Solubility and thermodynamic function of vanillin in ten different environmentally benign solvents

The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium

Various protein-rich foods are traditionally immersed in virgin olive oil (VOO), a medium rich in phenols, which are health-promoting and sensorially important compounds. Immersing tofu in VOO may modify the sensory properties and nutritional value of both due to the oil's hydrophilic phenol interactions with proteins and water. In this study, cubes of fresh tofu (T) (70% water) and freeze-dried tofu (FD-T) (5% water) were immersed in VOO for 7 days of cold storage. The changes in the phenolic compound content and standard quality parameters of the oil were noted after 1, 3, 5, and 7 days of contact with the tofu. The total phenols in the oil were determined using the Fast Blue BB assay, while single phenols were analyzed by HPLC-UV/VIS. During the 7 days, the total phenols in the oil decreased by up to 56% and 26% under the influence of fresh and freeze-dried tofu, respectively, including a significant decrease in hydroxytyrosol, oleacein, tyrosol, and oleocanthal. The water content and its release from fresh tofu significantly contributed to this decline. The degradation of the quality of the oil in contact with the fresh tofu was observed only in its sensory properties, with a marked reduction in the intensity of its fruitiness, bitterness and pungency.

Poly(vinyl alcohol) Modified via the Hantzsch Reaction for Biosafe Antioxidant Self-Healing Hydrogel

Efficient routes for the preparation of functional self-healing hydrogels from functional polymers are needed. In this study, we developed a strategy to effectively produce a vanillin-modified poly(vinyl alcohol) (PVA-vanillin) through the Hantzsch reaction. This polymer was cross-linked with a phenylboronic acid-containing polymer (PB) that was also prepared using the Hantzsch reaction to fabricate a hydrogel through borate ester linkages under mild conditions (25 °C, pH ∼ 7.4). This hydrogel had excellent antioxidant abilities due to the 1,4-dihydropyridine (DHP) rings and the vanillin moieties in the hydrogel structures; it was also self-healable and injectable owing to the dynamic borate ester linkages. Furthermore, the antioxidant self-healing hydrogel had low cytotoxicity and exhibited favorable safety in animal experiments, indicating its potential as a safe implantable cell or drug carrier. This study developed a method for preparing functional polymers and related self-healing hydrogels in a facile manner; it demonstrated the value of the Hantzsch reaction in exploiting antioxidant self-healing hydrogels for biomedical applications, which may provide insight into the design of other functional self-healing hydrogels through different multicomponent reactions.

Review on the oxidative catalysis methods of converting lignin into vanillin

Vanillin plays an important role not only in food and flavouring, but also as a platform compound for the synthesis of other valuable products, mainly derived from the oxidative decarboxylation of petroleum-based guaiacol production. In order to alleviate the problem of collapsing oil resources, the preparation of vanillin from lignin has become a good option from the perspective of environmental sustainability, but it is still not optimistic in terms of vanillin production. Currently, catalytic oxidative depolymerization of lignin for the preparation of vanillin is the main development trend. This paper mainly reviews four ways of preparing vanillin from lignin base: alkaline (catalytic) oxidation, electrochemical (catalytic) oxidation, Fenton (catalytic) oxidation and photo (catalytic) oxidative degradation of lignin. In this work, the working principles, influencing factors, vanillin yields obtained, respective advantages and disadvantages and the development trends of the four methods are systematically summarized, and finally, several methods for the separation and purification of lignin-based vanillin are briefly reviewed.

Comparative Analysis of Bio-Vanillin Recovery from Bioconversion Media Using Pervaporation and Vacuum Distillation

The increasing demand for natural products has led to biotechnological vanillin production, which requires the recovery of vanillin (and vanillyl alcohol at trace concentrations, as in botanical vanillin) from the bioconversion broth, free from potential contaminants: the substrate and metabolites of bioconversion. This work discusses the recovery and fractionation of bio-vanillin, from a bioconversion broth, by pervaporation and by vacuum distillation, coupled with fractionated condensation. The objective was to recover vanillin free of potential contaminants, with maximised fluxes and selectivity for vanillin against water and minimised energy consumption per mass of vanillin recovered. In vacuum distillation fractionated condensation, adding several consecutive water pulses to the feed increased the percentage of recovered vanillin. In pervaporation-fractionated condensation and vacuum distillation-fractionated condensation processes, it was possible to recover vanillin and traces of vanillyl alcohol without the presence of potential contaminants. Vacuum distillation-experiments presented higher vanillin fluxes than pervaporation fractionated condensation experiments, 2.7 ± 0.1 g·m^-2 h^-1 and 1.19 ± 0.01 g·m^-2 h^-1, respectively. However, pervaporation fractionated condensation assures a selectivity of vanillin against water of 4.5 on the pervaporation step (acting as a preconcentration step) and vacuum distillation fractionated condensation requires a higher energy consumption per mass of vanillin recovered when compared with pervaporation- fractionated condensation, 2727 KWh kg_VAN^-1 at 85 °C and 1361 KWh kg_VAN^-1 at 75 °C, respectively.

