Comparison of green solvents for the revalorization of orange by-products: Carotenoid extraction and in vitro antioxidant activity

Orange peels contain a considerable number of bioactive compounds such as carotenoids, that can be used as ingredients in high-value products. The aim of this study was to compare orange peel extracts obtained with different green solvents (vegetable oils, fatty acids, and deep eutectic solvents (DES)). In addition, the chemical characterization of a new hydrophobic DES formed by octanoic acid and l-proline (C8:Pro) was performed. The extracts were compared in terms of carotenoid extraction, antioxidant activity by three methods, color, and environmental impact. The results confirmed that the mixture of C8:Pro is a DES and showed the highest carotenoid extraction (46.01 µg/g) compared to hexane (39.28 µg/g). The antioxidant activity was also the highest in C8:Pro (2438.8 µM TE/mL). Finally, two assessment models were used to evaluate the greenness and sustainability of the proposed extractions. These results demonstrated the potential use of orange peels in the circular economy and industry.

A Low Transition Temperature Mixture-based viscosupplementation complemented with celecoxib for osteoarthritis treatment

Viscosupplementation consists of hyaluronic acid (HA) intra-articular injections, commonly applied for osteoarthritis treatment while non-steroidal anti-inflammatory drugs (NSAIDs) are widely administered for pain relief. Here, HA and a NSAID (celecoxib) were combined in a formulation based on a low transition temperature mixture (LTTM) of glycerol:sorbitol, reported to increase celecoxib's solubility, thus rendering a potential alternative viscosupplement envisioning enhanced therapeutic efficiency. The inclusion of glucosamine, a cartilage precursor, was also studied. The developed formulations were assessed in terms of rheological properties, crucial for viscosupplementation: the parameters of crossover frequency, storage (G') and loss (G'') moduli, zero-shear-rate viscosity, stable viscosity across temperatures, and shear thinning behaviour, support viscoelastic properties suitable for viscosupplementation. Additionally, the gels biocompatibility was confirmed in chondrogenic cells (ATDC5). Regarding drug release studies, high and low clearance scenarios demonstrated an increased celecoxib (CEX) release from the gel (6 to 73-fold), compared to dissolution in PBS. The low clearance setup presented the highest and most sustained CEX release, highlighting the importance of the gel structure in CEX delivery. NMR stability studies over time demonstrated the LTTM+HA+CEX (GHA+CEX) gel as viable candidate for further in vivo evaluation. In sum, the features of GHA+CEX support its potential use as alternative viscosupplement.

Expression of IL-17RA in Innate Cells of Patients with Common Variable Immunodeficiency (CVID) and its Clinical Implications

Summary

Background. Common Variable Immunodeficiency (CVID) is a primary immunodeficiency disorder characterized by B-cell dysfunction and immunoglobulin production deficiency. Dysregulation of interleukin-17 (IL-17) and its receptor IL-17RA have been reported in various immune disorders. This study aimed to investigate the expression of IL-17RA in innate immune cells of CVID patients and its correlation with clinical manifestations. Methods. A cross-sectional study included 22 CVID patients and 14 age- and sex-matched healthy controls. IL-17RA expression was assessed in various immune cell subsets using flow cytometry. Demographic and clinical data were collected, and statistical analysis was performed. Results. CVID patients had elevated IL-17RA expression in neutrophils, non-classical monocytes, and dendritic cells compared to healthy controls. Patients with a history of intestinal microbial colonization, particularly with Campylobacter jejuni and Giardia intestinalis, showed significantly higher IL-17RA expression in innate cells. Elevated IL-17RA expression in monocytes and dendritic cells also correlated with higher fecal calprotectin levels in CVID patients, regardless of microbial colonization. Conclusions. The study suggests that despite previous reports of reduced circulating Th17 cells and IL-17 levels in CVID patients, IL-17RA expression in innate cells may be elevated, potentially indicating altered IL-17 signaling. This heightened IL-17RA expression could contribute to a persistent pro-inflammatory state, possibly due to microbial translocation or other inflammatory factors. The association of IL-17RA expression with gastrointestinal microbial colonization and its correlation with fecal calprotectin underscores the complexity of IL-17RA's role in CVID pathophysiology. Further research in larger cohorts could elucidate the implications of IL-17RA expression in both infectious and non-infectious inflammatory aspects of CVID.

Enzymatic hydrolysis allows an integral valorization of Nannochloropsis oceanica resulting in the production of bioactive peptide extracts and an eicosapentaenoic acid enriched fraction

Nannochloropsis oceanica is a microalga with relevant protein content, making it a potential source of bioactive peptides. Furthermore, it is also rich in fatty acids, with a special focus on eicosapentaenoic acid (EPA), an omega-3 fatty acid mainly obtained from marine animal sources, with high importance for human health. N. oceanica has a rigid cell wall constraining protein extraction, thus hydrolyzing it may help increase its components' extractability. Therefore, a Box-Behnken experimental design was carried out to optimize the hydrolysis. The hydrolysate A showed 67% ± 0.7% of protein, antioxidant activity of 1166 ± 63.7 μmol TE g-1 of protein and an ACE inhibition with an IC50 of 379 μg protein mL-1 . The hydrolysate B showed 60% ± 1.8% of protein, antioxidant activity of 775 ± 13.0 μmol TE g-1 of protein and an ACE inhibition with an IC50 of 239 μg protein mL-1 . The by-product showed higher yields of total fatty acids when compared to "raw" microalgae, being 5.22% and 1%, respectively. The sustainable developed methodology led to the production of one fraction rich in bioactive peptides and another with interesting EPA content, both with value-added properties with potential to be commercialized as ingredients for different industrial applications, such as functional food, supplements, or cosmetic formulations.

