Intracellular Antioxidant Activity Research Articles

Exploring the Neuroprotective Potential of Desmodium Species: Insights into Radical Scavenging Capacity and Mechanisms against 6-OHDA-Induced Neurotoxicity.

In this study, we collected seven prevalent Taiwanese Desmodium plants, including three species with synonymous characteristics, in order to assess their antioxidant phytoconstituents and radical scavenging capacities. Additionally, we compared their inhibitory activities on monoamine oxidase (MAO) and 6-hydroxydopamine (6-OHDA) auto-oxidation. Subsequently, we evaluated the neuroprotective potential of D. pulchellum on 6-OHDA-induced nerve damage in SH-SY5Y cells and delved into the underlying neuroprotective mechanisms. Among the seven Desmodium species, D. pulchellum exhibited the most robust ABTS radical scavenging capacity and relative reducing power; correspondingly, it had the highest total phenolic and phenylpropanoid contents. Meanwhile, D. motorium showcased the best hydrogen peroxide scavenging capacity and, notably, D. sequax demonstrated remarkable prowess in DPPH radical and superoxide scavenging capacity, along with selective inhibitory activity against MAO-B. Of the aforementioned species, D. pulchellum emerged as the frontrunner in inhibiting 6-OHDA auto-oxidation and conferring neuroprotection against 6-OHDA-induced neuronal damage in the SH-SY5Y cells. Furthermore, D. pulchellum effectively mitigated the increase in intracellular ROS and MDA levels through restoring the activities of the intracellular antioxidant defense system. Therefore, we suggest that D. pulchellum possesses neuroprotective effects against 6-OHDA-induced neurotoxicity due to the radical scavenging capacity of its antioxidant phytoconstituents and its ability to restore intracellular antioxidant activities.

Assessing pollution degree and human health risks from hazardous element distribution in soils near gold mines in a Colombian Andean region: Correlation with phytotoxicity biomarkers

The assessment of human health risk due to the presence of hazardous elements in the environment is now necessary for environmental management and legislative initiatives. This study aims to determine the contamination by As, Cd, Pb, and Cr in soils near gold mines in three municipalities located in the Andean region of Colombia. One of the main objectives of the study is to explore possible correlations between the Lifetime Cancer Risk (LCR) and phytotoxicity biomarkers using a simple and rapid-response plant model, radish (Raphanus sativus L.). In the municipality of Yalí, Puerto Berrío, and Buriticá, the hazardous elements concentrations ranged from 8.1 to 35.5, 1.7 to 892, and 5.8 to 49.8 for As, 0.1 to 4.6, 0.1 to 65.2, and 0.5 to 18.2 for Cd, 18.5 to 201.3, 13.0 to 1908, and 189 to 2345 for Pb, and 5.4 to 118.4, 65.4 to 301, and 5.4 to 102.3 for Cr, respectively. The results showed that the biomarkers intracellular H2O2 concentration, antioxidant activity, and radicle elongation exhibited significant (P < 0.05) variations associated with the concentration of hazardous elements in the soils. Significant correlations (P < 0.05, r > 0.58) were found between the biomarkers and the LCR for Cd, Pb, and Cr, but not for As. The results using biomarkers reveal that soil pH and organic matter content are important variables that control the bioavailability of these elements in the soil. The use of indicators like LCR alone has limitations and should be accompanied by the use of biomarkers that allow for a better understanding of the biological system's response to exposure to potentially toxic elements. The results obtained show the urgent need to implement public policies to minimize exposure to hazardous substances in areas near gold mining projects.

