Ferritin-dependent radical generation in rat liver homogenates

The hypothesis of this study was that mammalian ferritin (FER) has the ability of releasing Fe in the tissue to catalyze the generation of free radicals, such as ascorbyl (A) and hydroxyl radical (OH), that might lead to the damage of FER itself. The rat liver homogenates exhibited an electron paramagnetic resonance (EPR) signal with the spectral features (a_H = 1.88 G, g = 2.0054) of A. The addition to the reaction medium of isolated rat liver FER increased by 3-fold the EPR signal, as compared to the recorded value in its absence. Isolated microsomes from rat liver incubated during 10 min showed a signal with the spectral features (a_H = 15 G, g = 2.0062) of OH. The addition of FER in the presence of either ethylenediamine-tetraacetic acid (EDTA) or adenosine-5′-triphosphate (ATP) significantly increased the recorded spectra. The labile Fe pool (LIP) in the homogenate was assessed by EPR. The rat liver homogenates exhibited an EPR signal with the spectral features (g = 4.3) of the Fe²⁺ and was significantly increased by the addition of FER (3-fold). The oxidation profile of the isolated FER from rat liver was analyzed after incubation with 10 mM ascorbate (AH^?). A drastic increase in the width of the band suggested alterations to the protein structure. The FER content of tryptophan (Trp) and thiols was significantly lower when the incubation was performed in the presence of AH^? as compared to the recorded effect in its absence. The data in tissue homogenates presented here showed that radical generation is associated to FER Fe release, and moreover that the FER protein itself was affected during this process.     

The co-application effects of fullerene and ascorbic acid on UV-B irradiated mouse skin

The role of fullerene as a pro-oxidant or anti-oxidant in Ultraviolet B ray (UV-B)-induced disorders in mouse skin was investigated. Fullerene gave no photo-toxic effect to UV-B-irradiated mouse skin. Since erythema was concentrated at the pore circumference in a UV-B irradiation experiment in mouse skin, the sebaceous gland pairs was strongly implicated as a site for the generation of reactive oxygen species (ROS). In a histological evaluation of the skin stained with CH₃MDFDA (ROS index) and YO-Pro-1 (apoptosis index), the fluorescence intensity of a sebaceous gland significantly increased with UV-B irradiation. With the application of fullerene to UV-irradiated mouse skin, no toxicity was recognized in comparison with the control, and erythema, the ROS index, and the apoptosis index decrease with the application of fullerene. Ascorbyl radical (AA) increased with the application of ascorbate (AA) to UV-B-irradiated mouse skin, and AA decreased with the application of fullerene. The co-application of AA and fullerene, which suppressed AA in vitro, significantly suppressed erythema, and also suppressed both the ROS index and apoptosis index in mouse skin after UV-B irradiation. In both mouse skin at 48 h after UV-B irradiation and in an attempt to reproduce this phenomenon artificially in vitro, a similar high AA peak (AA/H > 4) was observed in electron spin resonance (ESR) charts. The binding of fullerene with AA impairs the Fenton reaction between AA and Fe-protein based on the observation of ascorbate-specific UV absorption and a linear equation for the calibration curve. Therefore, fullerene may impair the intercalation of AA to a heme pocket by binding with AA. These results suggest that the co-application of AA and fullerene is effective against oxidative skin damage caused by UV-B irradiation, and the development of an AA inhibitor such as fullerene should be useful for reducing organ damage associated with Fe-protein oxidation.     

Acute iron overload and oxidative stress in brain

An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6 h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A)/ascorbate (AH^?) ratio, taken as oxidative stress index, was assessed. The A/AH^? ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8 h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21 h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6 h after Fe administration. CAT activity was significantly increased after 8 h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR generation rate after 6 h of Fe overload. This information has potential clinical relevance, as it could be the key to understand specific brain damage occurring in conditions of Fe overload.     

