agents in future antimicrobial preparations.

Investigation of molecular interaction, performance of green solvent in esterification of ethanol and acetic acid at 298.15 K and at 1 atm

AbstractIn the present study, the potential of a selective green solvent for the low temperature esterification were analysed. Hence, 1‐ethyl‐3‐methylimidazolium hydrogen sulphate {[EMIM][HSO4]},1‐ethyl‐3‐methylimidazolium ethylsulphate {[EMIM][EtSO4]}, choline chloride glycerol {[ChCl][Gly]} and choline chloride acetic acid {[ChCl][AA]} were chosen as a selective green solvent. Whereas water, ethanol, acetic acid can be treated as molecular solvent used in the esterification process. In this reason, density of eight binary mixtures over the entire mole fractions were measured at different temperature ranges. The results have been used to calculate the excess and derived thermodynamic properties, to measure the strength of molecular interaction between mixing components. Further, the sigma profile and sigma potential plot were generated and analysed. According to density, volumetric properties, molecular polarity results, 1‐ethyl‐3‐methylimidazolium hydrogen sulphate [EMIM][HSO4] was chosen as green solvent for the green esterification process. Finally, [EMIM][HSO4] based low temperature esterification were conducted at 298.15 K and 1 atm. 80.96% of n‐BuAc was achieved.

The attenuating ability of deep eutectic solvents towards the carboxylated multiwalled carbon nanotubes induced denatured β-lactoglobulin structure.

The stabilization of proteins has been a major challenge for their practical utilization in industrial applications. Proteins can easily lose their native conformation in the presence of denaturants, which unfolds the protein structure. Since the introduction of deep eutectic solvents (DESs), there are numerous studies in which DESs act as promising co-solvents that are biocompatible with biomolecules. DESs have emerged as sustainable biocatalytic media and an alternative to conventional organic solvents and ionic liquids (ILs). However, the superiority of DESs over the deleterious influence of denaturants on proteins is often neglected. To address this, we present the counteracting ability of biocompatible DESs, namely, choline chloride-glycerol (DES-1) and choline chloride-urea (DES-2), against the structural changes induced in β-lactoglobulin (Blg) by carboxylated multiwalled carbon nanotubes (CA-MWCNTs). The work is substantiated with various spectroscopic and thermal studies. The spectroscopic results revealed that the fluorescence emission intensity enhances for the protein in DESs. Contrary to this, the emission intensity extremely quenches in the presence of CA-MWCNTs. However, in the mixture of DESs and CA-MWCNTs, there was a slight increase in the fluorescence intensity. Circular dichroism spectral studies reflect the reappearance of the native band that was lost in the presence of CA-MWCNTs, which is a good indicator of the counteraction ability of DESs. Further, thermal fluorescence studies showed that the protein exhibited extremely great thermal stability in both DESs as well as in the mixture of DES-CA-MWCNTs compared to the protein in buffer. This study is also supported by dynamic light scattering and zeta potential measurements; the results reveal that DESs were successfully able to maintain the protein structure. The addition of CA-MWCNTs results in complex formation with the protein, which is indicated by the increased hydrodynamic size of the protein. The presence of DESs in the mixture of CA-MWCNTs and DESs was quite successful in eliminating the negative impact of CA-MWCNTs on protein structural alteration. DES-1 proved to be superior to DES-2 over counteraction against CA-MWCNTs and maintained the native conformation of the protein. Overall, both DESs act as recoiling media for both native and unfolded (denatured by CA-MWCNTs) Blg structures. Both the DESs can be described as potential co-solvents for Blg with increased structural and thermal stability of the protein. To the best of our knowledge, this study for the first time has demonstrated the role of choline-based DESs in the mixture with CA-MWCNTs in the structural transition of Blg. The DESs in the mixture successfully enhance the stability of the protein by reducing the perturbation caused by CA-MWCNTs and then amplifying the advantages of the DESs present in the mixture. Overall, these results might find implications for understanding the role of DES-CA-MWCNT mixtures in protein folding/unfolding and pave a new direction for the development of eco-friendly protein-protective solvents.