A new green approach for Lavandula stoechas aroma recovery and stabilization coupling supercritical CO2 and natural deep eutectic solvents

This work investigated a green approach to obtain and stabilize Lavandula stoechas L. volatile organic compounds with sensory aroma characteristics by using alternative solvents, namely supercritical carbon dioxide (scCO₂) and deep eutectic solvents (DES). The CO₂ extracts were dispersed in different DES mixtures (betaine:ethylene glycol (1:3), betaine:glycerol (1:2), and glycerol:glucose (4:1)) and their stability was monitored during 6 months of storage at room temperature by monitoring the headspace (HS) profile. The CO₂ extract was used as the control. It was initially determined that there was a dominant presence of oxygenated monoterpenes (67.33-77.50%) in the extracts. During storage, significant changes occurred in the samples' HS, such as the decrease in terpene hydrocarbons which also affected the presence of oxygenated terpenes, which increased in certain cases. Moreover, the highest formation of new components was recorded in the control which could be an indicator of decreased stability. The DESs-CO₂ were more stable than the CO₂ control and among them, betaine:ethylene glycol stood out as the most adequate systems for maintaining the stability of L. stoechas HS components. For the visual estimation of similarities and dissimilarities among the samples, chemometric pattern recognition approaches were applied including the hierarchical cluster analysis, principal component analysis, and sum of ranking differences.

Hydrophobic DES Based on Menthol and Natural Organic Acids for Use in Antifouling Marine Coatings

Marine biofouling negatively impacts industries with off-shore infrastructures, such as naval, oil, and aquaculture. To date, there are no ideal sustainable, economic, and environmentally benign solutions to deal with this phenomenon. The advances achieved in green solvents, as well as its application in different industries, such as pharmaceutical and biotechnology, have promoted the emergence of deep eutectic systems (DES). These eutectic systems have applications in various fields and can be revolutionary in the marine-based industrial sector. In this study, the main objective was to investigate the potential use of hydrophobic DES (HDES) based on menthol and natural organic acids for their use as marine antifouling coatings. Our strategy encompassed the physicochemical characterization of different formulations, which allowed us to identify the most appropriate molar ratio and intermolecular interactions for HDES formations. The miscibility of the resulting HDES with the marine coating has been evaluated and proven to be successful. The Men/OL (1:1) system proved to be the most promising in terms of cost-production and thus was the one used in subsequent antifouling tests. The cytotoxicity of this HDES was evaluated using an in vitro cell model (HaCat cells) showing no significant toxicity. Furthermore, the application of this system incorporated into coatings that are used in marine structures was also studied using marine species (Mytilus edulis mussels and Patella vulgata limpets) to evaluate both their antifouling and ecotoxicity effects. HDES Men/OL (1:1) incorporated in marine coatings was promising in reducing marine macrofouling and also proved to be effective at the level of microfouling without viability impairment of the tested marine species. It was revealed to be more efficient than using copper oxide, metallic copper, or ivermectin as antifouling agents. Biochemical assays performed on marine species showed that this HDES does not induce oxidative stress in the tested species. These results are a strong indication of the potential of this HDES to be sustainable and efficiently used in marine fouling control technologies.

Towards a Greener Approach for Biomass Valorization: Integration of Supercritical Fluid and Deep Eutectic Solvents

A green and sustainable procedure for obtaining Lavandula stoechas extracts with antioxidant and antimicrobial properties was investigated. Green solvents, supercritical CO₂, and natural deep eutectic solvents (NADES) together with ultrasound-assisted extraction were used for the sequential extraction of terpene and polyphenols fractions. After the CO₂ extraction of the terpene fraction, the residue material was used in an extraction with different NADES (betaine-ethylene glycol (Bet:EG), betaine-glycerol (Bet:Gly), and glycerol-glucose (Gly:Glu)), intensified with an ultrasound-assisted method (at 30 and 60 °C). In the CO₂ extract, the major group of components belonged to oxygenated monoterpenes, while the highest polyphenol content with the dominant rutin (438.93 ± 4.60 µg/mL) was determined in Bet:EG extracts (60 °C). Bet:EG extracts also exhibited the most potent antioxidant activity according to DPPH, ABTS, and FRAP assays. Moreover, Bet:EG extracts showed significant inhibitory activity against Gram-positive and Gram-negative bacteria, with minimum inhibitory activity of 0.781-3.125 and 1.563-6.250 mg·mL^-1, respectively. By comparing the polyphenolic content and antioxidant and antimicrobial activities of Bet:EG extracts with extracts obtained with conventional solvents (water and ethanol), the superiority of NADES was determined. The established environmentally friendly procedure unifies the requirements of green and sustainable development and modern pharmacognosy because it combines the use of safe alternative solvents, the absence of solvent waste generation, more rational use of resources, and the attainment of safe and quality extracts.

Using Natural Deep Eutectic Systems as Alternative Media for Ocular Applications

The major goal of this work was to study the potential of natural deep eutectic systems (NADES) as new media for ocular formulations. In formulating eye drops, it is important to increase the retention time of the drug on the surface of eye; hence, due to their high viscosity, NADES may be interesting candidates for formulation. Different systems composed of combinations of sugars, polyols, amino acids, and choline derivatives were prepared and then characterized in terms of rheological and physicochemical properties. Our results showed that 5-10% (w/v) aqueous solutions of NADES have a good profile in terms of viscosity (0.8 to 1.2 mPa.s), osmolarity (412 to 1883 mOsmol), and pH (7.4) for their incorporation of ocular drops. Additionally, contact angle and refractive index were determined. Acetazolamide (ACZ), a highly insoluble drug used to treat glaucoma, was used as proof-of-concept. Herein, we show that NADES can increase the solubility of ACZ in aqueous solutions by at least up to 3 times, making it useful for the formulation of ACZ into ocular drops and thereby enabling more efficient treatment. The cytotoxicity assays demonstrated that NADES are biocompatible up to 5% (w/v) in aqueous media, promoting cell viability (above 80%) when compared to the control after 24 h incubation in ARPE-19 cells. Furthermore, when ACZ is dissolved in aqueous solutions of NADES, the cytotoxicity is not affected in this range of concentrations. Although further studies are necessary to design an optimal formulation incorporating NADES, this study shows that these eutectics can be powerful tools in the formulation of ocular drugs.

