Search Results (66)

Flavonoids serve as crucial plant antioxidants in drought tolerance, yet their antioxidant regulatory mechanisms within mycorrhizal plants remain unclear. In this study, using a two-factor design, trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings in the four-to-five-leaf stage were either inoculated with Funneliformis mosseae or not, and subjected to well-watered (70–75% of field maximum water-holding capacity) or drought stress (50–55% field maximum water-holding capacity) conditions for 10 weeks. Plant growth performance, photosynthetic physiology, leaf flavonoid content and their antioxidant capacity, reactive oxygen species levels, and activities and gene expression of key flavonoid biosynthesis enzymes were analyzed. Although drought stress significantly reduced root colonization and soil hyphal length, inoculation with F. mosseae consistently enhanced the biomass of leaves, stems, and roots, as well as root surface area and diameter, irrespective of soil moisture. Despite drought suppressing photosynthesis in mycorrhizal plants, F. mosseae substantially improved photosynthetic capacity (measured via gas exchange) and optimized photochemical efficiency (assessed by chlorophyll fluorescence) while reducing non-photochemical quenching (heat dissipation). Inoculation with F. mosseae elevated the total flavonoid content in leaves by 46.67% (well-watered) and 14.04% (drought), accompanied by significantly enhanced activities of key synthases such as phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), 4-coumarate:coA ligase (4CL), and cinnamate 4-hydroxylase (C4H), with increases ranging from 16.90 to 117.42% under drought. Quantitative real-time PCR revealed that both mycorrhization and drought upregulated the expression of PtPAL1, PtCHI, and Pt4CL genes, with soil moisture critically modulating mycorrhizal regulatory effects. In vitro assays showed that flavonoid extracts scavenged radicals at rates of 30.07–41.60% in hydroxyl radical (•OH), 71.89–78.06% in superoxide radical anion (O₂^•−), and 49.97–74.75% in 2,2-diphenyl-1-picrylhydrazyl (DPPH). Mycorrhizal symbiosis enhanced the antioxidant capacity of flavonoids, resulting in higher scavenging rates of •OH (19.07%), O₂^•− (5.00%), and DPPH (31.81%) under drought. Inoculated plants displayed reduced hydrogen peroxide (19.77%), O₂^•− (23.90%), and malondialdehyde (17.36%) levels. This study concludes that mycorrhizae promote the level of total flavonoids in trifoliate orange by accelerating the flavonoid biosynthesis pathway, hence reducing oxidative damage under drought. Full article

This study employs a plasma-coupled calcium peroxide (CaO₂) system to degrade tetracycline (TC) and remove phosphorus from emergency wastewater in a chemical industry park. The plasma/CaO₂ system achieves optimal performance when the CaO₂ dosage reaches 0.13 g/L. Higher degradation efficiencies of TC were observed at increased discharge voltages, frequencies, and under weakly acidic and weakly alkaline conditions. Variations in discharge voltage and frequency have no significant impact on the phosphorus removal efficiency, but weakly alkaline conditions favor phosphorus removal. The reactive species (·OH, ¹O₂, O₂·⁻) within the plasma/CaO₂ system were identified, and their roles were elucidated using radical scavengers. Subsequently, the degradation process was characterized by measuring changes in total organic carbon (TOC), chemical oxygen demand (COD), and ammonia nitrogen during the reaction, along with three-dimensional fluorescence analysis and ultraviolet-visible spectroscopy (UV-Vis). Eight intermediate products were identified through LC-MS, and two degradation pathways were clarified based on density functional theory. The toxicity analysis of the intermediate products demonstrated that the plasma/CaO₂ system is an efficient, feasible, and environmentally friendly method for the synchronous removal of organic pollutants and phosphorus from emergency wastewater in a chemical industry park. Full article