Anion dynamics and motional decoupling in a glycerol-choline chloride deep eutectic solvent studied by one- and two-dimensional 35Cl NMR.

Chlorine-35 is among the few nuclides that provide an experimental handle on the anion dynamics in choline based deep eutectic solvents. By combining several nuclear magnetic resonance (NMR) techniques, the present work examines the Cl- motions within glyceline, a glycerol : choline chloride 2 : 1 solution, in a large temperature range down to the glass transition temperature Tg. The applied methods include spin relaxometry, second-order line shape analysis, as well as two-dimensional central-transition exchange and stimulated-echo spectroscopy. The finding of unstructured central-transition NMR spectra characterized by a relatively small average quadrupolar coupling attests to a highly disordered, essentially nondirectional anionic coordination in glyceline. For temperatures larger than about 1.3Tg the chlorine motions are well coupled to those of the glycerol and the choline moieties. At lower temperatures the local translational anion dynamics become Arrhenian and increasingly faster than the motion of glyceline's matrix molecules. Upon further cooling, the overall ionic conductivity continues to display a super-Arrhenius behavior, implying that the choline cations rather than the Cl anions dominate the long-range charge transport also near Tg.

Food-grade deep eutectic solvent extraction of antioxidant polyphenols from peppermint (Mentha × piperita L.): Screening, optimization and metabolite profile

Peppermint (Mentha × piperita L.) is a popular medicinal and aromatic plant, cultivated in several areas around the globe. Its functional and therapeutic potential has been largely attributed to its polyphenolic composition, yet rather a few investigations have delt with the preparation of polyphenol-enriched extracts from this plant. On this ground, this study was undertaken with the scope to establish a green, highly efficient extraction process, using food-grade deep eutectic solvents (DES). After an initial screening of several food-compatible DES reported in the literature, it was found that the most effective was glycerol-choline chloride (GL-ChCl), at a molar ratio of 2/1. This DES was subsequently used to carry out process optimization, using response surface methodology. The optimized conditions were determined to be DES/water proportion of 65 % (w/w), 143 min resident time and 80 °C. Under these conditions, the yield in total polyphenols was 72.78 ± 7.14 mg gallic acid equivalents g−1 of dry mass. Comparison with water and 60 % aqueous ethanol showed that extraction with GL-ChCl may provide extracts enriched in polyphenols, with increased antioxidant activity. The chromatographic analysis of the optimally produced extract revealed that the polyphenolic profile was dominated by eriocitrin, accompanied by luteolin glycosides and rosmarinic acid.

Ultrasound- and heat-assisted extraction of glycyrrhizin from licorice by two glycerol-based DESs - Modeling and optimization as per response surface methodology

Glycyrrhizin is an important bioactive compound of licorice (Glycyrrhiza glabra) having many pharmaceutical properties. The present study explored the extraction of glycyrrhizin from licorice in two glycerol-based deep eutectic solvents glycerol-ammonium acetate (GAA) and glycerol-choline chloride (GCC) and by two different techniques heat-assisted extraction (HAE) and ultrasound-assisted extraction (UAE). For optimization, response surface methodology (RSM) as per CCD (central composite design) was applied. Quantification of the compound was done by HPLC (high performance liquid chromatography). In GAA-HAE, the highest yield 36.96 mg/g was at 80 °C temperature, 25 min time, and 50% DES concentration and in GCC-HAE, the highest yield was 35.26 mg/g that was at temperature 80 °C, time 65 min and 50% DES concentration. In GAA-UAE, the highest yield 35.41 mg/g was at temperature 60 °C, time 79 min and 70% DES concentration, and in GCC-UAE, the highest yield 31.37 mg/g was at temperature 80 °C, time 25 min and 50% DES concentration. UAE-methanol gave the highest yield 31.36 mg/g that was at temperature 60 °C, time 45 min and 70% methanol. The predicted models had high fitness each having a significant p-value (<0.05) and a nonsignificant lack of fit p-value. The R2 values were about 94%, 98%, 93%, 95% and 95% for GAA-UAE, GCC-UAE, GAA-HAE, GCC-HAE and methanol-UAE models, respectively, which also indicated high adequacy of the models. In terms of yield, HAE and UAE were comparable but UAE has the advantage of being more environmentally friendly, and GAA was more powerful than GCC as extracting medium. As a result, GAA-UAE should be a viable option for extracting glycyrrhizin from licorice as an efficient and environmentally friendly method.