Alginate-Chitosan Membranes for the Encapsulation of Lavender Essential Oil and Development of Biomedical Applications Related to Wound Healing

Biopolymers such as chitosan (CHT) or alginate (ALG) are among the most prominent for health-related applications due to their broad bioactivity. Their combination for the preparation of membranes is hereby proposed as an application for wound healing with the incorporation of lavender essential oil (LEO), widely known for its antioxidant and antimicrobial properties. The preparation of CHT, CHT + LEO, ALG, ALG + LEO, and CHT/ALG + LEO membranes was accomplished, and its composition was analyzed using Fourier Transform Infrared Spectroscopy (FTIR). The water absorption capacity and oil release profile of the membranes revealed higher water uptake capacity when a lower LEO release was obtained. The combined CHT/ALG + LEO film showed a water uptake percentage of 638% after 48 h and a maximum LEO release concentration of 42 mg/L. Cytotoxicity and biocompatibility of the prepared membranes were studied using a HaCaT cell line, with an assessment of cell viability regarding film leachables, DNA quantification, and DAPI-phalloidin staining. The results revealed that the indirect contact of the prepared membranes via its leachables does not compromise cell viability, and upon direct contact, cells do not adhere or proliferate on the surface of the membranes. Moreover, the CHT/ALG + LEO membrane increases cell proliferation, making it suitable for applications in wound healing.

Characterization of tars from recycling of PHA bioplastic and synthetic plastics using fast pyrolysis

The aim of this study was to investigate the pyrolysis products of polyhydroxyalkanoates (PHAs), polyethylene terephthalate (PET), carbon fiber reinforced composite (CFRC), and block co-polymers (PS-b-P2VP and PS-b-P4VP). The studied PHA samples were produced at temperatures of 15 and 50 ^oC (PHA15 and PHA50), and commercially obtained from GlasPort Bio (PHAc). Initially, PHA samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) to determine the molecular weight, and structure of the polymers. Thermal techniques such as thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses were performed for PHA, CFRC, and block co-polymers to investigate the degradation temperature range and thermal stability of samples. Fast pyrolysis (500 ^oC, ∼10² °C s^-1) experiments were conducted for all samples in a wire mesh reactor to investigate tar products and char yields. The tar compositions were investigated by gas chromatography-mass spectrometry (GC-MS), and statistical modeling was performed. The char yields of block co-polymers and PHA samples (<2 wt. %) were unequivocally less than that of the PET sample (~10.7 wt. %). All PHA compounds contained a large fraction of ethyl cyclopropane carboxylate (~ 38-58 %), whereas PAH15 and PHA50 additionally showed a large quantity of 2-butenoic acid (~8-12 %). The PHAc sample indicated the presence of considerably high amount of methyl ester (~15 %), butyl citrate (~12.9 %), and tributyl ester (~17 %). The compositional analyses of the liquid fraction of the PET and block co-polymers have shown carcinogenic and toxic properties. Pyrolysis removed matrices in the CRFC composites which is an indication of potential recovery of the original fibers.

Cosmeceutical Potential of Extracts Derived from Fishery Industry Residues: Sardine Wastes and Codfish Frames

The fishery industry generates large amounts of waste (20–75% (w/w) of the total caught fish weight). The recovery of bioactive compounds from residues and their incorporation in cosmetics represents a promising market opportunity and may contribute to a sustainable valorisation of the sector. In this work, protein-rich extracts obtained by high-pressure technologies (supercritical CO₂ and subcritical water) from sardine (Sardina pilchardus) waste and codfish (Gadus morhua) frames were characterized regarding their cosmeceutical potential. Antioxidant, anti-inflammatory and antibacterial activities were evaluated through chemical (ORAC assay), enzymatic (inhibition of elastase and tyrosinase), antimicrobial susceptibility (Klebsiella pneumoniae, Staphylococcus aureus and Cutibacterium acnes) and cell-based (in keratinocytes-HaCaT) assays. Sardine extracts presented the highest antibacterial activity, and the extract obtained using higher extraction temperatures (250 °C) and without the defatting step demonstrated the lowest minimum inhibitory concentration (MIC) values (1.17; 4.6; 0.59 mg/mL for K. pneumoniae, S. aureus and C. acnes, respectively). Codfish samples extracted at lower temperatures (90 °C) were the most effective anti-inflammatory agents (a concentration of 0.75 mg/mL reduced IL-8 and IL-6 levels by 58% and 47%, respectively, relative to the positive control). Threonine, valine, leucine, arginine and total protein content in the extracts were highlighted to present a high correlation with the reported bioactivities (R² ≥ 0.7). These results support the potential application of extracts obtained from fishery industry wastes in cosmeceutical products with bioactive activities.

Assessing the Influence of Betaine-Based Natural Deep Eutectic Systems on Horseradish Peroxidase

To validate the use of horseradish peroxidase (HRP) in natural deep eutectic systems (NADES), five different betaine-based NADES were characterized in terms of water content, water activity, density, and viscosity experimentally and by thermodynamic modeling. The results show that the NADES under study have a water activity of about 0.4 at 37 °C for water contents between 14 and 22 wt %. The densities of the studied NADES had values between 1.2 and 1.3 g^.cm^-3 at 20 °C. The density was modeled with a state-of-the-art equation of state; an excellent agreement with the experimental density data was achieved, allowing reasonable predictions for water activities. The system betaine:glycerol (1:2) was found to be the most viscous with a dynamic viscosity of ∼600 mPa^.s at 40 °C, while all the other systems had viscosities <350 mPa^.s at 40 °C. The impact of the NADES on the enzymatic activity, as well as on, conformational and thermal stability was assessed. The system betaine/sorbitol:water (1:1:3) showed the highest benefit for enzymatic activity, increasing it by two-folds. Moreover, upon NADES addition, thermal stability was increased followed by an increment in a-helix secondary structure content.

Selective extraction and stabilization of bioactive compounds from rosemary leaves using a biphasic NADES