Black spot is a major postharvest disease of cherry tomatoes, caused by Alternaria alternata. This causes economic losses and storage challenges, so researchers are exploring alternative methods. The biological control of fruits and vegetables using antagonistic bacteria and yeasts is currently a research hotspot. Initially, the biological control impact of Bacillus velezensis T3 on cherry tomato black spot was investigated. Disease defense, scavenging reactive oxygen species, and antioxidant-related enzymes were determined during different storage periods. The relative gene expressions of these enzymes were also confirmed using RT-qPCR. The results showed that B. velezensis T3 reduced the incidence of black spot disease in cherry tomatoes. The growth of A. alternata was suppressed by B. velezensis T3 cell-free filtrate both in vitro and in vivo. In addition, B. velezensis T3 induced the activities of disease resistance-related enzymes such as polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), β-1,3-glucanase (GLU), and chitinase (CHI), and the activities of the ROS-related enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), and reduced the rate of O₂⁻ production and H₂O₂, and MDA content of cherry tomatoes. This approach offers a promising alternative for extending shelf life, though further studies are needed to fully characterize its effects on fruit quality. Full article

The study aimed to characterize the antioxidant properties of isolated lactic acid bacteria (LAB) and assess their impacts on fermentation quality and antioxidant status in alfalfa silage. Two LAB strains of Lactiplantibacillus plantarum XY15 and Lactiplantibacillus plantarum XY20 and a reference strain of Pediococcus acidilactici J17 were subjected to antioxidant property evaluation. This was followed by inoculation into alfalfa silage. The DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl (OH) radical scavenging activities and the glutathione peroxidase (GSH-Px) activity of the cell-free supernatants of L. plantarum YX15 and L. plantarum YX20 were significantly (p < 0.05) higher than those of P. acidilactici J17. In all three strains, the superoxide dismutase (SOD) activity was higher in the cell-free supernatants than in the intracellular lysates. Among all three strains, P. acidilactici J17 showed the highest total antioxidant capacity (T-AOC) in the cell-free supernatant. Inoculating L. plantarum YX20 and P. acidilactici J17 increased lactic acid (LA) concentration and LAB counts, decreased dry matter (DM) loss, ammonia-N concentration, and pH, compared with control (CON) and L. plantarum XY15 inoculated alfalfa silages. After 1 d of ensiling, alfalfa silage inoculated with L. plantarum XY20 exhibited higher SOD activity than other silages. Inoculating L. plantarum XY20 and P. acidilactici J17 increased the DPPH free radical scavenging rates in alfalfa silage, compared with CON and L. plantarum XY15 inoculated 90 d-silages. Both L. plantarum YX15 and L. plantarum YX20 demonstrated a dual function of enhancing the lactic fermentation and improving the antioxidant status in alfalfa silage. Full article

The destructive bacterial wilt disease caused by Ralstonia solanacearum leads to substantial losses in pepper production worldwide. Plant-derived pesticides exhibit advantages of high efficiency and broad spectrum when compared to traditional chemical pesticides. Artemisia annua and ‘Tai Jiao’ No. 1 were used as the experimental materials, and treated with 0.75 g·mL⁻¹, 1.5 g·mL⁻¹, and 3 g·mL⁻¹ of A. annua extract and inoculated with R. solanacearum at a concentration of OD600 = 0.1 for 14 days. The inhibitory activity of A. annua extracts against R. solanacearum, as well as the disease index, defense enzyme activities, and defense-related substances contents of pepper seedlings were determined. The results showed that the Minimum Inhibitory Concentration (MIC) of the A. annua extract was 3 g·mL⁻¹. As the concentration of A. annua extract increased, the extent of R. solanacearum cell crumpling intensified, accompanied by a gradual decline in its biofilm-forming ability. On the 14th day after treatment, the disease severity index and incidence rate were significantly reduced when the A. annua extract was applied at concentrations of 0.75 g·mL⁻¹ and 3 g·mL⁻¹. At both the 7th and 14th days after treatment, the application of A. annua extract at concentrations of 0.75 g·mL⁻¹ and 3 g·mL⁻¹ led to enhanced activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in peppers at different stages. Simultaneously, it reduced the levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), effectively scavenging reactive oxygen species and alleviating cellular lipid peroxidation. Furthermore, the extract increased the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL), as well as elevated the contents of soluble protein, flavonoids, and total phenols, ultimately enhancing the disease resistance of peppers. Considering the development costs, the application of A. annua extract at a concentration of 0.75 g·mL⁻¹ demonstrates great potential for green control measures against bacterial wilt in peppers. Full article

