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Interoception entails perceiving or being aware of the internal state of the body, playing a pivotal role in regulating processes such as heartbeat, digestion, glucose metabolism, and respiration. The carotid body (CB) serves as an interoceptive organ, transmitting information to the brain via its sensitive nerve, the carotid sinus nerve, to maintain homeostasis. While traditionally known for sensing oxygen, carbon dioxide, and pH levels, the CB is now recognized to possess additional interoceptive properties, detecting various mediators involved in blood pressure regulation, inflammation, and glucose homeostasis, among other physiological functions. Furthermore, in the last decades CB dysfunction has been linked to diseases like sleep apnea, essential hypertension, and diabetes. In this review manuscript, we make a concise overview of the traditional interoceptive functions of the CB, acting as a sensor for oxygen levels, carbon dioxide levels, and pH, and introduce the novel interoceptive properties of the CB related to vascular, glucose and energy regulation. Additionally, we revise the contribution of the CB to the onset and progression of metabolic diseases, delving into the potential dysfunction of its interoceptive metabolic functions as a contributing factor to pathophysiology. Finally, we postulate the use of therapeutic interventions targeting the metabolic interoceptive properties of the CB as a potential avenue for addressing metabolic diseases.
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Background: Sulphur containing natural compounds are among the most biologically relevant metabolites in vivo. Naringenin 8-sulphonate from Parinari excelsa Sabine was evaluated in a previous work, demonstrating ability to act as a natural anti-inflammatory. Although the interference of this molecule against different inflammatory mediators was described, there is no information regarding its potential toxicity and pharmacokinetics, which are essential for its capacity to reach its therapeutic targets. In fact, despite the existence of reports on naringenin ADMET properties, the influence of sulphation patterns on them remains unknown. Objectives: This work aims to assess the in vitro pharmacokinetic and toxicological behavior of naringenin 8-sulphonate, as well as to understand the importance of the presence and position of the sulphur containing group for that. Methods: Naringenin 8-sulphonate physicochemical and ADMET properties were investigated using in silico tools and cell-based in vitro models. At the same time, naringenin and naringenin 4'-O-sulphate were investigated to evaluate the impact of the sulphonate group on the results. ADMETlab 2.0 in silico tool was used to predict the compounds' physicochemical descriptors. Pharmacokinetic properties were determined experimentally in vitro. While MRC-5 lung fibroblasts and HaCaT keratinocytes were used to evaluate the cytotoxicity of samples through MTT and LDH assays, Caco-2 human intestinal epithelial cells were used for the determination of genotoxicity, through alkaline comet assay, and as a permeability model to assess the ability of compounds to cross biological barriers. Results: Experimental determinations showed that none of the compounds was cytotoxic. In terms of genotoxicity, naringenin 8-sulphonate and naringenin caused significant DNA fragmentation, whereas naringenin 4'-O-sulphate did not. When it comes to permeability, the two sulphur-containing compounds with a sulphur containing group were clearly less capable to cross the Caco-2 cell barrier than naringenin. Conclusion: In this study, we conclude that the sulphur containing group from naringenin 8-sulphonate is disadvantageous for the molecule in terms of ADMET properties, being particularly impactful in the permeability in intestinal barrier models. Thus, this work provides important insights regarding the role of flavonoids sulphation and sulphonation upon pharmacokinetics and toxicity.
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In this work, we aim to find physical evidence demonstrating the crucial role that the effective concentration of antioxidants (AOs) present at the interfacial region of emulsions has in controlling the inhibition of the lipid oxidation reaction. We prepared a series of antioxidants of different hydrophobicities derived from chlorogenic and protocatechuic acids. We first monitored, in intact emulsions, the (sigmoidal) production of conjugated dienes and determined the corresponding induction times, tind. Independently, we determined the effective concentrations of the antioxidants in the same intact emulsions. Results show that both the length of the induction periods and the antioxidant interfacial concentrations parallel each other, with a maximum at the octyl-dodecyl derivatives. The ratio between the interfacial antioxidant concentrations and the induction periods remains constant for all AOs in the same series, so that the rates of initiation of lipid oxidation are the same regardless of the hydrophobicity of the antioxidant employed. The constancy in the rate of initiation provides strong experimental evidence for a direct relationship between interfacial concentrations and antioxidant efficiencies. Results suggest new possibilities to investigate lipid peroxidation under non-forced conditions and are of interest to formulators interested in preparing emulsions with antimicrobial properties.