Kigelia africana (Lam.) Benth. fruit inhibits iron-induced lipid peroxidation and ?-amylase enzyme activity

Insufficiencies in insulin secretion and/or action cause diabetes mellitus (DM), a complex condition characterized by abnormal blood glucose levels. Diabetes is often treated by modifying either glucose metabolism, lipids metabolism, or both. A direct correlation has been found between high levels of lipid peroxide in individuals with diabetes and lower intracellular antioxidant activity. Therefore, this study was designed to investigate the effect of the aqueous extract of Kigelia africana fruit on the carbohydrate hydrolyzing enzyme, ?-amylase, and FeSO4-induced lipid peroxidation in the rat pancreas. The in vitro antioxidant potential, including assays for (1,1 diphenyl-2-picryl hydrazyl (DPPH), ferric reducing antioxidant property (FRAP), nitric oxide (NO), hydroxyl (OH) scavenging, and Fe2+ chelating abilities, of the fruit extract was also evaluated. The effect of the fruit extract on the ?-amylase enzyme, and FeSO4-induced lipid peroxidation in the rat pancreas was also evaluated. K. africana at a concentration of 0.5 mg/mL and 1 mg/mL scavenged DPPH radicals, with the lower concentration showing significant differences compared to the control. The K. africana fruit extract reduced ferric compounds significantly compared to the standard. The OH* radical scavenging results revealed that all concentrations of K. africana fruit scavenged OH* radicals without significant differences compared to the control. K. africana fruit also chelated iron significantly compared to the control. The fruit extract inhibited iron-induced lipid peroxidation in the rat pancreas and ?-amylase activity compared to the control. K. africana fruit displayed promising potential in inhibiting ?-amylase activity and associated lipid peroxidation in diabetics. Therefore, it holds strong promise for use in diabetes treatment, validating its traditional use for managing the condition.

Utilization of Nitrogen-Doped Graphene Quantum Dots to Neutralize ROS and Modulate Intracellular Antioxidant Pathways to Improve Dry Eye Disease Therapy.

Patients afflicted with dry eye disease (DED) experience significant discomfort. The underlying cause of DED is the excessive accumulation of ROS on the ocular surface. Here, we investigated the nitrogen doped-graphene quantum dots (NGQDs), known for their ROS-scavenging capabilities, as a treatment for DED. NGQDs were prepared by using citric acid and urea as precursors through hydrothermal method. The antioxidant abilities of NGQDs were evaluated through: scavenging the ROS both extracellular and intracellular, regulating the nuclear factor-erythroid 2-related factor (Nrf2) antioxidant pathway of human corneal epithelial cells (HCECs) and their transcription of inflammation related genes. Furthermore, NGQDs were modified by Arg-Gly-Asp-Ser (RGDS) peptides to obtain RGDS@NGQDs. In vivo, both the NGQDs and RGDS@NGQDs were suspended in 0.1% Pluronic F127 (w/v) and delivered as eye drops in the scopolamine hydrobromide-induced DED mouse model. Preclinical efficacy was compared to the healthy and DPBS treated DED mice. These NGQDs demonstrated pronounced antioxidant properties, efficiently neutralizing free radicals and activating the intracellular Nrf2 pathway. In vitro studies revealed that treatment of H2O2-exposed HCECs with NGQDs induced a preservation in cell viability. Additionally, there was a reduction in the transcription of inflammation-associated genes. To prolong the corneal residence time of NGQDs, they were further modified with RGDS peptides and suspended in 0.1% Pluronic F127 (w/v) to create RGDS@NGQDs F127 eye drops. RGDS@NGQDs exhibited superior intracellular antioxidant activity even at low concentrations (10 μg/mL). Subsequent in vivo studies revealed that RGDS@NGQDs F127 eye drops notably mitigated the symptoms of DED mouse model, primarily by reducing ocular ROS levels. Our findings underscore the enhanced antioxidant benefits achieved by modifying GQDs through nitrogen doping and RGDS peptide tethering. Importantly, in a mouse model, our novel eye drops formulation effectively ameliorated DED symptoms, thereby representing a novel therapeutic pathway for DED management.