Rosemary (Rosmarinus officinalis) is a natural source of bioactive compounds that have high antioxidant activity. It has been in use as a medicinal herb since ancient times, and it currently is in widespread use due to its inherent pharmacological and therapeutic potential, in the pharmaceutical, food, and cosmetic industries. Natural deep eutectic systems (NADESs) have recently been considered as suitable extraction solvents for bioactive compounds, with high solvent power, low toxicity, biodegradability, and low environmental impact. The present work concerns the extraction of compounds such as rosmarinic acid, carnosol, carnosic acid, and caffeic acid, from rosemary using NADESs. This extraction was carried out using heat and stirring (HS) and ultrasound-assisted extraction (UAE). A NADES composed of menthol and lauric acid at a molar ratio of 2:1 (Me:Lau) extracted carnosic acid and carnosol preferentially, showing that this NADES exhibits selectivity for nonpolar compounds. On the other hand, a system of lactic acid and glucose (LA:Glu (5:1)) extracted preferentially rosmaniric acid, which is a more polar compound. Taking advantage of the different polarities of these NADESs, a simultaneous extraction was carried out, where the two NADESs form a biphasic system. The system LA:Glu (5:1)/Men:Lau (2:1) presented the most promising results, reaching 1.00 ± 0.12 mg of rosmarinic acid/g rosemary and 0.26 ± 0.04 mg caffeic acid/g rosemary in the more polar phase and 2.30 ± 0.18 mg of carnosol/g of rosemary and 17.54 ± 1.88 mg carnosic acid/g rosemary in the nonpolar phase. This work reveals that is possible to use two different systems at the same time and extract different compounds in a single-step process under the same conditions. NADESs are also reported to stabilize bioactive compounds, due to their interactions established with NADES components. To determine the stability of the extracts over time, the compounds of interest were quantified by HPLC at different time points. This allows the conclusion that bioactive compounds from rosemary were stable in NADESs for long periods of time; in particular, carnosic acid presented a decrease of only 25% in its antioxidant activity after 3 months, whereas the carnosic acid extracted and kept in the methanol was no longer detected after 15 days. The stabilizing ability of NADESs to extract phenolic/bioactive compounds shows a great promise for future industrial applications.

Assessment of deep eutectic solvents toxicity in zebrafish (Danio rerio)

Deep Eutectic Systems (DES) have emerged as a "green alternative" to organic solvents and have been coined as biocompatible and biodegradable. However, the number of studies concerning the real biodegradability and biocompatibility are scarce. Thus, to study the toxicity of certain DES, two different approaches were used: i) zebrafish exposure via water, where the system (DES) was tested at potentially realistic environmental concentrations and ii) via intraperitoneal injection, where the system was tested in different concentrations, relevant to the pharmaceutical industry. These studies were performed using zebrafish, a standardized animal model often used in biomedicine and toxicological assays. The results show low toxicity according to tested concentrations (up to 73.47 μM), when the system CA:T:W, with a 2:1:3 molar ratio, was tested through exposure via water and also in the intraperitoneal injection tests with concentrations up to 6000 μM. The activity of different enzymes involved in antioxidant pathways (glutathione S-transferase, catalase, glutathione peroxidase), the total antioxidant capacity (TAC) and lipoperoxidation (MDA content) were determined suggesting low toxicity of the tested system (DES). The promising results herein presented show that DES present the potential to be used as the new class of green solvents, not only for use in the pharmaceutical industry, but also in cosmetic and chemical engineering processes without causing negative impact on living organisms.

Use of natural deep eutectic systems as new cryoprotectant agents in the vitrification of mammalian cells

In this work we present the potential of Natural Deep Eutectic Systems (NADES) as new vitrification media for the cryopreservation of mammalian cells. Several NADES composed of natural metabolites were prepared and tested as CPAs in two cell lines, L929 and HacaT cells. After the harvesting, cells were mixed with the eutectic systems, and frozen directly into liquid nitrogen to achieve a vitreous state. Then, the cells were thawed and it was observed that NADES were able to exert a significant cryoprotective effect in L929 cells, when compared with DMSO or in the absence of a CPA. For HacaT cells, only a eutectic system showed a slightly improvement in cell survival, while DMSO caused complete cell death. Moreover, the thermal behaviour of the best systems was studied for further understanding the protective properties of NADES as CPAs, and have shown a significant difference in terms of T_m and T_c when compared with DMSO and water. Additionally, the results obtained showed that NADES can be maintained in the growth media after the thawing step, without compromising cell viability. In summary, we have shown the great potential of NADES to be used as CPAs for the cryopreservation of different cell types, using the vitrification method.

Extraction of Bioactive Compounds From Cannabis sativa L. Flowers and/or Leaves Using Deep Eutectic Solvents

The increasing demand for medical cannabis urges the development of new and effective methods for the extraction of phytocannabinoids. Deep eutectic solvents (DESs) are an alternative to the use of hazardous organic solvents typically used in the industry. In this study, hydrophilic and hydrophobic DESs were developed based on terpenes, sugars, and natural organic acids as green extraction media for the extraction of cannabis bioactive compounds. The factors influencing the extraction of bioactive components, such as the type of DESs and extraction time, were investigated. Initial screening in hemp showed that the DES composed of Men: Lau (a 2:1-M ratio) had a greater extraction efficiency of cannabidiol (CBD) and cannabidiolic acid (CBDA) (11.07 ± 0.37 mg/g) of all the tested DESs and higher than ethanol. Besides having a higher or equivalent extraction yield as the organic solvents tested, DESs showed to be more selective, extracting fewer impurities, such as chlorophyll and waxes. These results, coupled with the non-toxic, biodegradable, low-cost, and environmentally friendly characteristics of DESs, provide strong evidence that DESs represent a better alternative to organic solvents.

White wine grape pomace as a suitable carbon source for lipid and carotenoid production by fructophilic Rhodorotula babjevae

AIM

We aim to explore the non-structural sugars from white wine grape pomace (WWGP) as the input carbon source for the co-production of multiple high-value products by the non-fastidious yeast Rhodotorula babjevae to create a sustainable and economically appealing process.

METHODS AND RESULTS

Water extraction of unfermented, soluble sugars from WWGP yielded extracts with similar amounts of glucose and fructose, which were used to prepare a growth medium. R. babjevae multiplied as fast on WWGP-based medium as on a reference medium but achieved higher cell dry weight (CDW) and lower intracellular triacylglycerol accumulation (22.5% vs 28.6%) in WWGP-based medium. In addition, R. babjevae produced mannitol and arabitol, carotenoids, and secreted polyol esters of fatty acids (PEFA), a rare type of glycolipid as confirmed by FTIR, NMR and HPLC analyses. Remarkably, R. babjevae consumed simultaneously both fructose and glucose when on WWGP-based medium and left glucose practically untouched in the reference medium, evidencing a fructophilic character.

CONCLUSIONS

R. babjevae, a metabolic versatile yeast, proliferated on a minimally processed extract and successfully converted glucose and fructose into high-value products.

SIGNIFICANCE AND IMPACT OF STUDY

Different chemicals with market potential can be produced through the valorization of abundant waste feedstocks generated by the wine industry to which R. babjevae can contribute.

