Thiobarbituric Acid Reactive Species Formation Research Articles

In vitro Studies on Antioxidant Potential of Aqueous Extract of Bridelia ferruginea Stem Bark in Brain and Liver of Wistar-albino Rats using Sodium Nitroprusside as Pro-oxidant

Thiobarbituric acid reactive species (TBARS) assay was used to study the antioxidant potential of Bridelia ferruginea, a widely used medicinal plant in Nigeria, sub-tropical Africa and parts of Asia. The aqueous extract of Bridelia ferruginea stem bark showed inhibition against the formation of TBARS induced by the pro-oxidant, sodium nitroprusside, in the liver and brain tissue homogenates of the locally bred male and female albino-Wistar rats. The inhibition of TBARS is an indication of the antioxidant potential of the plant extract. The extent of antioxidant potential depends on concentrations, showing varying degrees of inhibition with different concentrations. It showed a 54.16% inhibition in the liver and 60.65% in the brain, both at a concentration of 0.33 mg/ml, with IC50 values of 3.00 ± 1.58 mg/ml and 2.99 ± 1.59 mg/ml for the liver and brain homogenates respectively. The results suggest the effectiveness of the aqueous extract of Bridelia ferruginea stem bark in reversing the effect of lipid peroxidation that may result from sodium nitroprusside overload.

Peel oils from three Citrus species: volatile constituents, antioxidant activities and related contributions of individual components.

In the present study, peel oils were extracted through hydrodistillation and cold pressing from three Citrus species (Valencia orange, Ponkan and Eureka lemon) to investigate their volatile constituents and antioxidant activities. A total of 47 volatile components were identified by GC-MS, and then grouped by principal component analysis. The extraction methods were found to have an obvious effect on the proportion of terpenes and oxygenated compounds in the six Citrus oils, especially for Eureka lemon oils. The major fractions in the Citrus oils were found to be monoterpenes (78.65-96.57%), with limonene occupying a dominant percentage (51.22-86.65%). Furthermore, γ-terpinene and terpinolene displayed strong DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging abilities and efficient inhibition of lipid peroxidation, while oxygenated compounds of α-terpineol and terpinen-4-ol showed poor DPPH radical-scavenging abilities. Therefore, hydrodistillated Eureka lemon oil with high levels of α-terpineol (9.11%) and terpinen-4-ol (4.69%) presented low radical scavenging capability. Citral displayed a high pro-oxidant ability against thiobarbituric acid reactive species formation, which might lead to the decreased ability of the Eureka lemon oils in inhibition of lipid peroxidation, since citral was significantly high in Eureka lemon oils. This study facilitated the understanding of volatile constituents and antioxidant activities in different Citrus peel oils.

Fish oil-rich lipid emulsion modulates neuroinflammation and prevents long-term cognitive dysfunction after sepsis.

Sepsis is a severe organic dysfunction caused by an infection that affects the normal regulation of several organ systems, including the central nervous system. Inflammation and oxidative stress play crucial roles in the development of brain dysfunction in sepsis. The aim of this study was to determine the effect of a fish oil (FO)-55-enriched lipid emulsion as an important anti-inflammatory compound on brain dysfunction in septic rats. Wistar rats were subjected to sepsis by cecal ligation and perforation (CLP) or sham (control) and treated orally with FO (600 µL/kg after CLP) or vehicle (saline; sal). Animals were divided into sham+sal, sham+FO, CLP+sal and CLP+FO groups. At 24 h and 10 d after surgery, the hippocampus, prefrontal cortex, and total cortex were obtained and assayed for levels of interleukin (IL)-1β and IL-10, blood-brain barrier permeability, nitrite/nitrate concentration, myeloperoxidase activity, thiobarbituric acid reactive species formation, protein carbonyls, superoxide dismutase and catalase activity, and brain-derived neurotrophic factor levels. Behavioral tasks were performed 10 d after surgery. FO reduced BBB permeability in the prefrontal cortex and total cortex of septic rats, decreased IL-1β levels and protein carbonylation in all brain structures, and diminished myeloperoxidase activity in the hippocampus and prefrontal cortex. FO enhanced brain-derived neurotrophic factor levels in the hippocampus and prefrontal cortex and prevented cognitive impairment. FO diminishes the negative effect of polymicrobial sepsis in the rat brain by reducing inflammatory and oxidative stress markers.