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In this study, for the first time, red LED light radiation was applied to the fermentation process of table olives using the Negrinha de Freixo variety. Photostimulation using LED light emission (630 ± 10 nm) is proposed to shorten and speed up this stage and reduce time to market. Several physical-chemical characteristics and microorganisms (total microbial count of mesophilic aerobic, molds, yeasts, and lactic acid bacteria) and their sequence during fermentation were monitored. The fermentation occurred for 122 days, with two irradiation periods for red LED light. The nutritional composition and sensory analysis were performed at the end of the process. Fermentation under red LED light increased the viable yeast and lactic acid bacteria (LAB) cell counts and decreased the total phenolics in olives. Even though significant differences were observed in some color parameters, the hue values were of the same order of magnitude and similar for both samples. Furthermore, the red LED light did not play a relevant change in the texture profile, preventing the softening of the fruit pulp. Similarly, LED light did not modify the existing type of microflora but increased species abundance, resulting in desirable properties and activities. The species identified were yeasts - Candida boidinii, Pichia membranifaciens, and Saccharomyces cerevisiae, and bacteria - Lactobacillus plantarum and Leuconostoc mesenteroides, being the fermentative process dominated by S. cerevisiae and L. plantarum. At the end of fermentation (122 days), the irradiated olives showed less bitterness and acidity, higher hardness, and lower negative sensory attributes than non-irradiated. Thus, the results of this study indicate that red LED light application can be an innovative technology for table olives production.
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Fermentação , Luz , Olea , Olea/microbiologia , Olea/efeitos da radiação , Leveduras/efeitos da radiação , Leveduras/metabolismo , Fenóis/metabolismo , Fenóis/química , Fenóis/análise , Frutas/efeitos da radiação , Frutas/microbiologia , Microbiologia de AlimentosRESUMO
This study aimed to evaluate and identify the microbial community attached to the surfaces of fermenter tanks used in table olive Negrinha de Freixo cultivar processing through molecular analysis and verify if the cleaning/disinfection was done correctly. Four fermentation tanks previously used in table olive processing were sampled at three different inside areas: upper, middle, and lower. Before sampling, four cleaning/disinfection methods were applied to the tanks, including (i) pressurised water; (ii) a disinfectant product used to clean bowls (Vasiloxe); (iii) 10% sodium hydroxide solution (caustic soda liquid); and (iv) a disinfectant product used by the wine industry (Hosbit). For each sample collected, mesophilic aerobic bacteria, yeast and moulds (YMC), lactic acid bacteria (LAB), as well as total coliforms (TC) and Pseudomonas aeruginosa were evaluated. The results showed significant differences between the different cleaning/disinfection methods applied. The fermenter sanitised with only pressurised water showed a greater abundance of microorganisms than the others. Mesophilic aerobic bacteria were the predominant population, with counts ranging between 2.63 and 5.56 log10 CFU/100 cm2, followed by the moulds (3.11-5.03 log10 CFU/100 cm2) and yeasts (2.42-5.12 log10 CFU/100 cm2). High diversity of microbial communities was observed between the different fermenter tanks. The most abundant species belonged to Aureobasidium, Bacillaceae, Cladosporium, and Rhodotorula genera. LAB, TC, and P. aeruginosa were not detected. This study hopes to improve hygienic conditions and increase the quality assurance and safety of the final product.
