Efficient Antioxidant Research Articles

Tocopherols as antioxidants in lipid-based systems: The combination of chemical and physicochemical interactions determines their efficiency.

Lipid oxidation is a major concern in the food, cosmetic, and pharmaceutical sectors. The degradation of unsaturated lipids affects the nutritional, physicochemical, and organoleptic properties of products and can lead to off-flavors and to the formation of potentially harmful oxidation compounds. To prevent or slow down lipid oxidation, different antioxidant additives are used alone or in combination to achieve the best possible efficiency with the minimum possible quantities. In manufactured products, that is, heterogeneous systems containing lipids as emulsions or bulk phase, the efficiency of an antioxidant is determined not only by its chemical reactivity, but also by its physical properties and its interaction with other compounds present in the products. The antioxidants most widely used on the industrial scale are probably tocopherols, either as natural extracts or pure synthetic molecules. Considerable research has been conducted on their antioxidant activity, but results regarding their efficiency are contradictory. Here, we review the known mechanisms behind the antioxidant activity of tocopherols and discuss the chemical and physical features that determine their efficacy. We first describe their chemical reactivity linked with the main factors that modulate it between efficient antioxidant capacity and potential prooxidant effects. We then describe their chemical interactions with other molecules (phenolic compounds, metals, vitamin C, carotenes, proteins, and phospholipids) that have potential additive, synergistic, or antagonist effects. Finally, we discuss other physical parameters that influence their activity in complex systems including their specific interactions with surfactants in emulsions and their behavior in the presence of association colloids in bulk oils.

Sustainable and efficient protocols for in vitro germination and antioxidants production from seeds of the endangered species Araucaria araucana

BackgroundThe Pehuén or Monkey puzzle tree (Araucaria araucana) is an evergreen coniferous tree, which has been historically used for social, medicinal, and nutritional purposes. We have recently showed the value of A. araucana seeds as a rich source of micronutrients and antioxidants. This endemic species present in a reduced area in Argentina and Chile is endangered because of the low germination rate and the overexploitation of its edible seeds. Thus, the massive extraction of its seeds is ecologically non-viable resulting in limited availability of its active metabolites. However, biotechnological approaches are attractive strategies of production of valuable metabolites and healthy specimens of endangered plants. The aim of this work was to develop a protocol for in vitro production of antioxidants derived from A. araucana seeds and to obtain healthy plants by optimized seed germination. ResultsCalli of Pehuén seeds were induced in Murashige and Skoog medium with different combinations of auxins and cytokinins, in light and dark conditions. Callus from embryonic axes developed in medium with 1 mg/l α-naphthaleneacetic acid and 1.5 mg/l 6-benzylaminopurine in light conditions had efficient biomass production, antioxidant activity, high phenolic, and flavonoid content and no cytotoxicity on mammalian cells. Additionally, 100 % germination was obtained in vitro and healthy plants were acclimatized to non-sterile conditions. ConclusionIn conclusion, in vitro culture of A. araucana could provide new and sustainable options for production of its valuable metabolites with possible therapeutic and nutritional uses. Also, optimized plant germination and acclimatization of endangered species can contribute to the preservation of pristine environments.

Grape pomace in equine nutrition: effect on antioxidant status

Grape pomace in equine nutrition: effect on antioxidant status

Perception and First Defense Responses Against Pseudomonas syringae pv. phaseolicola in Phaseolus vulgaris: Identification of Wall-Associated Kinase Receptors.

