Selenium-containing allophycocyanin purified from selenium-enriched Spirulina platensis attenuates AAPH-induced oxidative stress in human erythrocytes through inhibition of ROS generation

Isolation, identification of antioxidant peptides from earthworm proteins and analysis of the structure-activity relationship of the peptides based on quantum chemical calculations

Earthworms are emerging sources of edible animal proteins. Earthworm extracts exhibit good in vivo antioxidant activity after oral administration. To better understand the antioxidant activity of earthworms, antioxidant peptides derived from earthworm proteins after gastrointestinal digestion were isolated and identified, and their structure-activity relationships were analysed in this research. Results showed that earthworm protein gastrointestinal digestion products exhibited good antioxidant activity, and 6030 peptide sequences were identified after separation using ion-exchange and gel-chromatography columns. Eleven peptides were screened using computer simulation activity scores, among which AFWYGLPCKL, WPWQMSLY, and GCFRYACGAFY showed the best antioxidant activities. Highest Occupied Molecular Orbital (HOMO) analysis indicated that N29-H10, O122-H38, and the peptide bond binding sites of serine and leucine were active sites of peptides AFWYGLPCKL, GCFRYACGAFY, and WPWQMSLY, respectively. This study provides a new understanding of substance basis of antioxidant activity in earthworms and contributes to application of earthworm proteins as antioxidants in health-foods.

Selenoproteins in Health

Selenium (Se) is a naturally occurring essential micronutrient that is required for human health. The existing form of Se includes inorganic and organic. In contrast to the inorganic Se, which has low bioavailability and high cytotoxicity, organic Se exhibits higher bioavailability, lower toxicity, and has a more diverse composition and structure. This review presents the nutritional benefits of Se by listing and linking selenoprotein (SeP) functions to evidence of health benefits. The research status of SeP from foods in recent years is introduced systematically, particularly the sources, biochemical transformation and speciation, and the bioactivities. These aspects are elaborated with references for further research and utilization of organic Se compounds in the field of health.

Next-generation analytical platforms for antioxidant capacity assessment: The urge for realistic and physiologically relevant methods

Bioactive compounds, such as carotenoids, alkaloids, and phenolics, are well known because of their alleged health benefits when consumed regularly in a balanced healthy diet. Some well-documented bioactivities are antioxidant, antihypertensive, antihyperglycemic, antilipidemic, anti-obesity, anti-inflammatory, and antimicrobial capacities. Trying to associate the chemical composition of distinct sources and their bioactivity using in vitro methods, several assays have been developed, implemented, and optimised to recapitulate human physiological conditions. However, in most cases, pitfalls are apparent, and no single test tube-based assay can predict in vivo responses. The need for a more physiologically relevant cell-based method to evaluate the antioxidant capacity of putative antioxidants is apparent. Therefore, in this Review, the current state-of-the-art in food science and nutrition is aligned with cell biology/bioengineering approaches to propose combining in vitro digestion and absorption to obtain a bioavailable fraction containing antioxidants. Overall, human plasma, 2-dimensional human cell lines, such as erythrocytes, lymphocytes, hepatocytes, enterocytes and, ultimately, 3-dimensional spheroids (organoids) could be used as biologically relevant models to assess the antioxidant activity of compounds, foods, and nutraceuticals. This versatile approach is deemed suitable, accurate, reproducible, and physiologically relevant to evaluate the protective effects of antioxidants against ROS-mediated oxidation in vitro.

A Review of the Health-Promoting Properties of Spirulina with a Focus on athletes' Performance and Recovery

Spirulina species are photosynthetic and filamentous bacteria, commonly called 'blue-green microalgae'. Spirulina has a high nutrient content. It contains 60-70% protein with all essential amino acids present, and is rich in several vitamins, minerals, and bioactive compounds. Spirulina is also rich in essential fatty acids, and antioxidants. This rich nutritional content provides to Spirulina several health benefits including antioxidant, anti-inflammatory, immunomodulation, and insulin-sensitizing properties as well as positive effects in various diseases which could be also interesting for athletes. This paper mainly aims to review the interest and effects of Spirulina supplementation in athletes at rest, and in relation to exercise/training. Spirulina's biochemical composition, health properties/effects in humans, and effects in athletes including nutritional status, body composition, physical performance and intense exercise-related disorders were discussed in this review. Literature data showed that Spirulina seems to have positive effects on body composition especially in overweight and obese subjects which could not be the case in other pathologies and athletes. Spirulina appears to be also effective in improving aerobic fitness especially in untrained and moderately trained subjects. Results reported in the literature suggest that Spirulina may improve strength and power performance despite the minor or no significant effects in highly trained subjects. Most studies have shown that Spirulina improves antioxidant status, prevents and accelerates the recovery of exercise-induced lipid peroxidation, muscle damage and inflammation in trained and untrained subjects. Taken together, the results from these studies are encouraging and may demonstrate the potential benefits of Spirulina supplementation in athletes despite methodological differences.