Effective enhancement of food oxidative stability induced by Lactobacillus strains: In vitro activity

The potential applications of Lactobacillus strains as natural additives with many health-beneficial effects have fueled current interests to discover their antioxidative activity to delay food oxidation and improve the nutritional and sensory properties. This review summarizes an updated overview of the last decade's progress in the research of food fermentation by Lactobacillus strains to enhance oxidative stability. Many studies assessed the isolation of Lactobacillus strains with antioxidant properties from foods. However, the research on the antioxidant activity of fermented foods incorporating these strains still lacks a comprehensive review. This review focuses on the importance of incorporating Lactobacillus strains in dairy, fruit, vegetable, meat, cereal, and other food products that are susceptible to oxidation. Moreover, the mechanism of action and the available methods for evaluating antioxidant activity by in vitro studies will also be discussed. L. acidophilus, L. helveticus, L. rhamnosus, L. fermentum, L. plantarum, and L. reuteri are the main examples of Lactobacillus stains that successfully improve the antioxidant activity of fermented foods through releasing antioxidant enzymes, producing secondary metabolites, proteolysis activity, scavenging radicals, and formation of intracellular and extracellular antioxidants. The antioxidant activity of fermented foods can be monitored via different mechanisms, mainly based on hydrogen atom transfer and single electron transfer. In conclusion, Lactobacillus stains can provide a good market for novel fermented foods with nutritional properties due to their antioxidant potential. However, more studies are required to discover the effect of the composition, structure, and processing of food on the antioxidant effect of novel identified strains in commercial fabrication.

Control of cyanobacterial bloom and purification of bloom-laden water by sequential electro-oxidation and electro-oxidation-coagulation

The outbreaks of cyanobacterial blooms have caused severe threat to aquatic ecosystem and public health. In this work, electrochemical technology with RuO2/IrO2/Ti (RIT) or/and Al as anode for cyanobacterial bloom control and simultaneous water purification were studied. Compared with RIT-Al and Al electrodes, RIT exhibited the highest effects on bloom algae inactivation and inhibition of algae regrowth. Live/dead analysis, SEM, intracellular reactive oxygen species (ROS) and antioxidant system activities revealed that RIT could disintegrate bloom flocs and damage embedded algal cells due to high intensity of oxidation. With the lysis of cyanobacterial bloom, high content of intracellular compounds containing organic carbon, nitrogen and phosphorus released, necessitating water quality restoration. In the subsequent water purification process, RIT-Al overtook RIT and Al in removal of organic and nutrient pollutants due to the complex effects of electro-oxidation, coagulation, co-precipitation, electro-nitrification and electro-denitrification. Therefore, sequential electro-oxidation and electro-oxidation-coagulation process was an effective method for control cyanobacteria bloom and simultaneous removal of DOM, microcystin-LR (MC-LR), nitrogen and phosphorus, which is a promising technology.

Liver Transcriptome Shows Differences between Acute Hypoxia-Tolerant and Intolerant Individuals of Greater Amberjack (Seriola dumerili).

Acute hypoxia is a common abiotic stress in commercial aquaculture and has significant effects on fish physiology and metabolism. Due to its large size and rapid growth, the greater amberjack (Seriola dumerili) is an economically important fish with high farming value. This species is intolerant to hypoxia, which makes it susceptible to mass mortality and hinders the progress of amberjack cultivation. Based on a comparative analysis of the liver transcriptome between acute hypoxia-tolerant (HT) and -intolerant (HS) groups, this study first explored the molecular mechanisms of acute hypoxia in greater amberjack. By simulating the acute hypoxic environment and using RNA sequencing (RNA-Seq), the differences in liver transcriptional changes between the acute hypoxia-tolerant (HT) and hypoxia-intolerant (HS) groups of greater amberjack were probed. Based on differential expression analysis, 829 differentially expressed genes (DEGs) were screened in both groups. Relative to the HS group, 374 DEGs were upregulated and 455 were downregulated in the HT group. Compared with the HS group, genes such as slc2a5 and prkaa2 related to promoting sugar transport and inhibiting lipid syntheses were upregulated, while genes that inhibit gluconeogenesis and promote lipid syntheses, such as pgp and aacs, were downregulated. The expression of odc1 was significantly and relatively downregulated in the HT group, which would lead to the inhibition of intracellular antioxidant activity and decreased scavenging of ROS. The NF-kB pathway was also promoted to some extent in individuals in the HT group relative to the HS group to resist apoptosis. In addition, the relative downregulation of apoptosis and autophagy-related genes, such as endog, hm13, and casp6, was also detected in the HT group. The present findings first reported the regulation mechanism by which liver tissue coped with the acute hypoxia stress in greater amberjack, which will provide important technical support for preventing acute hypoxia-induced death in advance and reducing economic losses.

