Hydroxyl Radical Scavenging Ability Research Articles

Targeted Screening of Lactiplantibacillus plantarum Strains Isolated from Tomatoes and Its Application in Tomato Fermented Juice

This study explores the functional attributes of Lactiplantibacillus plantarum (L. plantarum) strains isolated from fermented tomato juice, focusing on their physiological, biochemical, and probiotic characteristics. The identified 66 gram-positive strains included 36 L. plantarum ones, which exhibited robust growth in acidic environments (pH 2.0–5.0) and utilization of various carbohydrates. Notably, seven strains outperformed a commercial strain in extreme acidic conditions. Antioxidant activity varied, with strain A24 showing the highest hydroxyl radical scavenging ability, while strains with high surface hydrophobicity had lower DPPH scavenging activity, indicating no direct correlation between these properties. Strains also showed strain-specific differences in carbohydrate utilization and antibiotic resistance, with some resistant to gentamicin and ciprofloxacin. Survival rates under simulated gastrointestinal conditions were strain-specific, with some strains demonstrating high survival rates, indicating their potential as probiotics. Furthermore, 13 strains used as fermentation starters in tomato juice significantly enhanced antioxidant activity and reduced pH and total soluble solids, indicating efficient sugar utilization and lactic acid production. These findings suggest that L. plantarum strains are well-suited for functional food fermentation and probiotic applications, with strain-specific traits offering versatility for use in acidic food products and probiotic formulations.

Characterization of Exopolysaccharides from Lactiplantibacillus plantarum PC715 and Their Antibiofilm Activity Against Hafnia alvei

Exopolysaccharides (EPSs) secreted by lactic acid bacteria have the potential to enhance human health by showing various biological functions. This study investigated the biological role and antibiofilm properties of EPS715, a new neutral EPS produced by pickled vegetables originating from Lactobacillus plantarum PC715. The results indicate that EPS715 is primarily composed of rhamnose, glucose, and mannose. Its molecular weight (Mw) is 47.87 kDa, containing an α-glucoside linkage and an α-pyranose ring. It showed an amorphous morphology without a triple helix structure. Furthermore, EPS715 showed improved antioxidant activity. Specifically, its scavenging capacity of ABTS+ radicals, DPPH radicals, and the hydroxyl (·OH) reduction capacity at 5 mg/mL was 98.64 ± 2.70%, 97.37 ± 0.79%, and 1.64 ± 0.05%, respectively. Its maximal scavenging capacity was >40%, and the hydroxyl (·OH) radical scavenging ability was dose-dependent. Moreover, the biofilm of various pathogens including S. aureus, B. cereus, S. saprophyticus, Acinetobacter spp., and H. alvei was substantially dispersed and affected by EPS715, with a maximum inhibition rate of 78.17% for H. alvei. The possible mechanism by which EPS715 shows antibiofilm properties against the H. alvei may be attributed to its effects on the auto-aggregation, hydrophilic characteristics, and motility of Hafnia spp. Thus, EPS715 has significant antioxidant and antibiofilm characteristics that may hold substantial potential for applications in food and medicinal products.

Extraction, Characterization, and Antioxidant Activity of Eucommia ulmoides Polysaccharides.

Herein, the ultrasound-assisted extraction conditions affecting the yield of EUPS (Eucommia ulmoides polysaccharide) were analyzed using a Box-Behnken response surface design. The alleviation effect of EUPS on diquat-induced oxidative stress in mice was also studied. A maximum EUPS yield of 2.60% was obtained under the following optimized conditions: an extraction temperature of 63 °C, extraction time of 1 h, and ratio of liquid to raw materials of 22:1. EUPS exhibited strong 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging ability (87.05%), 2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical-scavenging ability (101.17%), and hydroxyl radical-scavenging ability (62.92%). The administration of EUPS increased the activities of superoxide dismutase, catalase, and glutathione peroxidase and decreased malondialdehyde levels in the livers of mice exposed to diquat. EUPS may inhibit the downregulation of NAD(P)H:quinoneoxidoreductase 1 and heme oxygenase 1 mRNA expression in the livers of diquat-administered mice through the Nrf2-Keap1 signaling pathway. Moreover, the abundance of Firmicutes and Ligilactobacillus was enhanced, whereas that of Helicobacter decreased in the gut of the remaining groups of mice compared with that of the diquat-treated mice. Therefore, EUPS exhibited an antioxidant effect and improved oxidative stress and intestinal flora abundance in mice.

