Formation Of Hydroperoxides Research Articles

Pediatric parenteral nutrition and hydroperoxide toxicity: Evaluation of the effectiveness of photoprotection medical devices.

Exposure of parenteral nutrition (PN) to light induces hydroperoxide (HPO) formation whose toxicity, especially in pediatrics, is documented. In this context, we evaluated the efficacy of photoprotection medical devices used in our institution to protect PN from degradation after two different exposures to light. A mixed oil lipid emulsion (Smoflipid®) in standard or opaque syringes and a ternary PN mixture bags (Numetah®) with or without opaque overwrap were exposed for at least 420 min to a xenon lamp. Samples of Smoflipid® in standard or opaque syringes were also exposed for 24 h to conditions reproducing those of a neonatal intensive care unit. The use of opaque syringes for Smoflipid® administration or opaque overwraps for Numetah® administration reduced HPO formation by an average of 14% and 40%, respectively, compared to standard conditions after at least 420 min to a xenon lamp. When Smoflipid® samples were administered with standard or opaque syringes and exposed to a phototherapy lamp, the fold-change in the HPO concentration increased, respectively, by 6.3 or 5.4 at 24 h compared with syringes unexposed to phototherapy lamp. Although the observed differences were non-significant, it nonetheless appears prudent to use photoprotection of PN during administration, particularly in patients with immature or compromised antioxidant capacity.

High internal phase emulsion-template oleogels stabilized by sodium caseinate:quercetin complexes and potential application in pound cakes

Oleogels have been pointed out as a potential alternative for saturated and trans-fat replacement, but their successful application in food remains a challenge. This research aimed to explore the production of oleogels formed by an indirect approach and their further application to pound cakes. Oleogels were obtained from a scaffold of percolating 3D network of biopolymer, primarily adsorbed at the interface of an oil-in-water high internal phase emulsion (HIPE) (φ = 0.80). Precursor HIPEs were stabilized by sodium caseinate (SC) - quercetin (Q) covalent complexes formed via an alkaline process or only SC. Better HIPEs for oleogel production were stabilized by SC-Q complexes instead of the native protein. SC-Q complexes acted as functional emulsifiers providing great protection against oil release after shearing and less formation of hydroperoxides and malonaldehyde in oleogels. In addition, oleogels obtained after drying (water removal) at the highest studied temperature (120 °C) did not show surface oil release. Finally, the performance of these oleogels was assessed in pound cakes in comparison to palm fat (PF) and sunflower oil (SO) as controls. Apparent viscosity and aeration of oleogel-based cake batters were lower than PF. However, after baking, the specific volume of cakes with oleogels was higher than the PF formulation. Nevertheless, the quality parameters of the cakes produced with oleogels (SC or SCQ) were similar to those prepared with SO. These outcomes incite further research guiding the practical application of oleogels, building knowledge to define components and processes to design saturated and trans-fat-free products.

Antioxidant peptides from alternative sources reduce lipid oxidation in 5% fish oil-in-water emulsions (pH 4) and fish oil-enriched mayonnaise.

Bioinformatics tools were used to predict radical scavenging and metal chelating activities of peptides derived from abundant potato, seaweed, microbial, and spinach proteins. The antioxidant activity was evaluated in 5% oil-in-water emulsions (pH4) and best-performing peptides were tested in mayonnaise and compared with EDTA. Emulsion physical stability was intact. The peptide DDDNLVLPEVYDQD showed the highest protection against oxidation in both emulsions by retarding the formation of oxidation products and depletion of tocopherols during storage, but it was less efficient than EDTA when evaluated in mayonnaise. In low-fat emulsions, formation of hydroperoxides was reduced 4-folds after 5days compared to control. The concentration effect of the peptide was confirmed in mayonnaise at the EDTA equimolar concentration. The second-best performing peptides were NNKWVPCLEFETEHGFVYREHH in emulsion and AGDWLIGDR in mayonnaise. In general, the peptide efficacy was higher in low-fat emulsions. Results demonstrated that peptide negative net charge was important for chelating activity.