The incorporation of biopolymers and natural colorants in smart packaging has garnered significant attention in the food packaging industry. This study investigates the design and characterization of novel fibrous films incorporating betalain extract (BE) from Stenocereus thurberi in poly (lactic acid) (PLA). An electrospinning technique was developed with varying PLA concentrations (2%–12% w/v) and BE concentrations (8%–12% w/v) to create a colorimetric freshness indicator. BE was characterized by quantifying its phytochemical content and assessing its antioxidant capacity. Morphological and structural analyses included scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), polydispersity index (PI), mechanical properties, and functional characteristics such as ammonia sensitivity and total antioxidant activity. The results indicated that the incorporation of BE significantly influenced the average diameter of the nanofibers, ranging from 313 ± 74 nm to 657 ± 99 nm. SEM micrographs showed that PLA12-BE12 films exhibited smooth surfaces without bead formation. The FTIR analysis confirmed effective BE incorporation, revealing intermolecular interactions between the betalain molecules and the PLA matrix, which contributed to enhanced structural and functional stability. The mechanical properties analysis revealed that moderate BE additions (8%–10% w/v) enhanced the Young’s modulus and tensile strength, while higher BE concentrations (12% w/v) disrupted the polymer network, reducing these properties. Additionally, the strain at break decreased significantly with BE incorporation, reflecting limited molecular chain mobility. Increasing BE concentration notably improved antioxidant activity, with the BE concentration of 12% (w/v), the ABTS•+, DPPH•, and FRAP radical scavenging activities at the highest values of 84.28 ± 1.59%, 29.95 ± 0.34%, and 710.57 ± 28.90 µM ET/g, respectively. Ammonia sensitivity tests demonstrated a significant halochromic transition from reddish-pink to yellow, indicating high sensitivity to low ammonia concentrations. The possible mechanism is alkaline pH induces aldimine bond hydrolysis and generates betalamic acid (yellow) and cyclo-DOPA-5-O-ß-glucoside (colorless) The fibrous films also exhibited reversible color changes and maintained good color stability over 30 days, emphasizing their potential for use in smart packaging applications for real-time freshness monitoring and food quality assessment. Full article

Abiotic stress not only elevates the synthesis of secondary metabolites in plant sprouts but also boosts their antioxidant capacity. In this study, the mechanisms of flavonoid biosynthesis and antioxidant systems in buckwheat sprouts exposed to ultraviolet-B (UV-B) radiation were investigated. The findings revealed that UV-B treatment significantly increased flavonoid content in buckwheat sprouts, with 3-day-old sprouts exhibiting a flavonoid content 1.73 times greater than that of the control treatment. UV-B radiation significantly increased the activities of key enzymes involved in flavonoid biosynthesis (phenylalanine ammonia-lyase, 4-coumarate-CoA ligase, cinnamate 4-hydroxylase, and chalcone synthase) and the relative expression levels of the corresponding genes. Although UV-B radiation caused damage to the cell membranes of buckwheat sprouts, promoting increases in hydrogen peroxide and malondialdehyde content and inhibiting the growth of sprouts, importantly, UV-B radiation also significantly increased the activities of catalase, peroxidase, and superoxide dismutase as well as the relative expression levels of the corresponding genes, thus enhancing the antioxidant system of buckwheat sprouts. This enhancement was corroborated by a notable increase in ABTS, DPPH, and FRAP radical scavenging activities in 3-day-old sprouts subjected to UV-B radiation. Additionally, UV-B radiation significantly increased chlorophyll a and chlorophyll b contents in sprouts. These results suggest that UV-B radiation is advantageous for cultivating buckwheat sprouts with increased flavonoid content and enhanced antioxidant capacity. Full article