Effect of ultrasound on the characterization and peptidomics of foxtail millet bran protein hydrolysates

Protein hydrolysates have attracted much attention for their high biological activity and are a crucial product form for the utilization of foxtail millet bran by-products. In this study, changes in the structure, functionality, activity and peptide profile of foxtail millet bran protein hydrolysates (FMBPHs) at different ultrasound powers (0 – 600 W) were investigated. The results showed that ultrasound promoted the transformation of α-helix and β-sheet to random coils and β-turn, and the exposure of hydrophobic groups and sulfhydryl groups in FMBPHs. The average particle size of the samples decreased, and the absolute value of the ζ-potential increased significantly. Simultaneously, smaller porous particles and loose fragments appeared on the surface of FMBPHs when the ultrasonic power was increased to 450 W. Additionally, 450 W ultrasound treatment improved solubility, foaming properties, emulsifying properties, thermal stability of FMBPHs. The DPPH, ABTS and hydroxyl radical scavenging ability (IC50, 2.65, 1.06 and 3.02 mg/mL), Fe2+ chelating activity (IC50, 2.62 mg/mL), and reducing power of the samples were also enhanced. The peptidomics results demonstrated that ultrasonication increased the number of active peptides in the hydrolysate, and the relative abundance of 17 active peptides was obviously elevated at 450 W. Peptide map analysis showed that ultrasound-induced structural modifications affected the peptide profiles of Ubiquitin-like domain-containing protein, Cupin type-1 domain-containing protein, 40S ribosomal protein S19, and Oleosin 1, showing changes in the abundance of certain peptides, which may be related to changes in the characterization of FMBPHs.

Spatial and Temporal Distribution Characteristics and Cytotoxicity of Atmospheric PM2.5 in the Main Urban Area of Lanzhou City.

PM2.5, as one of the most harmful pollutant in the atmospheric environment and population health, has received much attention. We monitored PM2.5 levels at five sampling sites in the Lanzhou City and collected PM2.5 particles from two representative sites for cytotoxicity experiment. The cytotoxicity of PM2.5 samples on A549 cells and migration ability of the cells were respectively detected by Cell Counting kit-8 (CCK-8) assay and scratch assay. We detected the levels of cellular inflammatory factors and oxidative damage-related biochemical indexes. RT-qPCR was used to detect the mRNA levels of NF-κB and epithelial-mesenchymal transition (EMT)-related genes. We found that the Lanlian Hotel station had the highest PM2.5 annual average concentration. The annual average concentration change curve of PM2.5 showed a roughly "U"-shaped distribution during the whole sampling period. The cytotoxicity experiment showed the viability of A549 cells decreased and the scratch healing rate increased in the 200 and 400μg/mL PM2.5-treated groups. We also found 400μg/mL PM2.5 induced changes in the mRNA levels of NF-κB and EMT-related genes, the mRNA levels of IKK-α, NIK, and NF-κB in the 400μg/mL PM2.5 group were higher than those in the control group. The mRNA levels of E-cadherin decreased and α-SMA increased in the 400μg/mL PM2.5 groups, and the mRNA levels of Fibronectin increased in the 400μg/mL PM2.5 groups. Moreover, we found hydroxyl radical scavenging ability and T-AOC levels were lower, and LPO levels were higher in the 200 and 400μg/mL PM2.5 groups, and the SOD activity of cells in the 400µg/mL PM2.5 group decreased. And compared with the control group, the levels of TNF-α were higher in the 200 and 400μg/mL PM2.5 groups and the levels of IL-1 were higher in the 400μg/mL PM2.5 group. The results indicated that the cytotoxicity of atmospheric PM2.5 was related to oxidative damage, inflammatory response, NF-κB activity and EMT.

Research on Extraction Process and Physicochemical Properties of Dietary Fiber

The attention of dietary fiber has been increasing in recent years. Dietary fiber can regulate blood lipid, blood glucose and intestinal flora, prevent colon cancer and diabetes and plays an active role in promoting human health. The advantages and disadvantages of extraction methods including chemical, fermentation, enzymatic method and multi methods assisted at home and abroad were analyzed. The physicochemical properties of dietary fiber, functional properties and antioxidant capacity were summarized. The physicochemical properties of dietary fiber such as water holding, expansibility, fat and oil holding capacity, the functional properties of dietary fiber including adsorption of glucose, cholesterol, nitrite ion, sodium cholate, cation exchange, adsorption of heavy metals and antioxidant capacity such as DPPH radical and hydroxyl radical scavenging ability were studied，which provided theoretical basis for the development and application in health products and food.