HCl removal and recovery using choline chloride-glycerol deep eutectic solvent in rotor–stator reactor: Molecular mechanism, experimental and modeling studies

Efficient removal and recovery of HCl from off-gas are significant for environmental protection and resource utilization. In this work, the absorption process of HCl using choline chloride-glycerol (ChCl-Gly) was studied in three aspects: molecular mechanism, experimental and modeling studies. Firstly, the molecular mechanism of HCl absorption into ChCl-Gly was studied by the σ-profiles, binding models and intermolecular interaction, and it was revealed that the H atom of HCl binds with O and Cl of ChCl-Gly to form hydrogen bonds. Secondly, in view of the absorption characteristics, the process intensification of HCl absorption into ChCl-Gly was proposed by using a rotor–stator reactor (RSR). The influences of the high gravity factor, gas flowrate, ratio of gas flowrate to liquid flowrate and HCl concentration in gas inlet on the removal efficiency of HCl and overall gas-phase volumetric mass-transfer coefficient (KGa) in the removal of HCl by ChCl-Gly in the RSR were explored, and it was found that a larger high-gravity factor led to a better mass transfer effect and higher HCl removal efficiency. In addition, a mass transfer model was built to describe the process of HCl absorption into ChCl-Gly in the RSR, and the model predictions agreed well with the experimental data, and the deviations between experimental and predicted KGa were generally less than ±25 %. Finally, the prospects for industrial applications of HCl removal and recovery using deep eutectic solvents in RSR were discussed.

Anionic H-bonds improve the disorganization of starch in metal chloride hydrate-natural deep eutectic solvents

In this study, several kinds of metal chloride hydrates were added into NADESs (natural deep eutectic solvents) and a series of three constituent-NADESs (3c-NADESs) were successfully developed. The results suggested that the addition of metal chloride hydrates can significantly enhance the solubility of starch, such as, the solubility in MgCl2-CGly-1 is 90.12 ± 3.49 g/100 g, which is 65 times higher than C-Gly (choline chloride-glycerol) (1.38 ± 0.65 g/100 g). The density functional calculation (DFT) suggested that a lower chloride occupancy of 3c-NADESs can provide more chloride ions used for the formation of hydrogen-bonding interaction with starch. Moreover, the molecular dynamic (MD) study demonstrates that Cl− may play a key role as “chisel” during the dissolution of starch, which can efficiently destroy the intra- and intermolecular hydrogen bonds (HO⋯O) of starch, allowed the penetration of other components and prevent the recovery crystal of starch.

Optimization of ultrasound-assisted extraction of valuable compounds from fruit of Melia azedarach with glycerol-choline chloride deep eutectic solvent

A green and cost-effective method was explored to extract phenolics, flavonoids, antioxidant, and iron chelating agents from fruits of medicinal tree Melia azedarach using natural deep eutectic solvent (NADES) and ultrasound treatment. NADES consisting of glycerol and choline chloride was prepared and used for extraction. Optimization of extraction was done as per response surface methodology using Box-Behnken design with three factors. The strategy proved successful with considerable extraction of total phenols, total flavonoids, radical scavengers, and iron chelators. Optimized conditions were found to be temperature (46.4 °C), ultrasound amplitude (100%; 130 Watt power) and DES concentration (50%) with predicted total phenols 9.154 mg Gallic acid equivalents/g dried weight (DW), total flavonoids 21.880 mg Rutin equivalents/g DW, iron chelating activity 33.254%, and anti-radical activity 51.166%. Validation experiments resulted in minimal errors (3.87–0.61%) that substantiated the proposed model. The model may be used in designing large scale extraction of phenolics and other antioxidant compounds from the fruit of M. azedarach using the green and low-cost glycerol-choline chloride NADES and ultrasound mediation.