Intracellular Redox Behavior of Quercetin and Resveratrol Singly and in Mixtures.

Polyphenols have attracted great interest as potent antioxidant compounds and nutraceuticals; however, their antioxidant properties represent a multifaceted phenomenon, including pro-oxidant effects under particular conditions and complex behavior when multiple polyphenols are simultaneously present. Moreover, their intracellular behavior cannot always be predicted from their ability to counteract the production of ROS in acellular assays. The present work aimed to study the direct intracellular redox activity of two polyphenols, resveratrol and quercetin, singly and in mixture in a cellular short-term bioassay under both basal and pro-oxidant conditions. The study was carried out by spectrofluorimetric assessment of the intracellular fluorescence of CM-H2DCFDA-charged HeLa cells under either basal conditions, due to the reactive species associated with the normal cellular oxidative metabolism, or pro-oxidant conditions induced by H2O2 exposure. Under basal conditions, the obtained results showed a significant antioxidant effect of quercetin and a weaker antioxidant effect of resveratrol when used singly, while antagonism of their effect was detected in their equimolar mixtures at all the concentrations used. Under exposure of the cells to H2O2, quercetin exhibited a dose-dependent intracellular antioxidant activity whereas resveratrol manifested a pro-oxidant intracellular activity, while their equimolar mixtures showed an intracellular interaction between the 2 polyphenols, with additive effects at 5 µM and synergic at 25 µM and 50 µM. Thus, the results clarified the direct intracellular antioxidant/pro-oxidant activity of quercetin and resveratrol alone and in their equimolar mixtures in the cell model HeLa cells and highlighted that the antioxidant properties of polyphenols in mixtures at the cellular level depend not only on the nature of the compounds themselves but also on the type of interactions in the cellular system, which in turn are influenced by the concentration and the oxidative status of the cell.

Growth differentiation factor 15 induces cisplatin resistance through upregulation of xCT expression and glutathione synthesis in gastric cancer.

Gastric cancer is a common cancer worldwide, particularly in East Asia. Chemotherapy is used in adjuvant or palliative therapies for gastric cancer. However, subsequent chemoresistance often develops. Growth differentiation factor 15 (GDF15) links to several cancers, but its effect on chemoresistance in gastric cancer remains unclear. Here, we analyzed clinical samples from genetic databases and included patients with gastric cancer. We dissected the regulatory mechanism underlying GDF15-mediated resistance of cisplatin in human gastric cancer cells. We showed that GDF15 serum levels might be a valuable biomarker for predicting prognosis in gastric cancer. The expressions of GDF15 and its receptor glial cell-derived neurotrophic factor family receptor a-like (GFRAL) in gastric tumors are important for malignant progression. Moreover, GDF15 expression is increased in gastric cancer cells with cisplatin resistance, resulting from elevated intracellular glutathione (GSH) and antioxidant activities. Upregulated GDF15 could increase intracellular GSH content by activating the GFRAL-GCN2-eIF2α-ATF4 signaling, enhancing cystine-uptake transporter xCT expression, and contributing biosynthesis of GSH in human gastric cancer cells. In conclusion, our results indicate that GDF15 could induce chemoresistance by upregulating xCT expression and GSH biosynthesis in human gastric cancer cells. Targeting GDF15 could be a promising treatment method for gastric cancer progression.

Revealing of Intracellular Antioxidants in Dendrobium nobile by High Performance Liquid Chromatography-Tandem Mass Spectrometry