Hydroxyl radical induced by lipid in Maillard reaction model system promotes diet-derived Nε-carboxymethyllysine formation

N_ε-carboxymethyllysine (CML) is commonly found in food, and is considered as a potential hazard to human health. However, the effect of lipids on CML formation in Maillard reaction is still not clarified. In this study, the content of diet-derived CML and its key intermediates, epsilon-fructoselysine (FL) and glyoxal (GO), is determined with high performance liquid chromatography mass spectrum (HPLC-MS) in model system containing lipid compounds. According to the results, hydroxyl radical (OH) induced by Fenton reagent can promote the three pathways of CML formation. Moreover, in the Maillard reaction system, linoleic acid (Lin), oleic acid (Ole) and glycerol trioleate (Tri) can induce more OH, which promotes CML formation. Their level of promoting CML formation is in the order of Ole > Lin > Tri. On the contrary, glycerol (Gly) can scavenge OH, which inhibit the CML formation. Finally, it is proved that FL content and GO content decreases with heating time in model system, while CML content increases with heating time. Thus, it is concluded that in the Maillard reaction system lipids can induce more OH, which promotes the conversion from FL and GO to CML. Our research may contribute to the development of inhibitory methods for diet-derived CML by scavenging OH.     

Chemical composition and bioactivities of flavonoids-rich extract from Davallia cylindrica Ching

The flavonoids profiles and bioactivities of flavonoids-rich extract from Davallia cylindrica Ching were investigated. The total flavonoids content in D. cylindrica was determined as about 164.41 mg/g. The main flavonoids in D. cylindrica were tentatively identified as quercetin-3-O-rutinoside, quercetin 7-O-glucoside, quercetin 7-O-glucoside, kaempferol 3-O-rutinoside, and quercitrin by UV and ESI-MS spectra. Flavonoids-rich extract (0.258 mg/ml) from D. cylindrica showed similar or higher free radical (O₂⁻, DPPH and ABTS) scavenging potential with that of rutin (0.25 mg/ml). The reducing power of flavonoids-rich extract (0.258 mg/ml) was slightly stronger than that of 0.25 mg/ml rutin. The flavonoids extract from D. cylindrica exhibited cytotoxic effects on A549 cells. It exhibited a dose-dependent inhibition against acetylcholinesterase.     

Angolan Cymbopogon citratus used for therapeutic benefits: Nutritional composition and influence of solvents in phytochemicals content and antioxidant activity of leaf extracts

Folk medicine is a relevant and effective part of indigenous healthcare systems which are, in practice, totally dependent on traditional healers. An outstanding coincidence between indigenous medicinal plant uses and scientifically proved pharmacological properties of several phytochemicals has been observed along the years.This work focused on the leaves of a medicinal plant traditionally used for therapeutic benefits (Angolan Cymbopogon citratus), in order to evaluate their nutritional value. The bioactive phytochemical composition and antioxidant activity of leaf extracts prepared with different solvents (water, methanol and ethanol) were also evaluated.The plant leaves contained ∼60% of carbohydrates, protein (∼20%), fat (∼5%), ash (∼4%) and moisture (∼9%). The phytochemicals screening revealed the presence of tannins, flavonoids, and terpenoids in all extracts. Methanolic extracts also contained alkaloids and steroids. Several methods were used to evaluate total antioxidant capacity of the different extracts (DPPH, NO, and H₂O₂ scavenging assays, reducing power, and FRAP). Ethanolic extracts presented a significantly higher antioxidant activity (p < 0.05) except for FRAP, in which the best results were achieved by the aqueous extracts. Methanolic extracts showed the lowest radical scavenging activities for both DPPH and NO radicals.     

Polyphenolic constituents of methanolic and aqueous extracts of Vitex negundo render protection to Hep3B cells against oxidative cytotoxicity

This study was aimed at investigating the phenolic constituents of methanolic and aqueous extracts of Vitex negundo in context of antioxidant potential and inhibition of oxidative stress-induced cytotoxicity. Antioxidant efficacies of both extracts were estimated by their abilities to scavenge DPPH and to reduce Fe⁺³ to Fe⁺². Their protective potential against H₂O₂-driven oxidative damage to cells were evaluated by XTT assay in Hep3B (human hepatoma) cells. Total phenolic content of both extracts were estimated, and were tested for correlation with antioxidant potential and protection against oxidative cytotoxicity. Polyphenolic levels in both extracts showed significant (P < 0.05) positive correlations with DPPH scavenging, Fe⁺³–Fe⁺² reduction and percentage decrease in H₂O₂-induced cytotoxicity. Major phenolic compounds in the extracts were identified by HPLC. It was concluded that both V. negundo extracts hold considerable potential as antitheses of free radical toxicity by virtue of their polyphenolic constituents, and might have significant clinical roles in prospect.     