Common bean (Phaseolus vulgaris) is attacked by several pathogens such as the biotrophic gamma-proteobacterium Pseudomonas syringae pv. phaseolicola. To study the P. syringae pv. phaseolicola-bean interaction during the first stages of infection, leaf discs of a susceptible bean cultivar Riñón were infected with pathogenic P. syringae pv. phaseolicola. Using this experimental system, we tested six new putative wall-associated kinase (WAK) receptors, previously identified in silico. These six P. vulgaris WAKs (PvWAKs) showed high protein sequence homology to the well-described Arabidopsis thaliana WAK1 (AtWAK1) receptor and, by phylogenetic analysis, clustered together with AtWAKs. The expression of PvWAK1 increased at very early stages after the P. syringae pv. phaseolicola infection. Time course experiments were performed to evaluate the accumulation of apoplastic H2O2, Ca2+ influx, total H2O2, antioxidant enzymatic activities, lipid peroxidation, and the concentrations of abscisic acid and salicylic acid (SA), as well as the expression of six defense-related genes: MEKK-1, MAPKK, WRKY33, RIN4, PR1, and NPR1. The results showed that overexpression of PR1 occurred 2 h after P. syringae pv. phaseolicola infection without a concomitant increase in SA levels. Although apoplastic H2O2 increased after infection, the oxidative burst was neither intense nor rapid, and an efficient antioxidant response did not occur, suggesting that the observed cellular damage was caused by the initial increase in total H2O2 early after infection. In conclusion, Riñón can perceive the presence of P. syringae pv. phaseolicola, but this recognition results in only a modest and slow activation of host defenses, leading to high susceptibility to P. syringae pv. phaseolicola.

Differential modulation of photosynthesis, ROS and antioxidant enzyme activities in stress-sensitive and -tolerant rice cultivars during salinity and drought upon restriction of COX and AOX pathways of mitochondrial oxidative electron transport

Drought and salt stresses are two major abiotic stress factors that hamper crop growth and productivity. Three rice cultivars with different sensitivity and tolerance towards abiotic stress were used in the current study. While cultivar Aiswarya is salt- and drought-sensitive, cultivar Vyttila is salt-tolerant and cultivar Vaisakh is drought-tolerant. We compared the physiological and biochemical responses of these rice cultivars under salt and drought stress conditions after restricting their cytochrome oxidase (COX) and alternative oxidase (AOX) pathways using antimycin A and salicylhydroxamic acid treatment. Further, changes in their expression of AOX genes and corresponding protein levels were compared and analysed. The sensitive and tolerant rice cultivars subjected to drought and salt stress showed differential responses in physiological and biochemical traits. Whereas Aiswarya showed clear phenotypic differences, such as stunted growth, leaf curling, and loss of greening in leaf tissues, with increase in salt content and progressive drought stress, Vyttila and Vaisakh showed no remarkable changes. Moreover, the drought-tolerant cultivar rehydrated after 10 days of drought exposure, whereas the sensitive variety did not show any rehydration of leaf tissue. The leaves of the tolerant cultivars showed lower reactive oxygen species (ROS) production than that of the sensitive plants under drought and salt stress conditions because of the activation of a stronger antioxidant defence. Although, the restriction of COX and AOX pathways increased the susceptibility of sensitive cultivars, it affected the tolerant varieties moderately. Higher photosynthetic rates, an efficient antioxidant system comprising higher superoxide dismutase, ascorbate peroxidase, and catalase activity along with higher AOX1a gene expression levels during drought and salt stress were observed in tolerant cultivars. The results suggest that an efficient antioxidant system and increased transcription of the AOX1a gene along with higher AOX protein levels are important for tolerant rice cultivars to maintain higher photosynthesis rates, lower ROS, and stress tolerance. Restriction of COX and AOX pathways impact the photosynthesis, ROS, and antioxidant enzymes in both sensitive and tolerant cultivars. The restriction of COX and AOX pathways have a stronger impact on gas exchange and fluorescence parameters of the sensitive cultivar than on that of the tolerant cultivars owing to the higher photosynthetic rates in tolerant cultivars.