Exopolysaccharides of lactic acid bacteria as protective agents against bacterial and viral plant pathogens

In this study, 25 exopolysaccharides produced by lactic acid bacteria (LAB) were screened for their effect on plant pathogens. The molecular masses of EPS were found to be 3,8-5,0 × 104 Da. The GC–MS analysis revealed that EPSs were majorly composed of glucose (85.85–97.98 %). The FT-IR spectra of EPSs were in agreement with the typical absorption peaks of polysaccharides. EPSs showed a hydroxyl radical scavenging ability. The scavenging rate of EPS ranged from 20 to 50 % at a concentration of 5.0 mg/mL. Significant growth delay of phytopathogenic bacteria was observed after 3–6 h of cultivation. Optical density values of indicator cultures growing in the medium with EPS (1 mg/mL) were lower compared to the control by 24–100 % for Pseudomonas fluorescens, 9–46 % for P. syringae, 47–79 % for Pectobacterium carotovorum, 14–90 % for Clavibacter michiganensis, 9–100 % for Xantomonas campestris, and 45–100 % for X. vesicatorium. EPS retained their inhibitory effect on the growth of X. campestris, X. vesicatorium and C. michiganensis strains after 24–48 h of cultivation, but stimulating effect on the growth of some strains also was observed. LAB EPS showed antibiofilm activity against P. carotovorum, P. syringae, and P. fluorescent, decreasing their biofilm formation by 16–50 %, 14–39 %, and 29–59 %, respectively. Also, stimulation of biofilm formation by X. campestris (by 8–29 %), X. vesicatorium (by 3–32 %) and C. michiganensis (by 31–41 %) strains was observed. EPSs showed antiviral activity against tobacco mosaic virus (TMV). At a concentration of 100 μg/mL, they decreased the infective ability of TMV by 61–92 %. This is the first study demonstrating that LAB EPS exhibited in vitro antibacterial and antibiofilm activity against phytopathogenic bacteria and anti-viral activity against TMV. Thus, LAB EPSs could have great potential for plant protection strategies.

Network Pharmacology and Molecular Docking Reveal the Antioxidant Potential of Mangiferin from Mango Peel

Background: As one of the main by-products of mango production, the mango peel is rich in multiple polyphenols, such as mangiferin. Therefore, there is an urgent need to explore the potential mechanism of mangiferin for nutrition intervention of oxidative stress-related diseases. Methods: Mangiferin was extracted and purified from the mango peel and was identified by the reverse phase high-performance liquid chromatography. The antioxidant potential of mangiferin was determined in vitro (potassium ferricyanide reducing capacity, DPPH, hydroxyl radicals scavenging ability, and superoxide anion radicals reducing capacity). In order to explore the potential mechanism for the antioxidant activity of mangiferin, a combination of network pharmacology and molecular docking approaches was performed. Results: The purity of mangiferin from the mango peel was ≥ 95.0%, and its antioxidant activity was confirmed by different in vitro assays. ALB, ESR1, CASP8, CASP3, BCL2L1, CXCL8, AKT1, CTNNB, and EGFR were identified as the potential oxidative stress-related targets of mangiferin. These results suggested that mangiferin might play a key role in the antioxidant process through multi-targets. Conclusion: Integrated with network pharmacology and molecular docking methods, this work demonstrated the potential mechanism of mangiferin for nutrition intervention of oxidative stress-related diseases.

Serum albumin-embedding copper nanoclusters inhibit Alzheimer’s β-amyloid fibrillogenesis and neuroinflammation