Chemical Profile and Hematoprotective Activity of Artisanal Jabuticaba (Plinia jabuticaba) Wine and Derived Extracts

The alcoholic fermentation of jabuticaba berries (Plinia spp.) originates from a beverage with an intense taste and aroma, popularly known as jabuticaba wine (JW). In addition, polyphenols transferred from fruit peels to the final product turn this beverage into a promising source of bioactive agents. Here, the chemical profile and antioxidant potential of artisanal JW and derivative extracts were determined. Volatile organic compounds were determined by HS-SPME/GC-MS analysis. The wine was dried by lyophilization and subjected to liquid-liquid partitioning (water: ethyl acetate), resulting in three fractions (JWF1-3). ABTS•+ and DPPH•+ scavenging assays were performed to evaluate the antioxidant capacity. In addition, the extracts’ hematoprotective activity was evaluated against oxidative stress. Finally, the extracts were analyzed by LC-HRMS/MS. HS-SPME/GC-MS analysis highlighted 1,8-cineole as the main compound that contributes to the camphor/mint flavor. JWF2 and JWF3 displayed the highest antioxidant capacity. JWF2 stood out for preventing oxidative damage in red blood cells at 7.8 µg·mL−1 The maximal protection of ascorbic acid occurred at 8.8 µg·mL−1. The LC-HRMS/MS analysis allowed the annotation of seventeen compounds, most of them with recognized antioxidant activity such as anthocyanins, catechins, flavanols, and phenolic acids. The results presented herein reinforce JW as a pleasant beverage with bioactive potential.

Protective Effect of Flavonoids from Mulberry Leaf on AAPH-Induced Oxidative Damage in Sheep Erythrocytes

To evaluate the antioxidant activity of flavonoids extracted from Chinese herb mulberry leaves (ML), flavonoids from mulberry leaves (FML) were extracted and purified by using ultrasonic-assisted enzymatic extraction and D101 macroporous resin. Using LC-MS/MS-Liquid Chromatography with tandem mass spectrometry analysis, hesperidin, rutoside, hyperoside, cyanidin-3-o-glucoside, myricitrin, cyanidin, and quercetin were identified, and NMR and UV were consistent with the verification of IR flavonoid characteristics. The antioxidant activity of FML has also been evaluated as well as the protective effect on 2,2 0-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress. The results showed that FML exhibited powerful antioxidant activity. Moreover, FML showed dose-dependent protection against AAPH-induced sheep erythrocytes’ oxidative hemolysis. In the enzymatic antioxidant system, pretreatment with high FML maintained the balance of SOD, CAT, and GSH-Px; in the non-enzymatic antioxidant system, the content of MDA can be effectively reduced after FML treatment. This study provides a research basis for the development of natural products from mulberry leaves.

Selenium Biofortification of Soybean Sprouts: Effects of Selenium Enrichment on Proteins, Protein Structure, and Functional Properties

Selenium (Se) biofortification during germination is an efficient method for producing Se-enriched soybean sprouts; however, few studies have investigated Se distribution in different germinated soybean proteins and its effects on protein fractions. Herein, we examined Se distribution and speciation in the dominant proteins 7S and 11S of raw soybean (RS), germinated soybean (GS), and germinated soybean with Se biofortification (GS-Se). The effects of germination and Se treatment on protein structure, functional properties, and antioxidant capacity were also determined. The Se concentration in GS-Se was 79.8-fold higher than that in GS. Selenomethionine and methylselenocysteine were the dominant Se species in GS-Se, accounting for 41.5–80.5 and 19.5–21.2% of the total Se with different concentrations of Se treatment, respectively. Se treatment had no significant effects on amino acids but decreased methionine in 11S. In addition, the α-helix contents decreased as the Se concentration increased; the other structures showed no significant changes. The Se treatment also had no significant effects on the water and oil-holding capacities in protein but increased the foaming capacity and emulsion activity index (EAI) of 7S, but only the EAI of 11S. The Se treatment also significantly increased the antioxidant capacity in 7S but not in 11S. This study indicates that the dominant proteins 7S and 11S have different Se enrichment abilities, and the protein structures, functional properties, and antioxidant capacity of GS can be altered by Se biofortification.

Selenium-containing protein from selenium-enriched Spirulina platensis antagonizes oxygen glucose deprivation-induced neurotoxicity by inhibiting ROS-mediated oxidative damage through regulating MPTP opening

CONTEXT

Selenium-containing protein from selenium-enriched Spirulina platensis (Se-SP) (syn. Arthrospira platensis [Microcoleaceae]) showed novel antioxidant activity. However, the protective effect of Se-SP against oxygen glucose deprivation (OGD)-induced neural apoptosis has not been reported yet.

OBJECTIVE

To verify whether Se-SP can inhibit OGD-induced neural apoptosis and explore the underlying mechanism.

MATERIALS AND METHODS

Primary hippocampal neurons were separated from Sprague-Dawley (SD) rats. 95% N₂ + 5% CO₂ were employed to establish OGD model. Neurons were treated with 5 and 10 µg/mL Se-SP under OGD condition for 6 h. Neurons without treatment were the control group. Neural viability and apoptosis were detected by MTT, immunofluorescence and western blotting methods.

RESULTS

Se-SP significantly improved neuronal viability (from 57.2% to 94.5%) and inhibited apoptosis in OGD-treated primary neurons (from 45.6% to 6.3%), followed by improved neuronal morphology and caspases activation. Se-SP co-treatment also effectively suppressed OGD-induced DNA damage by inhibiting ROS accumulation in neurons (from 225.6% to 106.3%). Additionally, mitochondrial dysfunction was also markedly improved by Se-SP co-treatment via balancing Bcl-2 family expression. Moreover, inhibition of mitochondrial permeability transition pore (MPTP) by CsA (an MPTP inhibitor) dramatically attenuated OGD-induced ROS generation (from 100% to 56.2%), oxidative damage, mitochondrial membrane potential (MPP) loss (from 7.5% to 44.3%), and eventually reversed the neuronal toxicity and apoptosis (from 57.4% to 79.6%).

