Antioxidant Production Research Articles

Impact of host species on assembly, composition, and functional profiles of phycosphere microbiomes.

As the main primary producers of the oceans, microalgae serve as cornerstones of the ecosystems they are part of. Additionally, they are increasingly used for biotechnological purposes such as the production of nutraceuticals, pigments, and antioxidants. Since the bacterial microbiomes of microalgae can affect their hosts in beneficial and detrimental ways, understanding these microbiomes is crucial to both the ecological and applied roles of microalgae. The present study advances the understanding of microalgal microbiome assembly, composition, and functionality across microalgal phyla, which may inform the modeling and engineering of microalgal microbiomes for biotechnological purposes.

Quantitation of antioxidant levels of soy-fern fermentation by DPPH assay

Fermentation biotechnology is one of the approaches to addressing the issues of food security worldwide, where the demand for healthier and safer foods is becoming mainstream. Even though fermentation has been practiced since ancient times, there are still an infinite number of topics that can serve as subjects for fermentative investigation. Among the popular nutraceutical research is the antioxidant properties of plants. In this study, the radical scavenging activities of soy-fern fermentation by mixed probiotics (13 species) have been quantified using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Four treatments were set up: soy-fern-probiotics, soy-fern, soy-probiotics, and soy. These treatments were fermented (submerged) for up to 72 h. Samples were taken at 0 h, 24 h, 48 h, and 72 h and were analyzed via a 96-well plate microplate photometer. Results showed that the production of antioxidants peaked at 24 h in soy-fern-probiotics and soy-fern (82.82% and 82.77%, respectively), suggesting that the presence of fern molecules could have affected the production of antioxidant molecules. It is also observed that the probiotics have less impact on the antioxidant levels. The analysis of variance (ANOVA) showed that there is a significant difference in this timeframe when compared to other timeframes. On average, the succession of antioxidant levels is as follows (highest to lowest): 24 h, 48 h, 0 h, 72 h. Overall, the level of antioxidants depends on the substrates, fermenting microorganisms, type of fermentation, and fermentation time. More studies on this matter are highly recommended.

Methionine Restriction Reduces Lung Cancer Progression and Increases Chemotherapy Response.

Targeting tumor metabolism through dietary interventions is an area of growing interest, and may help to improve the significant mortality of aggressive cancers, including non-small cell lung cancer (NSCLC). Here we show that the restriction of methionine in the aggressive KRAS /Lkb1- mutant NSCLC autochthonous mouse model drives decreased tumor progression and increased carboplatin treatment efficacy. Importantly, methionine restriction during early stages of tumorigenesis prevents the lineage switching known to occur in the model, and alters the tumor immune microenvironment (TIME) to have fewer tumor-infiltrating neutrophils. Mechanistically, mutations in LKB1 are linked to anti-oxidant production through changes to cystathionine-β-synthase (CBS) expression. Human cell lines with rescued LKB1 show increased CBS levels and resistance to carboplatin, which can be partially rescued by methionine restriction. Furthermore, LKB1 rescued cells, but not mutant cells, show less G2- M arrest and apoptosis in high methionine conditions. Knock-down of CBS sensitized both LKB1 mutant and non-mutated lines to carboplatin, again rescuing the carboplatin resistance of the LKB1 rescued lines. Given that immunotherapy is commonly combined with chemotherapy for NSCLC, we next wanted to understand if T cells are impaired by MR. Therefore, we examined the ability of T cells from MR and control tumor bearing mice to proliferate in culture and found that T cells from MR treated mice had no defects in proliferation, even though we continued the MR conditions ex vivo . We also identified that CBS is most highly correlated with smoking, adenocarcinomas with alveolar and bronchiolar features, and adenosquamous cell carcinomas, implicating its roles in oxidative stress response and lineage fate in human tumors. Taken together, we have shown the importance of MR as a dietary intervention to slow tumor growth and improve treatment outcomes for NSCLC.

Trioxidized cysteine and aging: a molecular binomial that extends far beyond classical proteinopathic paradigms.