Kinetic Study of <i>para</i>-<i>tert</i>-Butylcumene Oxidation in the Presence of <i>N</i>-Hydroxyphthalimide

The kinetics of the oxidation of para-tert-butylcumene to hydroperoxide by molecular oxygen in the presence of N-hydroxyphthalimide has been studied. Based on the study of the regularities in the formation of hydroperoxide and non-target reaction products, a mathematical model of the process was obtained that adequately describes the change in the main components of the reaction concentration over time. The main role of N-hydroxyphthalimide is that it converts peroxide radicals into the corresponding hydroperoxides, thereby reducing the formation of non-target reaction products by reducing the quadratic termination rate. Simultaneously formed N-oxyphthalimide radicals increase the rate of hydrocarbon oxidation. Thus, the use of N-hydroxyphthalimide in hydrocarbon oxidation processes results in an increase in the rate and selectivity of hydroperoxide formation.

New Insights into Selective Singlet Oxygen Production via the Typical Electroactivation of Oxygen for Water Decontamination.

Selective production of singlet oxygen (1O2) as an electrophilic oxidant is crucial for the precise control of chemical targets in environmental fields. Herein, we proposed a strategy to construct a redox interface on electrodes, which can in situ produce inorganic metal hydroperoxides with appropriate oxidative ability during oxygen activation. Benefiting from atomic Cu sites (CuN4) in a copper-carbon aerogel electrode, almost complete production of 1O2 was achieved, thereby refraining the competitive formation of other reactive oxygen species. The fast electron transfer rate between CuN4 and electrogenerated H2O2 promoted the in situ formation of copper hydroperoxide (N4-Cu-OOH), thereby selectively and efficiently oxidizing intermediate O2•- to 1O2. The optimized production of 1O2 was up to 2583 μmol L-1 without additional chemical reagents. We further considered the high production of 1O2 for efficiently removing electron-rich organic pollutants from a complex water matrix. Fast kinetics was achieved and considered for removing various pollutants with electron-donating substituents in a nonradical oxidation pathway. The BPA degradation efficiency is less susceptible to the coexisting natural organic matter (NOM) and inorganic ions. Specifically, the kinetic constant for BPA removal is 34 times higher than that for a nanoparticle of a copper-carbon electrode while producing a hydroxyl radical. Our findings highlight the innovative interfacial surface engineering of an electrocatalytic O2 activation system to selectively generate 1O2 for future potential applications.

Impact of Nonthermal Plasma on Lipid Oxidation from the Perspective of Plasma Treatment Parameters and Plasma Species: Identification of Key Reactive Species.

Nonthermal plasma is a mild processing technology for food preservation. Its impact on lipid oxidation was investigated in this study. Stripped methylesters were considered as a basic lipid model system and were treated by a multihollow surface dielectric barrier discharge. In dry air plasma, O3, ·NO2, ·NO3, and 1O2 were identified as the main reactive species reaching the sample surface. Treatment time was the most prominent parameter affecting lipid oxidation, followed by the (specific) power input and the plasma-sample distance. In humid air plasma, less O3 was detected, but ONOOH and O2NOOH were generated and presumed to play a role in lipid oxidation. Ozone mainly resulted in the formation of carbonyl substances via the trioxolane pathway, while reactive nitrogen species (i.e., ·NO2, ·NO3, ONOOH, and O2NOOH) led to the formation of hydroperoxides. The impact of short-living radicals (e.g., ·O, ·N, ·OH, and ·OOH) was restricted in general, since they dissipated too fast to reach the sample.·NO, HNO3, H2O2, and UV radiation did not induce lipid oxidation. All the reactive species identified in this study were associated with the presence of O2 in the input gas.

The Use of Soy and Egg Phosphatidylcholines Modified with Caffeic Acid Enhances the Oxidative Stability of High-Fat (70%) Fish Oil-in-Water Emulsions

This study investigated the effect of the combined use of sodium caseinate (CAS), commercial phosphatidylcholine (PC), and modified PCs on the physical and oxidative stability of 70% fish oil-in-water emulsions. Caffeic acid was covalently attached to both modified PCs (PCs originated from soy and eggs) in order to increase the antioxidant activity of PCs and investigate the advantage of bringing the antioxidant activity to the close proximity of the oil-water interface. Results showed that oxidative stability was improved when part of the PC was substituted with modified soy PC or egg PC. Emulsions containing a low concentration of modified PCs (10 wt.% of total PC) resulted in a prooxidative effect on the formation of hydroperoxides compared to emulsions with free caffeic acid. On the other hand, a decrease in the formation of volatile oxidation products was observed for emulsions containing higher levels of modified PCs (60 wt.% of total PC) compared to the emulsions with free caffeic acid added at its equivalent concentration. Increased concentrations of modified PCs provided better oxidative stability in high-fat emulsions, independent of the modified PC type. Moreover, when oxidation was initiated by producing singlet oxygen near a single oil droplet using a focused laser, fluorescence imaging showed that the oxidation did not propagate from one oil droplet to another oil droplet.