DISCUSSION AND CONCLUSIONS

Se-SP showed enhanced potential to inhibit OGD-induced neurotoxicity and apoptosis by inhibiting ROS-mediated oxidative damage through regulating MPTP opening, indicating that selenium-containing protein showed broad application in the chemoprevention and chemotherapy against human ischaemic brain injury.

Potentialities of selenium nanoparticles in biomedical science

Selenium nanoparticles (SeNPs) have revolutionized biomedical domain and are still developing rapidly. Hence, this perspective elaborates SeNPs properties, synthesis, and biomedical applications, together with their potential for management of SARS-CoV-2.

Selenium-Containing Proteins/Peptides from Plants: A Review on the Structures and Functions

Selenium is an essential microelement required for biological processes. Traditional selenium supplements (selenite and selenomethionine mainly) remain concerns due to toxicity and bioavailability. In recent decades, biofortification strategies have been applied to produce selenium-enriched edible plants to address the challenges of superior nutritional quality requirements. Plant-derived selenium-containing proteins/peptides offer potential health benefits beyond the basic nutritional requirements of Se. Highly nucleophilic seleno-amino acids, special peptide sequences, and favorable bioavailability contribute to the biological activities of selenium-containing proteins/peptides, such as antioxidant, antihypertensive, anti-inflammatory, and immunomodulatory effects. However, their applications on a commercial scale are insufficient owing to the complexity of purification and identification techniques and the sparse information on bioavailability and metabolism. In this review, selenium status, structural features, bioactivities, structure-activity relationships, and bioavailability, as well as the mechanisms underlying the bioactivities and metabolism of plant-derived selenium-containing proteins/peptides, are summarized and discussed for their nutraceutical use.

Polysaccharide from Lycium arabicum: Structural Features, in Vitro Antioxidant Activities and Protective Effect against Oxidative Damage in Human Erythrocytes

In this research work, a water-soluble polysaccharide (LAP) isolated from the fruits of Lycium arabicum was investigated. LAP contains carbohydrates (82.45±1.23 %), protein (1.56±0.21 %), and uronic acids (3.56±0.34 %). The analysis of the monosaccharide composition revealed the presence of rhamnose, arabinose, galactose, glucose and mannose in a molar ratio of 4.7 : 1.5 : 1 : 8.7 : 16.4 : 5.6. The extracted polysaccharide (PS) was considered as heterogeneous and highly branched by interpreting its GC/MS, FT-IR and NMR data. Crystallinity of LAP was inferred from its X-ray diffractometry (XRD) and Scanning Electron Microscopy (SEM) analysis. LAP exhibited an interesting stability at high temperatures (∼254 °C) and in a wide range of pH (3-9) deduced, respectively, from its DSC and zeta potential analysis. LAP displayed a strong antioxidant activity at low concentrations evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging, ferric reducing activity power (FRAP), free radical scavenging ability, superoxide radical-scavenging and hydroxyl radical-scavenging abilities. Inhibition of erythrocyte hemolysis and lipid peroxidation was also assessed. In 5 h, LAP treatment allowed the protection of the damaged erythrocytes caused by AAPH (2,2-azobis(2-amidinopropane) dihydrochloride), to reduce the level of malondialdehyde (MDA) as well as to increase the reduced glutathione (GSH) level.

Selenium-Containing Protein From Selenium-Enriched Spirulina platensis Attenuates High Glucose-Induced Calcification of MOVAS Cells by Inhibiting ROS-Mediated DNA Damage and Regulating MAPK and PI3K/AKT Pathways

Hyperglycemia is the main feature of diabetes and may increase the risk of vascular calcification (VC), which is an independent predictor for cardiovascular and cerebrovascular diseases (CCD). Selenium (Se) may decrease the risk of CCD, and previous studies confirmed that Se-containing protein from Se-enriched Spirulina platensis (Se-SP) exhibited novel antioxidant potential. However, the effect of Se-SP against VC has been not investigated. Herein, the protective effect and underlying mechanism of Se-SP against high glucose-induced calcification in mouse aortic vascular smooth muscle cells (MOVAS) were explored. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) results showed time-dependent uptake of Se-SP in MOVAS cells, which significantly inhibited high glucose-induced abnormal proliferation. Se-SP co-treatment also effectively attenuated high glucose-induced calcification of MOVAS cells, followed by decreased activity and expression of alkaline phosphatase (ALP). Further investigation revealed that Se-SP markedly prevented reactive oxygen species (ROS)-mediated DNA damage in glucose-treated MOVAS cells. ROS inhibition by glutathione (GSH) effectively inhibited high glucose-induced calcification, indicating that Se-SP could act as ROS inhibitor to inhibit high glucose-induced DNA damage and calcification. Moreover, Se-SP dramatically attenuated high glucose-induced dysfunction of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase/AKT (PI3K/AKT) pathways. Se-SP after Se addition achieved enhanced potential in inhibiting high glucose-induced calcification, which validated that Se-SP as a new Se species could be a highly effective treatment for human CCD.