Pulsed Electric Field-Assisted Extraction of Aroma and Bioactive Compounds From Aromatic Plants and Food By-Products

In this work, the effect of pulsed electric field (PEF) pre-treatment on the extractability in green solvents (i. e., ethanol–water mixture and propylene glycol) of target aroma and bioactive compounds, such as vanillin from vanilla pods, theobromine and caffeine from cocoa bean shells, linalool from vermouth mixture, and limonene from orange peels, was investigated. The effectiveness of PEF as a cell disintegration technique in a wide range of field strength (1–5 kV/cm) and energy input (1–40 kJ/kg) was confirmed using impedance measurements, and results were used to define the optimal PEF conditions for the pre-treatment of each plant tissue before the subsequent solid–liquid extraction process. The extracted compounds from untreated and PEF-treated samples were analyzed via GC-MS and HPLC-PDA analysis. Results revealed that the maximum cell disintegration index was detected for cocoa bean shells and vanilla pods (Z_p = 0.82), followed by vermouth mixture (Z_p = 0.77), and orange peels (Z_p = 0.55). As a result, PEF pre-treatment significantly enhanced the extraction yield of the target compounds in both solvents, but especially in ethanolic extracts of vanillin (+14%), theobromine (+25%), caffeine (+34%), linalool (+114%), and limonene (+33%), as compared with untreated samples. Moreover, GC-MS and HPLC-PDA analyses revealed no evidence of degradation of individual compounds due to PEF application. The results obtained in this work suggest that the application of PEF treatment before solid–liquid extraction with green solvents could represent a sustainable approach for the recovery of clean labels and natural compounds from aromatic plants and food by-products.

Vanillin augments liver regeneration effectively in Thioacetamide induced liver fibrosis rat model

AIMS

This study has been designed to investigate the role of vanillin either as prophylaxis or treatment in liver regeneration augmentation and liver fibrosis regression in thioacetamide (TAA) induced liver damage.

MATERIALS AND METHODS

Animals were injected with TAA to induce liver injury (200mg/kg twice weekly) for 8 weeks. In vanillin prophylaxis group; rats were administered vanillin (100 mg/Kg; IP, daily) from day 1 of TAA injection for 8 weeks. In vanillin treatment group; rats were confronted with the same dose of TAA injection for 8 weeks then treated with vanillin (100 mg/Kg, IP, daily) for 4 weeks. ALT, AST activities, serum albumin, hepatic GSH, MDA, HGF, VEGF, IL-6 and TNF-α levels were measured and also, MMP-2, TIMP-1 and cyclin D gene expression were determined. Liver sections were stained with H&E and Sirius red and immunostained for Ki-67 and α-SMA for histological and immunohistological changes analysis.

KEY FINDINGS

Vanillin improved liver function and histology. Also, showed a remarkable increase in hepatic HGF and VEGF level, and up-regulation of cyclin D1 expression accompanied by a significant up-regulation of MMP-2 and down- regulation of TIMP-1. All these effects were accompanied by TNF-α, IL-6 and oxidative stress significant attenuation.

SIGNIFICANCE

In conclusion, vanillin enhanced liver regeneration in TAA induced liver damage model; targeting growth factors (HGF, VEGF) and cellular proliferation marker cyclin D1. As well as stimulating fibrosis regression by inhibition of ECM accumulation and enhancing its degradation.

Extraction of Vanillin Following Bioconversion of Rice Straw and Its Optimization by Response Surface Methodology

Value-added chemicals, including phenolic compounds, can be generated through lignocellulosic biomass conversion via either biological or chemical pretreatment. Currently vanillin is one of the most valuable of these products that has been shown to be extractable on an industrial scale. This study demonstrates the potential of using rice straw inoculated with Serpula lacrymans, which produced a mixture of high value bio-based compounds including vanillin. Key extraction conditions were identified to be the volume of solvent used and extraction time, which were optimized using response surface methodology (RSM). The vanillin compounds extracted from rice straw solid state fermentation (SSF) was confirmed through LC-ESI MS/MS in selective ion mode. The optimum concentration and yield differed depending on the solvent, which was predicted using 60 mL ethyl acetate for 160 min were 0.408% and 3.957 μg g⁻¹ respectively. In comparison, when ethanol was used, the highest concentration and yields of vanillin were 0.165% and 2.596 μg g⁻¹. These were achieved using 40 mL of solvent, and extraction time increased to 248 min. The results confirm that fungal conversion of rice straw to vanillin could consequently offer a cost-effect alternative to other modes of production.