Increasing evidence suggests that the accumulations of reactive oxygen species (ROS), β-amyloid (Aβ), and neuroinflammation are crucial pathological hallmarks for the onset of Alzheimer’s disease (AD), yet there are few effective treatment strategies. Therefore, design of nanomaterials capable of simultaneously elimination of ROS and inhibition of Aβ aggregation and neuroinflammation is urgently needed for AD treatment. Herein, we designed human serum albumin (HSA)-embedded ultrasmall copper nanoclusters (CuNCs@HSA) via an HSA-mediated fabrication strategy. The as-prepared CuNCs@HSA exhibited outstanding multiple enzyme-like properties, including superoxide dismutase (>5000 U/mg), catalase, and glutathione peroxidase activities as well as hydroxyl radicals scavenging ability. Besides, CuNCs@HSA prominently inhibited Aβ fibrillization, and its inhibitory potency was 2.5-fold higher than native HSA. Moreover, CuNCs@HSA could significantly increase the viability of Aβ-treated cells from 60 % to over 96 % at 40 μg/mL and mitigate Aβ-induced oxidative stresses. The secretion of neuroinflammatory cytokines by lipopolysaccharide-induced BV-2 cells, including tumor necrosis factor-α and interleukin-6, was alleviated by CuNCs@HSA. In vivo studies manifested that CuNCs@HSA effectively suppressed the formation of plaques in transgenic C. elegans, reduced ROS levels, and extended C. elegans lifespan by 5 d. This work, using HSA as a template to mediate the fabrication of copper nanoclusters with robust ROS scavenging capability, exhibited promising potentials in inhibiting Aβ aggregation and neuroinflammation for AD treatment.

Target-Oriented Synthesis of Triphenylphosphine Functionalized Carbon Dots with Negative Charge for ROS Scavenging and Mitochondrial Targeting.

Triphenylphosphine functionalized carbon dots (TPP-CDs) showcase robust mitochondria targeting capacity owing to their positive electrical properties. However, TPP-CDs typically involve complicated synthesis steps and time-consuming postmodification procedures. Especially, the one-step target-oriented synthesis of TPP-CDs and the regulation of TPP linkage modes remain challenges. Herein, we propose a free-radical-initiated random copolymerization in combination with hydrothermal carbonation to regulate the TPP backbone linkage for target-oriented synthesis of triphenylphosphine copolymerization carbon dots (TPPcopoly-CDs). The linkage mechanism of random copolymerization reactions is directional, straightforward, and controllable. The TPP content and IC50 of hydroxyl radicals scavenging ability of TPPcopoly-CDs are 53 wt % and 0.52 mg/mL, respectively. TPP serves as a charge control agent to elevate the negatively charged CDs by 20 mV. TPPcopoly-CDs with negative charge can target mitochondria, and in the corresponding mechanism the TPP moiety plays a crucial role in targeting mitochondria. This discovery provides a new perspective on the controlled synthesis, TPP linkage modes, and mitochondrial targeting design of TPP-CDs.

Antioxidant capacity, anti-inflammatory activity, and mutagenicity of Sterculia lychnophora (Pangdahai) polysaccharide

Dried boat-fruited ripped seeds of Sterculia lychnophora, commonly known as Pangdahai, are frequently used in traditional Chinese medicines and functional foods. However, research on these constituents is limited. In this study, the extraction of Pangdahai polysaccharide (PP) was investigated using different solvents (deionized water, 50 % methanol, and 50 % ethanol), and its chemical composition, antioxidant capacity, and anti-inflammatory activity were analyzed. Additionally, the Ames test was used to evaluate PPs’ food safety and mutagenicity. The results showed that the yields of PPs extracted with the three solvents ranged from ∼ 19 % to 21 % and that their monosaccharide compositions (rhamnose, arabinose, galactose, and glucose) were similar, with slightly different proportions. Moreover, the antioxidant capacity of all three PPs showed concentration-dependent effects. The EC50 values for each antioxidant were approximately 0.71–1.35 mg/mL for 1, 1-diphenyl-2-picrylhydrazyl free radical scavenging ability, 1.88–46.13 µg/mL for 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging ability, 2.22–3.61 mg/mL for ferric reducing antioxidant power, and 0.52–3.11 mg/mL for hydroxyl radical scavenging ability. At concentrations below 500 µg/mL, the anti-inflammator activity of PPs promoted cell proliferation while inhibiting nitric oxide production at concentrations ranging from 31.25 to 125 µg/mL. In the Ames test, PPs (1–5 mg/plate) exhibited no toxicity or mutagenicity against the five strains of Salmonella typhimurium (TA98, TA100, TA102, TA1535, and TA1537). These findings will particularly be of interest to individuals involved in PP-related research or commercial enterprises. Thus, the findings of this study will elucidate the bioactive components and potential benefits of PP, making it especially valuable to researchers and practitioners in the Pangdahai industry and expanding opportunities for industrial development.