Effects of oxidative stress on apoptosis in manganese-induced testicular toxicity in cocks

Manganese (Mn) is a trace element known to be essential for maintaining the proper function and regulation of many biochemical and cellular reactions. However, little is known about the reproductive toxicity of Mn in birds. To investigate the toxicity of Mn on male reproduction in birds, 50-day-old cocks were fed either a commercial diet or a Mn-supplemented diet containing 600, 900, and 1800 mg/kg MnCl₂. After being treated with Mn for 30, 60, and 90 d, the following were determined: Mn content; histological and ultrastructural changes in the testes, apoptosis; the malondialdehyde (MDA) level; the activities of superoxide dismutase (SOD); the inhibition ability of hydroxyl radicals (OH); the levels of nitric oxide (NO), nitric oxide synthase (NOS), and protein carbonyl in the testes; the DNA–protein crosslinks (DPC); and the activity of the ATP enzyme. Exposure to Mn significantly lowered the activity of SOD and glutathione peroxidase (GPx) and the inhibition ability of OH. Mn exposure also increased the levels of MDA, NO, NOS, DPC, and protein carbonyl; the number of apoptotic cells; and the Mn content and caused obvious histopathological changes in the testes. These findings suggested that Mn exposure resulted in the oxidative damage of cock testicular tissue by altering radical formation, ATP enzyme systems, apoptosis, and DNA damage, which are possible underlying reproductive toxicity mechanisms induced by Mn exposure.     

Potent inhibition of human neutrophil activations by bractelactone,a novel chalcone from Fissistigma bracteolatum

Fissistigma bracteolatum is widely used in traditional medicine to treat inflammatory diseases. However, its active components and mechanisms of action remain unclear. In this study, (3Z)-6,7-dihydroxy-4-methoxy-3-(phenylmethylidene)-5-(3-phenylpropanoyl)-1-benzofuran-2(3H) (bractelactone), a novel chalcone from F. bracteolatum, showed potent inhibitory effects against superoxide anion (O₂^?) production, elastase release, and CD11b expression in formyl-l-methionyl-l-leucyl-l-phenylalanine (FMLP)-induced human neutrophils. However, bractelactone showed only weak inhibition of phorbol myristate acetate-caused O₂^? production. The peak cytosolic calcium concentration ([Ca^2 +]_i) was unaltered by bractelactone in FMLP-induced neutrophils, but the decay time of [Ca^2 +]_i was significantly shortened. In a calcium-free solution, changes in [Ca^2 +]_i caused by the addition of extracellular Ca^2 + were inhibited by bractelactone in FMLP-activated cells. In addition, bractelactone did not alter the phosphorylation of p38 MAPK, ERK, JNK, or AKT or the concentration of cAMP. These results suggest that bractelactone selectively inhibits store-operated calcium entry (SOCE). In agreement with this concept, bractelactone suppressed sustained [Ca^2 +]_i changes in thapsigargin-activated neutrophils. Furthermore, bractelactone did not alter FMLP-induced formation of inositol 1,4,5-triphosphate. Taken together, our results demonstrate that the anti-inflammatory effects of bractelactone, an active ingredient of F. bracteolatum, in human neutrophils are through the selective inhibition of SOCE.     

Hydrogen inhalation ameliorates lipopolysaccharide-induced acute lung injury in mice