Oxidative stability of emulsions made with self-extracted oil from euryhaline microalgae Spirulina and Scenedesmus

The fatty acid compositions and tocochromanol concentrations (α-, γ + β-, δ-tocopherol and δ-tocotrienol) of oil extracted from euryhaline microalgal strains (Spirulina subsalsa (Spi A), Scenedesmus MKB (Scnd) and Spirulina sp. (Spi B)) were analyzed. The oxidative stability of microalgae-based oil-in-water emulsions at pH 7 was also determined by measuring lipid hydroperoxide and headspace hexanal formation. The content of saturated fatty acids was highest in Spi B oil whereas n-3 linolenic and eicosapentaenoic acids were high in Spi A. No significant difference was reported in the total tocochromanol homolog contents of Spi A and Scnd oils, but it was significantly higher in Spi B oil. Tocochromanol depletion analysis revealed that δ-tocopherol and δ-tocotrienol had a slower depletion rate than other homologs and that their high content prolonged the hexanal lag phase of Spi B oil-in-water emulsions up to 21 days. The fact that Spi B had the lowest unsaturated fatty acid content and the highest tocochromanol concentration resulted in greater oxidative stability. Spi A oxidized faster than Scnd irrespective of their similar tocochromanol content which might be due to the higher amounts of unstable 18:3 and 20:5 fatty acids. These data suggest that these microalgal oils could have applications in sustainable food systems.

Metformin Impedes Oxidation of LDL In Vitro.

Metformin is the most commonly prescribed glucose-lowering drug for the treatment of type 2 diabetes. The aim of this study was to investigate whether metformin is capable of impeding the oxidation of LDL, a crucial step in the development of endothelial dysfunction and atherosclerosis. LDL was oxidized by addition of CuCl2 in the presence of increasing concentrations of metformin. The extent of LDL oxidation was assessed by measuring lipid hydroperoxide and malondialdehyde concentrations, relative electrophoretic mobilities, and oxidation-specific immune epitopes. Cytotoxicity of oxLDL in the vascular endothelial cell line EA.hy926 was assessed using the alamarBlue viability test. Quantum chemical calculations were performed to determine free energies of reactions between metformin and radicals typical for lipid oxidation. Metformin concentration-dependently impeded the formation of lipid hydroperoxides, malondialdehyde, and oxidation-specific immune epitopes when oxidation of LDL was initiated by addition of Cu2+. The cytotoxicity of oxLDL was reduced when it was obtained under increasing concentrations of metformin. The quantum chemical calculations revealed that only the reaction of metformin with hydroxyl radicals is exergonic, whereas the reactions with hydroperoxyl radicals or superoxide radical anions are endergonic. Metformin, beside its glucose-lowering effect, might be a suitable agent to impede the development of atherosclerosis and associated CVD. This is due to its capability to impede LDL oxidation, most likely by scavenging hydroxyl radicals.

Tuning the 1O2 Oxidation of a Phenol at the Air/Solid Interface of a Nanoparticle: Hydrophobic Surface Increases Oxophilicity.