Increased oxidative stress (OS) and the disruption of the equilibrium between the production of reactive oxygen species and antioxidants are key molecular features of unhealthy aging. OS results in the formation of oxidative posttranslational modifications (PTMs), some of which involve cysteine (Cys) residues in aging proteomes, and specifically, the formation of trioxidized Cys (t-Cys), which leads to permanent protein damage. Recent findings in rodents have uncovered that irregular regulation of t-Cys residues in the aging proteome disrupts homeostatic phosphorylation signaling, resulting in alterations to proteins that are analogous to those caused by phosphorylated serine (p-Ser) residues. This work contextualizes these significant findings and discusses the implications and molecular role(s) of t-Cys in the aging proteome. Furthermore, we present novel data, validating the increase of specific t-Cys sites associated with aging in a blood-related circulating human proteome. The scope and findings included here support the hypothesis that t-Cys residues may serve as important mechanistic and biological markers, warranting further exploration in the context of unhealthy aging and age-related major diseases.

Low-Molecular-Weight Peptides Prepared from Hypsizygus marmoreus Exhibit Strong Antioxidant and Antibacterial Activities.

Hypsizygus marmoreus has abundant proteins and is a potential source for the development of bioactive peptides. However, currently, the research on the bioactive components of H. marmoreus mainly focuses on polysaccharides, and there is no relevant research on the preparation of bioactive peptides. In this article, an ultrasound-assisted extraction method was used to extract proteins from H. marmoreus, and then, four peptides with different molecular weight ranges were prepared through protease hydrolysis and molecular classification. The antioxidant and antibacterial activities were also studied. Under the optimal conditions, the extraction rate of H. marmoreus proteins was 53.6%. Trypsin exhibited the highest hydrolysis rate of H. marmoreus proteins. The optimal parameters for enzymatic hydrolysis were a substrate concentration of 3.7%, enzyme addition of 5700 U/g, pH value of 7, extraction temperature of 55 °C, and time of 3.3 h. Under these conditions, the peptide yield was 59.7%. The four types of H. marmoreus peptides were prepared by molecular weight grading. Among them, peptides with low molecular weight (<1 kDa) had stronger antioxidant and antibacterial activities. This study provides a theoretical basis for the efficient preparation of H. marmoreus peptides and the development of antioxidant and antibacterial peptide products.

Strategies for combating plant salinity stress: the potential of plant growth-promoting microorganisms.

Global climate change and the decreasing availability of high-quality water lead to an increase in the salinization of agricultural lands. This rising salinity represents a significant abiotic stressor that detrimentally influences plant physiology and gene expression. Consequently, critical processes such as seed germination, growth, development, and yield are adversely affected. Salinity severely impacts crop yields, given that many crop plants are sensitive to salt stress. Plant growth-promoting microorganisms (PGPMs) in the rhizosphere or the rhizoplane of plants are considered the "second genome" of plants as they contribute significantly to improving the plant growth and fitness of plants under normal conditions and when plants are under stress such as salinity. PGPMs are crucial in assisting plants to navigate the harsh conditions imposed by salt stress. By enhancing water and nutrient absorption, which is often hampered by high salinity, these microorganisms significantly improve plant resilience. They bolster the plant's defenses by increasing the production of osmoprotectants and antioxidants, mitigating salt-induced damage. Furthermore, PGPMs supply growth-promoting hormones like auxins and gibberellins and reduce levels of the stress hormone ethylene, fostering healthier plant growth. Importantly, they activate genes responsible for maintaining ion balance, a vital aspect of plant survival in saline environments. This review underscores the multifaceted roles of PGPMs in supporting plant life under salt stress, highlighting their value for agriculture in salt-affected areas and their potential impact on global food security.