Structure and Dynamic Properties of a Glycerol-Betaine Deep Eutectic Solvent: When Does a DES Become an Aqueous Solution?

Deep eutectic solvents (DESs) are an emerging class of green solvents with a wide spectrum of potential applications whose properties may be further tailored through the addition of water. Here, we study, through molecular dynamics, the influence of water on the properties of a betaine-glycerol-water (B:G:W) DES (1:2:ζ; ζ = 0 to 100), aiming at getting insight into the structural and dynamic crossover between a DES and an aqueous solution. The density, shear viscosity, and diffusion coefficients are found to exhibit a non-linear dependence of ζ, similar to that observed for the solvation layers' composition. Each Gly and Bet are replaced, respectively, by ∼3 and ∼5 water molecules, with the highest rates of depletion being found for Gly around Bet and Gly around Gly. Above ζ = 7 (70 mol %; 29.5 wt %), a major structural transformation occurs, with the complete disruption of the second Bet-Gly solvation layer and the formation of a new second layer at a shorter distance, accompanied by a sudden change in the rate of increase of the components' diffusion. Nonetheless, opposite to other DES, our results indicate a smooth crossover between a DES and an aqueous solution.

Fractionated extraction of polyphenols from mate tea leaves using a combination of hydrophobic/ hydrophilic NADES

A new methodology for the selective extraction of antioxidants from mate tea leaves (and decaffeinated mate tea leaves), using different natural deep eutectic systems (NADES), is reported in this paper. A fractionated extraction was carried out and the optimization of the extraction conditions such as solid/liquid ratio, temperature, time, stirring and the use of ultrasound assisted extraction (UAE) technology was performed. The results demonstrate that a sequential extraction using, in a first step, an hydrophobic system Men:Lau (2:1) and, in a second step, an hydrophilic lactic acid-based NADES, leads to two distinct extracts: the first one rich in pigments and the second one rich in polyphenols.

NADES systems were able to extract 30% more of the polyphenolic components of the mate tea leaves matrices, when compared with traditional solvents/techniques. Moreover, it has been shown that the incorporation of the extract in the NADES, compared to the same extract in aqueous medium was beneficial for the stabilization of the antioxidants. It maintains their functionality at least for three months, reaching 41% more versus the extracts obtained by traditional solvents/techniques. The absence of caffeine in the extracts did not shown to have any effects on the stability results.

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NADES proved to be more effective extraction solvent compared to conventional techniques.

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Fractionated extraction method using different classes of NADES as extraction medium.

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Novel technique to extract the major compounds of mate tea leaves.

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The extract incorporated in the NADES is beneficial for the stabilization of the antioxidants.

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Final product is 100% natural.

Simultaneous Hydrolysis of Ellagitannins and Extraction of Ellagic Acid from Defatted Raspberry Seeds Using Natural Deep Eutectic Solvents (NADES)

Defatted raspberry seeds were used as an alternative source of antioxidants and ellagic acid (EA) extracted using Natural deep eutectic solvents (NADES). In the preliminary study, the best NADES combination (citric acid-betaine) and the most influential variables (temperature, time, and NADES/plant ratio) were selected for the further optimization process. All samples were analyzed in terms of total polyphenol, EA content, and antioxidant activity. Two sets of optimal conditions were generated by response surface methodology. The first set (Opt1) was designed for higher conversion of ellagitannins to EA while the latter set (Opt2) for higher EA content/100 g extract. Opt1 and Opt2 had higher values for all investigated responses compared to 80% ethanolic extract but had a lower conversion rate of ellagitannins to EA compared to acidified methanol extract. The third set of parameters (Opt3) selected beyond the initial experimental domain was used to obtain a sample with the highest EA content/100 g extract. Due to their nature, NADES extracts are ready to use and could have various technological roles in products since they are antioxidants, acidifiers, and colorants. NADES raspberry extracts exhibited higher anti-proliferative activity compared to ethanolic extracts in terms of EC50 values. However, the main contributor of anti-cancer activity in NADES raspberry extracts were individual NADES compounds and/or their newly formed NADES structure.

On the Not So Anomalous Water-induced Structural Transformations of Choline Chloride-Urea (Reline) Deep Eutectic System

The choline chloride-urea binary mixture in the molar ratio (1:2), commonly known as reline, is an archetypal solvent among deep eutectic solvents (DES). Neutron diffraction (ND) and empirical potential structure...

Evaluation of Deep Eutectic Systems as an Alternative to Solvents in Painting Conservation

Natural deep eutectic solvents (NADESs) are considered as green solvents, and due to their promising sustainability, they have been applied in many research fields. In this study, the main goal is to use various NADES systems to replace the traditional solvents used in conservation and restoration to remove varnish layers in a painting. The toxicity of traditional solvents, such as toluene or acetone, is well known in the chemistry field. To replace them, it is important to understand the intrinsic physicochemical properties of a solvent that may act as a substitute. Polarity and solubility are proposed as the best parameters required for this study. The Nile red probe was used to confirm the similarity between the polarity of deep eutectic systems (DESs) and traditional solvents. According to their polarities and Hansen solubility parameters, it is possible to predict the best solvents to solubilize the natural resin varnishes. Besides this, some arithmetic models can also be applied to estimate the critical or thermodynamic properties, which are useful tools to predict the behavior of these solvents. We have further proven the possibility of dissolving natural varnishes such as dammar or mastic in hydrophobic DESs, such as menthol + lauric acid, menthol + decanoic acid, or menthol + thymol.

Low-Phytotoxic Deep Eutectic Systems as Alternative Extraction Media for the Recovery of Chitin from Brown Crab Shells

The versatility of chitin and its derivatives has allowed their utilization in a wide range of applications, from wastewater treatment to pharmaceutical or biomedical industries. However, even though the extraction method used industrially is extremely efficient, it involves the use of strong acids and bases and results in the disposal of large quantities of toxic effluents. Deep eutectic systems (DESs) have emerged as a promising new class of alternative solvents, including for chitin recovery. Yet, the assessment of their toxicity has often been neglected. Therefore, in this work, the phytotoxicity of choline chloride (ChCl)/organic acid-based DESs toward wheat seeds was evaluated by measuring different growth parameters and stress biomarkers. DESs were then explored for the efficient recovery of chitin contained in brown crab shell residues at varying conditions of temperature and processing time as well as with and without water addition. The obtained chitin was then characterized through different analytical techniques and compared to a standard as well as to chitin obtained by a conventional acid/alkaline hydrolysis. Results have shown that by applying a ChCl/lactic acid-based DES (which was the system that showed the least phytotoxic effects on wheat; EC50 ≥ 1.6 mg/mL) at 130 °C, it was possible to obtain pure chitin (up to 98%) with characteristics similar to those presented by commercial chitin or chitin recovered by conventional hydrolysis in a shorter time (more than 8-fold faster), thus suggesting that ChCl/organic acid-based DESs can truly represent a low-phytotoxic alternative extraction media for the recovery of chitin from the crab shell biomass.