Although silica surfaces have been used in organic oxidations for the production of peroxides, studies of airborne singlet oxygen at interfaces are limited and have not found widespread advantages. Here, with prenyl phenol-coated silica and delivery of singlet oxygen (1O2) through the gas phase, we uncover significant selectivity for dihydrofuran formation over allylic hydroperoxide formation. The hydrophobic particle causes prenyl phenol to produce an iso-hydroperoxide intermediate with an internally protonated oxygen atom, which leads to dihydrofuran formation as well as O atom transfer. In contrast, hydrophilic particles cause prenyl phenol to produce allylic hydroperoxide, due to phenol OH hydrogen bonding with SiOH surface groups. Mechanistic insight is provided by air/nanoparticle interfaces coated with the prenyl phenol, in which product yield was 6-fold greater on the hydrophobic nanoparticles compared to the hydrophilic nanoparticles and total rate constants (ASI-kT) of 1O2 were 13-fold greater on the hydrophobic vs hydrophilic nanoparticles. A slope intersection method was also developed that uses the airborne 1O2 lifetime (τairborne) and surface-associated 1O2 lifetime (τsurf) to quantitate 1O2 transitioning from volatile to non-volatile and surface boundary (surface···1O2). Further mechanistic insights on the selectivity of the reaction of prenyl phenol with 1O2 was provided by density functional theory calculations.

High internal phase emulsion stabilized by sodium caseinate:quercetin complex as antioxidant emulsifier

High internal phase emulsion (HIPE) was produced and stabilized using a novel antioxidant emulsifier formed by the complexation between sodium caseinate (SC) and quercetin (Q). Colloidal complexes, produced via an alkaline process, showed great ability to reduce the interfacial tension between oil–water phases, promoting stabilization of the HIPEs even at low concentrations (1.5% w/v in the aqueous fraction). HIPEs at 0.80 volume fraction of dispersed phase presented remarkable viscosity due to the high-packing network of oil droplets surrounded by a thin liquid layer. Moreover, the emulsions showed a gel-like behavior and kinetic stability for 45-days at 25 °C. The approach of SC:Q complexes on HIPEs development is promising to reduce lipid oxidation, translated by the formation of hydroperoxides and malondialdehyde during storage, especially for the complex formed with the highest amount of the phenolic compound. In this study, the development of HIPEs with outstanding kinetic and oxidative stability is reported as a potential alternative for the development of healthier products with reduced saturated and trans-fat content.

Principles of aerobic oxidation of ethylbenzene to hydroperoxide under the presence of phthalimide catalysts

The article describes a study of basic principles of aerobic liquid-phase oxidation of ethylbenzene to hydroperoxide. According to the research, the use of phthalimide catalysts (N-hydroxyphthalimide and its derivatives) can increase the oxidation rate of this hydrocarbon by 1.5-2 times compared with initiators of different nature. At the same time, high selectivity of target hydroperoxide formation is still present - about 90%. The authors recommend conditions for oxidation of ethylbenzene in the presence of phthalimide catalysts based on experimental data. The results obtained can be used to improve the technology for co-production of propylene oxide and styrene, valuable products of the main chemical and petrochemical synthesis.

Human umbilical cord mesenchymal stem cells derived exosome shuttling mir-129-5p attenuates inflammatory bowel disease by inhibiting ferroptosis

BackgroundFerroptosis, a unique form of non-apoptotic cell death, is dependent on iron and lipoperoxidation, and has been shown to be associated with the pathogenesis of inflammatory bowel disease (IBD). Human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Ex) are involved in cell survival, immune conditioning, and damage repair. However, the relationship between hucMSC-Ex, IBD, and ferroptosis is unknown. This paper explores the role of hucMSC-Ex in the repair of IBD through the regulation of the ferroptosis signaling pathway.ResultsIn this study, we used small RNA sequencing to find that miR-129-5p was highly expressed in hucMSC-Ex, and by predicting its targeting to ACSL4, we verified the effect of miR-129-5p on mice IBD in vitro and human colonic epithelial cells (HCoEpiC) in vivo. We found that miR-129-5p reduces ferroptosis in intestinal epithelial cells by targeting ACSL4 to repair IBD, which provides new strategies for the prevention and treatment of IBD.ConclusionIn conclusion, our results demonstrate that hucMSC-Ex relieves IBD by targeting ACSL4 with miR-129-5p to inhibit lipid peroxidation (LPO) and ferroptosis, reducing intestinal inflammation and repairing damages.Graphic abstractMechanism of hucMSC-Ex inhibiting ferroptosis in intestinal epithelial cells. System Xc− mediates the transport of extracellular cystine into the cell, which gets reduced to cysteine to participate in GSH-mediated metabolism. GPX4 strongly inhibits ferroptosis by helping scavenge reactive oxygen species. The depletion of GSH correlates with decreased GPX4, and the imbalance of the antioxidant system leads to the formation of toxic phospholipid hydroperoxide, which promotes the occurrence of ferroptosis with the participation of irons. HucMSC-Ex has the ability to relieve GSH and GPX4 depletion and repair the intracellular antioxidant system. Ferric ions enter the cytosol through DMT1 and participate in lipid peroxidation. HucMSC-Ex can reduce the expression of DMT1 and alleviate this process. HucMSC-Ex-derived miR-129-5p targets ACSL4 and reduces the expression of ACSL4, an enzyme that mediates the conversion of PUFAs into phospholipids in intestinal epithelial cells, and is a positive regulator of lipid peroxidation. Abbreviations: GSH, glutathione; GPX4, glutathione peroxidase 4; GSSG, oxidized glutathione; DMT1, divalent metal transporter 1; ACSL4, acyl-CoA synthetase long-chain family member 4; PUFAs, polyunsaturated fatty acids; ALOXs, lipoxygenases; CoA, coenzyme A; PL, phospholipid; PLOOH, hydroperoxides, LOH, phospholipid alcohols; LPO, lipid peroxidation.