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Desinfetantes , Lactobacillales , Olea , Fermentação , Olea/microbiologia , Desinfecção , Bactérias Gram-Negativas , Leveduras/genética , Desinfetantes/farmacologia , Água , Microbiologia de AlimentosRESUMO
The association between obstructive sleep apnea (OSA) and metabolic disorders is well-established; however, the underlying mechanisms that elucidate this relationship remain incompletely understood. Since the liver is a major organ in the maintenance of metabolic homeostasis, we hypothesize that liver dysfunction plays a crucial role in the pathogenesis of metabolic dysfunction associated with obstructive sleep apnea (OSA). Herein, we explored the underlying mechanisms of this association within the liver. Experiments were performed in male Wistar rats fed with a control or high fat (HF) diet (60% lipid-rich) for 12 weeks. Half of the groups were exposed to chronic intermittent hypoxia (CIH) (30 hypoxic (5% O2) cycles, 8 h/day) that mimics OSA, in the last 15 days. Insulin sensitivity and glucose tolerance were assessed. Liver samples were collected for evaluation of lipid deposition, insulin signaling, glucose homeostasis, hypoxia, oxidative stress, antioxidant defenses, mitochondrial biogenesis and inflammation. Both the CIH and HF diet induced dysmetabolism, a state not aggravated in animals submitted to HF plus CIH. CIH aggravates hepatic lipid deposition in obese animals. Hypoxia-inducible factors levels were altered by these stimuli. CIH decreased the levels of oxidative phosphorylation complexes in both groups and the levels of SOD-1. The HF diet reduced mitochondrial density and hepatic antioxidant capacity. The CIH and HF diet produced alterations in cysteine-related thiols and pro-inflammatory markers. The results obtained suggest that hepatic mitochondrial dysfunction and oxidative stress, leading to inflammation, may be significant factors contributing to the development of dysmetabolism associated with OSA.
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Pathogen genome sequencing during epidemics enhances our ability to identify and understand suspected clusters and investigate their relationships. Here, we combine genomic and epidemiological data of the 2022 mpox outbreak to better understand early viral spread, diversification and transmission dynamics. By sequencing 52% of the confirmed cases in Portugal, we identified the mpox virus sublineages with the highest impact on case numbers and fitted them into a global context, finding evidence that several international sublineages probably emerged or spread early in Portugal. We estimated a 62% infection reporting rate and that 1.3% of the population of men who have sex with men in Portugal were infected. We infer the critical role played by sexual networks and superspreader gatherings, such as sauna attendance, in the dissemination of mpox virus. Overall, our findings highlight genomic epidemiology as a tool for the real-time monitoring and control of mpox epidemics, and can guide future vaccine policy in a highly susceptible population.
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Mpox , Minorias Sexuais e de Gênero , Masculino , Humanos , Portugal/epidemiologia , Homossexualidade Masculina , Surtos de Doenças , Análise por ConglomeradosRESUMO
Snoezelen Multisensory Stimulation (SMSS) is a non-pharmacological intervention that provides controlled multisensorial environments to stimulate the primary senses: sight, hearing, smell, touch, taste, proprioceptive and vestibular. Even though the use and potential of SMSS have been widespread in the literature regarding certain target populations (autism, developmental disabilities) and settings (e.g. leisure, therapeutic), its effectiveness in older adults with neurocognitive disorders (e.g. dementia, mild cognitive impairment) and other pathologies (e.g. psychiatric disorders, oncological diseases) is still unclear. Therefore, a systematic review of the literature was conducted to address this issue. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and of the Cochrane Collaboration were followed. An initial search on PubMed and Scopus databases resulted in 86 articles of which 14 met inclusion criteria and were reviewed in detail. The outcomes showed that most of the studies (n = 13) focused on the effects of SMSS on behaviour and mood in older adults with major cognitive disorders (i.e. dementia). Although there is scarce literature on its impact on cognition, psychophysiological measures (e.g. heart rate, oxygen saturation), daily living functionality and quality of life, this type of intervention seems to contribute to delaying the worsening in severity of the neurocognitive disorders from the mildest to the most severe stages. Likewise, it is legitimate to consider the possibility of potential benefits to older adults with less severe neurocognitive disorders or other pathologies, but more research is needed.
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Endothelial dysfunction is an essential intermediary for development of cardiovascular diseases associated with diabetes and hypertension (HT). The carotid body (CB) dysfunction contributes to dysmetabolic states, and the resection of carotid sinus nerve (CSN) prevents and reverts dysmetabolism and HT. Herein, we investigated if CSN denervation ameliorates systemic endothelial dysfunction in an animal model of type 2 diabetes mellitus (T2DM).We used Wistar male rats submitted to HFHSu diet during 25 weeks and the correspondent age-matched controls fed with a standard diet. CSN resection was performed in half of the groups after 14 weeks of diet. In vivo insulin sensitivity, glucose tolerance and blood pressure, ex vivo aortic artery contraction and relaxation and nitric oxide (NO) levels in plasma and aorta, aorta nitric oxide synthase (NOS) isoforms, and PGF2αR levels were evaluated.We demonstrated that, alongside to dysmetabolism and HT reversion, CSN resection restores endothelial function in the aorta and decreases the NO levels in plasma and aorta at the same time that restores normal levels of iNOS in aorta without changing eNOS or PGF2αR levels.These results suggest that the modulation of CB activity can be important for the treatment of HT and endothelial dysfunction related with T2DM.