The medicinal plant Dendrobium nobile is an important natural antioxidant resource. To reveal the antioxidants of D. nobile, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for metabolic analysis. The H2O2-induced oxidative damage was used in human embryonic kidney 293T (H293T) cells to assess intracellular antioxidant activities. Cells incubated with flower and fruit extracts showed better cell survival, lower levels of reactive oxygen species (ROS), and higher catalase and superoxide dismutase activities than those incubated with root, stem, and leaf extracts (p &lt; 0.01). A total of 13 compounds were newly identified as intracellular antioxidants by association analysis, including coniferin, galactinol, trehalose, beta-D-lactose, trigonelline, nicotinamide-N-oxide, shikimic acid, 5′-deoxy-5′-(methylthio)adenosine, salicylic acid, isorhamnetin-3-O-neohespeidoside, methylhesperidin, 4-hydroxybenzoic acid, and cis-aconitic acid (R2 &gt; 0.8, Log2FC &gt; 1, distribution &gt; 0.1%, and p &lt; 0.01). They showed lower molecular weight and higher polarity, compared to previously identified in vitro antioxidants in D. nobile (p &lt; 0.01). The credibility of HPLC-MS/MS relative quantification was verified by common methods. In conclusion, some saccharides and phenols with low molecular weight and high polarity helped protect H293T cells from oxidative damage by increasing the activities of intracellular antioxidant enzymes and reducing intracellular ROS levels. The results enriched the database of safe and effective intracellular antioxidants in medicinal plants.

Overexpressing Carotenoid Biosynthetic Genes in Synechocystis sp. PCC 6803 Improved Intracellular Pigments and Antioxidant Activity, Which Can Decrease the Viability and Proliferation of Lung Cancer Cells In Vitro.

In the antioxidant system in cyanobacteria, non-enzymatic antioxidants, such as carotenoids, are considered good candidates for coping with oxidative stress, particularly light stress, and pharmaceutical therapeutic applications. A significant amount of carotenoid accumulation has been recently improved by genetic engineering. In this study, to achieve higher carotenoid production with higher antioxidant activity, we successfully constructed five Synechocystis sp. PCC 6803 strains overexpressing (OX) native genes related to the carotenoids biosynthetic pathway, including OX_CrtB, OX_CrtP, OX_CrtQ, OX_CrtO, and OX_CrtR. All of the engineered strains maintained a significant quantity of myxoxanthophyll, while increasing zeaxanthin and echinenone accumulation. In addition, higher components of zeaxanthin and echinenone were noted in all OX strains, ranging from 14 to 19% and from 17 to 22%, respectively. It is worth noting that the enhanced echinenone component responded to low light conditions, while the increased β-carotene component contributed to a high light stress response. According to the higher antioxidant activity of all OX strains, the carotenoid extracts presented lower IC50 in lung cancer cell lines H460 and A549, with values less than 157 and 139 µg/mL, respectively, when compared with those of WTc, particularly OX_CrtR and OX_CrtQ. A higher proportion of zeaxanthin and β-carotene in OX_CrtR and OX_CrtQ, respectively, may considerably contribute to the ability to treat lung cancer cells with antiproliferative and cytotoxic effects.

Efficient inactivation of harmful algae K. mikimotoi by a novel algicidal bacterium via a rare direct contact pathway: Performances and mechanisms

Harmful algal blooms (HABs) caused by Karenia mikimotoi have posed great threats to marine ecosystems, and algal inactivation by symbiotic bacteria has been recognized as environmental benign methods for controlling HABs. However, the identified algicidal bacteria for K. mikimotoi is limited and exclusively based on indirect algicidal pathways, which may cause secondary pollution due to releasing toxic algicidal agents. In this study, a novel strain of algicidal bacteria Tenacibaculum sp. GD3 was isolated from the phycosphere of K. mikimotoi. The bacterial strain GD3 could achieve 92.6 % of inactivation efficiency against K. mikimotoi within 8 h of co-culturing period, which outperformed those in existing literatures reported so far. The algicidal mechanisms were revealed to be a rare direct cell-to-cell contact pathway, and the GD3 could grow by utilizing metabolites from K. mikimotoi, exhibiting excellent bacterial adaptability in the phycosphere. Cell morphology changes were monitored by live cell imaging system combined with SEM and TEM observations, which showed that the GD3 was first attached to the algal cell membrane, followed by lipid peroxidation and lysis of membrane protein. Oxidative stress responses were induced as reveled by up-regulation of intracellular ROSs and antioxidant enzyme activity. Photosynthetic parameters including rETRmax, Fv/Fm, YII and NPQ were reduced, and expression of functional genes involved in decomposition of chlorophyll and cell wall was significantly suppressed. Moreover, the intracellular release profile and acute toxicity assessment indicated that the GD3 could also detoxify the K. mikimotoi cultures and the released biomolecules would not cause adverse effect to marine environment. This study not only provides a novel algicidal bacterium against K. mikimotoi via a rare direct mode, but also helps to better understand the algicidal mechanisms at physiological and genetic level, thus moving forward the areas of HABs control by microbiological strategies.