Acute lung injury (ALI) is a serious illness, the incidence and mortality of which are very high. Free radicals, such as hydroxyl radicals (OH) and peroxynitrite (ONOO⁻), are considered to be the final causative molecules in the pathogenesis of ALI. Hydrogen, a new antioxidant, can selectively reduce OH and ONOO⁻. In the present study, we investigated the hypothesis that hydrogen inhalation could ameliorate ALI induced by intra-tracheal lipopolysaccharide (LPS, 5 mg/kg body weight). Mice were randomized into three groups: sham group (physiological saline + 2% hydrogen mixed gas), control group (LPS + normal air) and experiment group (LPS + 2% hydrogen mixed gas). Bronchoalveolar lavage fluid (BALF) was performed to determine the total protein concentrations and pro-inflammatory cytokines. Lung tissues were assayed for oxidative stress variables, wet/dry (W/D) ratio, histological, immunohistochemistry and Western blotting examinations. Our experiments exhibited that hydrogen improved the survival rate of mice and induced a decrease in lung W/D ratio. In addition, hydrogen decreased malonaldehyde and nitrotyrosine content, inhibited myeloperoxidase and maintained superoxide dismutase activity in lung tissues and associated with a decrease in the expression of TNF-α, IL-1β, IL-6 and total protein concentrations in the BALF. Hydrogen further attenuated histopathological alterations and mitigated lung cell apoptosis. Importantly, hydrogen inhibited the activation of P-JNK, and also reversed changes in Bax, Bcl-xl and caspase-3. In conclusion, our data demonstrated that hydrogen inhalation ameliorated LPS-induced ALI and it may be exerting its protective role by preventing the activation of ROS–JNK–caspase-3 pathway.     

Luteolin reduces high glucose-mediated impairment of endothelium-dependent relaxation in rat aorta by reducing oxidative stress

While luteolin, a flavone rich in many plants, has some cardiovascular activity, it is not clear whether luteolin has beneficial effects on the vascular endothelial impairment in hyperglycemia/high glucose. Here, we reveal the protective effect of luteolin on endothelium-dependent relaxation in isolated rat aortic rings exposed to high glucose. The thoracic aorta of male Sprague–Dawley rats was rapidly dissected out and the effect of luteolin on the tension of aortic rings pretreated with high glucose (44 mM) for 4 h was measured in an organ bath system. The levels of nitric oxide (NO), hydroxy radical (OH^?) and reactive oxygen species (ROS), and the activity of superoxide dismutase (SOD) and nitric oxide synthase (NOS) were measured in aortas. The vasorelaxation after treatment with luteolin for 8 weeks in aortic rings from diabetic rats was also determined. We found that exposure to high glucose decreased acetylcholine-induced endothelium-dependent relaxation. However, high mannitol had no effect on vasorelaxation. Luteolin evoked a concentration-dependent relaxation in aortic rings previously contracted by phenylephrine, and the pD₂ value was 5.24 ± 0.04. The EC₅₀ of luteolin markedly attenuated the inhibition of relaxation induced by high glucose, which was significantly weakened by pretreatment with l-NAME (0.1 mM), but not by indomethacin (0.01 mM). Luteolin significantly inhibited the increase of ROS level and OH^? formation, and the decrease of NO level, NOS and SOD activity caused by high glucose. The improving effect of luteolin on endothelium-dependent vasorelaxation in diabetic rat aortic rings was reversed by pretreatment with l-NAME or methylene blue. The results indicate that the decrease of endothelium-dependent relaxation in rat aortic rings exposed to high glucose is markedly attenuated by luteolin, which may be mediated by reducing oxidative stress and enhancing activity in the NOS–NO pathway.     

Epigallocatechin-3-gallate induces cytokine production in mast cells by stimulating an extracellular superoxide-mediated calcium influx

The green tea polyphenol (−)-epigallocatechin-3-O-gallate (EGCG) has various biological activities, including anti-inflammatory, anti-neoplastic, anti- and pro-apoptotic, and neuroprotective effects. Although these are often associated with increased intracellular reactive oxygen species (ROS) and Ca²⁺ levels, their involvement in biological effects is poorly understood. Here we report that EGCG induces cytokine production in mast cells via Ca²⁺ influx and ROS generation. EGCG at concentrations of ≥50 μM induced interleukin-13 and tumor necrosis factor-α production in RBL-2H3 and bone marrow-derived mast cells. The effects were dependent on extracellular Ca²⁺, and EGCG induced Ca²⁺ release from intracellular stores and Ca²⁺ influx. Ca²⁺ influx was suppressed by 2-aminoethoxydiphenyl borate, an inhibitor of store-operated Ca²⁺ (SOC) channels, including Ca²⁺ release-activated Ca²⁺ channels and transient receptor potential canonical channels. EGCG failed to induce Ca²⁺ influx through SOC channels. EGCG-activated Ca²⁺ channels were genetically and pharmacologically distinct from Ca_v1.2 L-type Ca²⁺ channels, another route of Ca²⁺ influx into mast cells. EGCG evoked release of superoxide (O₂⁻) into the extracellular space. Exogenous superoxide dismutase, but not catalase, inhibited EGCG-evoked Ca²⁺ influx and cytokine production, indicating that extracellular O₂⁻ regulates these events. EGCG can serve as a powerful tool for studying O₂⁻-regulated Ca²⁺ channels, which may be selectively involved in the regulation of cytokine production but have yet to be elucidated.     