Antigenotoxic and antimutagenic effects of diphenyl ditelluride against several known mutagens in Chinese hamster lung fibroblasts.

The present study evaluates antigenotoxic and antimutagenic properties of diphenyl ditelluride (DPDT) against several known mutagens in Chinese hamster lung fibroblasts (V79 cells). DPDT was not cytotoxic and genotoxic at concentrations ranging from 0.01 to 0.1 μM. The pre-treatment for 2h with this organotellurium compound at non-cytotoxic dose range (0.01, 0.05 and 0.1 μM) increased cell survival after challenge with hydrogen peroxide (H2O2), t-butyl hydroperoxide (t-BOOH), methylmethanesulphonate (MMS) or ultraviolet (UV)C radiation. In addition, the pre-treatment with DPDT decreased the DNA damage and Formamidopyrimidine DNA-glycosylase (Fpg)- and Endonuclease III (Endo III) sensitive sites induction by the studied genotoxic agents, as verified by comet assay and modified comet assay, respectively. The pre-treatment also reduced micronucleus frequency, revealing the protector effect of DPDT against MMS and UVC-induced mutagenesis. Our results demonstrate that DPDT-treated cells at concentration range of 0.01-0.1 μM do not change thiobarbituric acid reactive species (TBARS) levels and ROS generation. Moreover, DPDT pre-treatment at this concentration range decreases the ROS induction by H2O2 and t-BOOH treatment indicating antioxidant potential. On the other hand, concentrations higher than 0.1 μM increase TBARS formation and inhibited superoxide dismutase (SOD) activity, suggesting pro-oxidative effect of this compound at high concentrations. Our results suggest that DPDT presents antigenotoxic and antimutagenic properties at concentration range of 0.01-0.1 μM. The protection effect could be attributed to antioxidant capacity of DPDT at this concentration range in V79 cells.

Exposure to Sublethal Concentrations of Copper Changes Biochemistry Parameters in Silver Catfish, Rhamdia quelen, Quoy & Gaimard

The effects of Cu exposure on catalase (CAT) and acetylcholinesterase (AChE) activity, formation of thiobarbituric acid-reactive species (TBARS) and metabolic parameters were evaluated in silver catfish (Rhamdia quelen). The fish were exposed for 45 days to 0, 16 and 29 μg/L Cu. The fish that were exposed to Cu exhibited lower TBARS levels in the muscle and higher TBARS levels in the liver. They also showed lower CAT activity in the liver and lower AChE activity in the brain and muscle. Higher glucose and lactate and lower protein plasma levels were observed in the fish exposed to Cu. The changes in the hepatic metabolic parameters were Cu concentration dependent. In the muscle, lower glycogen and higher lactate levels were observed in the fish exposed to Cu. Alterations in the metabolic parameters showed a preference for the anaerobic pathway of energy production and liver protein catabolism to supply the energy demand.

Superoxid dismutase activity in portal vein endothelium after partial liver resection

To investigate superoxide dismutase (SOD) activity in the portal vein endothelium and malondialdehyde acid (MDA) production in liver tissue of rats submitted to 70% hepatectomy. Twelve rats were distributed in two groups (hepatectomy and sham). Animals were sacrificed on post operative day 1 and portal vein, liver tissue and blood samples were collected. Portal vein SOD production was measured using lucigenin-amplified chemiluminescence assays. MDA measurement was used as an index of oxidative stress through the formation of TBARS (Thiobarbituric Acid Reactive Species). There was no difference in post operative bilirubin, AST, ALT levels between groups. DHL level was higher in the hepatectomy group (p=0.01). MDA production in the remnant liver tissue and endothelial portal vein SOD activity were also significantly (p<0.05) elevated in the hepatectomy group when compared to control group. There was no correlation between MDA and SOD activity. SOD activity, on the other hand, showed a positive correlation with LDH level (p=0.038) and MDA levels showed a positive correlation with AST and ALT levels (p<0.001). There is an increased production of malondialdehyde acid in liver tissue after partial hepatectomy and increased activity of superoxide dismutase in portal vein endothelium as well.