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Corpo Carotídeo , Diabetes Mellitus Tipo 2 , Hipertensão , Resistência à Insulina , Ratos , Animais , Masculino , Corpo Carotídeo/cirurgia , Ratos Wistar , Diabetes Mellitus Tipo 2/cirurgia , Resistência à Insulina/fisiologia , Endotélio Vascular , Hipertensão/cirurgia , Denervação , Óxido NítricoRESUMO
Individuals who develop type 2 diabetes (T2D) at an early age are at higher risk of developing neurodegenerative disorders such as Alzheimer's and Parkinson's disease. A shared dysfunctional characteristic between T2D and these neurodegenerative disorders is insulin resistance. Recently, it was shown that prediabetes animals and patients exhibited increased carotid body (CB) activity. Moreover, these organs are deeply involved in the development of metabolic diseases, since upon abolishment of their activity via carotid sinus nerve (CSN) resection, several dysmetabolic features of T2D were reverted. Herein, we investigated if CSN resection may also prevent cognitive impairment associated with brain insulin resistance. We explored a diet-induced prediabetes animal model where Wistar rats are kept in a high fat-high sucrose (HFHSu) diet for 20 weeks. We evaluated CSN resection effects on behavioral parameters and on insulin signaling-related proteins levels, in the prefrontal cortex and the hippocampus. HFHSu animals exhibited impaired short-term memory evaluated by the y-maze test. Remarkably, CSN resection prevented the development of this phenotype. HFHSu diet or CSN resection did not promote significant alterations in insulin signaling-associated proteins levels. Our findings suggest that CBs modulation might have a role in preventing short-term spatial memory deficits associated with peripheral dysmetabolic states.
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Corpo Carotídeo , Diabetes Mellitus Tipo 2 , Resistência à Insulina , Estado Pré-Diabético , Ratos , Animais , Insulina/metabolismo , Corpo Carotídeo/fisiologia , Resistência à Insulina/fisiologia , Estado Pré-Diabético/cirurgia , Estado Pré-Diabético/metabolismo , Ratos Wistar , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/cirurgia , Diabetes Mellitus Tipo 2/metabolismo , Memória de Curto Prazo , Dieta Hiperlipídica/efeitos adversos , Transtornos da Memória/etiologia , Transtornos da Memória/prevenção & controle , Hipocampo/metabolismo , Córtex Pré-Frontal/metabolismoRESUMO
The inflammatory response is a vital mechanism for repairing damage induced by aberrant health states or external insults; however, persistent activation can be linked to numerous chronic diseases. The nuclear factor kappa ß (NF-κB) inflammatory pathway and its associated mediators have emerged as critical targets for therapeutic interventions aimed at modulating inflammation, necessitating ongoing drug development. Previous studies have reported the inhibitory effect of a hydroethanol extract derived from Parinari excelsa Sabine (Chrysobalanaceae) on tumour necrosis factor-alpha (TNF-α), but the phytoconstituents and mechanisms of action remained elusive. The primary objective of this study was to elucidate the phytochemical composition of P. excelsa stem bark and its role in the mechanisms underpinning its biological activity. Two compounds were detected via HPLC-DAD-ESI(Ion Trap)-MS2 analysis. The predominant compound was isolated and identified as naringenin-8-sulphonate (1), while the identity of the second compound (compound 2) could not be determined. Both compound 1 and the extract were assessed for anti-inflammatory properties using a cell-based inflammation model, in which THP-1-derived macrophages were stimulated with LPS to examine the treatments' effects on various stages of the NF-κB pathway. Compound 1, whose biological activity is reported here for the first time, demonstrated inhibition of NF-κB activity, reduction in interleukin 6 (IL-6), TNF-α, and interleukin 1 beta (IL-1ß) production, as well as a decrease in p65 nuclear translocation in THP-1 cells, thus highlighting the potential role of sulphur substituents in the activity of naringenin (3). To explore the influence of sulphation on the anti-inflammatory properties of naringenin derivatives, we synthesized naringenin-4'-O-sulphate (4) and naringenin-7-O-sulphate (5) and evaluated their anti-inflammatory effects. Naringenin derivatives 4 and 5 did not display potent anti-inflammatory activities; however, compound 4 reduced IL-1ß production, and compound 5 diminished p65 translocation, with both exhibiting the capacity to inhibit TNF-α and IL-6 production. Collectively, the findings demonstrated that the P. excelsa extract was more efficacious than all tested compounds, while providing insights into the role of sulphation in the anti-inflammatory activity of naringenin derivatives.