Changes in the level of oxidative stress markers in Indian catfish (Wallago attu) infected with Isoparorchis hypselobagri

BackgroundHelminth infection and infestation in fishes are detrimental and have a major effect on fish health and fish production. Among various factors, parasitic infections are known to modulate antioxidant defences in fish. Similar to other aerobic animals, fish are also susceptible to the effect of reactive oxygen species and thus have well established intrinsic and efficient antioxidant defences. ‘Oxidative stress markers are an important indicator of the physiological state of the parasite and its host’. Indian catfish,Wallago attu is a freshwater fish that serves as the definitive host of the adult piscine trematode Isoparorchis hypselobagri. Our two years prevalence data signifies the intensity of the problem revealing a minimum of 5.5% and a maximum of 54% I. hypselobagri infection in Indian catfish W. attu (unpublished data). The present study aimed to achieve baseline data attributed to changes in some oxidative markers due to parasitic infection.ResultsDuring the present study, the level of enzyme activities of Catalase (CAT), Glutathione reductase (GR), Glutathione-S-transferase (GST), Glutathione peroxidase (GPx), Superoxide dismutase (SOD) and lipid peroxidation was investigated to explore the pathogenic impact on the fish host. The level of these oxidative stress markers was monitored in the swim bladder, liver, intestine and muscle of the host. We also recorded the enzyme activities in the parasite I. hypselobagri. Analysis of data revealed an elevation in GST, SOD, GR, GPx and CAT activity in the infected host tissue as compared to the non-infected fish. Further, we observed presence of GST, SOD, GR and GPx enzymes in the parasite I. hypselobagri while CAT did not show any enzyme activity.ConclusionsIncreased level of enzyme activity in liver, muscle and intestine of infected host has been recorded which indicates increased oxidative stress in the host due to parasitic invasion. The presence of antioxidant enzymes in the parasites suggests an active antioxidant defence system to avoid immune responses to long term survival and establishment in their host.

Mitochondrial Management of Reactive Oxygen Species

Mitochondria in aerobic eukaryotic cells are both the site of energy production and the formation of harmful species, such as radicals and other reactive oxygen species, known as ROS. They contain an efficient antioxidant system, including low-molecular-mass molecules and enzymes that specialize in removing various types of ROS or repairing the oxidative damage of biological molecules. Under normal conditions, ROS production is low, and mitochondria, which are their primary target, are slightly damaged in a similar way to other cellular compartments, since the ROS released by the mitochondria into the cytosol are negligible. As the mitochondrial generation of ROS increases, they can deactivate components of the respiratory chain and enzymes of the Krebs cycle, and mitochondria release a high amount of ROS that damage cellular structures. More recently, the feature of the mitochondrial antioxidant system, which does not specifically deal with intramitochondrial ROS, was discovered. Indeed, the mitochondrial antioxidant system detoxifies exogenous ROS species at the expense of reducing the equivalents generated in mitochondria. Thus, mitochondria are also a sink of ROS. These observations highlight the importance of the mitochondrial antioxidant system, which should be considered in our understanding of ROS-regulated processes. These processes include cell signaling and the progression of metabolic and neurodegenerative disease.

Studies on the Antioxidant and Antibacterial Activities of In Situ Green Synthesized Graphene‐Gold Nanocomposite

AbstractThe current protocol is focused on the fabrication and applications of gold nanoparticles (Au NPs) distributed on graphene sheets with an emphasis on green synthesis using Kigelia Africana (KA) stem extract. The reducing and stabilizing molecules present in the stem of the KA plant were involved in the transformation of metal ions and graphene oxide in to metal nanoparticles anchored on to reduced graphene oxide sheets. Thus, the obtained graphene‐gold nanocomposite was investigated using sophisticated characterization techniques such as UV‐Visible, Infra‐Red, XRD, Raman, SEM and HRTEM techniques. All these techniques proved the formation of graphene‐gold nanocomposite with the characteristic spectroscopic peaks of graphene and gold. The graphene‐gold nanocomposite exhibited superior antioxidant activity than ascorbic acid standard thus finds medical application as a potential antioxidant agent. Moreover, the nanocomposite also showed good antibacterial activity against five pathogens. These results suggest that the in situ green synthesized graphene‐gold nanocomposite can be used as efficient antibacterial and antioxidants for controlling pathogenic microbes.