Cauda equina syndrome following combined spinal-epidural anesthesia with levobupivacaine for cesarean section

Cauda equina syndrome (CES) is a rare but possible complication of neuroaxial anesthesia. Damage to the nerve roots may occur due to compression, inflammation, stretching, direct trauma, spinal ischemia or neurotoxicity, usually with lidocaine or bupivacaine. We describe a case of a 33-year-old patient that underwent an uneventful cesarean section with a combined spinal-epidural technique anesthesia, with levobupivacaine. 48 h after the procedure, she presented diminished muscular strength and abolished osteotendinous reflexes in the left lower limb, limited flexion of the right hallux, urinary retention and saddle anesthesia. Imaging exams excluded hematoma, thickening or compression of the cauda equina nerve roots. CES was suspected and treatment was initiated. 9-month follow up revealed diminished osteotendinous reflexes on the left lower limb and perianal hypoesthesia. Despite being unusual, neurological complications require prompt recognition and management to avoid permanent damage.

Natural deep eutectic systems, an emerging class of cryoprotectant agents

This work aimed at evaluating the potential of using natural deep eutectic systems (NADES) as cryoprotectant agents (CPAs). Several combinations between natural primary metabolites that have been identified in animals that live in extreme cold climates were prepared. All systems showed very little cytoxicity towards L929 cells at concentrations high as 1–2 M. Moreover, this cell line was highly tolerant to 10% (w/v) of NADES when compared to Me₂SO. To test NADES as CPAs, two cell lines were used, L929 and HacaT cells. After freeze/thawing cycle, it was possible to observe that for L929 cells, NADES presented similar behaviour to Me₂SO. For Hacat cell line a significant improvement on post-thawing recovery was observed. Moreover, the results presented herein showed that NADES do not need to be removed from the freezing media after thawing the cells, which is a great advantage of these materials. Additionally, we have shown that NADES can act as CPA when cells are frozen at −20 °C. In overall, the results demonstrate the high potential of NADES to be used in cryobiology as alternative CPAs.

Molecular Dynamics Studies of Therapeutic Liquid Mixtures and Their Binding to Mycobacteria

Tuberculosis is an highly contagious disease still considered by the WHO as one of most infectious diseases worldwide. The therapeutic approach, used to prevent and treat tuberculosis targets the Mycobacterium tuberculosis complex, comprises a combination of drugs administrated for long periods of time, which, in many cases, could cause several adverse effects and, consequently, low compliance of the patient to the treatment and drug-resistance. Therefore, therapeutic liquid mixtures formulated with anti-tuberculosis drugs and/or adjuvants in tuberculosis therapy are an interesting approach to prevent toxic effects and resistance to anti-tuberculosis drugs. The herein formulated therapeutic liquid mixtures, including ethambutol, arginine, citric acid and water under different molar ratios, were studied through a molecular dynamics approach to understand how ethambutol and arginine could be stabilized by the presence of citric acid and/or water in the mixture. To gain insights on how the uptake of these mixtures into the mycobacteria cell may occur and how a mycobacterial ABC transporter could contribute to this transport, multiple simultaneous ligand docking was performed. Interactions between citric acid and ethambutol involving the carboxyl and hydroxyl groups of citric acid with the amines of ethambutol were identified as the most critical ones. Water molecules present in the mixture provides the necessary network of hydrogen bonds that stabilize the mixture. Molecular docking additionally provided an interesting hypothesis on how the different mixture components may favor binding of ethambutol to an ABC importer. The data presented in this work helps to better understand these mixtures as well as to provide cues on the mechanisms that allow them to cross the mycobacterial cell membrane.

The Role of Hydrogen Bond Donor on the Extraction of Phenolic Compounds from Natural Matrices Using Deep Eutectic Systems

Recently, deep eutectic systems (DESs) as extraction techniques for bioactive compounds have surfaced as a greener alternative to common organic solvents. In order to study the effect of these systems on the extraction of phenolic compounds from different natural sources, a comprehensive review of the state of the art was carried out. In a first approach, the addition of water to these systems and its effect on DES physicochemical properties such as polarity, viscosity, and acidity was investigated. This review studied the effect of the hydrogen bond donor (HBD) on the nature of the extracted phenolics. The effects of the nature of the HBD, namely carbon chain length as well as the number of hydroxyl, methyl, and carbonyl groups, have shown to play a critical role in the extraction of different phenolic compounds. This review highlights the differences between DES systems and systematizes the results published in the literature, so that a more comprehensive evaluation of the systems can be carried out before any experimental trial.

Unravelling the nature of citric acid:L-arginine:water mixtures: the bifunctional role of water

The use of water as a component of deep eutectic systems (DES) has raised some questions regarding its influence on the nature of the mixture. Does it form a DES or an aqueous solution and what is the role of water? In this work, the nature of citric acid:l-arginine:water mixtures was explored through phase equilibria studies and spectroscopic analysis. In a first step, PC-SAFT was validated as a predictive tool to model the water influence on the solid liquid equilibria (SLE) of the DES reline using the individual-component approach. Hence, activity coefficients in the ternary systems citric acid:l-arginine:water and respective binary combinations were studied and compared using ePC-SAFT. It was observed that the water-free mixtures citric acid:l-arginine showed positive deviation from Raoult's law, while upon addition of water strong negative deviation from Raoult's law was found, yielding melting depressions around 100 K. Besides these strong interactions, pH was found to become acidic (pH = 3.5) upon water addition, which yields the formation of charged species ([H2Cit]- and [l-arg]+). Thus, the increased interactions between the molecules upon water addition might be caused by several mechanisms such as hydrogen bonding or ionic forces, both being induced by water. For further investigation, the liquid mixtures citric acid:l-arginine:water were studied by FTIR and NMR spectroscopy. FTIR spectra disproved a possible solubility enhancement caused by salt formation between citric acid and l-arginine, while NMR spectra supported the formation of a hydrogen bonding network different from the binary systems citric acid:water and l-arginine:water. Either being a DES or other type of non-ideal solution, the liquefaction of the studied systems is certainly caused by a water-mediator effect based on the formation of charged species and cross interactions between the mixture constituents.