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Chrysobalanaceae , NF-kappa B , Humanos , NF-kappa B/metabolismo , Interleucina-6/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Chrysobalanaceae/metabolismo , Casca de Planta/metabolismo , Anti-Inflamatórios/uso terapêutico , Inflamação/metabolismo , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Lipopolissacarídeos/farmacologiaRESUMO
In recent years, partitioning of antioxidants in oil-water two-phase systems has received great interest because of their potential in the downstream processing of biomolecules, their benefits in health, and because partition constant values between water and model organic solvents are closely related to important biological and pharmaceutical properties such as bioavailability, passive transport, membrane permeability, and metabolism. Partitioning is also of general interest in the oil industry. Edible oils such as olive oil contain a variety of bioactive components that, depending on their partition constants, end up in an aqueous phase when extracted from olive fruits. Frequently, waste waters are subsequently discarded, but their recovery would allow for obtaining extracts with antioxidant and/or biological activities, adding commercial value to the wastes and, at the same time, would allow for minimizing environmental risks. Thus, given the importance of partitioning antioxidants, in this manuscript, we review the background theory necessary to derive the relevant equations necessary to describe, quantitatively, the partitioning of antioxidants (and, in general, other drugs) and the common methods for determining their partition constants in both binary (PWOIL) and multiphasic systems composed with edible oils. We also include some discussion on the usefulness (or not) of extrapolating the widely employed octanol-water partition constant (PWOCT) values to predict PWOIL values as well as on the effects of acidity and temperature on their distributions. Finally, there is a brief section discussing the importance of partitioning in lipidic oil-in-water emulsions, where two partition constants, that between the oil-interfacial, POI, and that between aqueous-interfacial, PwI, regions, which are needed to describe the partitioning of antioxidants, and whose values cannot be predicted from the PWOIL or the PWOCT ones.
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Learning to eat complementary foods is a crucial milestone for infants, having implications across development. The most used method for introducing complementary foods is Traditional Spoon-Feeding (TSF). However, the alternative method Baby-Led Weaning (BLW) is increasingly becoming used as it has been associated with positive outcomes. Research analyzing associations between complementary feeding methods and responsive parenting is practically non-existent. Therefore, the objective of this study was to analyze differences in emotional and feeding responsiveness between caregivers who previously implemented traditional vs. non-traditional feeding approaches. Caregivers (mostly mothers) of 179 children between 3 and 5 years were asked about the complementary feeding method that they had followed previously (70.4% reported using the TSF, 16.8% said they used the BLW and 12.8% used both methods simultaneously). In addition, they reported on their feeding practices using the Comprehensive Feeding Practices Questionnaire and on their responses to children's distress using the Coping with Children's Negative Emotions Scale. The results showed that parents who reported using a non-traditional (BLW or both) complementary feeding method reported less pressure to eat and minimization of reactions to children's negative emotions, compared to parents who used a traditional method (although these reported using more problem-focused reactions). The findings suggest that complementary feeding methods and responsive parenting may be linked, leaving the question of which one sets the stage for the other.