Exogenous calcium reduces boron toxicity by regulating efficient antioxidant system and boron forms in trifoliate rootstock

Boron (B) toxicity is a major limiting factor for crop production, and calcium (Ca) has been reported to alleviate B toxicity. However, mechanisms of Ca alleviating B toxicity in trifoliate rootstock are not clear. Therefore, the present investigation was conducted on trifoliate seedlings to explore the underneath mechanisms. We included two B (10 and 100 µM) and three Ca levels (0, 1.23 and 2.46 mM) to explore the effect of supplementary Ca supply on mitigating B toxicity in order to gain a better understanding of tolerance mechanism in citrus production. The results showed that Ca (2.46 mM) application significantly increased root dry weight and fresh weight by 32.26% and 24.60% under B toxicity condition, respectively. Meanwhile, the root growth was improved with a greater proportion of new roots. The supply of Ca did not reduce the total absorption of B, however, lowered the R-value of B and reduced its utilization efficiency in cell walls. Moreover, Ca also triggered the antioxidant enzyme system to scavenge reactive oxygen species and reduced malondialdehyde content. Nevertheless, total soluble protein did not show any significant effect. Taken together it could be concluded that Ca application can mitigate B toxicity by maintaining antioxidant enzyme system and free B concentration, thereby reducing the utilization efficiency of B in cell wall for avoiding excessive accumulation of B in cells.

MiR169q and NUCLEAR FACTOR YA8 enhance salt tolerance by activating PEROXIDASE1 expression in response to ROS

Salt stress significantly reduces the productivity of crop plants including maize (Zea mays). miRNAs are major regulators of plant growth and stress responses, but few studies have examined the potential impacts of miRNAs on salt stress responses in maize. Here, we show that ZmmiR169q is responsive to stress-induced ROS signals. After detecting that salt stress and exogenous H2O2 treatment reduced the accumulation of ZmmiR169q, stress assays with transgenic materials showed that depleting ZmmiR169q increased seedling salt tolerance whereas overexpressing ZmmiR169q decreased salt tolerance. Helping explain these observations, we found that ZmmiR169q repressed the transcript abundance of its target NUCLEAR FACTOR YA8 (ZmNF-YA8), and overexpression of ZmNF-YA8 in maize improved salt tolerance, specifically by transcriptionally activating the expression of the efficient antioxidant enzyme PEROXIDASE1. Our study reveals a direct functional link between salt stress and a miR169q-NF-YA8 regulatory module that plants use to manage ROS stress and strongly suggests that ZmNF-YA8 can be harnessed as a resource for developing salt-tolerant crop varieties.

Comparative study of the antioxidant activity of the essential oils of five plants against the H2O2 induced stress in Saccharomyces cerevisiae

The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H2O2 (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H2O2. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H2O2 only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress.

The nitroxide/antioxidant 3-carbamoyl proxyl attenuates disease severity in murine models of severe asthma

Asthma is characterized by airway inflammation, hyper-responsiveness, symptoms of dyspnea, wheezing and coughing. In most patients, asthma is well controlled using inhaled corticosteroids and bronchodilators. A minority of patients with asthma develop severe disease, which is frequently only partially responsive or even resistant to treatment with corticosteroids. Severe refractory asthma is associated with structural changes in the airways, termed “airway remodeling”, and/or with neutrophilic rather than eosinophilic airway inflammation. While oxidative stress plays an important role in the pathophysiology of asthma, cyclic nitroxide stable radicals, which are unique and efficient catalytic antioxidants, effectively protect against oxidative injury. We have demonstrated that the nitroxide 3-carbamoyl proxyl (3-CP) attenuates airway inflammation and hyperresponsiveness in allergic asthma as well as bleomycin-induced fibrosis both using murine models, most probably through modulation of oxidative stress. The present study evaluates the effect of 3-CP on airway inflammation and remodeling using two murine models of severe asthma where mice are sensitized and challenged either by ovalbumin (OVA) or by house dust mite (HDM). 3-CP was orally administered during the entire period of the experiment or during the challenge period alone where its effect was compared to that of dexamethasone. The induced increase by OVA and by HDM of BALf cell counts, airway hyperresponsiveness, fibrosis, transforming growth factor-beta (TGF-β) levels in BALf and protein nitration levels of the lung tissue was significantly reduced by 3-CP. The effect of 3-CP, using two different murine models of severe asthma, is associated at least partially with attenuation of oxidative stress and with TGF-β expression in the lungs. The results of this study suggest a potential use of 3-CP as a novel therapeutic agent in different forms of severe asthma.