Selenium accumulation in protein fractions of Tenebrio molitor larvae and the antioxidant and immunoregulatory activity of protein hydrolysates

Although numerous types of organisms have been used to enrich selenium, a low-cost and efficient organism is yet to be identified. This study aimed to develop a new means of selenium enrichment using Tenebrio molitor larvae. Our results indicated that the total selenium content in larvae was increased 83-fold to 54.21 ± 1.25 μg/g, and of this content, organic selenium accounted for over 97% after feeding the larvae with 20 μg/g of sodium selenite. Selenium was distributed unequally in the protein fraction with following order: alkali-soluble protein-bound selenium (36.32%) > salt-soluble protein-bound selenium (19.41%) > water-soluble protein-bound selenium (17.03%) > alcohol-soluble protein-bound selenium (3.21%). Additionally, 81% of the selenium within the soluble proteins was distributed in subunits possessing molecular weights of <40 kDa. After hydrolysis by alcalase, the protein hydrolysate of selenium-enriched larvae possessing 75% selenium recovery exhibited stronger antioxidant and immunoregulatory activities than those of regular larvae.

Changes in Antioxidant Activity of Peptides Identified from Brown Rice Hydrolysates under Different Conditions and Their Protective Effects against AAPH-Induced Oxidative Stress in Human Erythrocytes

Four antioxidant peptides (Ile-Tyr, Leu-Tyr, Val-Tyr, and Tyr-Leu-Ala), identified from brown rice protein hydrolysates, showed strong ROO· and ABTS^·+ scavenging activities. Changes in the antioxidant activity of peptides and GSH (control) under different processing conditions, namely, NaCl, temperature, pH, and gastrointestinal proteases, were evaluated by the oxygen radical absorbance capacity assay and the Trolox equivalent antioxidant capacity assay. Results indicated that with the increase in NaCl concentration, temperature, and pH (beyond neutral), the antioxidant activity of the peptides decreased, while the decrease was lower than that of GSH. The antioxidant activity of the four antioxidant peptides changed slightly after in vitro digestion, indicating a relatively high digestion resistance. The protective effect on the oxidative damage model of 2,2-azobis (2-methylpropionamide)-dihydrochloride-induced human red blood cells was also studied. Leu-Tyr and Tyr-Leu-Ala could alleviate but not totally inhibit oxidative damage in red blood cells, and their protective effects were dependent on concentration.

Single NIR Laser-Activated Multifunctional Nanoparticles for Cascaded Photothermal and Oxygen-Independent Photodynamic Therapy

Inconvenient dual-laser irradiation and tumor hypoxic environment as well as limited judgment of treating region have impeded the development of combined photothermal and photodynamic therapies (PTT and PDT). Herein, Bi₂Se₃@AIPH nanoparticles (NPs) are facilely developed to overcome these problems. Through a one-step method, free radical generator (AIPH) and phase transition material (lauric acid, LA, 44-46 °C) are encapsulated in hollow bismuth selenide nanoparticles (Bi₂Se₃ NPs). Under a single 808-nm laser irradiation at the tumor area, hyperthermia produced by Bi₂Se₃ not only directly leads to cell death, but also promotes AIPH release by melting LA and triggers free radical generation, which could further eradicate tumor cells in hypoxic environments. Moreover, Bi₂Se₃ with high X-ray attenuation coefficient endows the NPs with high computed tomography (CT) imaging capability, which is important for treating area determination. The results exhibit that Bi₂Se₃@AIPH NPs possesses 31.2% photothermal conversion efficiency for enhanced PTT, ideal free radical generation for oxygen-independent PDT, and 37.77 HU mL mg^-1 X-ray attenuation coefficient for CT imaging with high quality. Most importantly, the tumor growth inhibition rate by synergistic PTT, PDT, and following immunotherapy is 99.6%, and even one tumor disappears completely, which demonstrates excellent cascaded synergistic effect of Bi₂Se₃@AIPH NPs for the tumor therapy.

Selenium-enriched Bacillus paralicheniformis SR14 attenuates H2O2-induced oxidative damage in porcine jejunum epithelial cells via the MAPK pathway

Oxidative stress plays a detrimental role in gastrointestinal disorders. Although selenium-enriched probiotics have been shown to strengthen oxidation resistance and innate immunity, the potential mechanism remains unclear. Here, we focused on the biological function of our material, selenium-enriched Bacillus paralicheniformis SR14 (Se-BP), and investigated the antioxidative effects of Se-BP and its underlying molecular mechanism in porcine jejunum epithelial cells. First, we prepared Se-BP and quantified for its selenium and bacterial contents. Then, in vitro free radical scavenging activity was measured to evaluate the potential antioxidant effect of Se-BP. Third, to induce an appropriate oxidative stress model, we adopted different concentrations of H₂O₂ and determined the most suitable concentration by a methyl thiazolyl tetrazolium (MTT) assay. Regarding treatment with Se-BP and H₂O₂, we found that Se-BP increased cell viability and prevented lactate dehydrogenase release when administered prior to H₂O₂ exposure. Additionally, Se-BP markedly suppressed reactive oxygen species and malondialdehyde production in cells and effectively attenuated apoptosis. Compared with incubation with H₂O₂ alone, treatment with Se-BP significantly promoted phosphorylation of ERK and p38 MAPK signaling molecules. When administered with ERK and p38 MAPK inhibitors, Se-BP did not alleviate the decrease in cell viability. Our results suggest that Se-BP prevents H₂O₂-induced cell damage by activating the ERK/p38 MAPK signaling pathways.