Protection of coronary endothelial cells from cigarette smoke-induced oxidative stress by a new MnII-containing polyamine-polycarboxilate scavenger of superoxide anion

Oxidative stress plays a major role in cardiovascular injury and dysfunction induced by cigarette smoke. Smoke-borne pro-oxidants impair endothelial function and predispose to thrombosis, inflammation and atherosclerosis. This in vitro study evaluates whether Mn^II(4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diacetate).2H₂O (Mn^II(Me₂DO2A)), a polyamine–polycarboxilate, Mn^II-containing O₂⁻ scavenger, has a direct protective action on guinea pig coronary endothelial (GPCE) cells exposed to cigarette smoke extracts (CSE).Mn^II(Me₂DO2A) (1–10 μmol/l) was added to the culture medium together with CSE and maintained for 4 h. In parallel experiments, the inactive congener Zn^II(Me₂DO2A), in which Zn^II replaced the functional Mn^II center in the same organic scaffold, was used as negative control.Mn^II(Me₂DO2A), mostly at the higher doses (5 and 10 μmol/l), significantly increased GPCE cell viability (trypan blue assay), improved mitochondrial activity (MTT test, mitochondrial membrane potential Δψ), reduced cellular apoptosis (mPTP, caspase-3 activity, TUNEL assay), decreased intracellular ROS levels (H₂DCFDA), lipoperoxidation (BODIPY 581/591) and decreased protein nitrosylation. Of note, Zn^II(Me₂DO2A) did not preserve cell viability. These findings suggest that Mn^II(Me₂DO2A) is a promising O₂⁻ scavenging compound able to protect from cigarette smoke-induced oxidative cell injury. In perspective, should its efficacy be confirmed in future in vivo studies, this molecule might represent a therapeutic or preventive drug to counteract cigarette smoke toxicity.     

In vitro cellular responses to silicon carbide particles manufactured through the Acheson process: Impact of physico-chemical features on pro-inflammatory and pro-oxidative effects

Silicon carbide (SiC) an industrial-scale product manufactured through the Acheson process, is largely employed in various applications. Its toxicity has been poorly investigated. Our study aims at characterizing the physico-chemical features and the in vitro impact on biological activity of five manufactured SiC powders: two coarse powders (SiC C1/C2), two fine powders (SiC F1/F2) and a powder rich in iron impurities (SiC I). RAW 264.7 macrophages were exposed to the different SiC particles and the cellular responses were evaluated. Contrary to what happens with silica, no SiC cytotoxicity was observed but pro-oxidative and pro-inflammatory responses of variable intensity were evidenced. Oxidative stress (H₂O₂ production) appeared related to SiC particle size, while iron level regulated pro-inflammatory response (TNFα production). To investigate the impact of surface reactivity on the biological responses, coarse SiC C1 and fine SiC F1 powders were submitted to different thermal treatments (650–1400 °C) in order to alter the oxidation state of the particle surface. At 1400 °C a decrease in TNFα production and an increase in HO, COO⁻ radicals production were observed in correlation with the formation of a surface layer of crystalline silica. Finally, a strong correlation was observed between surface oxidation state and in vitro toxicity.     