Dry tea residue is a byproduct generated during the production, processing, and storage of tea leaves. The active ingredients and microbial composition of dried tea residue vary depending on different tea processing techniques. This study investigated the effects of six processed dry tea residues—green tea (G), black tea (B), raw Pu’er tea (Z), white tea (W), and ripe Pu’er tea (D)—at two addition ratios (5% and 10%) on the nutritional composition, fermentation quality, in vitro fermentation, and bacterial community of sweet sorghum (Sorghum bicolor) in the ensiling process. Compared to the control group (CK), the addition of tea residue significantly increased the crude protein (CP) content in silage by 17.9% to 180% (p < 0.05), and the content increased with increasing ratios of tea residue. The G10 treatment resulted in the highest CP content, reaching 16.4%. Including tea residue also influenced the ratio of ammonia nitrogen (NH₃-N) to non-protein nitrogen (NPN). Furthermore, the G and Z treatments at both addition levels increased the total phenolic content, DPPH free-radical scavenging activity, and total antioxidant capacity of the sweet sorghum silage. Except for the Z5 and W10 treatments, the addition of tea residue did not significantly affect in vitro dry matter digestibility. Overall, this study showed that incorporating tea residue could enhance the nutritional quality and antioxidant capacity of sweet sorghum silage, and the G5 treatment performed the best. The research results suggested that dried tea residues have potential as silage additives. Full article

Macrophomina phaseolina is a vital seed and soil-borne phytopathogen responsible for substantial crop yield losses. Although various methods exist for managing soil-borne pathogens, such as agronomic practices, chemical treatments, and varietal tolerance, biological control utilizing plant growth-promoting rhizobacteria (PGPR) or their secondary metabolites presents promising avenues. In this study, a screening of 150 isolates from the rhizosphere of Vigna radiata L. was conducted to identify strains capable of promoting host growth and controlling charcoal rot disease. Among the tested isolates, only 15 strains demonstrated the ability to produce plant growth-related metabolites, including indole acetic acid, hydrogen cyanide, ammonia, and lytic enzymes, and solubilize inorganic phosphate. Subsequently, these potent strains were evaluated for their antifungal activity against Macrophomina phaseolina in vitro. Three strains, namely MRP-7 (58% growth inhibition), MRP-12 (55% growth inhibition), and MRP-8 (44% growth inhibition), exhibited the highest percent growth inhibition (PGI.). Furthermore, a pot experiment demonstrated that the selected strains acted as effective growth promoters and ROS (reactive oxygen species) scavengers, and served as potential biocontrol agents, significantly reducing the incidence of charcoal rot disease and improving various agronomic attributes of the host plant. These findings highlight the potential of these strains to be utilized as biofertilizers and biocontrol agents for sustainable agricultural practices. Full article

Ammonia synthesis is one of the most important chemical reactions. Due to thermodynamic restrictions and the reaction requirements of the current commercial iron catalysts, it is also one of the worst reactions for carbon dioxide emissions and energy usage. Ruthenium-based catalysts can substantially improve the environmental impact as they operate at lower pressures and temperatures. In this work, we provide a screening of more than 40 metals as possible promoter options based on a Ru/Pr₂O₃ catalyst. Cesium was the best alkali promoter and was held constant for the series of double-promoted catalysts. Ten formulations outperformed the Ru-Cs/PrO_x benchmark, with barium being the best second promoter studied and the most cost-effective option. Designs of experiments were utilized to optimize both the pretreatment conditions and the promoter weight loadings of the doubly promoted catalyst. As a result, optimization led to a more than five-fold increase in activity compared to the unpromoted catalyst, therefore creating the possibility for low-ruthenium ammonia synthesis catalysts to be used at scale. Further, we have explored the roles of promoters using kinetic analysis, X-ray Photoelectron Spectroscopy (XPS), and in situ infrared spectroscopy. Here, we have shown that the role of barium is to act as a hydrogen scavenger and donor, which may permit new active sites for the catalyst, and have demonstrated that the associative reaction mechanism is likely used for the unpromoted Ru/PrO_x catalyst with hydrogenation of the triple bond of the dinitrogen occurring before any dinitrogen bond breakage. Full article