Bimodal Behavior of Ascorbic Acid in Musca domestica Larvae

Ascorbic acid (Vitamin C) is an excellent water-soluble dietary antioxidant, well known to protect the biomolecules from oxidative stress-linked damages. It is reported to show a contrary behavior by inflicting pro-oxidant effects under varied, altered circumstances. The present work is an attempt to study the antioxidant and pro-oxidant behavior of ascorbic acid in Musca domestica larvae. Its pro-oxidant properties were tested by exposing the larvae to various concentrations of ascorbic acid. For confirming its oxidant scavenging properties, its effects on the antioxidant enzyme profiles were studied in both the normal and stress-induced M. domestica larvae. Oxidative stress was induced by adding D-Galactose (D-Gal) to the normal food supplement of the larvae. Outcomes of the study demonstrate that ascorbic acid acts as an efficient antioxidant when added in lower concentrations, but at high concentrations, it induces oxidative stress in the larvae, thus acting as a pro-oxidant. At the concentration of 10 mM, ascorbic acid significantly reduced the oxidative stress induced by D-Gal (p < 0.05) and maintained the percent pupal survival and percent eclosion. In conclusion, we suggest that ascorbic acid may function as an antioxidant and pro-oxidant in a concentration-dependent manner under normal physiological conditions.

Oxidative stress and its impact on skin, scalp and hair.

Oxidative stress is an unbalanced condition in which the tissues of the body are not sufficiently able to counteract either exogenous or endogenous sources of reactive oxygen species. Oxidative stress is strongly associated with ageing, both local and systemic, as well as a wide range of local health conditions. This review focuses on the oxidative stress data known for skin, scalp and hair. This oxidative stress may be the 'currency' by which an unhealthy scalp leads to deleterious consequences to the hair. The ramifications of this scalp oxidative stress to normal hair elongation, retention and replacement are discussed.

Molecular characterization of superoxide dismutase and catalase genes, and the induction of antioxidant genes under the zinc oxide nanoparticle-induced oxidative stress in air-breathing magur catfish (Clarias magur).

The deduced amino acid sequences from the complete cDNA coding sequences of three antioxidant enzyme genes (sod1, sod2, and cat) demonstrated that phylogenetically the magur catfish (Clarias magur) is very much close to other bony fishes with complete conservation of active site residues among piscine, amphibian, and mammalian species. The three-dimensional structures of three antioxidant enzyme proteins are very much similar to mammalian counterparts, thereby suggesting the functional similarities of these enzymes. Exposure to ZnO NPs resulted in an oxidative stress as evidenced by an initial sharp rise of intracellular concentrations of hydrogen peroxide (H2O2) and malondialdehyde (MDA) but decreased gradually at later stages. The level of glutathione (GSH) also increased gradually in all the tissues examined after an initial decrease. Biochemical and gene expression analyses indicated that the magur catfish has the ability to defend the ZnO NP-induced oxidative stress by inducing the SOD/CAT enzyme system and also the GSH-related enzymes that are mediated through the activation of various antioxidant-related genes both at the transcriptional and translational levels in various tissues. Furthermore, it appeared that the stimulation of NO, as a consequence of induction nos2 gene, under NP-induced oxidative stress serves as a modulator to induce the SOD/CAT system in various tissues of magur catfish as an antioxidant strategy. Thus, it can be contemplated that the magur catfish possesses a very efficient antioxidant defensive mechanisms to defend against the oxidative stress and also from related cellular damages during exposure to ZnO NPs into their natural environment.

The effects of Curcuma longa L. leaf extracts on the prevention of oxidation in soybean oil.