English

The hawthorn Crataegus mexicana is a traditional Mexican fruit with properties that make this fruit useful for the treatment of many ailments, including diseases of the respiratory and urinary tract. This paper reports the antioxidant capacity of the n-hexane, dichloromethane, ethyl acetate, acetone, ethanol and methanol extracts of C. mexicana. Samples were evaluated for total phenolic and carotenoid contents, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, the inhibition of the formation of thiobarbituric acid reactive species (TBARS) and the neutralization of the cation-radical 2,2´-azino-bis(3ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS). The total phenolic content was 2.65 ± 0.23 mg of gallic acid equivalents per gram, and the carotenoid content was 26.4 ± 0.02 µg/g in dry hawthorn skin. The most active extract in scavenging DPPH radicals and inhibiting TBARS formation was the acetone extract, with activities of 21.9 ± 0.15 and 13.27 ± 0.70%, respectively, at 10 mg/L. The extracts were compared for activity against ascorbic acid, caffeic acid, α- tocopherol and quercetin. The acetone extract was the most active, with an IC50 value of 15.2 mg/L in DPPH and 17.7 mg/L in TBARS. A high correlation was observed between the results for TBARS and DPPH. These results demonstrate the potential nutritional and antioxidant value of this Mexican fruit.

Total Phenol , Antioxidant and Cytotoxic Properties of Wild Macrofungi Collected from Akure Southwest Nigeria

Three wild macrofungi, Lenzites betulina (Fries), Trametes vesicolor (Lloyd) and Coriolopsis polyzona (Pers) collected in Akure southwest of Nigeria were assessed for their total phenol, antioxidant and cytotoxic activities. The antioxidant and cytotoxic properties of the hexane, ethyl acetate and ethanol extracts from the fruit bodies of these macrofungi were assessed using DPPH scavenging capacity, inhibition of the formation of thiobarbituric acid reactive species (TBARS), and the protein-binding dye sulforhodamine B (SRB) microculture assay to measure cell growth using six human cancer cell lines. Total phenol content ranged from 8.22µgGAE/mg to 60.54 µgGAE/mg. The DPPH and inhibition of the formation of TBARS ranged between 7.97% to 91.18% at 1000µg/mL. Ethanolic extracts (LET, TET and CET) with higher phenol content exhibited better antioxidant property. The inhibition of human cancer cell lines varies from one extract to the other. However, ethanolic extract of Trametes vesicolor (TET) demonstrated the best cytotoxic activity with 100% inhibition of HCT-5, MCF-7 and SKLU-1 human cancer cell lines. The study suggests that these three wild macrofungi could be source of effective antioxidant and anticancer agents.

Irrigation of Solanum lycopersicum L. with magnetically treated water increases antioxidant properties of its tomato fruits

Antioxidant effects of tomatoes (Solanum lycopersicum L.) have been studied and an association between dietary intake of tomatoes and lowered risk of cancer, neurodegenerative, and cardiovascular diseases has been suggested. Here we used magnetically treated water (MTW; 0.03–0.15 T), which promotes better germination and productivity in tomatoes, and we investigated the effects of aqueous and ethanolic (10–400 μg/ml) extracts of S. lycopersicum as potential antioxidant against 10 μM Fe(II)-induced thiobarbituric acid reactive species (TBARS) in liver and brain homogenates from rats. The ethanolic extracts from magnetically treated plants were more effective than aqueous extracts in preventing TBARS formation in brain and liver. The protective effects of ethanolic extract can be associated with antioxidants (polyphenols and flavonoids), lycopene and other lipophilic components found in the extract. In effect, magnetically treated plants had higher content of polyphenolic and flavonoid compounds than nontreated plants and they can be a better source of antioxidants than nontreated plants. Consequently, MTW can be used to produce functional foods with high contents of antioxidant components and may have better beneficial health effects than traditionally produced foods.

Modulation of diorganoyl dichalcogenides reactivity by non-bonded nitrogen interactions