Increased oxidative stress response in circulating blood of systemic sclerosis patients – relation to disease characteristics and inflammatory blood biomarkers

BackgroundSystemic sclerosis (SSc) is a rare connective tissue disorder of unknown etiology characterized by organ fibrosis and microcirculation dysfunction. Emerging evidence suggests that SSc is related to increased oxidative stress, which contributes to further tissue and vascular damage. MethodsOxidative stress response in the peripheral blood was assessed in patients with SSc (n = 55) and well-matched controls (n = 44) using real-time monitoring of protein hydroperoxide (HP) formation by the coumarin boronic acid (CBA) assay. We also analyzed the relationship between HP generation and SSc clinics, systemic inflammation, and cellular fibronectin, an emerging biomarker of endothelial damage. ResultsSSc was characterized by a significantly faster (2-fold) fluorescent product generation in the CBA assay and higher cumulative HP formation (3-fold) compared to controls (p<0.001, both). The dynamics of HP generation were not associated with the form of the disease (diffuse vs. limited SSc), current immunosuppressive therapy use, presence of abnormal nailfold capillaries, and autoantibody profile. Still, it was enhanced in patients with more severe illness and certain clinical manifestations (i.e., pulmonary hypertension, digital ulcers, and cyclophosphamide treatment) and in smokers (current or past). Higher serum CRP, blood eosinophil count, and cellular fibronectin with lower hemoglobin levels were independent determinants of increased HP formation. ConclusionsOur data indicate a pro-oxidant imbalance in SSc, likely related to systemic inflammation and endothelial injury. However, extensive prospective studies are needed to verify whether it is also associated with clinical disease progression.

Formation of protein adducts with Hydroperoxy-PE electrophilic cleavage products during ferroptosis

Ferroptosis is an iron dependent form of cell death, that is triggered by the discoordination of iron, lipids, and thiols. Its unique signature that distinguishes it from other forms of cell death is the formation and accumulation of lipid hydroperoxides, particularly oxidized forms of polyunsaturated phosphatidylethanolamines (PEs), which drives cell death. These readily undergo iron-catalyzed secondary free radical reactions leading to truncated products which retain the signature PE headgroup and which can readily react with nucleophilic moieties in proteins via their truncated electrophilic acyl chains. Using a redox lipidomics approach, we have identified oxidatively-truncated PE species (trPEox) in enzymatic and non-enzymatic model systems. Further, using a model peptide we demonstrate adduct formation with Cys as the preferred nucleophilic residue and PE(26:2) +2 oxygens, as one of the most reactive truncated PE-electrophiles produced. In cells stimulated to undergo ferroptosis we identified PE-truncated species with sn-2 truncations ranging from 5 to 9 carbons. Taking advantage of the free PE headgroup, we have developed a new technology using the lantibiotic duramycin, to enrich and identify the PE-lipoxidated proteins. Our results indicate that several dozens of proteins for each cell type, are PE-lipoxidated in HT-22, MLE, and H9c2 cells and M2 macrophages after they were induced to undergo ferroptosis. Pretreatment of cells with the strong nucleophile, 2-mercaptoethanol, prevented the formation of PE-lipoxidated proteins and blocked ferroptotic death. Finally, our docking simulations showed that the truncated PE species bound at least as good to several of the lantibiotic-identified proteins, as compared to the non-truncated parent molecule, stearoyl-arachidonoyl PE (SAPE), indicating that these oxidatively-truncated species favor/promote the formation of PEox-protein adducts. The identification of PEox-protein adducts during ferroptosis suggests that they are participants in the ferroptotic process preventable by 2-mercaptoethanol and may contribute to a point of no return in the ferroptotic death process.