Mitigating drought-induced oxidative stress in wheat (Triticum aestivum L.) through foliar application of sulfhydryl thiourea

Drought stress is a major abiotic stress affecting the performance of wheat (Triticum aestivum L.). The current study evaluated the effects of drought on wheat phenology, physiology, and biochemistry; and assessed the effectiveness of foliar-applied sulfhydryl thiourea to mitigate drought-induced oxidative stress. The treatments were: wheat varieties; V1 = Punjab-2011, V2 = Galaxy-2013, V3 = Ujala-2016, and V4 = Anaaj-2017, drought stress; D1 = control (80% field capacity [FC]) and D2 = drought stress (40% FC), at the reproductive stage, and sulfhydryl thiourea (S) applications; S0 = control-no thiourea and S1 = foliar thiourea application @ 500 mg L−1. Results of this study indicated that growth parameters, including height, dry weight, leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), net assimilation rate (NAR) were decreased under drought stress-40% FC, as compared to control-80% FC. Drought stress reduced the photosynthetic efficiency, water potential, transpiration rates, stomatal conductances, and relative water contents by 18, 17, 26, 29, and 55% in wheat varieties as compared to control. In addition, foliar chlorophyll a, and b contents were also lowered under drought stress in all wheat varieties due to an increase in malondialdehyde and electrolyte leakage. Interestingly, thiourea applications restored wheat growth and yield attributes by improving the production and activities of proline, antioxidants, and osmolytes under normal and drought stress as compared to control. Thiourea applications improved the osmolyte defense in wheat varieties as peroxidase, superoxide dismutase, catalase, proline, glycine betaine, and total phenolic were increased by 13, 20, 12, 17, 23, and 52%; while reducing the electrolyte leakage and malondialdehyde content by 49 and 32% as compared to control. Among the wheat varieties, Anaaj-2017 showed better resilience towards drought stress and also gave better response towards thiourea application based on morpho-physiological, biochemical, and yield attributes as compared to Punjab-2011, Galaxy-2013, and Ujala-2016. Eta-square values showed that thiourea applications, drought stress, and wheat varieties were key contributors to most of the parameters measured. In conclusion, the sulfhydryl thiourea applications improved the morpho-physiology, biochemical, and yield attributes of wheat varieties, thereby mitigating the adverse effects of drought. Moving forward, detailed studies pertaining to the molecular and genetic mechanisms under sulfhydryl thiourea-induced drought stress tolerance are warranted.

The Role of PGC-1α in Aging Skin Barrier Function.

Skin provides a physical and immune barrier to protect the body from foreign substances, microbial invasion, and desiccation. Aging reduces the barrier function of skin and its rate of repair. Aged skin exhibits decreased mitochondrial function and prolonged low-level inflammation that can be seen in other organs with aging. Peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1α (PGC-1α), an important transcriptional coactivator, plays a central role in modulating mitochondrial function and antioxidant production. Mitochondrial function and inflammation have been linked to epidermal function, but the mechanisms are unclear. The aim of this review is to discuss the mechanisms by which PGC-1α might exert a positive effect on aged skin barrier function. Initially, we provide an overview of the function of skin under physiological and aging conditions, focusing on the epidermis. We then discuss mitochondrial function, oxidative stress, cellular senescence, and inflamm-aging, the chronic low-level inflammation observed in aging individuals. Finally, we discuss the effects of PGC-1α on mitochondrial function, as well as the regulation and role of PGC-1α in the aging epidermis.

Mango peel extracts and mangiferin chromatographic Fourier-transform infrared correlation with antioxidant, antidiabetic, and advanced glycation end product inhibitory potentials using in silico modeling and in vitro assays.