Selenium-Containing Protein From Selenium-Enriched Spirulina platensis Attenuates Cisplatin-Induced Apoptosis in MC3T3-E1 Mouse Preosteoblast by Inhibiting Mitochondrial Dysfunction and ROS-Mediated Oxidative Damage

Accumulated evidences have verified that cancer chemotherapy may increase the risk of osteoporosis and severely affected the life quality. Osteoclasts hyperactivation was commonly accepted as the major pathogenesis of osteoporosis. However, the role of osteoblasts dysfunction in osteoporosis was little investigated. Our previous study has confirmed that selenium-containing protein from selenium-enriched Spirulina platensis (Se-SP) exhibited enhanced hepatoprotective potential through inhibiting oxidative damage. Herein, the protective effect of Se-SP against cisplatin-induced osteoblasts dysfunction in MC3T3-E1 mouse preosteoblast was investigated, and the underlying mechanism was evaluated. The results indicated that cisplatin dramatically decreased cell viability of preosteoblast by triggering mitochondria-mediated apoptosis pathway. Cisplatin treatment also caused mitochondrial dysfunction and reactive oxide species (ROS)-mediated oxidative damage. However, Se-SP pre-treatment effectively prevented MC3T3-E1 cells from cisplatin-induced mitochondrial dysfunction by balancing Bcl-2 family expression and regulating the opening of mitochondrial permeability transition pore (MPTP), attenuated cisplatin-induced oxidative damage through inhibiting the overproduction of ROS and superoxide anion, and eventually reversed cisplating-induced early and late apoptosis by inhibiting PARP cleavage and caspases activation. Our findings validated that Se-SP as a promising Se species could be a highly effective way in the chemoprevention and chemotherapy of oxidative damage-mediated bone diseases.

Structure-Activity Relationship Analysis on Antioxidant and Anticancer Actions of Theaflavins on Human Colon Cancer Cells

The roles of natural products as effective cancer prevention and therapeutic agents have been documented by various studies in recent years, but the action mechanisms and structure-activity relationship need more elucidation. The present study showed that theaflavins (theaflavin and its derivatives, TFs) from black tea caused an inhibitory effect on the proliferation of human colon adenocarcinoma cancer SW480 cells and human colon cancer SW620 cells [half maximal inhibitory concentration (IC₅₀) < 32.0 μM] by the induction of cell cycle arrest but exerted lower toxicity against normal cells with a high safety index (1.89-6.26). Moreover, TFs triggered a decrease in reactive oxygen species in SW480 cells as a result of their excellent radical-scavenging ability (e.g., the IC₅₀ value of TF4 to ABTS^• + was 1.91 ± 0.21 μM). More importantly, the structure-activity relationship analysis of TFs exhibited that the galloyl group was an important factor to affect these activities. Taken together, we revealed that the TFs could act as substitutes for natural antioxidants and promising anticancer agents with beneficial influence on human health and then anticipated that this study may provide useful information on the development of therapeutic natural products.

Protective effects of p-coumaric acid against oxidant and hyperlipidemia-an in vitro and in vivo evaluation

Dietary phenols are antioxidants with diverse physiological functions that are beneficial for human health. The objective of this research work was to investigate antioxidant activity of p-coumaric acid (p-CA) using four in vitro methods, the protective effects against oxidative stress in PC12 cells, and hypolipidemic effects on High fat-diet (HFD) mice model. The p-CA exhibited moderate antioxidant activity in the selected in vitro assay. The highest chelating activity of p-CA at 50 μg/mL was found to be 52.22%. Pretreatment with p-CA significantly enhanced cell viability of PC12 cell and suppressed AAPH-induced intracellular ROS generation and AAPH-induced LDH release. The hypolipidemic effects of p-CA (100 mg/kg BW) was directly linked to the increased expression of nuclear factor erythroid 2-related factor (Nrf2) by 2.0-fold, Glutathione peroxidase (Gpx) by 3.8-fold, Superoxide dismutase (SOD-1) by 1.6-fold, Heme oxygenase (HO-1) by 1.72-fold and NAD(P)H Quinone Dehydrogenase 1 (NQO-1) by 1.5-fold compared with HFD group. In addition to these effects, p-CA decreased total cholesterol and atherosclerosis index levels, and increased catalase (CAT) level in serum, total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) levels in liver as compared HFD group. Administration of p-CA also promoted the recovery of hyperlipidemia steatohepatitis in mice by ameliorating lipid peroxidation. These results suggested that p-CA is a potent antioxidant with potential therapeutic efficacy for treating hyperlipidemia symptoms.

Spectrophotometric Determination of Phycobiliprotein Content in Cyanobacterium Synechocystis

This is a simple protocol for the quantitative determination of phycobiliprotein content in the model cyanobacterium Synechocystis. Phycobiliproteins are the most important components of phycobilisomes, the major light-harvesting antennae in cyanobacteria and several algae taxa. The phycobilisomes of Synechocystis contain two phycobiliproteins: phycocyanin and allophycocyanin. This protocol describes a simple, efficient, and reliable method for the quantitative determination of both phycocyanin and allophycocyanin in this model cyanobacterium. We compared several methods of phycobiliprotein extraction and spectrophotometric quantification. The extraction procedure as described in this protocol was also successfully applied to other cyanobacteria strains such as Cyanothece sp., Synechococcuselongatus, Spirulina sp., Arthrospira sp., and Nostoc sp., as well as to red algae Porphyridium cruentum. However, the extinction coefficients of specific phycobiliproteins from various taxa can differ and it is, therefore, recommended to validate the spectrophotometric quantification method for every single strain individually. The protocol requires little time and can be performed in any standard life science laboratory since it requires only standard equipment.