Improvement of New Dianionic Ionic Liquids vs Monoanionic in Solubility of Poorly Water-Soluble Drugs

New ionic liquids (ILs) based on dianionic phosphonate anions and ammonium cations were prepared and characterized. They were used as excipients to increase the water solubility of two oral drugs, piroxicam and ibuprofen, that are slightly soluble in water. An increment in solubility of 300-fold was achieved for ibuprofen when compared with pure water, with only 0.25 mol% of IL in water. Interestingly, this was achieved with the less toxic dianionic ionic liquid [N_{4 1 2OH 2OH}]₂ [C₂H₅PO₃], which presents an IC₅₀ of 120 mM (≈0.25 mol%). On the other hand, piroxicam showed an increase of 480-fold for the same dianionic ionic liquid, with the same ionic liquid percentage. In contrast, for monoanionic ionic liquids, the effect was not so pronounced, and only a 10-fold was obtained, in the presence of 0.3 mol% of IL. The lipophilicity (logP) of drugs decreased in the presence of these ILs. Cytotoxicity profile of these ILs was determined and they did not show a significant impact towards healthy fibroblasts. The cytotoxicity of ibuprofen and piroxicam was also determined, and cellular viability almost did not change when ionic liquid was in the presence of 1 mM of oral drug.

Valorization of Cork Using Subcritical Water

Granulated cork was submitted to subcritical water extraction/hydrolysis in a semi-continuous reactor at temperatures in the range of 120–200 °C and with a constant pressure of 100 bar. The influence of temperature on the composition of the cork extracts obtained was assessed—namely, their content of carbohydrates and phenolics. The extraction yield increased with the temperature, and this was associated with the decrease in the dielectric constant of water and the increase in its ionic product. Extracts composed of up to 36% phenolics were obtained at temperatures of up to 120 °C, with an antioxidant activity only two times lower than that of pure gallic acid, but in low amounts. Assays at higher temperatures generated extracts richer in carbohydrates and with a phenolics content of ca. 20 wt.% in comparatively far higher amounts. Neither the amount of suberin nor its structure were affected by the subcritical water treatment.

Subcutaneous emphysema as a complication of the use of a laryngeal mask in a child

The use of supraglottic airway devices has been increasing in popularity, mostly due to their high success rate and low complications. However, there is very little information available about the potential and group specific concerns regarding their use in children. We present the first description of a child that developed subcutaneous emphysema after the use of a laryngeal mask. We believe that more awareness to the risk of perioperative adverse events with laryngeal mask insertion in the paediatric population is needed.

Elevated soluble TNFα levels and upregulated TNFα mRNA expression in purified peripheral blood monocyte subsets associated with high-grade hepatocellular carcinoma

BACKGROUND

Chronic inflammation is involved in the initiation and progression of various cancers, including liver cancer. The current study focuses on the characterization of the peripheral immune response in hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) patients, before and after surgical procedure, in order to assess the effect of tumor resection in the immune system homeostasis and to determine possible prognostic factors associated with high-grade tumors. We developed a whole-blood assay to monitor immune alterations and functional competence of peripheral monocytes in a group of 10 healthy individuals (HG), in 20 HCC patients and 8 CCA patients, by multi-color flow cytometry, qRT-PCR, and ELISA techniques.

RESULTS

The qRT-PCR analysis showed an upregulation of TNFα expression by classical and intermediate monocytes purified from HCC patients presenting tumors in grade G3-G4 as compared to G1-G2 HCC patients. Moreover, ELISA assay confirmed elevated serum levels of TNFα in G3-G4 compared to G1-G2 HCC patients. A significant decrease of circulating non-classical monocytes was detected in both CCA and HCC patients before and after surgical procedure. In addition, a functional defect in circulating classical and intermediate monocytes was observed in both groups of cancer patients when compared to the HG, with partial recovery after the surgical intervention.

CONCLUSIONS

This integrated analysis permitted the identification of altered functional competence of monocyte subsets in CCA and HCC patients. In addition, our results point to a potential role of TNFα as a prognostic peripheral biomarker in HCC patients, indicating the presence of high-grade tumors that should be further validated.

Electrodialytic removal of tungsten and arsenic from secondary mine resources - Deep eutectic solvents enhancement

Tungsten is a critical raw material for European and U.S. economies. Tungsten mine residues, usually considered an environmental burden due to e.g. arsenic content, are also secondary tungsten resources. The electrodialytic (ED) process and deep eutectic solvents (DES) have been successfully and independently applied for the extraction of metals from different complex environmental matrices. In this study a proof of concept demonstrates that coupling DES in a two-compartment ED set-up enhances the removal and separation of arsenic and tungsten from Panasqueira mine secondary resources. Choline chloride with malonic acid (1:2), and choline chloride with oxalic acid (1:1) were the DES that in batch extracted the average maximum contents of arsenic (16%) and tungsten (9%) from the residues. However, when ED was operated at a current intensity of 100 mA for 4 days, the extraction yields increased 22% for arsenic and 11% for tungsten, comparing to the tests with no current. From the total arsenic and tungsten extracted, 82% and 77% respectively were successfully removed from the matrix compartment, as they electromigrated to the anolyte compartment, from where these elements can be further separated. This achievement potentiates circular economy, as the final treated residue could be incorporated in construction materials production, mitigating current environmental problems in both mining and construction sectors.

Preparation of Binary and Ternary Deep Eutectic Systems

The preparation of deep eutectic systems (DES) is a priori a simple procedure. By definition, two or more components are mixed together at a given molar ratio to form a DES. However, from our experience in the laboratory, there is a need to standardize the procedure to prepare, characterize and report the methodologies followed by different researchers, so that the results published can be reproduced. In this work, we test different approaches reported in the literature to prepare eutectic systems and evaluated the importance of water in the successful preparation of liquid systems at room temperature. These published eutectic systems were composed of citric acid, glucose, sucrose, malic acid, β-alanine, L-tartaric acid and betaine and not all of preparation methods described could be reproduced. However, in some cases, it was possible to reproduce the systems described, with the inclusion of water as a third component of the eutectic mixture.