Reactive oxygen species regulate properties of transformation in UROtsa cells exposed to monomethylarsonous acid by modulating MAPK signaling

UROtsa cells exposed to 50 nM monomethylarsonous acid [MMA(III)] for 52 wk (MSC52) achieved hyperproliferation, anchorage independent growth, and enhanced tumorgenicity. MMA(III) has been shown to induce reactive oxygen species (ROS), which can lead to activation of signaling cascades causing stress-related proliferation of cells and even cellular transformation. Previous research established the acute activation of MAPK signaling cascade by ROS produced by MMA(III) as well as chronic up regulation of COX-2 and EGFR in MSC52 cells. To determine if ROS played a role in the chronic pathway perturbations by acting as secondary messengers, activation of Ras was determined in UROtsa cells [exposed to MMA(III) for 0–52 wk] and found to be increased through 52 wk most dramatically after 20 wk of exposure. Ras has been shown to cause an increase in O₂^? and be activated by increases in O₂^?, making ROS important to study in the transformation process. COX-2 upregulation in MSC52 cells was confirmed by real time RT-PCR. By utilizing both antioxidants or specific COX inhibitors, it was shown that COX-2 upregulation was dependent on ROS, specifically, O₂^?. In addition, because previous research established the importance of MAPK activation in phenotypic changes associated with transformation in MSC52 cells, it was hypothesized that ROS play a role in maintaining phenotypic characteristics of the malignant transformation of MSC52 cells. Several studies have demonstrated that cancer cells have lowered superoxide dismutase (MnSOD) activity and protein levels. Increasing levels of MnSOD have been shown to suppress the malignant phenotype of cells. SOD was added to MSC52 cells resulting in slower proliferation rates (doubling time = 42 h vs. 31 h). ROS scavengers of OH also slowed proliferation rates of MSC52 cells. To further substantiate the importance of ROS in these properties of transformation in MSC52 cells, anchorage independent growth was assessed after the addition of antioxidants, both enzymatic and non-enzymatic. Scavengers of OH, and O₂^? blocked the colony formation of MSC52 cells. These data support the role for the involvement of ROS in properties of transformation of UROtsa cells exposed to MMA(III).     

Polycyclic aromatic hydrocarbons enhance the production of phorbol 12-myristate 13-acetate-induced superoxide ions in human monocytes

Monocytes, separated from peripheral blood, preincubated with a mixture of polycyclic aromatic hydrocarbons (PAHs) show an enhanced production of superoxide ions (O₂⁻) when the cells are stimulated with phorbol 12-myristate 13-acetate (PMA, direct activator of protein kinase C). When opsonized-zymosan is used as a stimulus (receptor-dependent stimulus), no enhanced production of O₂⁻ is observed. Superoxide production increases dose dependently up to a PAH concentration of 5 μg/ml. Although the effect was rather small (125–145% of the control value), it was significant and reproducible. Similar enhancing activity was also observed in the production of hydrogen peroxide (H₂O₂) excluding an inhibitory effect of PAHs on the enzyme superoxide dismutase (SOD). Since the effect is related to the concentration of PMA and in the absence of stimulus, the O₂⁻ is undetectable in both the control and in the PAHs-treated cells, it is concluded that the over production of O₂⁻ is due to an increased activity of the NADPH oxidase.     

Effects of red wine intake on human salivary antiradical capacity and total polyphenol content

The protective effects of grape polyphenols have been reported on oral health, though unreasonable alcohol consumption represents a risk factor for developing oral cancer. The possible effects of red wine consumption on salivary antiradical activity were investigated in healthy volunteers for the first time, to the best of our knowledge. Time-course (from 0 min to 240 min) changes of salivary radical-scavenging capacity were measured by the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, in twelve healthy volunteers, after the intake of red wine (125 mL), a capsule of red wine extract (300 mg) or water (125 mL). Furthermore, time-course of salivary total polyphenol levels, detected by the Folin–Ciocalteu colorimetric method, was also determined. Both ABTS and DPPH tests showed that red wine consumption did not increase salivary antiradical activity in volunteers. Conversely, red wine extract administration caused a marked rise in salivary ABTS radical-scavenging capacity within 30 min, followed by a plateau up to 240 min. The same treatment also raised salivary DPPH radical-scavenging activity at any time point, though to a minor extent. The highest salivary polyphenol concentration was reached 30 min after wine drinking, followed by a steady decrease up to 240 min. Wine drinking was not associated to a reduced salivary antiradical capacity. However, wine extract greatly improved the salivary antioxidant status.     