Preparation, characterization, antioxidant, and antifungal activity of phenyl/indolyl-acyl chitooligosaccharides

In this study, carboxylic acids compounds were grafted onto chitooligosaccharides to prepare seven phenyl/indolyl-acyl chitooligosaccharides derivatives. The structures of the derivatives were characterized by IR spectroscopy, 13C NMR and elemental analysis. Meanwhile, antioxidant activities in vitro of the novel derivatives were analyzed. Compared to COS and carboxylic acid, the derivatives showed higher scavenging capacity for superoxide anion and DPPH radicals, with scavenging rates of 59.39% and 94.86%, respectively. The hydroxyl radical scavenging ability of the derivatives was only 18.89%. The antifungal activities of chitooligosaccharide derivatives against Diaporthe batatas and Phytophthora capsici were studied by the growth rate method. Compared with chitooligosaccharide itself, derivatives were inhibited by 97.77% and 100%. The above results showed that chitooligosaccharide derivatives have good biocompatibility and can be used in food, agriculture and medicine.

A novel fullerene composite material for directional oil control and antioxidant.

There are very few cosmetic ingredients that can target oil control and extend the wear time. Fullerenes have been reported to have excellent antioxidant capacity and a variety of biological activities, such as quenching free radicals, inhibiting lipid peroxidation, and promoting lipid flocculation. The purpose of applying foundation makeup on the face is to make the skin color even, but the secretion and oxidation of skin oil will make the makeup mottled and dull. In order to solve this problem, a fullerene composite material that can directionally absorb oil and resist oil oxidation has been developed. Fullerenes and hydroxyapatite composite was prepared by high pressure homogenization under alkaline condition. The indicated morphology and structure were characterized by SEM, UV-Vis, Raman, and XRD. The oil absorption capacity was determined by adding the C60-hydroxyapatite composite to a mixed solution of hexane and oil, shaking for 1 h, filtering, analyzed by GC-MS, and calculating the oil absorption by external standard method. Artificial sebum was prepared by adding different mass of water and oleic acid to screen the optimum ratio. C60-hydroxyapatite mixture and C60-hydroxyapatite composite were added to the artificial sebum to test the oil-absorbing capacity of the materials. The hydroxyl radical scavenging ability of C60-hydroxyapatite composite containing different fullerene contents was measured by X-band ESR spectroscopy, and the long-term radical scavenging ability of the composites was tested in comparison with VC. Antioxidant experiment is adding C60-hydroxyapatite composite material, and hydroxyapatite to oleic acid, then the UV light irradiation is aimed to accelerate the oxidation of oleic acid. Oleic acid act as a control group, and make the detection of oleic acid peroxide value after 7 days. The safety of the materials was tested by using culture media to soak the C60-hydroxyapatite composite for 24 h and then used to culture cells. The characterization of SEM, UV-Vis, Raman, and XRD showed that fullerene clusters were dispersed on the surface of hydroxyapatite stably, and they formed a stable composite. The adsorption rates of C60-hydroxyapatite composites for oleic acid, phenyl trimethicone, caprylic capric glyceride, isooctyl palmitate, mineral oil, olive oil, and dimethicone were 60.5%, 9.3%, 9.15%, 5.24%, 2.94%, 1.01%, and 0%, respectively. The flocculation amount of artificial sebum was 5.9 g per gram of C60-hydroxyapatite mixture and 24.2 g per gram of C60-hydroxyapatite composite. C60-hydroxyapatite composites have excellent quenching ability for hydroxyl radicals. When the fullerene content is 1, 2, 3, and 4 mg/kg, the quenching rates are 25.02%, 39.57%, 49.75%, and 62.24%, respectively. The quenching effect was enhanced with the increase of fullerene content, and it had strong long-term antioxidant properties. It can also be proved that C60-hydroxyapatite composites have strong antioxidant capacity through antioxidant experiments. The peroxide value of oleic acid on Day 0 was 2.8, and after 7 days of UV irradiation, the peroxide values of blank control, hydroxyapatite group, C60-hydroxyapatite composite containing 0.5% and 1% fullerenes four groups of materials were 8.02 meq O2/kg, 7.98 meq O2/kg, 7.11 meq O2/kg, and 6.87 meq O2/kg, respectively. The cell activity was 20.94% and 99.2% after the cells were cultured for 24 h using C60-hydroxyapatite composite and hydroxyapatite extracts, respectively, and the addition of fullerene was able to significantly increase the cell activity. Fullerene hydroxyapatite complex has excellent directional oil absorption characteristics, which can effectively remove free radicals and reduce skin oil oxidation.