Unexpectedly Efficient Aging of Organic Aerosols Mediated by Autoxidation.

Multiphase oxidative aging is a ubiquitous process for atmospheric organic aerosols (OA). But its kinetics was often found to be slow in previous laboratory studies where high hydroxyl radical concentrations ([•OH]) were used. In this study, we performed heterogeneous oxidation experiments of several model OA systems under varied aging timescales and gas-phase [•OH]. Our results suggest that OA heterogeneous oxidation may be 2-3 orders of magnitude faster when [•OH] is decreased from typical laboratory flow tube conditions to atmospheric levels. Direct laboratory mass spectrometry measurements coupled with kinetic simulations suggest that an intermolecular autoxidation mechanism mediated by particle-phase peroxy radicals greatly accelerates OA oxidation, with enhanced formation of organic hydroperoxides, alcohols, and fragmentation products. With autoxidation, we estimate that the OA oxidation timescale in the atmosphere may be from less than a day to several days. Thus, OA oxidative aging can have greater atmospheric impacts than previously expected. Furthermore, our findings reveal the nature of heterogeneous aerosol oxidation chemistry in the atmosphere and help improve the understanding and prediction of atmospheric OA aging and composition evolution.

Can Iron and Polyunsaturated Fatty Acid Supplementation Induce Ferroptosis?

Ferroptosis is a regulated non-apoptotic cell death process triggered by excessive iron-induced lipid peroxidation. Excess intracellular iron promotes lipid peroxidation by increasing reactive oxygen species formation through the Fenton reaction. Thus, iron and polyunsaturated fatty acid intake may trigger ferroptosis under certain conditions. The aims of this review were to compile and examine evidence in the literature for the effects of iron and polyunsaturated fatty acid supplementation on ferroptosis. Omega-6 polyunsaturated fatty acids have relatively greater susceptibility to lipid peroxidation and could, therefore, participate in ferroptosis. By contrast, omega-3 polyunsaturated fatty acids promote intracellular antioxidants synthesis and reduce the formation of hydroperoxides that induce ferroptosis. As intestinal iron absorption is regulated by iron nutritional status, individuals with normal functioning of the hepcidin-ferroportin axis are at low risk of developing iron overload in response to ingestion of iron-rich foods. Therefore, iron supplementation is potentially toxic mainly for the intestinal epithelium and the microbiota. In animal models, iron-rich diets increased oxidative damage, lowered the glutathione concentration within hepatocytes, and downregulated desaturases that synthesize long-chain polyunsaturated fatty acids. These adverse effects of iron supplementation were prevented by omega-3 fatty acid co-supplementation. The impact of food and supplement intake on ferroptosis has seldom been investigated. Scientific evidence still does not allow us to know for sure whether iron and PUFA supplementation are capable of inducing ferroptosis. As the mechanisms that control ferroptosis can determine whether cells proliferate or die, future studies should directly investigate the effects of nutrient supplementation and food intake on the ferroptosis process in different types of cells and tissues.

Gastroprotective effect of Artemisia absinthium L.: A medicinal plant used in the treatment of digestive disorders