Mangifera indica peels are a rich source of diverse flavonoids and xanthonoids; however, generally these are discarded. Computational studies revealed that mangiferin significantly interacts with amino acid residues of transcriptional regulators 1IK3, 3TOP, and 4f5S. The methanolic extract of Langra variety of mangoes contained the least phenol concentrations (22.6 ± 0.32 mg/gGAE [gallic acid equivalent]) compared to the chloroform (214.8 ± 0.12 mg/gGAE) and ethyl acetate fractions (195.6 ± 0.14 mg/gGAE). Similarly, the methanolic extract of Sindhri variety contained lower phenol concentrations (42.3 ± 0.13 mg/gRUE [relative utilization efficiency]) compared with the chloroform (85.6 ± 0.15 mg/gGAE) and ethyl acetate (76.1 ± 0.32 mg/gGAE) fractions. Langra extract exhibited significant α-glucosidase inhibition (IC50 0.06 mg/mL), whereas the ethyl acetate fraction was highly active (IC50 0.12 mg/mL) in Sindhri variety. Mangiferin exhibited significant inhibition (IC50 0.026 mg/mL). A moderate inhibition of 15-LOX was observed in all samples, whereas mangiferin was least active. In advanced glycation end product inhibition assay, the chloroform fraction of Langra variety exhibited significant inhibition in nonoxidative (IC50 64.4μg/mL) and oxidative modes (IC50 54.7μg/mL). It was concluded that both Langra and Sindhri peel extracts and fractions possess significant antidiabetic activities. The results suggest the potential use of peel waste in the management and complications of diabetes.

Quantitative 3D electron microscopy characterization of mitochondrial structure, mitophagy, and organelle interactions in murine atrial fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, however there is limited understanding of its pathophysiology including the cellular and ultrastructural changes rendered by the irregular rhythm, which limits pharmacological therapy development. Prior work has demonstrated the importance of reactive oxygen species (ROS) and mitochondrial dysfunction in the development of AF. Mitochondrial structure, interactions with other organelles such as sarcoplasmic reticulum (SR) and T-tubules (TT), and degradation of dysfunctional mitochondria via mitophagy are important processes to understand ultrastructural changes due to AF. However, most analysis of mitochondrial structure and interactome in AF has been limited to two-dimensional (2D) modalities such as transmission electron microscopy (EM), which does not fully visualize the morphological evolution of the mitochondria during mitophagy. Herein, we utilize focused ion beam-scanning electron microscopy (FIB-SEM) and perform reconstruction of three-dimensional (3D) EM from murine left atrial samples and measure the interactions of mitochondria with SR and TT. We developed a novel 3D quantitative analysis of FIB-SEM in a murine model of AF to quantify mitophagy stage, mitophagosome size in cardiomyocytes, and mitochondrial structural remodeling when compared with control mice. We show that in our murine model of spontaneous and continuous AF due to persistent late sodium current, left atrial cardiomyocytes have heterogenous mitochondria, with a significant number which are enlarged with increased elongation and structural complexity. Mitophagosomes in AF cardiomyocytes are located at Z-lines where they neighbor large, elongated mitochondria. Mitochondria in AF cardiomyocytes show increased organelle interaction, with 5X greater contact area with SR and are 4X as likely to interact with TT when compared to control. We show that mitophagy in AF cardiomyocytes involves 2.5X larger mitophagosomes that carry increased organelle contents. In conclusion, when oxidative stress overcomes compensatory mechanisms, mitophagy in AF faces a challenge of degrading bulky complex mitochondria, which may result in increased SR and TT contacts, perhaps allowing for mitochondrial Ca2+ maintenance and antioxidant production.

Non-lactic acid bacteria probiotics isolated from intestine or various circumstances.

Probiotics are live microorganisms beneficial to host health, predominantly comprising lactic acid bacteria (LAB) such as Lactobacillus. Additional non-LAB probiotics, termed intestinal isolates, encompass next-generation strains like Akkermansia muciniphila, Faecalibacterium prausnitzii, Christensenella minuta, Anaerobutyricum soehngenii, Oxalobacter formigenes, etc. and alongside externally sourced Bacillus, Saccharomyces cerevisiae, Clostridium butyricum, and Propionibacterium. Intestinal-derived probiotics represent strictly anaerobic strains with challenging culturing requirements, contrasting with the aerobic nature of Bacillus probiotics and the ease of culturing S. cerevisiae. These strains exhibit diverse health-promoting properties, encompassing antimicrobial, anticancer, antioxidant, and vitamin production capabilities, albeit contingent upon strain specificity. This review delineates the characteristics, culturing conditions, and health advantages associated with non-LAB probiotics.