The study was designed to explore the biochemical influence of non bonding nitrogen interactions (N⋯Se/S) on organochalcogens potency. Approximately five and six times higher thiol peroxidase (TPx) like activity was observed for compound (C)-2 than C-1 and C-3, respectively. C-2 also displayed significantly (p<0.05) higher activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and deoxyribose degradation assays. All compounds, except C-4 and C-6 significantly inhibited Fe (II) and sodium nitroprusside (SNP) induced thiobarbituric acid reactive species (TBARS) production in rat’s brain, liver and kidney preparations with highest activity observed for C-2. The highest C-2 activity was attributed to the presence of non-bonded nitrogen interactions which were absent in C-1 and blocked with butoxycarbonyl (BOC group) in C-3. The same structural activity analogy was extended to organosulfur compounds and it was observed that compound with non-bonding nitrogen interactions, i.e. C-5 has significantly (p<0.05) higher TPx like activity than C-6 and C-4. C-5 at the highest tested concentration significantly (p<0.05) protected against Fe (II) and SNP induced TBARS formation in rat’s brain, kidney and liver preparations but did not display activity in DPPH and deoxyribose degradation assays. This study confirms the influence of not only N⋯Se interaction but also for the first time the effect of non bonded N⋯S interactions on organochalcogens potency. C-2 (with the highest activity) was also tested in vivo and was administered at three different doses, i.e. 15, 30 and 50mg/kg to get an exact idea about its interaction with thiol containing molecules (NPSH) and enzyme α-ALA-D (sulfhydryl containing enzyme). Oxidative stress parameters, i.e. free radical concentration by dichlorofluoreseein (DCF) assay, TBARS, ascorbic acid level, hepatic (ALT and AST) and renal (urea and creatinine) toxicity markers were also estimated to get an insight about its possible toxicological profile. Our data indicates that C-2 has higher TPx and Antioxidant activity and importantly, C2 did not induce toxicity even when tested at relatively high doses, indicating that its pharmacological properties should be further explored in models of diseases associated with oxidative stress.

Hepatoprotective effects and HSV-1 activity of the hydroethanolic extract of Cecropia glaziovii (embaúba-vermelha) against acyclovir-resistant strain

Context: Cecropia glaziovii Snethl. (Cecropiaceae), commonly known as “embaúba-vermelha”, is widely distributed throughout Latin America and has been reported in Brazilian folk medicine to treat cough, asthma, high blood pressure and inflammation.Objective: Investigate the hepatoprotective properties of crude hydroethanolic extract of C. glaziovii as well as its in vitro antioxidant and antiviral (HSV-1 acyclovir resistant strain) activities.Materials and methods: The hepatoprotective effect, the antioxidant properties and antiviral activity of crude hydroethanol extract (RCE40) from C. glaziovii leaves were evaluated by carbon-tetrachloride (CCl4)-induced hepatotoxicity, by TBARS (thiobarbituric acid reactive species) and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assays, respectively.Results: The RCE40 extract (20 mg/kg) inhibited lipid peroxidation on liver in post injury treatment and decreased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, in this protocol the RCE40 (20 mg/kg) enhanced the activity of hepatic enzymes (SOD/CAT) which are involved in combating reactive oxygen species (ROS), suggesting that it possesses the capacity to attenuate the CCl4-induced liver damage. Moreover the RCE40 (20 mg/kg) inhibited TBARS formation induced by several different inductors of oxidative stress showing significant antioxidant activity, including physiologically relevant concentration, as low as 2 µg/mL. Concerning antiviral activity, the RCE40 was effective against herpes simplex virus type 1 replication (29R acyclovir resistant strain) with EC50 = 40 µg/mL and selective index (SI) = 50.Discussion and conclusion: These results indicate that C. glaziovii could be a good source of antioxidant and anti-HSV-1 lead compounds.

Effects of diphenyl diselenide on oxidative stress induced by sepsis in rats

Sepsis is a potentially deadly complication that can be caused by different factors. Actually, it is known that oxidative stress is involved in the pathogenesis of sepsis. Thus, the aim of this study was to evaluate the effect of diphenyl diselenide (PhSe) 2, an emergent compound, on oxidative stress parameters induced by sepsis in rats. Animals were pre-injected with (PhSe) 2 or vehicle. Twenty-four hours later, sepsis was induced by cecal ligation puncture (CLP). After 12 h, liver was taken for thiobarbituric acid reactive species (TBARS) measurement, δ-aminolevunic acid dehydratase (δ-ALA-D), Cu/Zn superoxide dismutase (Cu/Zn SOD) and catalase (CAT) activities assay. The sepsis increased TBARS, inhibited δ-ALA-D, activated Cu/Zn SOD and had a tendency to decrease CAT activity. However, (PhSe) 2 prevented the TBARS formation, but did not prevent the inhibition of δ-ALA-D activity in the animals with damage. Thus, this study showed that (PhSe) 2 partially prevents the oxidative stress induced by sepsis, indicating the potential of this compound as a treatment for this pathology. Nevertheless, more tests should be performed to confirm the hypothesis suggested here.