Nutritionally Available Selenocysteine Derivative Antagonizes Cisplatin-Induced Toxicity in Renal Epithelial Cells through Inhibition of Reactive Oxygen Species-Mediated Signaling Pathways

Discovery of nutritionally available agents that could antagonize cisplatin-induced nephrotoxicity is of great significance and clinical application potential. 3,3'-Diselenodipropionic acid (DSePA) is a seleno-amino acid derivative that exhibits strong antioxidant activity. Therefore, this study aimed to examine the protective effects of DSePA on cisplatin-induced renal epithelial cells damage as well as the molecular mechanisms. The results revealed that DSePA effectively inhibited cell apoptosis induced by cisplatin through suppressing the caspase activation and poly(ADP-ribose) polymerase cleavage. In addition, DSePA blocked the cisplatin-induced mitochondrial dysfunction, as evidenced by the loss of mitochondrial membrane potential and reduction of mitochondrial mass. The results of western blot analysis showed that DSePA reversed the expression level of Bcl-2 family proteins altered by cisplatin. The cisplatin-activated AKT pathway was also modulated by DSePA. Moreover, these results indicate that DSePA could protect HK-2 cells from cisplatin-induced toxicity in renal epithelial cells by inhibiting intracellular reactive oxygen species-mediated apoptosis while showing an unobvious effect on its anticancer efficacy. Taken together, this study demonstrates that selenocysteine could be further developed as novel nutritionally available agents to antagonize cisplatin-induced nephrotoxicity during cancer therapy.

The In Vitro Anti-Tumor Activity of Phycocyanin against Non-Small Cell Lung Cancer Cells

Phycocyanin, a type of functional food colorant, is shown to have a potent anti-cancer property. Non-small cell lung cancer (NSCLC) is one of the most aggressive form of cancers with few effective therapeutic options. Previous studies have demonstrated that phycocyanin exerts a growth inhibitory effect on NSCLC A549 cells. However, its biological function and underlying regulatory mechanism on other cells still remain unknown. Here, we investigated the in vitro function of phycocyanin on three typical NSCLC cell lines, NCI-H1299, NCI-H460, and LTEP-A2, for the first time. The results showed that phycocyanin could significantly induce apoptosis, cell cycle arrest, as well as suppress cell migration, proliferation, and the colony formation ability of NSCLC cells through regulating multiple key genes. Strikingly, phycocyanin was discovered to affect the cell phenotype through regulating the NF-κB signaling of NSCLC cells. Our findings demonstrated the anti-neoplastic function of phycocyanin and provided valuable information for the regulation of phycocyanin in NSCLC cells.

Silicon dioxide nanoparticle exposure affects small intestine function in an in vitro model

The use of nanomaterials to enhance properties of food and improve delivery of orally administered drugs has become common, but the potential health effects of these ingested nanomaterials remain unknown. The goal of this study is to characterize the properties of silicon dioxide (SiO₂) nanoparticles (NP) that are commonly used in food and food packaging, and to investigate the effects of physiologically realistic doses of SiO₂ NP on gastrointestinal (GI) health and function. In this work, an in vitro model composed of Caco-2 and HT29-MTX co-cultures, which represent absorptive and goblet cells, was used. The model was exposed to well-characterized SiO₂ NP for acute (4 h) and chronic (5 d) time periods. SiO₂ NP exposure significantly affected iron (Fe), zinc (Zn), glucose, and lipid nutrient absorption. Brush border membrane intestinal alkaline phosphatase (IAP) activity was increased in response to nano-SiO₂. The barrier function of the intestinal epithelium, as measured by transepithelial electrical resistance, was significantly decreased in response to chronic exposure. Gene expression and oxidative stress formation analysis showed NP altered the expression levels of nutrient transport proteins, generated reactive oxygen species, and initiated pro-inflammatory signaling. SiO₂ NP exposure damaged the brush border membrane by decreasing the number of intestinal microvilli, which decreased the surface area available for nutrient absorption. SiO₂ NP exposure at physiologically relevant doses ultimately caused adverse outcomes in an in vitro model.

Effect of Spirulina platensis ingestion on the abnormal biochemical and oxidative stress parameters in the pancreas and liver of alloxan-induced diabetic rats

CONTEXT

Previous studies have shown that Spirulina platensis Gomont (Phormidiaceae) (SP) extract has beneficial effects on many disease conditions. The putative protective effects of SP were investigated in diabetic rats.

OBJECTIVE

The current study investigates the antioxidant effects of SP in diabetic Wistar rats.

MATERIALS AND METHODS

Alloxan monohydrate (150 mg/kg body weight) was intraperitoneally administrated to induce diabetes. An aqueous suspension of SP powder in distillate water (10% w/v) was administrated orally by gavage (1 mL/day) for 50 days. Histopathological, biochemical and antioxidant analyses were performed. Glycemia, liver function and HOMA-IR were assessed using Spinreact and ELISA kits.

RESULTS

SP exhibited high-antioxidant activity. The IC₅₀ values of the SP aqueous extract were 70.40 and 45.69 mg/L compared to those of the standard antioxidant BHT, which were 27.97 and 19.77 mg/L, for the DPPH and ABTS tests, respectively. The diabetic animals showed a significant increase in glycaemia (from 4.05 to 4.28 g/L) and thiobarbituric acid reactive substances (50.17 mmol/g protein) levels. Treatment with SP significantly reduced glycaemia by 79% and liver function markers [glutamate pyruvate transaminase (GPT), glutamate oxaloacetate transaminase (GOT) and alkaline phosphatase (Alk-p)]) by 25, 36 and 20%, respectively, compared to that of the controls. There was a significant increase in superoxide dismutase (48%), total antioxidant status (43%), glutathione peroxidase (37%) and glutathione reductase (16%) in the diabetic rats treated with SP.