Chronic stress intensify PTZ-induced seizures by triggering neuroinflammation and oxidative stress

BackgroundEpilepsy is a paroxysmal abnormal hypersynchronous electrical discharge characterized by recurrent seizures. It affects more than 50 million people worldwide. Stress is the leading cause of neurodegeneration and can produce seizures that may lead to or aggravate epilepsy. Inflammation plays a vital role in epilepsy by modulating oxidative stress, and levels of neuroinflammatory cytokines including NF-κB, TNF-α, and IL-1β. MethodsStress-induced changes in behavior were evaluated in mice by employing behavioral assessment tests such as an elevated plus maze, light-dark box, open field test, tail suspension test, Y-maze, novel object recognition test, and Morris water maze in pentylenetetrazole (PTZ) kindled mice. Behavioral changes in all these paradigms including seizure score, latency, and frequency showed an increase in symptoms in PTZ (35 mg/kg) induced seizures in stressed mice (RS-PTZ) as compared to PTZ, Stress, and normal animals. ResultsThe Enzyme-linked immunosorbent assay (ELISA) results confirmed increased in serum cortisol levels. Histological examinations showed neurodegenerative changes in the hippocampus and cortex regions. The spectrophotometric evaluation showed an increase in oxidative stress by decreasing antioxidant production i.e. reduced glutathione, glutathione -s- transferase, and catalase (CAT), and increasing oxidant levels such as maloaldehyde and nitric oxide. Immunohistochemistry results showed increased expression of NF-κB, TNF-α, and IL-1β in the cortex and hippocampus of mice brains. ConclusionsResults from the study conclude that stress increases the likelihood of eliciting an epileptic attack by increasing the level of reactive oxygen species and neuroinflammation.

Enhancing antioxidant properties of lime juice powder through polyelectrolyte microparticles of chitosan-alginate: Formulation, characterization and stability study.

Lime (Citrus aurantifolia) juice was reported to contain ascorbic acid (AA) and flavonoids, which has bioactivity as antioxidants. To develop an antioxidant product, improving its stability is necessary due to the perishable characteristics of compounds in lime. Therefore, the formulation of polyelectrolyte microparticles using chitosan and alginate was conducted to overcome the weaknesses. This study aims to evaluate the effect of various chitosan, alginate, and lime juice powder (LJP) concentrations on the physical characteristics and antioxidant activity of LJP encapsulated in chitosan-alginate microparticles (CALM). Microparticles with various concentrations of chitosan and alginate were prepared by ionic gelation method using CaCl2 as a crosslinker. The microparticles were evaluated for its physical properties and its antioxidant activity using 2-2-diphenyl-1-picrylhydrazyl reagent. A one-way ANOVA test and Tukey's honest significant difference post hoc were used to determine the effect of LJP amount on the antioxidant activity. The highest AA content in CALM was 0.14 mg/100 mg, with a % encapsulation efficiency of 18.38% ± 0.02%. Antioxidant activity tests revealed that LJP possessed the strong antioxidant activity with an IC50 value of 32.59 μg/mL, whereas IC50 values of the microparticles ranged from 24.79 ± 0.03 μg/mL to 39.96 ± 0.07 μg/mL. During storage, the IC50 of LJP decreased from 32.59 ± 0.13 μg/mL to 65.53 ± 0.03 μg/mL, whereas the IC50 of microparticles remained stable. This study concluded that the chitosan-alginate polyelectrolyte microparticle formulation can improve and protect LJP's antioxidant activity.

Analysis of the Variation in Antioxidant Activity and Chemical Composition upon the Repeated Thermal Treatment of the By-Product of the Red Ginseng Manufacturing Process.