The use of natural plant antioxidants has been an alternative approach to synthetic antioxidants for food applications. This study investigated the antioxidant properties of the leaves of Curcuma longa L. against the oxidation of soybean oil using leaf extracts obtained from seven different types of organic solvents and compared to the action of efficient synthetic antioxidants which are widely used and low cost but with toxicity risk. The application of natural alternatives from sources still little studied is a proposal and the extraction of compounds with high antioxidant capacity may vary according to the type of solvent, its mixture, its polarity and other factors that burden or harm the health of the consumer. The leaf extracts were sanitized, dried, and obtained for solvent selection. The quantification of total phenolic compounds (TPC) and antioxidants was performed by using different combinations and proportions of solvents: water (100%), ethanol (100%), methanol (100%), ethanol/water (70%:30%), methanol/water (70%:30%), methanol/acetic acid (99.5%:0.5%), and acetone/water/acetic acid (70%:28:2%). The solvent selected was the one that extracted the highest content of phenolic and antioxidant compounds (using the free radical DPPH scavenging method and FRAP assay). It used an accelerated storage test and experimental design to assess oxidative stability (using peroxide index (PI), thiobarbituric acid reactive substances (TBARS), dienes (DC) and triple conjugates (TC) and statistical analysis). The ethanol/water solvent was efficient in the extraction of TPC (2422 mg GAE 100 g-1). The mixture of solvents extracted an average of 23.65% more TPC when compared to the single solvents. Regarding the antioxidant capacity, the ethanol/water solvent showed 1847 mg TE 100 g-1 using the DPPH and 217 μmol of FeSO4 100 g-1 using the FRAP assays. In addition, the oxidation of soybean oil was delayed by the accelerated storage test showing equivalent results to BHT at 0.02% for the values of PI, TBARS and DC/TC. The E/W extract showed the highest yield in the extraction of phenolic compounds and is a safe solvent for food. The addition of Curcuma longa L. leaf extract to soybean oil caused reductions in PI, TBARS, CD and CT values. The leaf extract of C. longa L. is considered to be a good alternative to synthetic antioxidants against the oxidative degradation of soybean oil.

Effect of Rhizophagus intraradices on growth and physiological performance of Finger Millet (Eleusine coracana L.) under drought stress

Under abiotic stress conditions, arbuscular mycorrhizal (AM) fungi help plants by improving nutrient and water uptake. Finger millet (Eleusine coracana L.) is an arid crop having soils with poor water holding capacity. Therefore, it is difficult for the plants to obtain water and mineral nutrients from such soil to sustain life. To understand the role of mycorrhizal symbiosis in water and mineral up-take from the soil, we studied the role of Rhizophagus intraradices colonization and its beneficial role for drought stress tolerance in finger millet seedlings. Under severe drought stress condition, AM inoculation led to the significant increase in plant growth (7 %), phosphorus and chlorophyll content (29 %). Also, under drought stress the level of osmolytes such as proline and soluble sugars were found to be increased in AM inoculated seedlings. Under water stress, the lipid peroxidation in leaves of mycorrhized seedlings was reduced by 29 %. The flavonoid content of roots in AM colonized seedlings was found 16 % higher compared to the control, whereas the leaves were accumulated more phenol. Compared to the control, ascorbate level was found to be 25 % higher in leaf tissue of AM inoculated seedlings. Moreover, glutathione (GSH) level was also increased in mycorrhiza inoculated seedlings with a maximum increment of 182 % under severe stress. The results demonstrated that AM provided drought tolerance to the finger millet seedlings through a stronger root system, greater photosynthetic efficiency, a more efficient antioxidant system and improved osmoregulation.

Comparison of Volatile Constituents, Antioxidant and Antimicrobial Activities of Thymus leucotrichus (Lamiaceae) Stem and Leaves Essential Oils from Both Natural Resources and In vitro Derived Shoots