Effective Removal of Copper Ion from Aqueous Solution using Beads of Chitosan-Choline Chloride/Glycerol Deep Eutectic Solvent

Herein, an adsorption process based on a new adsorbent was utilized to remove copper ion (Cu(II)), an environmental pollutant, from water. Reprocessed porous beads based on powder chitosan highly aid the industrial treatment of water. Chitosan–deep eutectic solvent (DES) beads were prepared from chitosan and DES. The DES used were choline chloride–urea (DES A) and choline chloride–glycerol (DES B). Both chitosan–DES beads were used to remove Cu(II) from an aqueous solution. Based on the characterisation results, chitosan-DES A showed a higher chemical and thermal stability when compared to chitosan-DES B. For the type of adsorbents, chitosan-DES B showed a higher removal percentage of Cu(II) (90.92 %) than chitosan-DES A (7.5 %). Therefore, chitosan-DES B was chosen as the preferred adsorbent for Cu(II). The optimum conditions for the removal of Cu(II) from an aqueous solution were using 0.09 g of chitosan-DES B with 40 min of shaking time and 1 mg L-1 of initial concentration.

Microwave-Assisted Extraction of Phenolic Compounds from Pineapple Peel Using Deep Eutectic Solvents

Approximately half of the world’s pineapple production is marketed as a processed product, leading to the generation of a significant quantity of industrial waste, mainly composed of pineapple peels, cores, and crowns. This study evaluated deep eutectic solvents (DESs) for the assisted microwave extraction of phenolic compounds from pineapple peels and their antioxidant capacity. DESs are considered environmentally friendly solvents characterized by their low toxicity and high capacity for the extraction of bioactive compounds. DESs (choline chloride-glycerol and choline-chloride-malic acid) were used for phenolic compound extraction and compared with traditional solvents such as water, ethanol, methanol, ethanol-water (50%), and methanol-water (50%). A higher concentration of phenolic compounds was achieved using choline chloride-glycerol than traditional solvents as an extraction solvent (7.98 mg eq of gallic acid/g of dry weight). In all the treatments, the antioxidant capacity was higher than 85%. The process variables (drying temperature, extraction time, and solvent/solid ratio) were optimized using choline chloride-glycerol as a solvent. It was found that a drying temperature of 67 °C, an extraction time of 87 s, and a solvent/solid ratio of 60.5 mL/g allow maximizing the content of phenolic compounds and the antioxidant capacity of the extract.

Biomass valorization by integrating ultrasonication and deep eutectic solvents: Delignification, cellulose digestibility and solvent reuse

Biomass valorization in converting biomass into value-added products and energy has gained researchers’ attention. In this study, valorization of oil palm empty fruit bunch (OPEFB) towards biofuels production was focused. Combination of deep eutectic solvent (DES) and ultrasonication was employed to pretreat the OPEFB. The pretreatment was conducted in a sonicator at 210 W, 50 °C for 30 min. Choline chloride-lactic acid (ChCl-LA) outperformed choline chloride-urea (ChCl-U) and choline chloride-glycerol (ChCl-G) because of its acidity and low viscosity properties. Besides having the highest cellulose digestibility (36.7% of reducing sugars yield), ChCl-LA pretreated biomass had the lowest lignin content of 18.8% and biomass crystallinity of 0.895. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) results further confirmed its biomass disruption ability. Ultrasonic-assisted DES pretreatment exhibited a synergetic effect, whereby the reducing sugars yield was double compared to without ultrasound. Also, its pretreatment performance was better than other pretreatment methods, such as acid, alkaline and steam explosion pretreatments. The DESs were effectively recovered with a slight decrease in delignification and cellulose digestibility efficiencies. These collectively proven the feasibility and effectiveness of ultrasound-assisted DES pretreatment in converting the biomass to sugars, which could be essential for biofuels production.