Steamed ginseng water (SGW) is a by-product of the repeated thermal processing of red ginseng, which is characterized by a high bioactive content, better skin care activity, and a large output. However, its value has been ignored, resulting in environmental pollution and resource waste. In this study, UHPLC-Q-Exactive-MS/MS liquid chromatography-mass spectrometry and multivariate statistical analysis were conducted to characterize the compositional features of the repeated thermal-treated SGW. The antioxidant activity (DPPH, ABTS, FRAP, and OH) and chemical composition (total sugars, total saponins, and reducing and non-reducing sugars) were comprehensively evaluated based on the entropy weighting method. Four comparison groups (groups 1 and 3, groups 1 and 5, groups 1 and 7, and groups 1 and 9) were screened for 37 important common difference markers using OPLS-DA analysis. The entropy weight method was used to analyze the weights of the indicators; the seventh SGW sample was reported to have a significant weight. The results of this study suggest that heat treatment time and frequency can be an important indicator value for the quality control of SGW cycling operations, which have great potential in antioxidant products.

Optimizing Cellulase-Limosilactobacillus fermentum ZC529 Synergy Fermentation for Preserving Macadamia integrifolia Pericarp's Potential Use as Antioxidants.

Macadamia integrifolia pericarps (MIP) are byproducts of nut production which are rich in natural antioxidant compounds, making them an excellent source for extracting bioactive compounds. However, the antioxidant compounds in MIP are easily oxidized under natural storage conditions, resulting in significant biomass loss and resource wastage. To preserve the potential of MIP to be used as an antioxidant product, we employed cellulase and Limosilactobacillus fermentum ZC529 (L.f ZC529) fermentation and utilized response surface methodology to optimize the fermentation parameters for mitigating the antioxidant loss. Total antioxidant capacity (T-AOC) was used as the response variable. The fermented MIP water extract (FMIPE) was obtained via ultrasound-assisted extraction, and its biological activity was evaluated to optimize the best fermentation conditions. Results indicated that a cellulase dosage of 0.9%, an L.f ZC529 inoculation size of 4 mL/100 g, and a fermentation time of 7 days were the optimal conditions for MIP fermentation. Compared to spontaneous fermentation, these optimal conditions significantly increased the total phenolic and total flavonoid contents (p < 0.05). T-AOC was 160.72% increased by this optimal fermentation (p < 0.05). Additionally, supplementation with varying concentrations of FMIPE (6.25%, 12.5%, and 25%) increased the T-AOC, SOD activity, and GSH content, and reduced MDA levels of the oxidative-stressed Drosophila melanogaster (p < 0.05). Moreover, 12.5% and 25% of FMIPE treatments elevated CAT activity in the Drosophila melanogaster (p < 0.05). The effects of FMIPE on GSH and MDA in Drosophila melanogaster were equivalent to the 0.5% vitamin C (Vc) treatment. In summary, synergistic fermentation using cellulase and L.f ZC529 effectively preserves the antioxidant activity of the MIP, offering a simple, eco-friendly method to promote the utilization of MIP resources.

RSM-based optimization of microwave- and ultrasound-assisted green extraction of iron-chelating and antioxidant natural products from Azadirachta indica leaves

Azadirachta indica is an abundantly available plant and known for its medicinal properties. Some studies showed its iron chelating activity (ICA) with possible implications for iron overload disorders. The present study aimed to discover efficient and green methods for obtaining ICA-rich extract from A. indica leaves. Microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) methods were optimized using response surface methodology (RSM). Four-factor Box-Behnken designs were used (with 29 runs) with five response factors for each technique. Aqueous choline chloride-glycerol (CCG) DES was employed as an extractant. ICA, total phenolic content (TPC), total flavonoid content (TFC), radical scavenging activity (RSA), and ferric-reducing antioxidant power (FRAP) were the responses. The optimal conditions discovered for MAE were 30 mL/g solvent-to-solid ratio (SSR), 38 % DES concentration, 330 W power and 15 s time with predicted ICA, TPC, TFC, FRAP, and RSA as 127.64 mg EDTAE/g d.w., 23.55 mg GAE/g d.w., 19.94 RE/g d.w., 26.77 mg AAE/g d.w. and 5.37 mg AAE/g d.w., respectively. For UAE, the optimal parameters were 30 mL/g SSR, 39 % DES concentration, 54.8 ͦ C temperature and 17.48 min time with predicted ICA, TPC, TFC, FRAP, and RSA as 127.80 mg EDTAE/g d.w., 18.58 mg GAE/g d.w., 23.36 RE/g d.w., 23.33 mg AAE/g d.w., and 5.79 mg AAE/g d.w., respectively. The models were efficient and supported by statistical and validation studies. MAE, however, used far less time than UAE. The outcomes of the study have important implications for iron overload syndrome and oxidative stress. The developed methods can, thus, be proposed as strong candidates for industrial applications obtaining bioactive compounds from abundantly available leaves of A. indica.