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Parabens are esters of p-hydroxybenzoic acid, used for decades as a preservative in many products, including agrochemicals, pharmaceuticals, foods and cosmetics. Concerns regarding parabens toxicity include adverse effects on endocrine activity, carcinogenesis, infertility, spermatogenesis, and adipogenesis. The present study aimed to investigate the in vivo administration of methyl and butylparaben at concentrations of 100 and 200 mg/kg body weight, by subcutaneous injection, in variable murinometric measurements, antioxidant systems and genotoxicity. The administration of parabens did not affect the consumption of water and food. However, there was a decrease in the weight of the testes and the seminal vesicle (p < 0.05). The administration of parabens caused an increase in superoxide dismutase for methylparaben (200 mg/kg) and both concentrations of butylparaben (p < 0.05). Catalase showed increased activity in all groups treated with parabens. In contrast, glutathione reductase and glutathione S-transferase suffered a decrease in the groups treated with both parabens. These results show that parabens, especially butyl, can affect the rat testis enzymatic antioxidant system, decreasing the cellular antioxidant capacity, which was confirmed by the decrease in the glutathione reducing power, expressed by the reduced glutathione/oxidized glutathione ratio. Therefore, an increase in lipid peroxidation was observed, which was significant in the case of butyl. Genetic Damage Indicator values show that butylparaben treatments displayed significantly higher values than the control. This study shows for the first time that parabens can induce genotoxicity in the rat male reproductive organ.
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Maternal obesity and gestational diabetes predispose the next generation to metabolic disturbances. Moreover, the lactation phase also stands as a critical phase for metabolic programming. Nevertheless, the precise mechanisms originating these changes remain unclear. Here, we investigate the consequences of a maternal lipid-rich diet during gestation and lactation and its impact on metabolism and behavior in the offspring. Two experimental groups of Wistar female rats were used: a control group (NC) that was fed a standard diet during the gestation and lactation periods and an overnutrition group that was fed a high-fat diet (HF, 60% lipid-rich) during the same phases. The offspring were analyzed at postnatal days 21 and 28 and at 2 months old (PD21, PD28, and PD60) for their metabolic profiles (weight, fasting glycemia insulin sensitivity, and glucose tolerance) and euthanized for brain collection to evaluate metabolism and inflammation in the hypothalamus, hippocampus, and prefrontal cortex using Western blot markers of synaptic dynamics. At 2 months old, behavioral tests for anxiety, stress, cognition, and food habits were conducted. We observed that the female offspring born from HF mothers exhibited increased weight gain and decreased glucose tolerance that attenuated with age. In the offspring males, weight gain increased at P21 and worsened with age, while glucose tolerance remained unchanged. The offspring of the HF mothers exhibited elevated levels of anxiety and stress during behavioral tests, displaying decreased predisposition for curiosity compared to the NC group. In addition, the offspring from mothers with HF showed increased food consumption and a lower tendency towards food-related aggression. We conclude that exposure to an HF diet during pregnancy and lactation induces dysmetabolism in the offspring and is accompanied by heightened stress and anxiety. There was sexual dimorphism in the metabolic traits but not behavioral phenotypes.
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Ansiedade , Lactação , Humanos , Gravidez , Ratos , Masculino , Animais , Feminino , Pré-Escolar , Lactente , Ratos Wistar , Aumento de Peso , Glucose , LipídeosRESUMO
Natural antioxidants from fruits and vegetables, meats, eggs and fish protect cells from the damage caused by free radicals. They are widely used to reduce food loss and waste, minimizing lipid oxidation, as well as for their effects on health through pharmaceutical preparations. In fact, the use of natural antioxidants is among the main efforts made to relieve the pressure on natural resources and to move towards more sustainable food and pharmaceutical systems. Alternative food waste management approaches include the valorization of by-products as a source of phenolic compounds for functional food formulations. In this review, we will deal with the chemistry of antioxidants, including their molecular structures and reaction mechanisms. The biochemical aspects will also be reviewed, including the effects of acidity and temperature on their partitioning in binary and multiphasic systems. The poor bioavailability of antioxidants remains a huge constraint for clinical applications, and we will briefly describe some delivery systems that provide for enhanced pharmacological action of antioxidants via drug targeting and increased bioavailability. The pharmacological activity of antioxidants can be improved by designing nanotechnology-based formulations, and recent nanoformulations include nanoparticles, polymeric micelles, liposomes/proliposomes, phytosomes and solid lipid nanoparticles, all showing promising outcomes in improving the efficiency and bioavailability of antioxidants. Finally, an overview of the pharmacological effects, therapeutic properties and future choice of antioxidants will be incorporated.