Self-Cascade Redox Modulator Trilogically Renovates Intestinal Microenvironment for Mitigating Endotoxemia.

Endotoxemia is a life-threatening multiple organ failure disease caused by bacterial endotoxin infection. Unfortunately, current single-target therapy strategies have failed to prevent the progression of endotoxemia. Here, we reported that alanine fullerene redox modulator (AFRM) remodeled the intestinal microenvironment for multiple targets endotoxemia mitigation by suppressing inflammatory macrophages, inhibiting macrophage pyroptosis, and repairing epithelial cell barrier integrity. Specifically, AFRM exhibited broad-spectrum and self-cascade redox regulation properties with superoxide dismutase (SOD)-like enzyme, peroxidase (POD)-like enzyme activity, and hydroxyl radical (•OH) scavenging ability. Guided by proteomics, we demonstrated that AFRM regulated macrophage redox homeostasis and down-regulated LPS/TLR4/NF-κB and MAPK/ERK signaling pathways to suppress inflammatory hyperactivation. Of note, AFRM could attenuate inflammation-induced macrophage pyroptosis via inhibiting the activation of gasdermin D (GSDMD). In addition, our results revealed that AFRM could restore extracellular matrix and cell-tight junction proteins and protect the epithelial cell barrier integrity by regulating extracellular redox homeostasis. Consequently, AFRM inhibited systemic inflammation and potentiated intestinal epithelial barrier damage repair during endotoxemia in mice. Together, our work suggested that fullerene based self-cascade redox modulator has the potential in the management of endotoxemia through synergistically remodeling the inflammation and epithelial barriers in the intestinal microenvironment.

Preparation and antioxidant properties of tannic acid/copper ion nanozyme hybrid nanofibrous membranes.

Excess free radicals can have some negative effects on human health. In this paper, a nanozyme was successfully constructed by the coordination of copper ions and tannic acid, and its structure and elemental distribution were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. Free radical scavenging experiments confirmed that it possessed superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical scavenging ability. The results of thermogravimetric analysis experiments demonstrated that it possessed good thermal stability. A polyacrylonitrile hybrid nanofibrous membrane loaded with Cu/TA nanozyme was successfully constructed by electrospinning technology, and the maximum scavenging rate of DPPH and ABTS radicals can reach 64.22% and 58.44%, respectively. The nanofiber membrane also exhibited the ability to protect cells from oxidative stress damage. Therefore, the hybrid nanofibrous membrane has a broad application prospect in fields such as food preservation and biomedicine.

Preparation and Antioxidant Activity of New Carboxymethyl Chitosan Derivatives Bearing Quinoline Groups.

A total of 16 novel carboxymethyl chitosan derivatives bearing quinoline groups in four classes were prepared by different synthetic methods. Their chemical structures were confirmed by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and elemental analysis. The antioxidant experiment results in vitro (including DPPH radical scavenging ability, superoxide anion radical scavenging ability, hydroxyl radical scavenging ability, and ferric reducing antioxidant power) demonstrated that adding quinoline groups to chitosan (CS) and carboxymethyl chitosan (CMCS) enhanced the radical scavenging ability of CS and CMCS. Among them, both N, O-CMCS derivatives and N-TM-O-CMCS derivatives showed DPPH radical scavenging over 70%. In addition, their scavenging of superoxide anion radicals reached more than 90% at the maximum tested concentration of 1.6 mg/mL. Moreover, the cytotoxicity assay was carried out on L929 cells by the MTT method, and the results indicated that all derivatives showed no cytotoxicity (cell viability > 75%) except O-CMCS derivative 1a, which showed low cytotoxicity at 1000 μg/mL (cell viability 50.77 ± 4.67%). In conclusion, the carboxymethyl chitosan derivatives bearing quinoline groups showed remarkable antioxidant ability and weak cytotoxicity, highlighting their potential use in food and medical applications.