Cross-talk between antioxidant production and secondary metabolite biosynthesis under combined effects of ozone stress and nitrogen amendments: A case study of lemongrass

The present experiment was done to study the interactive effects of soil nitrogen (N) amendments and elevated ozone (O3) (N–O3) on a medicinal plant, lemongrass [Cymbopogon flexuosus (Steud.) (Wats.)]. The experiment used two doses of inorganic soil nitrogen (N1, recommended and N2, 1.5-times recommended dose) in open-top chambers under ambient and elevated (ambient + 15 ppb and ambient + 30 ppb) O3 conditions. To analyze various characteristics, samples were collected at 45 and 90 days after transplantation (DAT). Additionally, at 110 days after transplantation (DAT), the metabolite contents of the leaves and essential oils were analyzed. The present study aims to investigate the mechanistic approach involving the crosstalk between antioxidant production and secondary metabolite biosynthesis in lemongrass upon N–O3 interactions. The present experiment showed that N amendments can be an efficient measure to manage O3 injury in plants, along with ensuring a balance between primary and secondary metabolic pathways, thus sustaining the plant defense and production of bioactive compounds, simultaneously. Under N–O3, not only the Halliwell asada pathway was stimulated resulting in the increased activities and concentrations of antioxidant pools; the shikimate, phenylpropanoid and mevalonic acid pathways were also invigorated, producing more number and contents of secondary metabolites (SMs), compared with plants that were not treated with N doses. This study suggests that soil nitrogen amendments will improve the therapeutic qualities of lemongrass, along with the strengthening of its antioxidant machinery, upon exposure to O3 stress.

Melatonin differentially refines the metabolome to improve seed formation during grain developmental stages and enhances yield in two contrasting rice cultivars, grown in arsenic-contaminated soil

The manuscript revealed the ameliorative effects of exogenous melatonin in two distinct reproductive stages, i.e., developing grains (20 days after pollination) and matured grains (40 days after pollination) in two contrasting indica rice genotypes, viz., Khitish (arsenic-susceptible) and Muktashri (arsenic-tolerant), irrigated with arsenic-contaminated water throughout their life-cycle. Melatonin administration improved yield-related parameters like rachis length, primary and secondary branch length, number of grains per panicle, number of filled and empty grains per panicle, grain length and breadth and 1000-grain per weight. Expression of GW2, which negatively regulates grain development, was suppressed, along with concomitant induction of positive regulators like GIF1, DEP1 and SPL14 in both Khitish and Muktashri. Melatonin lowered arsenic bioaccumulation in grains and tissue biomass, more effectively in Khitish. Unregulated production of reactive oxygen species, leading to cellular necrosis caused by arsenic, was reversed in presence of melatonin. Endogenous melatonin level was stimulated due to up-regulation of the key biosynthetic genes, SNAT and ASMT. Melatonin enhanced the production of diverse antioxidants like anthocyanins, flavonoids, total phenolics and ascorbic acid and also heightened the production of thiol-metabolites (cysteine, reduced glutathione, non-protein thiols and phytochelatin), ensuring effective chelation and arsenic detoxification. Altogether, our observation, supported by principal component analysis, proved that melatonin re-programs the antioxidative metabolome to enhance plant resilience against arsenic stress to mitigate oxidative damages and reduce arsenic translocation from the soil to tissue biomass and edible grains.