This study showed the eliciting effect of aqueous extracts from Ascophyllum nodosum on the development of Eruca sativa microgreens in a quartz-based substrate. There is no information in the literature on the impact of its use on the quality, bioactive compound content, and nutritional value of arugula microgreens. Assays that have been made include the following: total phenolic content (TPC), total flavonoid content (TFV), enzymes such as phenylalanine ammonia (PAL) and polyphenol oxidase (PPO), and enzymes involved in the scavenging of reactive oxygen species such as catalase (CAT) and superoxide dismutase (SOD). The antioxidant activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) was also evaluated. The total phenolic content of arugula microgreens increased significantly after an application of aqueous extracts of A. nodosum to the substrate. The greatest increase in flavonoid content (89%) and antioxidant activity against DPPH (82%) was observed at a concentration of 2.5%. The highest increase in activity of CAT (68.2%), SOD (25%), PAL (13-fold), and PPO (84.2%) was observed with the application of 5% extract. In conclusion, the use of Ascophyllum nodosum algae affects TPC and TFV, antioxidant activity, PAL, PPO, SOD, and CAT in the microgreens studied. By prioritising organic and environmentally friendly extracts, growers can contribute to a more sustainable and healthier food system, especially in the case of the production of Eruca sativa microgreens. Full article

Grapes are susceptible to mold and decay during postharvest storage, and developing new technologies to extend their storage period has important application value. Photodynamic technology (PDT) in concurrence with carbon dots (CDs) proposes an innovative and eco-friendly preservation strategy. We examined the effects of carbon dots combined with photodynamic treatment on postharvest senescence and antioxidant system of table grape. The compounding of photodynamic technology with a 0.06 g L⁻¹ CDs solution could possibly extend the postharvest storage period of grape berries. Through this strategy, we achieved a decreased rate of fruit rotting and weight loss alongside the delayed deterioration of fruit firmness, soluble solids, and titratable acid. As paired with photodynamic technology, CDs considerably decreased the postharvest storage loss of phenols, flavonoids, and reducing sugars as compared to the control group. Concurrently, it remarkably postponed the build-up of hydrogen peroxide (H₂O₂), superoxide anion (O₂^∙−), and malondialdehyde (MDA); elevated the levels of reduced ascorbic acid (AsA) and reduced glutathione (GSH); lowered the levels of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG); raised the ratios of AsA/DHA and GSSH/GSSG; encouraged the activities of superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL); and inhibited the activities of polyphenol oxidase (PPO) and lipoxygenase (LOX). Furthermore, it enhanced the iron reduction antioxidant capacity (FRAP) and DPPH radical scavenging capacity of grape berries. CDs combined with photodynamic treatment could efficiently lessen postharvest senescence and decay of grape berry while extending the storage time. Full article