DISCUSSION AND CONCLUSION

These results showed that SP has high antioxidant activity, free radical scavenging, antihyperglycemic and hepatoprotective effects in diabetes.

Phycocyanin-Functionalized Selenium Nanoparticles Reverse Palmitic Acid-Induced Pancreatic β Cell Apoptosis by Enhancing Cellular Uptake and Blocking Reactive Oxygen Species (ROS)-Mediated Mitochondria Dysfunction

Accumulation of palmitic acid (PA) in human bodies could cause damage to pancreatic β cells and lead to chronic diseases by generation of reactive oxygen species (ROS). Therefore, it is of great significance to search for nutrition-available agents with antioxidant activity to protect pancreatic islet cells against PA-induced damage. Phycocyanin (PC) and selenium (Se) have been reported to have excellent antioxidant activity. In this study, PC-functionalized selenium nanoparticles (PC-SeNPs) were synthesized to investigate the in vitro protective effects on INS-1E rat insulinoma β cells against PA-induced cell death. A potent protective effect was achieved by regulation of particle size and PC content. Among three PC-SeNPs (165, 235, and 371 nm), PC-SeNPs-235 nm showed the highest cellular uptake and the best protective activities. For cell cycle analysis, PC-SeNPs showed a better protective effect on PA-induced INS-1E cell apoptosis than PC or SeNPs, and PC-SeNPs-235 nm exhibited the best effect. Further mechanistic studies demonstrated that PA induced overproduction of intracellular ROS, mitochondria fragmentation, activation of caspase-3, -8, and -9, and cleavage of PARP. However, pretreatment of the cells with PC-SeNPs effectively blocked these intracellular events, which suggests that PC-SeNPs could protect INS-1E cells against PA-induced cell apoptosis via attenuating oxidative stress and downstream signaling pathways. This finding provides a great promising nutritional approach for protection against diseases related to islet damage.

A Hybrid Nanomaterial for the Controlled Generation of Free Radicals and Oxidative Destruction of Hypoxic Cancer Cells

Anticancer modalities based on oxygen free radicals, including photodynamic therapy and radiotherapy, have emerged as promising treatments in the clinic. However, the hypoxic environment in tumor tissue prevents the formation of oxygen free radicals. Here we introduce a novel strategy that employs oxygen-independent free radicals generated from a polymerization initiator for eradicating cancer cells. The initiator is mixed with a phase-change material and loaded into the cavities of gold nanocages. Upon irradiation by a near-infrared laser, the phase-change material is melted due to the photothermal effect of gold nanocages, leading to the release and decomposition of the loaded initiator to generate free radicals. The free radicals produced in this way are highly effective in inducing apoptosis in hypoxic cancer cells.

Antioxidant, Immunomodulating, and Microbial-Modulating Activities of the Sustainable and Ecofriendly Spirulina

The highly nutritional and ecofriendly Spirulina (Arthrospira platensis) has hypolipidemic, hypoglycemic, and antihypertensive properties. Spirulina contains functional compounds, such as phenolics, phycocyanins, and polysaccharides, with antioxidant, anti-inflammatory, and immunostimulating effects. Studies conducted on Spirulina suggest that it is safe in healthy subjects, but attitude to eating probably affects the acceptability of Spirulina containing foods. Although the antioxidant effect of Spirulina is confirmed by the intervention studies, the concerted modulation of antioxidant and inflammatory responses, suggested by in vitro and animal studies, requires more confirmation in humans. Spirulina supplements seem to affect more effectively the innate immunity, promoting the activity of natural killer cells. The effects on cytokines and on lymphocytes' proliferation depend on age, gender, and body weight differences. In this context, ageing and obesity are both associated with chronic low grade inflammation, immune impairment, and intestinal dysbiosis. Microbial-modulating activities have been reported in vitro, suggesting that the association of Spirulina and probiotics could represent a new strategy to improve the growth of beneficial intestinal microbiota. Although Spirulina might represent a functional food with potential beneficial effects on human health, the human interventions used only supplements. Therefore, the effect of food containing Spirulina should be evaluated in the future.

Selenadiazole derivatives antagonize glucocorticoid-induced osteoblasts cells apoptosis by blocking ROS-mediated signaling, a new anti-osteoporosis strategy

Herein we demonstrate that synthetic selenadiazole derivatives could protect osteoblasts cells against Dex-induced cell apoptosisviaattenuating oxidative stress and downstream signalling pathways.

Selenium–phycocyanin from selenium-enriched cultures of Nostoc sp. isolated from rice field prevents human kidney cells from paraquat-induced damage

Herein we demonstrate that Se-containing phycocyanin (Se–PC) purified from Se-enriched cultures of Nostoc sp. could reverse paraquat (PQ)-induced DNA cell apoptosis through inhibition of superoxide overproduction in human kidney cells.