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During the last years, the formalism of the pseudophase kinetic model (PKM) has been successfully applied to determine the distributions of antioxidants and their effective interfacial concentrations, and to assess the relative importance of emulsion and antioxidant properties (oil and surfactant nature, temperature, acidity, chemical structure, hydrophilic-liphophilic balance (HLB), etc.) on their efficiency in intact lipid-based emulsions. The PKM permits separating the contributions of the medium and of the concentration to the overall rate of the reaction. In this paper, we report the results of a specifically designed experiment to further test the suitability of the PKM to evaluate the distributions of antioxidants among the various regions of intact lipid-based emulsions and provide insights into their chemical reactivity in multiphasic systems. For this purpose, we employed the antioxidants α- and δ-TOCopherol (α- and δ-TOC, respectively) and determined, at different acidities well below their pKa, the interfacial rate constants kI for the reaction between 16-ArN2+ and α- and δ-TOC, and the antioxidant distributions in intact emulsions prepared with olive and soybean oils. Results show that the effective interfacial concentration of δ-TOC is higher than that of α-TOC in 1:9 (v/v) soybean and 1:9 olive oil emulsions. The effective interfacial concentrations of tocopherols are much higher (15-96-fold) than the stoichiometric concentrations, as the effective interfacial concentrations of both δ-TOC and α-TOC in soybean oil emulsions are higher (2-fold) than those in olive oil emulsions. Overall, the results demonstrate that the PKM grants an effective separation of the medium and concentration effects, demonstrating that the PKM constitutes a powerful non-destructive tool to determine antioxidant concentrations in intact emulsions and to assess the effects of various factors affecting them.
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The anti-inflammatory potential of oleacein, the main polyphenolic compound found in olive oil, and its main metabolites were characterized by their effects on RAW 264.7 macrophages challenged with lipopolysaccharide (LPS), and by their ability to inhibit enzymes of the arachidonic acid metabolism with a key role in the synthesis of pro-inflammatory lipid mediators. Oleacein at 12.5 µM significantly decreased the amount of L-citrulline and âNO generated by LPS-stimulated macrophages. Hydroxytyrosol, hydroxytyrosol acetate and hydroxytyrosol acetate sulfate were also able to reduce the cellular amount of âNO, although to a lesser extent. In contrast, hydroxytyrosol glucuronide and sulfate did not show detectable effects. Oleacein was also able to inhibit the coupled PLA2 + 5-LOX enzyme system (IC50 = 16.11 µM), as well as the 5-LOX enzyme (IC50 = 45.02 µM). Although with lower activity, both hydroxytyrosol and hydroxytyrosol acetate were also capable of inhibiting these enzymes at a concentration of 100 µM. None of the other tested metabolites showed a capacity to inhibit these enzymes. In contrast, all compounds, including glucuronides and sulfate metabolites, showed a remarkable capacity to inhibit both cyclooxygenase isoforms, COX-1 and COX-2, with IC50 values lower than 3 µM. Therefore, oleacein and its metabolites have the ability to modulate âNO- and arachidonic acid-dependent inflammatory cascades, contributing to the anti-inflammatory activity associated with olive oil polyphenols.
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The chemistry of the phenolic compounds found in virgin olive oil (VOO) is very complex due, not only to the different classes of polyphenols that can be found in it, but, above all, due to the existence of a very specific phenol class found only in oleaceae plants: the secoiridoids. Searching in the Scopus data base the keywords flavonoid, phenolic acid, lignin and secoiridoid, we can find a number of 148174, 79435, 11326 and 1392 research articles respectively, showing how little is devote to the latter class of compounds. Moreover, in contrast with other classes, that include only phenolic compounds, secoiridoids may include phenolic and non-phenolic compounds, being the articles concerning phenolic secoiridoids much less than the half of the abovementioned articles. Therefore, it is important to clarify the structures of these compounds and their chemistry, as this knowledge will help understand their bioactivity and metabolism studies, usually performed by researchers with a more health science's related background. In this review, all the structures found in many research articles concerning VOO phenolic compounds chemistry and metabolism was gathered, with a special attention devoted to the secoiridoids, the main phenolic compound class found in olives, VOO and olive leaf.
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Insulin resistance is a complex condition in which the body does not respond adequately to insulin, a hormone secreted by the pancreas with an essential role in the regulation of blood sugar levels [...].