Low-intensity infrared laser increases plasma proteins and induces oxidative stress in vitro

Low-intensity laser therapy is based on the excitation of endogenous chromophores in biotissues and free-radical generation could be involved in its biological effects. In this work, the effects of the low-intensity infrared laser on plasma protein content and oxidative stress in blood from Wistar rats were studied. Blood samples from Wistar rats were exposed to low-intensity infrared laser in continuous wave and pulsed-emission modes at different fluencies. Plasma protein content and two oxidative stress markers (thiobarbituric acid-reactive species formation and myeloperoxidase activity) were carried out to assess the effects of laser irradiation on blood samples. Low-intensity infrared laser exposure increases plasma protein content, induces lipid peroxidation, and increases myeloperoxidase activity in a dose- and frequency-dependent way in blood samples. The low-intensity infrared laser increases plasma protein content and oxidative stress in blood samples, suggesting that laser therapy protocols should take into account fluencies, frequencies, and wavelengths of the laser before beginning treatment.

Treatment with cannabidiol reverses oxidative stress parameters, cognitive impairment and mortality in rats submitted to sepsis by cecal ligation and puncture

Oxidative stress plays an important role in the development of cognitive impairment in sepsis. Here we assess the effects of acute and extended administration of cannabidiol (CBD) on oxidative stress parameters in peripheral organs and in the brain, cognitive impairment, and mortality in rats submitted to sepsis by cecal ligation and perforation (CLP). To this aim, male Wistar rats underwent either sham operation or CLP. Rats subjected to CLP were treated by intraperitoneal injection with “basic support” and CBD (at 2.5, 5, or 10 mg/kg once or daily for 9 days after CLP) or vehicle. Six hours after CLP (early times), the rats were killed and samples from lung, liver, kidney, heart, spleen, and brain (hippocampus, striatum, and cortex) were obtained and assayed for thiobarbituric acid reactive species (TBARS) formation and protein carbonyls. On the 10th day (late times), the rats were submitted to the inhibitory avoidance task. After the test, the animals were killed and samples from lung, liver, kidney, heart, spleen, and brain (hippocampus) were obtained and assayed for TBARS formation and protein carbonyls. The acute and extended administration of CBD at different doses reduced TBARS and carbonyl levels in some organs and had no effects in others, ameliorated cognitive impairment, and significantly reduced mortality in rats submitted to CLP. Our data provide the first experimental demonstration that CBD reduces the consequences of sepsis induced by CLP in rats, by decreasing oxidative stress in peripheral organs and in the brain, improving impaired cognitive function, and decreasing mortality.

Studies on the antioxidant effect and interaction of diphenyl diselenide and dicholesteroyl diselenide with hepatic δ-aminolevulinic acid dehydratase and isoforms of lactate dehydrogenase

Studies on the interaction of dicholesteroyl diselenide (DCDS) and diphenyl diselenide (DPDS) with hepatic delta-aminolevulinic acid dehydratase (ALA-D) and different isoforms of lactate dehydrogenase (LDH) from different tissues were investigated. In addition, their antioxidant effects were tested in vitro by measuring the ability of the compounds to inhibit the formation of hepatic thiobarbituric acid reactive species (TBARS) induced by both iron (II) and sodium nitroprusside (SNP). The results show that while DPDS markedly inhibited the formation of TBARS induced by both iron (II) and SNP, DCDS did not. Also, the activities of hepatic delta-aminolevulinic acid dehydratase (ALA-D) and different isoforms of lactate dehydrogenase (LDH) were significantly inhibited by both DPDS and DCDS. Moreover, we further observed that the in vitro inhibition of different isoforms of lactate dehydrogenase by DCDS and DPDS likely involves the modification of the groups at the NAD+ binding site of the enzyme. Since organoselenides interacts with thiol groups on proteins, we conclude that the inhibition of different isoforms of lactate dehydrogenase by DPDS and DCDS possibly involves the modification of the thiol groups at the NAD+ binding site of the enzyme.