Thermophysical and rheological properties of sorbitol + ([mmim](MeO)2PO2) ionic liquid solutions: Solubility, density and viscosity

In this study, the solubility, density and viscosity of sorbitol as a sugar alcohol in the ([mmim](MeO)₂PO₂) ionic liquid (IL) were measured. The results indicated that sorbitol is highly soluble in this IL. The Flory-Huggins model with an average value for the χ parameter was successfully applied to predict the solubility of sorbitol in IL. The thermodynamic properties such as enthalpy, entropy and Gibbs free energy of dissolution were obtained using experimental solubility data, which demonstrated that the dissolution process is endothermic and non-spontaneous and includes an entropy increase. In addition, the apparent molar volume, apparent molar expansion and thermal expansion coefficient were calculated. The study of the rheological behavior revealed that the sorbitol/IL solution is Newtonian and the Arrhenius, Litovitz, Orrick-Erbar-Type and Vogel-Fulcher-Tamman models were used to correlate the viscosity data.

Techno-economic analysis of vanillin production from Kraft lignin: Feasibility study of lignin valorization

Kraft lignin waste is valorized by converting it into vanillin via the oxidation process. To obtain the highest yield of vanillin, feed concentration of lignin, reaction temperature, and oxygen partial pressure are optimized. Three separation cases, i.e. solvent extraction followed by distillation (Case I), solvent extraction (Case II), and vacuum distillation (Case III) are simulated and compared to identify the most suitable separation process. The results reveal that the highest vanillin yield of 9.25% is attainable using feed concentration of Kraft lignin of 30 g/l, operating temperature of 110 °C, and oxygen partial pressure of 5 bars. Case I appears to be the most suitable method of separation since it consumes the lowest amount of energy and gives the best economic returns, with a payback period of 6.19 years and internal rate of return (IRR) of 22.63%.

Solubility measurement, Hansen solubility parameters and solution thermodynamics of gemfibrozil in different pharmaceutically used solvents

Gemfibrozil (GEM) is cholesterol-lowering agent which is being proposed as poorly water soluble drug (PWSD). Temperature based solubility values of GEM are not yet available in literature or any pharmacopoeia/monograph. Hence, the present studies were carried out to determine the solubility of PWSD GEM (as mole fraction) in various pharmaceutically used solvents such as water (H2O), methanol (MeOH), ethanol (EtOH), isopropanol (IPA), 1-butanol (1-BuOH), 2-butanol (2-BuOH), ethylene glycol (EG), propylene glycol (PG), polyethylene glycol-400 (PEG-400), ethyl acetate (EA), dimethyl sulfoxide (DMSO) and Transcutol® (THP) at the temperatures ranging from T = 298.2 K-318.2 K under atmospheric pressure P = 0.1 MPa. Equilibrium/experimental solubilities of GEM were recorded by applying a saturation shake flask methodology and regressed using 'van't Hoff and Apelblat models'. Hansen solubility parameters for GEM and various pharmaceutically used solvents were estimated using HSPiP software. The solid states of GEM (both in pure and equilibrated states) were studied by 'Differential Scanning Calorimetry' which confirmed no transformation of GEM after equilibrium. Experimental solubilities of GEM in mole fraction were observed maximum in THP (1.81 × 10-1) followed by DMSO, PEG-400, EA, 1-BuOH, 2-BuOH, IPA, EtOH, PG, MeOH, EG and H2O (3.24 × 10-6) at T = 318.2 K and similar tendencies were also recorded at T = 298.2 K, T = 303.2 K, T = 308.2 K and T = 313.2 K. 'Apparent thermodynamic analysis' on experimental solubilities furnished 'endothermic and entropy-driven dissolution' of GEM in each pharmaceutically used solvent.

Selecting Excipients Forming Therapeutic Deep Eutectic Systems-A Mechanistic Approach

The majority of all newly identified active pharmaceutical ingredients (APIs) have a low solubility in water (partly smaller than marble). In order to enhance their solubility and bioavailability, the formulation of these APIs, as part of therapeutic deep eutectic systems (THEDES), has been recently shown to be a promising approach. By choosing the right excipient, the melting point of the API/excipient mixture can be lowered below body temperature or even room temperature, resulting in a liquid formulation. To date, because of a lack of mechanistic understanding of how THEDES are formed, the identification of suitable excipients for a given API is almost exclusively based on heuristic decisions and trial-and-error-based approaches. This is both very time-consuming and expensive. The purpose of this work is to reduce the experimental effort to identify suitable excipients for a given API solely based on the melting properties (melting temperature and melting enthalpy) of the API and excipient and accounting for intermolecular interactions via a predictive thermodynamic model [in this case, UNIFAC(Do)]. Lidocaine, ibuprofen, and phenylacetic acid were considered as model APIs, whereas thymol, vanillin, lauric acid, para-toluic acid, benzoic acid, and cinnamic acid were considered as model excipients. The formation of THEDES from these components was predicted and confirmed using differential scanning calorimetry. The results indicate that the experimental effort for the identification of suitable API/excipient combinations can be drastically reduced by thermodynamic modeling, leading to more efficient and tailor-made formulations in the future.