Antioxidant and antimicrobial activity of extracts from selected Mediterranean agro-food by-products, their mutual interaction and interaction with phenolic compounds

The by-products of Mediterranean agriculture that remain after the production of fruit wines, juices and extracts represent a large source of raw materials rich in phenolic compounds. As a contribution to the current state of knowledge, this study investigated the biological activity and phenolic composition of extracts obtained from blackberry, chokeberry and juniper by-products, as well as the interactions of the extracts in mixtures. The total phenolic content of the samples ranged from 44.42 to 250.28 mg gallic acid equivalents (GAE)/g dry extract, with the extracts from blackberry leaves and juniper needles being the highest. The highest concentration of phenolics detected by high performance liquid chromatography (HPLC) was also found in blackberry leaves (41.30 mg/g dry extract), with rutin dominating. The antioxidant activity of the samples, as measured by ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ranged from 3.4 to 26.8 mM Trolox equivalents (TE), 15.8–58.4 mM TE and 80.1%–91.8%, respectively. Among the extract mixtures, the highest synergistic interaction was observed between blackberry leaves and juniper by-products extracts at 1:2 and 2:1 ratios. The antimicrobial activity of the extracts was tested against Gram-positive and Gram-negative foodborne pathogens and spoilage bacteria, with the lowest minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values against Staphylococcus aureus, Listeria innocua, Bacillus cereus, Campylobacter jejuni, Pseudomonas spp. and Shewanella spp. On the other hand, the antimicrobial activity of blackberry leaf extract in combination with selected phenolic compounds (vanillic acid, catechin, rutin and apigenin) showed no synergy against the tested microorganisms. Overall, the results suggest that the tested by-products extracts could be utilized for the production of natural antioxidants and antimicrobials for further use in the food industry.

Persistent organic pollutants disrupt the oxidant/antioxidant balance of INS-1E pancreatic β-cells causing their physiological dysfunctions

BackgroundPersistent organic pollutants (POPs) have emerged as potent diabetogenic agents, but their mechanisms of action remain poorly identified. ObjectivesIn this study, we aim to determine the mechanisms regulating the damaging effects of POPs in pancreatic β-cells, which have a central role in the development of diabetes. MethodsWe treated INS-1E pancreatic β-cells with PCB-153, p,p’-DDE, PCB-126, or TCDD at doses ranging from 1 × 10-15to 5 × 10-6M. We measured insulin content and secretion, cell viability and assessed the mRNA expression of the xenobiotic nuclear receptors Nr1i2 and Nr1i3, and the aryl hydrocarbon receptor (Ahr). In addition, we evaluated the antioxidant defense and production of reactive oxygen species (ROS). Finally, we studied the ability of the antioxidant N-acetyl-L-cysteine (NAC) to counteract the effects of POPs in INS-1E cells. ResultsWhen exposed to environmental POP levels, INS-1E cells had impaired production and secretion of insulin. These defects were observed for all tested POPs and were paralleled by reduced Ins1 and Ins2 mRNA expression. While POP treatment for 3 days did not affect INS-1E cell viability, longer treatment progressively killed the cells. Furthermore, we found that the xenobiotic detoxification machinery is poorly expressed in the INS-1E cells, as characterized by the absence of Nr1i2 and Nr1i3 and their respective downstream targets Cyp3a1/Cyp3a2 and Cyp2b1/Cyp2b3, and the weak functionality of the Ahr/Cyp1a1 signaling. Interestingly, POPs dysregulated key antioxidant enzymes such as glutathione peroxidases, peroxiredoxins, thioredoxins, and catalases. In parallel, the production of intracellular ROS, including superoxide anion (O2•−) and hydrogen peroxide (H2O2), was increased by POP exposure. Improving the oxidant scavenging capacity of INS-1E cells by NAC treatment restored the production and secretion of insulin. ConclusionBy promoting oxidative stress and impairing the ability of INS-1E cells to produce and secrete insulin, this study reveals how POPs can mechanistically act as diabetogenic agents, and provides new scientific evidence supporting the concept that POPs are fueling the diabetes epidemics.