Composition and antioxidant activity of anthocyanins from Aronia melanocarpa extracted using an ultrasonic-microwave-assisted natural deep eutectic solvent extraction method

A time-saving, efficient, and environmentally friendly ultrasonic-microwave-assisted natural deep eutectic solvent (UMAE-NADES) extraction method was developed for the extraction of anthocyanins from Aronia melanocarpa. Eight different natural eutectic solvents were screened initially, and choline chloride-glycerol was selected as the extraction solvent. The extraction conditions were optimized using the response surface methodology, and the extraction rate of anthocyanins was higher than those achieved using the traditional ethanol method, natural deep eutectic solvent extraction method, and ultrasonic-microwave-assisted ethanol method. Six anthocyanins, including cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, cyanidin-3-O-arabinoside, cyanidin-3-O-xyloside, cyanidin-3,5-O-dihexoside, and the dimer of cyanidin-hexoside were identified and extracted at a purity of 448.873 mg/g using high performance liquid chromatography-mass spectrometry (HPLC-MS). The compounds extracted using UMAE-NADES had higher antioxidant capacities than those extracted by the other three methods. The UMAE-NADES demonstrated significant efficiency toward the extraction of bioactive substances and has potential utility in the food and pharmaceutical industries.

Farklı Derin Ötektik Çözücülerin pH ve Elektriksel İletkenlik Değerlerinin Sıcaklık ile Değişimi

In this study, the variation of pH and electrical conductivity values of 6 different deep eutectic solvents (choline chloride-acetic acid, choline chloride-urea, choline chloride-citric acid, choline chloride-glycerol, choline chloride-lactic acid, and glycerol-citric acid) most likely to be used in food processes with temperature (25 °C, 50 °C and 75 °C) were investigated. The molar ratio was used as 1:1 for the glycerol-citric acid combination, and the molar ratio was applied as 1:2 for other solvents. Besides, 30% water by mass was added to all solvents. As a result, it was observed that the variation of pH values with temperature changed depending on the hydrogen bond donor type, while the electrical conductivity values increased in direct proportion to the increase in temperature. It was seen that linear model compatibility was high for both values. When the relations between pH and electrical conductivity values were examined, it was seen that deep eutectic solvent combinations formed with acid-based hydrogen bond donors showed a positive correlation, while other combinations showed a negative correlation. Finally, when the activation energies are examined, the combinations using citric acid as hydrogen bond donor for pH and urea for electrical conductivity have the highest value

Deep eutectic solvents and alkaline extraction of protein from seabuckthorn seed meal: a comparison study

Seabuckthorn seed meal (SSM) is a waste of oil extraction industry that rich in protein. In order to seek suitable protein extraction method, three different deep eutectic solvents (DESs) (including choline chloride-glycerol, choline chloride-oxalic acid and choline chloride-urea) were developed for extracting protein from SSM and compared with alkaline. Result indicated that alkaline could effectively extract 56.9% protein from SSM and its protein content was 73.1%, higher than DES at 31.0%41.4% and 64.3%67.5%, respectively. However, compared to alkali, DES led to a product with less β-sheet, more β-turn, more essential amino acids, higher total amino acid content, especially choline chloride-urea which extracted protein showing an integrated and similar protein weight distribution compared to SSM. Also, this protein extracted chloride-urea showed a highest digestibility in vitro (by pepsin) (54.2%). These results indicated that choline chloride-urea extraction is better than alkaline extraction for SSM.