Antioxidant Activity, Metabolism, and Bioavailability of Polyphenols in the Diet of Animals.

As the world's population grows, so does the need for more and more animal feed. In 2006, the EU banned the use of antibiotics and other chemicals in order to reduce chemical residues in food consumed by humans. It is well known that oxidative stress and inflammatory processes must be combated to achieve higher productivity. The adverse effects of the use of pharmaceuticals and other synthetic compounds on animal health and product quality and safety have increased interest in phytocompounds. With the use of plant polyphenols in animal nutrition, they are gaining more attention as a supplement to animal feed. Livestock feeding based on a sustainable, environmentally friendly approach (clean, safe, and green agriculture) would also be a win-win for farmers and society. There is an increasing interest in producing healthier products of animal origin with a higher ratio of polyunsaturated fatty acids (PUFAs) to saturated fatty acids by modulating animal nutrition. Secondary plant metabolites (polyphenols) are essential chemical compounds for plant physiology as they are involved in various functions such as growth, pigmentation, and resistance to pathogenic organisms. Polyphenols are exogenous antioxidants that act as one of the first lines of cell defense. Therefore, the discoveries on the intracellular antioxidant activity of polyphenols as a plant supplement have contributed significantly to the improvement of antioxidant activity, as polyphenols prevent oxidative stress damage and eliminate excessively produced free radicals. To achieve animal welfare, reduce stress and the need for medicines, and increase the quality of food of animal origin, the addition of polyphenols to research and breeding can be practised in part with a free-choice approach to animal nutrition.

In Vitro Fermentation Characteristics of Pine Needles (Pinus densiflora) as Feed Additive

In this study, the fermentation characteristics of pine needles were investigated for the first time and the possibility of using them as plant-derived feed additives was confirmed. Four types of fermented pine needle were prepared: (1) natural fermentation (CON); (2) Lactobacillus plantarum SK4315 fermentation (LPF); (3) Saccharomyces cerevisiae SK3587 fermentation (SCF); and (4) co-culture fermentation (CCF). Fermentation lasted 48 h, and samples were taken at 4-h intervals until 12 h, then at 24 and 48 h. As analysis items, fermentation characteristics, antibacterial, antioxidant, and enzymatic activities were investigated. As a result, all pine needle cultures were fermented with changes in the number of viable cells and pH. LPF inhibited the growth of the most pathogens, and the activity became stronger with fermentation. Total polyphenol content (TPC) was the highest in the 48 h SCF and LPF samples, ABTS radical scavenging ability and intracellular antioxidant activity were higher in SCF. Enzymatic activities were different depending on each pine needle culture medium and the fermentation time. In summary, all pine needle cultures were normally fermented, and as fermentation progressed, LPF strengthened antibacterial activity and SCF strengthened antioxidant activity. This study confirmed the potential of fermented pine needles as a feed additive, showing an enhancement of biological activity.

Encapsulation of lycopene into electrospun nanofibers from whey protein isolate-Tricholoma lobayense polysaccharide complex stabilized emulsions: Structural characterization, storage stability, in vitro release, and cellular evaluation

In this study, lycopene-loaded nanofibers were successfully fabricated by electrospinning of oil-in-water (O/W) emulsions stabilized by whey protein isolate-polysaccharide TLH-3 (WPI–TLH-3) complexes. The lycopene encapsulated in the emulsion-based nanofibers exhibited enhanced photostability and thermostability, and achieved improved targeted small intestine-specific release. The release of lycopene from the nanofibers followed Fickian diffusion mechanism in simulated gastric fluid (SGF) and first-order model in simulated intestinal fluid (SIF) with the enhanced release rates. The bioaccessibility and cellular uptake efficiency of lycopene in micelles by Caco-2 cells after in vitro digestion were significantly improved. The intestinal membrane permeability and transmembrane transport efficiency of lycopene in micelles across Caco-2 cells monolayer were greatly elevated, thus promoting the effective absorption and intracellular antioxidant activity of lycopene. This work opens a potential approach for electrospinning of emulsions stabilized by protein–polysaccharide complexes as a novel delivery system for liposoluble nutrients with enhanced bioavailability in functional food industries.