A uremic toxin, 3-carboxy-4-methyl-5-propyl-2-furanpropionate induces cell damage to proximal tubular cells via the generation of a radical intermediate

3-Carboxy-4-methyl-5-propyl-2-furanpropionate (CMPF), a furan fatty acid uremic toxin (UT) and a substrate for organic ion transporters, contributes to the accumulation of CMPF in renal tubular cells. Although oxidative stress induced by UTs has been proposed as a mechanism of its toxicity in chronic kidney disease, little information is available regarding the redox property of CMPF and its relation to renal cell damage. The findings herein show that CMPF enhances the production of reactive oxygen species (ROS) in HK-2 cells in the presence of angiotensin II (A-II), an inducer of O₂^?. When iron is also present, CMPF and A-II induce the Fenton reaction, resulting in a further increase in ROS production. Such CMPF-induced oxidative stress increases TGF-β1secretion in HK-2 cells, and a positive correlation between CMPF-induced ROS production and the secretion of active TGF-β1 was observed. CMPF caused a reduction in cell viability which was negatively correlated with intracellular ROS production. These negative effects of CMPF in HK-2 cells were completely suppressed by probenecid, an inhibitor of organic anion transport. Interestingly, in vitro ROS assays indicate that CMPF directly interacts with superoxide anion radicals (O₂^?) and peroxy radicals (LOO) to produce CMPF radicals. The subsequent interaction of CMPF radicals with dissolved oxygen leads to the overproduction of O₂^?. Based on these findings, we conclude that CMPF, which accumulates in the renal cells, appears to play a prominent role as a pro-oxidant which subsequently leads to renal cellular damage via the overproduction of O₂^?.     

Characterization of flavonoids from Dryopteris erythrosora and evaluation of their antioxidant,anticancer and acetylcholinesterase inhibition activities

The profiles and bioactivities of flavonoids extracted from Dryopteris erythrosora were investigated. The total flavonoid content in full plant of D. Erythrosora is about 14.33%. The main flavonoids in D. Erythrosora were identified as gliricidin 7-O-hexoside, apigenin7-O-glucoside, quercetin 7-O-rutinoside, quercetin 7-O-galactoside, keampferol 7-O-gentiobioside, keampferol-3-O-rutinoside, myricetin 3-O-rhamnoside and quercitrin by means of HPLC-DAD–ESI-MS. Flavonoids (0.36 mg/ml) extract from D. erythrosora showed similar 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS), superoxide anion scavenging potential and ferric reducing antioxidant potential (FRAP) with that of rutin (0.80 mg/ml). However, the antioxidant power by FRAP assay of 0.36 mg/ml flavonoids extract from D. erythrosora was much weaker than that of 0.80 mg/ml rutin. Moreover, the flavonoids extract from D. erythrosora showed obvious cytotoxic effects on A549 cells. The antioxidant activities of flavonoids extracts from 69 ferns showed a significant reciprocal proportion to the total flavonoids contents. The flavonoids extract from D. erythrosora exhibited a dose-dependent inhibition against acetylcholinesterase. Moreover, the anticancer activity slightly increased with improving antioxidant potential of fern flavonoids. Fern flavonoids are excellent function foods.     

Evaluation of radioprotective efficacy and possible mechanism of action of Aloe gel

The present study was undertaken to determine the optimum effective dose, dose reduction factor (DRF) and possible mechanism of action of Aloe gel. Three different doses of gel (250, 500 and 750 mg/kg body weight) were tested against 8 Gy induced damage in Swiss albino mice. A dose of 750 mg/kg body weight of Aloe was found the most effective while, 250 mg/kg body weight was the least effective in providing protection, as observed in the form of higher concentrations of blood GSH and vitamin C and lower level of serum LPO than irradiated animals at 1 h post irradiation and higher percent of survivors up to day 30 post irradiation.Treatment of mice with Aloe before irradiation with different doses of gamma radiation (6–12 Gy) delayed the onset and reduced the severity of signs of radiation sickness. The LD_50/30 was calculated as 6.77 and 10 Gy for untreated irradiated and Aloe treated irradiated animals, respectively and its dose reduction factor was also calculated as 1.47. Aloe gel scavenged the free radicals, DPPH, ABTS⁺ and NO in a concentration dependent manner in vitro and therefore, scavenging of free radicals seems to be its important mechanism of action.