Ethnopharmacological relevanceWormwood (Artemisia absinthium L.) is traditionally used for stomach pain and gastric relief. However, its possible gastroprotective effect has not yet been experimentally evaluated. Aim of the studyThis study evaluated the gastroprotective effect of aqueous extracts obtained through hot and room temperature maceration of A. absinthium aerial parts in rats. Materials and methodsThe gastroprotective effect of hot aqueous extract (HAE) and room temperature aqueous extract (RTAE) from A. absinthium aerial parts were evaluated in rats using a model of acute gastric ulcer induced by ethanol p.a. The stomachs were collected to measure the gastric lesion area and histological and biochemical analysis. UHPLC-HRMS/MS analysis was used to determine the chemical profile of the extracts. ResultsEight main peaks in the UHPLC chromatogram were identified in both HAE and RTAE extracts: tuberonic acid glycoside (1), rupicolin (2), 2-hydroxyeupatolide (3), yangabin (4), sesartemin (5), artemetin (6), isoalantodiene (7), and dehydroartemorin (8). For RTAE, a higher diversity of sesquiterpene lactones was observed. The groups treated with RTAE at 3%, 10%, and 30% presented a gastroprotective effect, reducing the lesion area by 64.68%, 53.71%, and 90.04%, respectively, when compared with the vehicle (VEH)-treated group. On the other hand, the groups treated with HAE at 3%, 10%, and 30% presented values of lesion areas higher than those of the VEH group. Changes in the submucosa layer, inflammatory process with edema, cellular infiltration, and mucin depletion were detected in the gastric mucosa exposed to ethanol, which was fully prevented by RTAE treatment. Neither HAE nor RTAE could increase the reduced glutathione levels in the injured gastric tissue, but RTAE (30%) reduced the formation of lipid hydroperoxides. When the rats were pre-treated with NEM (a chelator of non-protein thiols) or L-NAME (non-selective nitric oxide synthase inhibitor), the RTAE lost the ability to protect the gastric mucosa. ConclusionsThis study corroborates the ethnopharmacological use of this specie to treat gastric disorders revealing the gastroprotective effect of the room-temperature aqueous extract of A. absinthium aerial parts. Its mode of action may involve the ability of the infusion to maintain the gastric mucosal barrier integrity.

Effects of Non-Enzymatic Browning and Lipid Oxidation on Color of Ready-to-Eat Abalone during Accelerated Storage and Its Control.

The deepening of color of ready-to-eat (RTE) abalone during storage leads to sensory quality degradation, which seriously affects the shelf life of products and consumers' purchasing desire. The goal of this study is to look into the causes of non-enzymatic browning and lipid oxidation, as well as how to control them, and their effect on the color of RTE abalone during storage. The control, bloodletting and antioxidants groups (lactic acid, citric acid and 4-hexylresorcinol) of RTE abalone were stored for 0, 20 and 40 days at 40 °C, respectively, to explore the rule and mechanism of the color change in RTE abalone. This research shows that RTE abalone undergoes browning during storage. Meanwhile, the content of reducing sugar, phenols and unsaturated fatty acids decreases, while the formation of lipid hydroperoxides and aldehydes increases during storage. In addition, the color change in RTE abalone during storage is mainly related to the Maillard reaction, while the lipid oxidation mainly forms pyrrole and participates in the Strecker degradation process as part of the Maillard reaction. The quality of RTE abalone can be maintained by controlling browning effectively as well as lipid oxidation through bloodletting and the addition of antioxidants to ensure that RTE abalone has high storage stability. According to our research, bloodletting and the addition of antioxidants to RTE abalone have a good application prospect and popularizing value in the storage of RTE abalone.

Antioxidant and Antiradical Activities of Hibiscus sabdariffa L. Extracts Encapsulated in Calcium Alginate Spheres

The interest in natural sources with high antioxidant powder has recently increased in several sectors. Ionic gelation methods could be used to protect bioactive substances to control the kinetics and release of these ingredients to the food matrix. This study dealt with the evaluation of the antioxidant capacity and scavenging activity of extracts of Hibiscus Sabdariffa L. (HSL) (with 50% ethanol) encapsulated in calcium alginate spheres as a new source for preserving food against oxidative damage. Their antioxidant activity was measured in different o/w emulsions in which HSL spheres reduced the formation of hydroperoxides (~80%) and thiobarbituric-acid-reactive substance products (~20%). The scavenging activity of HSL extracts was measured in different food simulants (water, water acidified with 3% acetic acid, ethanol at 50%, and pure ethanol), and corresponded to 0.20-0.43, 0.31-0.62, and 11.13-23.82 mmol Trolox/mL extract for Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenylpicrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) assays, respectively. In general, the best antiradical activity was observed in the ethanolic and acidified mediums, in which the highest concentration of released polyphenols ranged from 0.068 to 0.079 mg GAE/mL. This work indicates the potential of alginate spheres for encapsulating antioxidant compounds as an innovative strategy for several industrial applications.