This study aimed to compare the volatile constituents, antioxidant and antimicrobial potentials of Thymus leucotrichus essential oils (EOs) obtained from natural plants and in vitro derived shoots. MS medium fortified 0.5 mg/L kinetin was preferred for an efficient micropropagation protocol and was produced T. leucotrichus shoots. The most efficient antioxidant activity was up to IC50 0.823 μg/ml in DPPH, 275.021 mg TE/ml in TEAC, and 25.531 mg GAE/ml in reducing power were found. Total phenolics were determined as 69.249 mg/ml GAE in micropropagated samples while 63.377 mg/ml GAE in natural resources. Thymol was determined as the main volatile compound of both natural plants and in vitro derived shoots. The EOs showed a strong antimicrobial effect on selected seven gram-positive, nine gram-negative bacteria, seven gram-negative aquatic bacteria and a fungus. The highest disc diffusion value was obtained as 44.3 mm for P. damselae subsp. damselae from in vitro derived shoots. In both groups of tested EOs, the most effective MICs were obtained with 12.21 μg/ml against V. parahaemolyticus. The novelty of this report is the first comprehensive and comparative study on volatile constituents, antioxidant, and antimicrobial properties of naturally growing plants and in vitro derived shoots of T. leucotrichus.

The role of Nrf2 pathway in alleviating fluorine-induced apoptosis by different selenium sources in the chicken duodenum and jejunum

In order to evaluate the alleviative effects and molecular mechanisms of sodium selenite (SS) and selenomethionine (SM) on excessive apoptosis induced by high fluorine (HF) in the duodenum and jejunum of broilers, 720 1 day old Lingnan Yellow broilers were randomly divided into 4 groups (each group assigned 180 chickens with 6 replicates) and offered either a control diet or test diets (800 mg/kg F, HF group; 800 mg/kg F + 0.15 mg selenium (Se)/kg as SS (SS group) or SM (SM group)) for 50 days. High F intake significantly increased (P < 0.05) apoptosis rates of duodenum and jejunum by inducing oxidative stress and leading to mitochondrial damage. Selenomethionine supplementation effectively alleviated mitochondrial damage and severe apoptosis of duodenum and jejunum caused by HF through decreasing oxidative stress parameters. Selenomethionine added group significantly increased (P < 0.05) nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and nuclear Nrf2 protein levels as well as Nrf2 downstream antioxidant enzymes expressions in the duodenum and jejunum when compared with the HF group. Selenomethionine was superior to SS in activating the Nrf2 pathway and reducing the apoptosis rate of duodenum. It was concluded that dietary SM supplementation could ameliorate F-induced excessive apoptosis by inducing the Nrf2 pathway. Our findings will bring a promising tactics for the utilization of SM as an efficient antioxidant additive for reducing the intestinal damage caused by fluorosis in poultry.

Aedes aegypti Infection With Trypanosomatid Strigomonas culicis Alters Midgut Redox Metabolism and Reduces Mosquito Reproductive Fitness.

Aedes aegypti mosquitoes transmit arboviruses of important global health impact, and their intestinal microbiota can influence vector competence by stimulating the innate immune system. Midgut epithelial cells also produce toxic reactive oxygen species (ROS) by dual oxidases (DUOXs) that are essential players in insect immunity. Strigomonas culicis is a monoxenous trypanosomatid that naturally inhabits mosquitoes; it hosts an endosymbiotic bacterium that completes essential biosynthetic pathways of the parasite and influences its oxidative metabolism. Our group previously showed that S. culicis hydrogen peroxide (H2O2)-resistant (WTR) strain is more infectious to A. aegypti mosquitoes than the wild-type (WT) strain. Here, we investigated the influence of both strains on the midgut oxidative environment and the effect of infection on mosquito fitness and immunity. WT stimulated the production of superoxide by mitochondrial metabolism of midgut epithelial cells after 4 days post-infection, while WTR exacerbated H2O2 production mediated by increased DUOX activity and impairment of antioxidant system. The infection with both strains also disrupted the fecundity and fertility of the females, with a greater impact on reproductive fitness of WTR-infected mosquitoes. The presence of these parasites induced specific transcriptional modulation of immune-related genes, such as attacin and defensin A during WTR infection (11.8- and 6.4-fold, respectively) and defensin C in WT infection (7.1-fold). Thus, we propose that A. aegypti oxidative response starts in early infection time and does not affect the survival of the H2O2-resistant strain, which has a more efficient antioxidant system. Our data provide new biological aspects of A. aegypti–S. culicis relationship that can be used later in alternative vector control strategies.