Sun-drying diminishes the antioxidative potentials of leaves of Eugenia uniflora against formation of thiobarbituric acid reactive substances induced in homogenates of rat brain and liver

Extracts from leaves of Pitanga cherry ( Eugenia uniflora) are considered to be effective against many diseases, and are therefore used in popular traditional medicines. In the present study, the antioxidative effect of sun-dried (PCS) and air-dried (PCA) ethanolic extracts of Pitanga cherry leaves were investigated. The antioxidant effects were tested by measuring the ability of both PCS and PCA to inhibit the formation of thiobarbituric acid reactive species (TBARS) induced by prooxidant agents such as iron (II) and sodium nitroprusside (SNP) in rat brain and liver tissues. The results showed that while PCA significantly ( P<0.0001) inhibited the formation of TBARS in both liver and brain tissues homogenates, PCS did not. Further investigation reveals that the phenolic content of the PCS was significantly ( P<0.0001) lower compared to PCA. Since phenolics in plants largely contributed to the antioxidative potency of plants, we conclude that air-drying should be employed in the preparation of extracts of Pitanga cherry leaves before it is administered empirically as a traditional medicament, and hence this study serves a public awareness to traditional medical practitioners.

Water-extractable phytochemicals from Phyllanthus niruri exhibit distinct in vitro antioxidant and in vivo hepatoprotective activity against paracetamol-induced liver damage in mice

The antioxidative and hepatoprotective potential of Phyllanthus niruri, a widely used medicinal plant in Brazil, were investigated. The aqueous extracts of leaves showed inhibition against thiobarbituric acid-reactive species (TBARS), induced by different pro-oxidants (10 μM FeSO 4 and 5 μM sodium nitroprusside) in rat liver, brain and kidney homogenates. The extracts also lowered the formation of TBARS in phospholipids extracted from egg yolk. The plant exhibited strong antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl free radical (IC 50, 43.4 ± 1.45 μg/ml) and iron chelation assay. The hepatoprotective activity of the extracts were also demonstrated in vivo against paracetamol-induced liver damage, as evidenced by the decrease in serum glutamate oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT), and increased catalase activity in the liver in treatment groups, compared to the control. The results of the present study suggest the potential use of P. niruri in the treatment of various diseases, among which liver disease is the most important, due to its ability to act as an antioxidant. Furthermore, since the treatment of human intoxications with paracetamol is always limited to the administration of N-acetyl-cysteine, additional studies would be important to determine whether aqueous extracts of P. niruri could increase the efficacy of N-acetyl-cysteine against paracetamol acute hepatotoxicity.

Combined cupric- and cuprous-binding peptides are effective in preventing IL-8 release from endothelial cells and redox reactions

Copper mobilization and subsequent redox reactions have been implicated in the pathogenesis of numerous inflammation-based diseases. Reduction of the cupric ion (Cu 2+) to the cuprous ion (Cu +) is necessary for the production of copper-induced reactive oxygen species (ROS). Peptides, designed to bind both Cu 2+ and Cu + and have the ability to prevent copper redox reactions, were studied. The peptides DAHGMTCA NC and DAHKGMTCA NC were effective at preventing the formation of thiobarbituric acid-reactive species (TBARS) in a copper/ascorbate solution at a 1:1 peptide/Cu ratio. This was observed in the reducing potential of the copper/ascorbate solutions containing these peptides at a 1:1 ratio based on oxidation–reduction potential (ORP) measurements. The peptide DAHGMTCA RC was effective at a 2:1 ratio, but not at a 1:1 ratio in which an increase in the oxidation potential was observed. This suggests that a positively charged amino acid such as arginine (R) in the Cu +-binding motif interferes with metal chelation. All peptides tested were effective at preventing IL-8 release from phorbol 12-myristate 13-acetate (PMA)/copper-stimulated human umbilical vein endothelial cells (HUVEC). The use of Cu +/Cu 2+-binding peptides might be beneficial in the treatment of ROS-related diseases associated with copper.

Distachyasin: A New Antioxidant Metabolite from the Leaves of Carex distachya

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Distachyasin: A new antioxidant metabolite from the leaves of Carex distachya

A novel antioxidant prenylated stilbenoid, distachyasin, has been isolated from the leaves of Carex distachya. Its structure has been elucidated on the basis of the spectroscopic characteristics. Bidimensional NMR, and crystallographic data and computational calculations have furnished important data useful for the characterization and the stereochemistry of the molecule. The compound has a tetracyclic skeleton derived from carexane. The compound has been assayed, for the antioxidant activity, by measuring its capacity to scavenge the H 2O 2, nitric oxide, superoxide radical and to inhibit formation of TBARS (thiobarbituric acid reactive species).