Extractive distillation of ethyl acetate-ethanol-water ternary system using deep eutectic solvent (DES): A techno economic and energy assessment

The extractive distillation (ED) process has been established as a commercially viable process that can be used to break the azeotropic systems. The present study investigates the performance and feasibility of conventional solvent (glycerol) and choline chloride-glycerol based deep eutectic solvent (DES) as entrainers for the separation of ethyl acetate-ethanol-water ternary mixture through ED. A comprehensive approach is proposed with phase-equilibrium measurements and process simulation through Aspen Plus for different entrainer to feed ratio (E/F). Optimization of the process is based on performance indicators such as Total Annual Cost, CO2 emissions, and Specific Energy Consumption. A sequential iterative algorithm was used to find the optimum E/F in distillation trains. The performance analysis has shown a reduction of 45.89% in global TAC with DES as an entrainer. The combined entrainer requirement for the dehydration was 268.3 kmol/h and 118.86 kmol/h with glycerol and DES respectively. The process sees a 58.21% total energy saving with a 15% and 44.5% reduction in Specific Energy Consumption and CO2 emissions respectively as compared to glycerol as an entrainer. The study provides a comparison and proves that DES is an effective entrainer to break the azeotropic point as a low-cost and eco-friendly alternative to conventional solvents.

Influence of choline-based ionic liquids as neoteric green solvents on aqueous solubility of lamotrigine and piroxicam drugs

Background: The low aqueous solubility of three important drugs (betamethasone (BETA), meloxicam (MEL) and piroxicam (PIR)) have been increased by use of deep eutectic solvents (DESs) based choline chloride/urea (ChCl/U), choline chloride/ethylene glycol (ChCl/EG) and choline chloride/glycerol (ChCl/G) as new class of solvents at T = (298.15 to 313.15) K. Methods: DESs were prepared by combination of the ChCl/EG, U and G with the molar ratios: 1:2. The solubility of drugs in the aqueous DESs solutions was measured at different temperatures with shake flask method. Results: The solubility of the investigated drugs increased with increasing the weight fraction of DESs. The solubility data were correlated by e-NRTL and Wilson models. Also, the thermodynamic functions, Gibbs energy, enthalpy, and entropy of dissolution were calculated. Conclusion: At the same composition of co-solvents and temperature, the BETA, PIR and MEL solubility was highest in (ChCl/U + water), (ChCl/U + water) and (ChCl/EG + water) respectively. The calculated solubility based on these models was in good agreement with the experimental values. In addition, the results show that, the main contribution for drugs solubility in the aqueous DES solutions is the enthalpy.

Comparison of the Deep Euteutic Solvent (DES) Solvent for Extracting Lignin from the Lignocellulosic Material of Pineapple Leaves

Background: Lignocellulosic biomass is one of the materials that has the potential to produce cellulose. Lignocellulose material consists of lignin, hemicellulose and cellulose so that the three materials must be separated first to get pure cellulose. The main problem faced in the process of separating cellulose is the difficulty of separating lignin. One of the processes in separating lignin is by pretreatment of lignocellulosic material. Methods: In this study, Deep Euteutic Solvent (DES) choline (ChCl) as a hydrogen bond acceptor was synthesized and eight hydrogen bond donors (HBD) were mixed. Eight types of DESs, i.e. , choline chloride-acetic acid (ChCl-AA), ChCl: formic acid (ChCl-FA). ), choline chloride: Lactic acid (ChCl-LA), choline chloride:Citric acid (ChCl-SA), choline chloride: Glycerol (ChCl-G), choline chloride: Ethylenglycol (ChCl-EG), choline chloride: Sorbitol (ChCl-S), and choline chloride: Urea (ChCl -U) with a ratio of 1: 2 were investigated. Each. DES solvent was applied as a pretreatment for the lignocellulosic material of pineapple leaves. The results of the pretreatment formed were characterized by the Infra Red spectroscopic method to determine the typical functional groups. Result: The results showed that the pretreatment process using DES solvent resulted in a decrease in lignin levels in pineapple leaf powder, the highest in DES with linear saturated acid-based HBD, formic acid at 32.05%, glycerol at 30.18% and then in alpha hydroxy-based HBD, acetic acid at 29.90%. Meanwhile, the FT-IR results show that ChCl-FA has a high delignification ability during pretreatment. Pineapple leaves that have been pretreted with DES solvent can be a potential raw material for the next conversion process. This study presents DES as an effective and easy pretreatment method for lignin extraction.