Chemical composition and biological evaluation of the essential oil of the flowering aerial parts of Aegopodium alpestre Ledeb

Aegopodium alpestre Ledeb (A. alpestre) is a plant known for its fragrant smell and has been traditionally used to treat influenza. However, despite its widespread use, there is no research on its flowering aerial parts. This study aims to contribute to the understanding the flowering aerial parts by investigating its volatile oil. The essential oil was extracted through hydrodistillation and analysed using GC-MS. The analysis identified 54 compounds, which accounted for 95.16% of the oil composition. The major components are germacrene D (31.68%), β-caryophyllene (16.07%), and (E)-β-farnesene (7.99%). To evaluate the antioxidant activity of volatile oil, six antioxidant experiments were conducted. The results indicated that volatile oil exhibited significant 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt and hydroxyl radical scavenging abilities. Furthermore, the antibacterial activity of volatile oil was assessed against four common pathogenic bacteria. The findings demonstrated that volatile oil displayed potent antibacterial activity against Escherichia coli and Aerogenic bacterium.

Antioxidant characteristics of hydrolysate from low-value sea cucumber: In vitro and in vivo activities of Caenorhabditis elegans.

The antioxidant activity in vitro and in vivo of Actinopyga miliaris hydrolysate (AMH) was investigated. The proportion of oligopeptides with 150-1000Da in AMH was 65.48%. The IC50 values of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), hydroxyl radical scavenging ability, and ferric ion reducing power of AMH were 0.37, 3.43, and 24.15mg/mL, respectively. Compared with the control group, the body length of Caenorhabditis elegans fed with 8mg/mL AMH extended from 632.08μm to 1009.57μm, and the swallowing frequency and head-swing frequency increased significantly. After being fed with AMH, the lifespan of C. elegans can be prolonged even under stress conditions, primarily due to superoxide dismutase activity, catalase activity, reduced glutathione content, and total antioxidant capacity in C. elegans increased, whereas reactive oxygen species level was reduced. The results showed that AMH had in vitro and in vivo antioxidant activity, which can alleviate oxidative damage and prolong life of C. elegans.

Synthesis, characterization, biological activity, and in vitro digestion of selenium nanoparticles stabilized by Antarctic ice microalgae polypeptide

A new type of uniformly dispersed selenium nanoparticles (SeNPs) was prepared using Antarctic ice microalgae polypeptides (AIMP) as the stabilizer and dispersant. Different characterization techniques and tests show that the SeNPs are effectively combined with AIMP through physical adsorption and hydrogen bonding to form a more stable structure. Orange-red, zero-valence, amorphous, and spherical AIMP-SeNPs with a diameter of 52.07 ± 1.011 nm and a zeta potential of −41.41 ± 0.882 mV were successfully prepared under the optimal conditions. The AIMP-SeNPs had significantly higher DPPH, ABTS and hydroxyl radicals scavenging abilities compared with AIMP and Na2SeO3, and prevented the growth of both Gram-negative and Gram-positive bacteria by disrupting the integrity of cell walls, cell membranes and mitochondrial membranes. The AIMP-SeNPs had higher gastrointestinal stability compared with SeNPs. Thus, this research highlights the crucial role of AIMP as a biopolymer framework in the dispersion, stabilization, and size management of SeNPs and concludes that AIMP-SeNPs can be exploited as a potent antioxidant supplement and antibacterial substance in foods and medicine.

Preparation and functional characteristics of protein from Ginkgo endophytic Pseudomonas R6 and Ginkgo seed

Ginkgo seed protein (GSP) has excellent processing characteristics and antioxidant properties. In this study, Gingko endophytic protein (GEP) was synthesized by Ginkgo endophytic Pseudomonas R6. SDS-PAGE analysis indicated that the molecular weights of GSP and GEP were mainly distributed at 17 KDa and 48 KDa, respectively. FTIR showed that GEP and GSP exhibited characteristic absorption in the amide I, II, and III bands, and absorption in amide A and B indicated the presence of hydrogen bonding. HPLC analysis showed that both proteins had 17 amino acids, but their relative abundance was different, with GSP having the highest Ser content (74.713 mg/g) and GEP having the highest Val content (35.905 mg/g). Stomata were observed on the surface of both proteins by SEM, and there were lamellar and some spherical structures on GEP, while the opposite was observed on GSP. GEP had superior solubility, OHC, FC and EC, while GSP showed good WHC. Both proteins exhibited antioxidant activities, with GSP exhibiting stronger hydroxyl radical scavenging ability than GEP, with IC50 of 0.46 mg/mL and 1.54 mg/mL, respectively. This work demonstrates the antioxidant potential of GEP as an alternative to GSP in the food industry.