Phytochemical and biological study of phenolic components from Geoffroea decorticans stem bark

The stem bark of Geoffroea decorticans(Gill.ex Hook. etArn.) Burk. was used medicinally to cure several skin affections; however, phytochemical and biological antecedents were not found. Analyses of purified methanolic extract from G. decorticansbark (PFGB), realized by silylation derivatization for GC/MS, C18-CC and HPLC followed by two-dimensional TLC and UV-Vis spectroscopy, allowed to characterize nine phenolic compounds, among these, two methoxy flavonoids. Antibacterial assays of PFGB showed the highest activity (MICs= 125 μg/mL) against Staphylococcus aureus(25923) and Enterococcus faecalis(29212) ATCC strains. Moreover, PFGB showed the highest intracellular antioxidant activity at low concentration (5 μg/mL), evaluated by using the fluorescent DA-H2DCF probe on lymphocyte culture; cytotoxic effects on lymphocytes activated or not by LPS were not observed, through Trypan Blue Exclusion and MTT colorimetric assays.The results obtained from the ethnomedicinal approach of this work contribute to the scientific validation of the vulnerary medicinal use of G. decorticans.

Evaluation of the extract of traditional Chinese medicine formula Si Ben Cao for skin whitening

ObjectiveTo evaluate the safety, potential benefits and possible mechanisms of the extract of Si Ben Cao (SBC), a traditional Chinese medicine formula composed of four herbs, for skin whitening. MethodsThe reflux method was performed to prepare the extract of SBC. MTT assay was used to evaluate the cytotoxic of SBC extract in vitro. Skin irritation test and skin allergy test on rats were performed to evaluate the safety of SBC extract in vivo. Intercellular melanin production was analyzed to assess the function of SBC extract for whitening. Afterwards, we analyzed the activity of intracellular tyrosinase, Ultraviolet (UV) absorption, and anti-oxidant activity, which were related to melanin production. ResultsThe aqueous extract and ethanol extract of SBC were prepared separately. MTT assay results showed aqueous extract of SBC at a concentration of 100 μg/mL had no inhibitory effect on the proliferation of B16F10 cells even after treatment for 96 h, indicating that aqueous extract of SBC was not cytotoxic. Thus, we conducted subsequent experiments using aqueous extract of SBC. The results on rats showed SBC extract was safe to apply on the skin without causing irritation and allergies. Analysis of melanin content showed SBC extract had inhibitory effect on cellular melanin generation and secretion. Moreover, we found that SBC extract was able to reduce cellular tyrosinase activity, as well as absorb UV light and scavenge DPPH radicals for anti-oxidants. ConclusionOur data clearly demonstrated that SBC extract is safe and effective for skincare, and it is suitable for use with the purpose of skin whitening and health benefits.

Application of a HyPer-3 sensor to monitor intracellular H2O2 generation induced by phenolic acids in differentiated Caco-2 cells

Intestinal epithelial cells (IECs) are an important point of contact between dietary food components consumed and subsequent whole-body utilization for body maintenance and growth. Selective bioactive phenolic acids, widely present in fruits, vegetables and beverages can generate hydrogen peroxide (H2O2) and contribute to the cellular redox balance, hence influencing well-known cellular antioxidant and pro-oxidant mechanisms. Our findings have showed that increasing extracellular H2O2 resulted in associated changes in intracellular H2O2 levels in Caco-2 cells (p < 0.05) which was facilitated by activity of a family of water channel membrane proteins, termed aquaporins (AQPs). To demonstrate this, a HyPer-3 genetically encoded fluorescent H2O2 sensitive indicator was used to enable fluorescent real-time imaging of intracellular H2O2 levels as a measure of changes occurring in extracellular H2O2 in differentiated Caco-2 cells exposed to different phenolic acids. The use of confocal microscopy and flow cytometry, respectively, captured visualization and quantification of H2O2 uptake in differentiated Caco-2 cells. DFP00173, an aquaporin 3 (AQP3) inhibitor was effective at inhibiting the intracellular uptake of H2O2 and was sensitive to varied levels of H2O2 generated when different phenolic acids were added to the culture media. In summary, HyPer-3 was shown to be an effective technique to demonstrate relative capabilities of structurally different dietary phenolic acids that have potential to alter intestinal redox balance by changing intracellular H2O2, and either antioxidant or pro-oxidant activity, respectively.