Waterlogging stress causes substantial destruction to plant growth and production under climatic fluctuations globally. Plants hormones have been widely explored in numerous crops, displaying an imperative role in crop defense and growth mechanism. However, there is a paucity of research on the subject of plant hormones regulating waterlogging stress responses in wheat crop. In this study, we clarified the role of 6-BA in waterlogging stress through inducing phenylpropanoid biosynthesis in wheat. The application of 6-BA (6-benzyladenine) enhanced the growth and development of wheat plants under waterlogging stress, which was accompanied by reduced electrolyte leakage, high chlorophyll, and soluble sugar content. ROS scavenging was also enhanced by 6-BA, resulting in reduced MDA and H₂O₂ accumulation and amplified antioxidant enzyme activities. Additionally, under the effect of 6-BA, the acceleration of lignin content and accumulation in the cell walls of wheat tissues, along with the activation of PAL (phenylalanine ammonia lyase), TAL (tyrosine ammonia lyase), and 4CL (4-hydroxycinnamate CoA ligase) activities and the increase in the level of transcription of the TaPAL and Ta4CL genes, were observed under waterlogging stress. Also, 6-BA improved the root growth system under waterlogging stress conditions. Further qPCR analysis revealed increased auxin signaling (TaPR1) in 6-BA-treated plants under waterlogging stress that was consistent with the induction of endogenous IAA hormone content under waterlogging stress conditions. Here, 6-BA also reduced yield loss, as compared to control plants. Thus, the obtained data suggested that, under the application of 6-BA, phenylpropanoid metabolism (i.e., lignin) was stimulated, playing a significant role in reducing the negative effects of waterlogging stress on yield, as evinced by the improved plant growth parameters. Full article

Mild heat (MH) treatment and ascorbic acid (AsA) addition can improve the quality of fresh-cut produce when used individually; however, their combined effect remains unclear. Herein, fresh-cut carrots were used as models to explore the effects of MH (50 °C)–AsA (0.5%) on quality properties including reactive oxygen species (ROS) metabolism, antioxidants, lignin metabolism, naturally present microbes, and inoculated pathogens (Escherichia coli O157: H7 and Salmonella Typhimurium) during storage (0–5 d, 4 °C). The results indicate that the antioxidant properties in the MH–AsA group were consistent with those of single treatments, resulting in a consistent ROS-scavenging effect. From day 3–5, lignin synthesis was significantly inhibited by MH–AsA as compared with single treatments, probably because the two enzymes (phenylalanine ammonia-lyase and peroxidase) responsible for lignin synthesis exhibited lower expressions. Microbial analysis revealed that MH–AsA treatment led to the lowest counts of both pathogens and aerobic mesophilic bacteria at 0–5 d. Conversely, the inhibitory effect of MH–AsA treatment on mold and yeast was consistent with the single treatments. These results suggest that MH–AsA is a low-cost and safe approach to improve the physiological characteristics of fresh-cut produce while reducing microbial risk. Full article

Helicobacter pylori has been implicated in various gastrointestinal disorders, including functional dyspepsia. This study aimed to compare the anti-H. pylori activity and gastroprotective effects of three typical herbal formulas used for gastrointestinal disorders in Korea: Shihosogan-tang (ST), Yijung-tang (YT), and Pyeongwi-san (PS). Firstly, we assessed the total phenolic and flavonoid contents, as well as the antioxidative capacity. Additionally, we evaluated the antibacterial effect on H. pylori using an ammonia assay, minimum inhibitory concentration (MIC) test, and the disk agar diffusion method. Furthermore, we examined alterations in the gene expression of tight junction proteins, pro-inflammatory cytokines, and cellular vacuolation using an AGS cell model infected with H. pylori. While ST exhibited a higher total phenolic content, superior free radical scavenging, and inhibition of H. pylori compared to YT and PS, YT more evidently inhibited gastric cellular morphological changes such as vacuolation. All formulations significantly ameliorated changes in inflammatory and gastric inflammation-related genes and cellular morphological alterations induced by H. pylori infection. Overall, the present in vitro study suggests that all three herbal formulas possess potential for ameliorating gastrointestinal disorders, with ST relatively excelling in inhibiting H. pylori infection and inflammation, while YT potentially shows greater efficacy in directly protecting the gastric mucosa. Full article