Therapeutic effect of TMZ-POH on human nasopharyngeal carcinoma depends on reactive oxygen species accumulation

Nasopharyngeal carcinoma (NPC) is a common head and neck malignancy without efficient chemotherapeutic agents for it. In our current study, we demonstrated the cytotoxicity effects of a newly patented compound temozolomide–perillyl alcohol (TMZ-POH) on NPC in vitro and in vivo, and the possible mechanisms involved. Human NPC cell lines CNE1, CNE2, HNE2, and SUME-α were treated with control (DMSO), TMZ, POH, TMZ plus POH, and TMZ-POH. Our data indicated that TMZ-POH could inhibit NPC cell proliferation, cause G₂/M arrest and DNA damage. TMZ-POH triggered apoptosis in NPC cells via significant activation of caspase-3 and poly(ADP-ribose) polymerase (PARP). Importantly, TMZ-POH-induced cell death was found to be associated with (i) the loss of inner mitochondrial membrane potential (ΔΨm) and release of mitochondrial Cytochrome c, (ii) the increase in ROS generation, and (iii) the activation of stress-activated protein kinases (SAPK)/c-Jun N-terminal kinases (JNK) signaling pathway. The generation of ROS in response to TMZ-POH seems to play a crucial role in the cell death process since the blockage of ROS production using the antioxidant N-acetyl-L-cysteine or catalase reversed the TMZ-POH-induced JNK activation, DNA damage, and cancer cell apoptosis. These results provide the rationale for further research and preclinical investigation of the antitumor effect of TMZ-POH against human NPC.

Enhancing the Antioxidant Ability of Trametes versicolor Polysaccharopeptides by an Enzymatic Hydrolysis Process

Polysaccharopeptides (PSPs) are among the main bioactive constituents of Trametes versicolor (T. versicolor). The purpose of this research was to investigate the antioxidant activities of enzymatic hydrolysates obtained from T.versicolor polysaccharopeptides by 80 U/mL β-1,3-glucanase (PSPs-EH80). The half-inhibitory concentration (IC₅₀) of PSPs-EH80 in metal chelating assay, ABTS and DPPH radical scavenging test results were 0.83 mg/mL, 0.14 mg/mL and 0.52 mg/mL, respectively, which were lower than that of PSPs-EH 20 U/mL. The molecular weights of the PSPs-EH80 hydrolysates were 300, 190, 140 and 50 kDa, respectively, and the hydrolysis of polysaccharides by β-1,3-glucanase did not change the original functional group. PSPs-EH80 reduced the reactive oxygen species (ROS) content at least twice that of treatment without PSPs-EH80. In addition, an oxidative damage test showed that PSPs-EH80 can improve HaCaT cell survival. According to our results, PSP demonstrates the potential of anti-oxidative damage; besides, enzyme hydrolysis can improve the ability of the PSP.

Silica Nanoparticle-Generated ROS as a Predictor of Cellular Toxicity: Mechanistic Insights and Safety by Design

Evaluating toxicological responses of engineered nanomaterials such as silica nanoparticles is critical in assessing health risks and exposure limits. Biological assays can be used to evaluate cytotoxicity of individual materials, but specific nano-bio interactions-which govern its physiological response-cannot currently be predicted from materials characterization and physicochemical properties. Understanding the role of free radical generation from nanomaterial surfaces facilitates understanding of a potential toxicity mechanism and provides insight into how toxic effects can be assessed. Size-matched mesoporous and nonporous silica nanoparticles in aminopropyl-functionalized and native forms were investigated to analyze the effects of porosity and surface functionalization on the observed cytotoxicity. In vitro cell viability data in a murine macrophage cell line (RAW 264.7) provides a model for what might be observed in terms of cellular toxicity upon an environmental or industrial exposure to silica nanoparticles. Electron paramagnetic resonance spectroscopy was implemented to study free radical species generated from the surface of these nanomaterials and the signal intensity was correlated with cellular toxicity. In addition, in vitro assay of intracellular reactive oxygen species (ROS) matched well with both the EPR and cell viability data. Overall, spectroscopic and in vitro studies correlate well and implicate production of ROS from a surface-catalyzed reaction as a predictor of cellular toxicity. The data demonstrate that mesoporous materials are intrinsically less toxic than nonporous materials, and that surface functionalization can mitigate toxicity in nonporous materials by reducing free radical production. The broader implications are in terms of safety by design of nanomaterials, which can only be extracted by mechanistic studies such as the ones reported here.

Oxymatrine synergistically enhances the inhibitory effect of 5-fluorouracil on hepatocellular carcinoma in vitro and in vivo

Oxymatrine (OMT), one of the main active components of extracts from the dry roots of Sophora flavescens, has long been employed clinically to treat cancers. Here, we investigated the synergistic effect of OMT with 5-fluorouracil (5-Fu) on the tumor growth inhibition of hepatocellular carcinoma cells (HCC; Hep-G2 and SMMC-7721) and explored the underlying mechanism. Cells were treated with OMT and/or 5-Fu and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay, and immunohistochemistry. OMT and 5-Fu inhibited the proliferation of Hep-G2 and SMMC-7721 cells, and combination treatment with OMT and 5-Fu resulted in a combination index <1, indicating a synergistic effect. Co-treatment with OMT and 5-Fu caused G0/G1 phase arrest by upregulating P21 and P27 and downregulating cyclin D, and induced apoptosis through increasing the production of reactive oxygen species (ROS) and decreasing the levels of p-ERK. In addition, the inhibition of ROS respectively reversed the cell death induced by 5-Fu + OMT, suggesting the key roles of ROS in the process. More importantly, 5-Fu and OMT in combination exhibit much superior tumor weight and volume inhibition on SMMC-7721 xenograft mouse model in comparison to 5-Fu or OMT alone. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which was consistent with our in vitro results. Taken together, our findings indicated that OMT sensitizes HCC to 5-Fu treatment by the suppression of ERK activation through the overproduction of ROS, and combination treatment with OMT and 5-Fu would be a promising therapeutic strategy for HCC treatment.