Unveil the Anticancer Potential of Limomene Based Therapeutic Deep Eutectic Solvents

Deep eutectic solvents have been recently reported as an interesting alternative to improve the therapeutic efficacy of conventional drugs, hence called therapeutic deep eutectic solvents (THEDES). The main objective of this work was to evaluate the potential of limonene (LIM) based THEDES as new possible systems for cancer treatment. LIM is known to have antitumor activity, however it is highly toxic and cell viability is often compromised, thus this compound is not selective towards cancer cells. Different THEDES based on LIM were developed to unravel the anticancer potential of such systems. THEDES were prepared by gently mixing saturated fatty acids menthol or ibuprofen (IBU) with LIM. Successful THEDES were obtained for Menthol:LIM (1:1), CA:LIM (1:1), IBU:LIM (1:4) and IBU:LIM(1:8). The results indicate that all the THEDES present antiproliferative properties, but IBU:LIM (1:4) was the only formulation able to inhibit HT29 proliferation without comprising cell viability. Therefore, IBU:LIM (1:4) was the formulation selected for further assessment of anticancer properties. The results suggest that the mechanism of action of LIM:IBU (1:4) is different from isolated IBU and LIM, which suggest the synergetic effect of DES. In this work, we unravel a methodology to tune the selectivity of LIM towards HT29 cell line without compromising cell viability of healthy cells. We demonstrate furthermore that coupling LIM with IBU leads also to an enhancement of the anti-inflammatory activity of IBU, which may be important in anti-cancer therapies.

Therapeutic Role of Deep Eutectic Solvents Based on Menthol and Saturated Fatty Acids on Wound Healing

The breakthroughs achieved in green solvents promote the emergence of therapeutic deep eutectic solvents (THEDES), which possess intriguing possible applications in the biomedical field. Herein, the main aim was to unravel the biomedical potential of hydrophobic THEDES based in menthol and saturated fatty acids with different chain lengths (e.g., stearic acid (SA), myristic acid (MA), and lauric acid (LA)). Our comprehensive strategy resulted in the thermophysical characterization of different formulations, which allow one to identify the most suitable molar ratio, as well as the intermolecular interactions behind the successful formation of THEDES. The evaluation of their biological performance was also performed toward bacteria and HaCaT cells. Among the different formulations of THEDES, the one based on menthol and SA establishes stronger hydrogen bonding interactions, being also the most promising formulation because it did not elicit any relevant cytotoxicity, and potentiated wound healing, while presenting antibacterial properties against Staphylococcus epidermis and Staphylococcus aureus strains, some of which were methicillin resistant. This work provides clues on the future use of THEDES based on menthol:SA in wound dressings.

Functional and Phenotypic Characterization of Tumor-Infiltrating Leukocyte Subsets and Their Contribution to the Pathogenesis of Hepatocellular Carcinoma and Cholangiocarcinoma

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) represent the most common primary liver malignancies whose outcome is influenced by the immune response. In the present study, we evaluated the tumor-infiltrating leukocyte (TIL) populations in 21 HCC patients and 8 CCA patients by flow cytometry immediately after the surgical procedure. Moreover, CD4⁺ T cells, CD8⁺ T cells, monocytes, and macrophages were purified by cell sorting for further analysis of gene expression by quantitative reverse-transcription polymerase chain reaction. Regarding tumor-infiltrating macrophages, we observed a significantly higher expression of markers associated with M2 phenotype and a higher expression of PD-L1 in patients with HCC in comparison to CCA. In addition, for HCC patients, we found a significant increase in the expression of CD200R in macrophages from tumors that were in grade G3-G4 as compared to tumors in grade G1-G2. Besides, a significantly higher frequency of tumor-infiltrating lymphocytes, CD8⁺CD56⁺ T cells, and natural killer cells was detected in HCC biopsies in comparison to CCA. In summary, this study has revealed functional and phenotypic differences in TIL cell subpopulations between CCA and HCC, as well as among different histopathological grades and tumor aggressiveness degrees, and it has provided evidence to better understand the tumor immune microenvironment of CCA and HCC.

Polymer Science and Engineering Using Deep Eutectic Solvents

The green and versatile character of deep eutectic solvents (DES) has turned them into significant tools in the development of green and sustainable technologies. For this purpose, their use in polymeric applications has been growing and expanding to new areas of development. The present review aims to summarize the progress in the field of DES applied to polymer science and engineering. It comprises fundamentals studies involving DES and polymers, recent applications of DES in polymer synthesis, extraction and modification, and the early developments on the formulation of DES–polymer products. The combination of DES and polymers is highly promising in the development of new and ‘greener’ materials. Still, there is plenty of room for future research in this field.

Lipoxidation and cancer immunity

Lipoxidation is a well-known reaction between electrophilic carbonyl species, formed during oxidation of lipids, and specific proteins that, in most cases, causes an alteration in proteins function. This can occur under physiological conditions but, in many cases, it has been associated to pathological process, including cancer. Lipoxidation may have an effect in cancer development through their effects in tumour cells, as well as through the alteration of immune components and the consequent modulation of the immune response. The formation of protein adducts affects different proteins in cancer, triggering different mechanism, such as proliferation, cell differentiation and apoptosis, among others, altering cancer progression. The divergent results obtained documented that the formation of lipoxidation adducts can have either anti-carcinogenic or pro-carcinogenic effects, depending on the cell type affected and the specific adduct formed. Moreover, lipoxidation adducts may alter the immune response, consequently causing either positive or negative alterations in cancer progression. Therefore, in this review, we summarize the effects of lipoxidation adducts in cancer cells and immune components and their consequences in the evolution of different types of cancer.

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Lipoxidation in tumour cells may lead to mechanism that interfere with cancer.

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Lipoxidation adducts can have either anti-carcinogenic or pro-carcinogenic effects.

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The triggered effects depend on the affected cell and the specific adduct formed.

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Lipoxidation affecting immune components may influence cancer progression.

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Lipoxidation may inhibit tumour progression through the inhibition of NFκB pathway.