Solubility and Solution Thermodynamics of Baricitinib in Six Different Pharmaceutically Used Solvents at Different Temperatures

The preset study was undertaken to determine solubility and solution thermodynamics of a novel anticancer drug baricitinib in some pharmaceutically used mono/pure solvents including “water, ethanol, polyethylene glycol-400 (PEG-400), ethyl acetate (EA), dichloromethane (DCM) and dimethyl sulfoxide (DMSO)” at “T = 298.2 K to 323.2 K” and “p = 0.1 MPa”. The solubility of baricitinib after equilibrium (saturation state) was analyzed spectrophotometrically by applying an isothermal technique. Characterization of solid phases of initial and equilibrated baricitinib was confirmed with the help of differential scanning calorimetry (DSC). Measured solubilities of baricitinib were regressed using “van’t Hoff and Apelblat models”. DSC spectra of baricitinib showed no change in physical state of baricitinib after equilibrium. Solubilities of baricitinib (as mole fraction) were estimated highest in DMSO (1.65 × 10−1) followed by PEG-400 (1.42 × 10−1), DCM (1.29 × 10−3), ethanol (7.41 × 10−4), EA (4.74 × 10−4) and water (1.76 × 10−4) at “T = 323.2 K” and same tendencies were also noted at other temperatures studied. With the help of theoretical solubilities of baricitinib, activity coefficients were estimated. The estimated data of activity coefficients indicated higher molecular interactions in baricitinib-DMSO and baricitinib-PEG-400 as compared with baricitinib-water, baricitinib-EA, baricitinib-DCM and baricitinib-ethanol. Thermodynamic treatment of solubility values of baricitinib showed “endothermic and entropy-driven dissolution” of baricitinib in all pharmaceutically used solvents evaluated.

Solubility and Thermodynamic Analysis of Antihypertensive Agent Nitrendipine in Different Pure Solvents at the Temperature Range of 298.15 to 318.15°K

The aim of the present study was to ascertain the solubility of nitrendipine (NP), an antihypertensive drug in six different pure solvents such as water, ethyl acetate (EA), ethanol, isopropyl alcohol (IPA), polyethylene glycol-400 (PEG-400), and Transcutol at temperature from 298.15 to 318.15 K under atmospheric pressure (p) of 0.1 MPa. Experimental solubility data of NP was fitted with Apelblat and ideal models. The mole fraction solubility of NP was found maximum in PEG-400 (6.85 × 10-2 at 318.15 K) followed by Transcutol (4.65 × 10-2 at 318.15 K), EA (1.68 × 10-2 at 318.15 K), ethanol (2.83 × 10-3 at 318.15 K), IPA (2.69 × 10-3 at 318.15 K), and water (1.29 × 10-7 at 318.15 K). The dissolution activity of NP was observed as an endothermic, spontaneous, and an entropy-driven in most of studied pure solvents. The solubility data of NP obtained in the present study could be useful in purification, recrystallization, and dosage forms design of NP.

Solubility and thermodynamic behavior of vanillin in propane-1,2-diol+water cosolvent mixtures at different temperatures

The solubilities of bioactive compound vanillin were measured in various propane-1,2-diol+water cosolvent mixtures at T=(298-318)K and p=0.1 MPa. The experimental solubility of crystalline vanillin was determined and correlated with calculated solubility. The results showed good correlation of experimental solubilities of crystalline vanillin with calculated ones. The mole fraction solubility of crystalline vanillin was recorded highest in pure propane-1,2-diol (7.06×10(-2) at 298 K) and lowest in pure water (1.25×10(-3) at 298 K) over the entire temperature range investigated. Thermodynamic behavior of vanillin in various propane-1,2-diol+water cosolvent mixtures was evaluated by Van't Hoff and Krug analysis. The results showed an endothermic, spontaneous and an entropy-driven dissolution of crystalline vanillin in all propane-1,2-diol+water cosolvent mixtures. Based on solubility data of this work, vanillin has been considered as soluble in water and freely soluble in propane-1,2-diol.