Polysaccharides from tropical green seaweed Chaetomorpha antennina induces non-specific immune responses and improves antioxidative activities in common carp (Cyprinus carpio) leukocyte culture cell line

Polysaccharides from seaweeds are promising biomolecules that could sustainably improve the health status of cultured fish species. In this study, water-soluble polysaccharides extracted from Chaetomorpha antennina were investigated to determine their physicochemical characteristics and biological activities. C. antennina water-soluble polysaccharides (CAWP) comprised mainly of carbohydrate (69.0 ± 2.3 %), sulphate (12.6 ± 0.5 %), uronic acid (8.8 ± 0.1 %) and protein (3.5 ± 0.2 %). High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD) analysis revealed that CAWP contained mostly arabinose (17.1 ± 2.3 mg/L), galactose (9.3 ± 1.0 mg/L), glucose (5.1 ± 0.6 mg/L), xylose/mannose (1.4 ± 0.6 mg/L) and a small proportion of fucose (0.3 ± 0.1 mg/L). CAWP, with intrinsic viscosity of 0.66 dL/g and estimated molecular weight of 318 kDa, were non-toxic to Carp leukocyte culture (CLC) cell line at concentrations ≤25 μg/mL. CAWP at concentrations of 12.5 and 25 μg/mL stimulated CLC to release significant amount of nitric oxide (NO), reactive oxygen species (ROS) and augmented phagocytic activity. Intracellular antioxidant activities indicated that CAWP did not induce oxidative damage in CLC but could improve superoxide dismutase activity (SOD), total glutathione (tGSH) and decrease malondialdehyde (MDA) level. The findings from our study provide a foundation for the applicability of water-soluble polysaccharides from C. antennina in the aquaculture industry as a potent immunomodulatory agent. • Chaetomorpha antennina is a rich source of sulphated polysaccharides. • Induction of oxidative burst response in Carp leucocytes • Phagocytosis of Red Zymosan® bioparticles by Carp leucocytes • Improved intracellular antioxidant activities

Size-effect on the intracellular antioxidative activity of Prussian blue nanoparticles investigated by atomic force microscopy

Nanoparticles-based antioxidative therapy has been highlighted in a series of diseases triggered by excessive reactive oxygen species (ROS). Prussian blue nanoparticles (PBNPs), as a representative artificial nanozyme, have been proved as highly effective ROS scavengers. However, its detailed intracellular antioxidant mechanism is not clear yet. Herein, a series of PBNPs with different particle sizes were synthesized and their intracellular antioxidant activities were studied by atomic force microscopy (AFM) from a biomechanical perspective. We first validated the ROS scavenging ability of PBNPs in vitro. It indicated that PBNPs had great scavenging effect on multiple ROS, such as hydroxyl radicals (•OH), superoxide radicals (O2•−) and hydrogen peroxide (H2O2). By observing the changes in morphology and mechanical properties of human umbilical vascular endothelium cells (HUVECs), it was further found that PBNPs could apparently alleviate the decrease of Young's modulus caused by oxidative stress damage and kept cells in their normal morphology. In addition, the distribution of F-actin revealed that the enhancement of cytoskeleton stability by PBNPs might be a key way to protect HUVECs from oxidative damage. Importantly, the antioxidant activities of PBNPs were found to be size-dependent, which indicated the smaller particle size had better antioxidant activities compared with the larger particle size. This study serves as a novel medium to reveal the mechanism of nanoparticles on cells at the single-cell level and demonstrates the great potential of atomic force microscopy in studying the application of nanoparticles in cell biology.