Hydroalcoholic Extract of Cyperus rotundus Ameliorates H2O2-Induced Human Neuronal Cell Damage via Its Anti-oxidative and Anti-apoptotic Machinery

Hydrogen peroxide (H₂O₂), a major reactive oxygen species produced during oxidative stress, has been implicated in the pathophysiology of various neurodegenerative conditions. Cyperus rotundus is a traditional medicinal herb that has recently found applications in food and confectionary industries. In the current study, the neuroprotective effects of Cyperus rotundus rhizome extract (CRE) through its antioxidant and anti-apoptotic machinery to attenuate H₂O₂-induced cell damage on human neuroblastoma SH-SY5Y cells have been explored. The results obtained demonstrate that pretreatment of cells with CRE for 2 h before administration of H₂O₂ for 24 h ameliorates the cytotoxicity induced by H₂O₂ as evidenced by MTT and LDH assays. CRE exhibited potent antioxidant activity by regulating the enzymes/proteins levels such as SOD, CAT, GPx, GR, HSP-70, Caspase-3, and Bcl-2. The pretreatment restored H₂O₂-induced cellular, nuclear, and mitochondrial morphologies as well as increased the expression of Brain derived nerve growth factor (BDNF). The anti-oxidant and anti-apoptotic potentials of the plant extract may account for its high content of phenolics, flavonoids, and other active principles. Taken together, our findings suggest that CRE might be developed as an agent for neurodegeneration prevention or therapy.     

Neuroprotective Effects of Farnesene Against Hydrogen Peroxide-Induced Neurotoxicity In vitro

Oxidative stress is highly damaging to cellular macromolecules and is also considered a main cause of the loss and impairment of neurons in several neurodegenerative disorders. Recent reports indicate that farnesene (FNS), an acyclic sesquiterpene, has antioxidant properties. However, little is known about the effects of FNS on oxidative stress-induced neurotoxicity. We used hydrogen peroxide (H₂O₂) exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of different FNS isomers (α-FNS and β-FNS) and their mixture (Mix-FNS) in H₂O₂-induced toxicity in newborn rat cerebral cortex cell cultures for the first time. For this aim, both MTT and lactate dehydrogenase assays were carried out to evaluate cell viability. Total antioxidant capacity (TAC) and total oxidative stress (TOS) parameters were used to assess oxidative alterations. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG) levels in vitro, the comet assay was also performed for measuring the resistance of neuronal DNA to H₂O₂-induced challenge. Our results showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage (comet assay) increased in the group treated with H₂O₂ alone. But pretreatment of FNS suppressed the cytotoxicity, genotoxicity and oxidative stress, which were increased by H₂O₂ in clear type of isomers and applied concentration-dependent manners. The order of antioxidant effectiveness for modulating H₂O₂-induced oxidative stress-based neurotoxicity and genotoxicity is as β-FNS > Mix-FNS > α-FNS.     

Antioxidant and Neuroprotective Effects of Scrophularia striata Extract Against Oxidative Stress-Induced Neurotoxicity

In this study, the neuroprotective effect of Scrophularia striata Boiss (Scrophulariaceae) extract, a plant growing in northeastern of Iran, against oxidative stress-induced neurocytotoxicity in PC12 was evaluated. The PC12 cell line pretreated with different concentrations (10, 50, 100, and 200 μg/ml) of the extract and then treated with H₂O₂ to induce oxidative stress and neurotoxicity. Survival of the cells, reactive oxygen species (ROS) generation, and apoptosis were measured using MTT assay, fluorescent probe 2′,7′-dichlorofluorescein diacetate, and annexin V/propidium iodide, respectively. Moreover, the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) was used to evaluate the antioxidant capacity of the plant extract. Phytochemical assay by thin layer chromatography showed that the main components, including phenolic compounds, phenyl propanoids and flavonoids, were presented in the S. striata extract. The extract in concentrations of 50–200 μg/ml protected PC12 cells from H₂O₂-induced toxicity. The survival of the cells at concentration of 200 μg/ml was 64 % compared to that of H₂O₂ alone-treated cells (48 %) (p < 0.001). The extract also dose-dependently reduced intracellular ROS production (p < 0.001). Moreover, the extract showed antioxidative effects and decreased apoptotic cells. Collectively, these findings indicated the ability of S. striata to decrease ROS generation and cell apoptosis and also suggest the presence of the neuroprotective agents in this plant.     

Antioxidant and Neuroprotective Activities of Hyptis suaveolens (L.) Poit. Against Oxidative Stress-Induced Neurotoxicity

The present study was carried out to investigate the antioxidant and neuroprotective effects of Hyptis suaveolens methanol extract (HSME) using various in vitro systems. The total phenol and flavonoids contents of the HSME were quantified by colorimetric methods. The HSME extract exhibited potent antioxidant activity as determined by 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power assays. The neuroprotective activity of HSME was determined on mouse N2A neuroblastoma cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, intracellular ROS assays, and upregulation of brain neuronal markers at genetic level. The N2A cells were pretreated with different concentrations (0.5, 1, 1.5, and 2 mg/ml) of the extract and then exposed to H₂O₂ to induce oxidative stress and neurotoxicity. The survival of the cells treated with different concentrations of HSME and H₂O₂ increased as compared to cells exposed only to H₂O₂ (47.3 %) (p < 0.05). The HSME also dose-dependently reduced LDH leakage and intracellular ROS production (p < 0.05). Pretreatment with HSME promotes the upregulation of tyrosine hydroxylase (2.41-fold, p < 0.05), and brain-derived neurotrophic factor genes (2.15-fold, p < 0.05) against H₂O₂-induced cytotoxicity in N2A cells. Moreover, the HSME showed antioxidant activity and decreased neurotoxicity. These observations suggest that HSME have marked antioxidant and neuroprotective activities.     

Neuroprotective Effects of Bikaverin on H2O2-Induced Oxidative Stress Mediated Neuronal Damage in SH-SY5Y Cell Line

The generation of free radicals and oxidative stress has been linked to several neurodegenerative diseases including Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and Amyotrophic lateral sclerosis. The use of free radical scavenging molecules for the reduction of intracellular reactive oxygen species is one of the strategies used in the clinical management of neurodegeneration. Fungal secondary metabolism is a rich source of novel molecules with potential bioactivity. In the current study, bikaverin was extracted from Fusarium oxysporum f. sp. lycopersici and its structural characterization was carried out. Further, we explored the protective effects of bikaverin on oxidative stress and its anti-apoptotic mechanism to attenuate H₂O₂-induced neurotoxicity using human neuroblastoma SH-SY5Y cells. Our results elucidate that pretreatment of neurons with bikaverin attenuates the mitochondrial and plasma membrane damage induced by 100 µM H₂O₂ to 82 and 26 % as evidenced by MTT and LDH assays. H₂O₂ induced depletion of antioxidant enzyme status was also replenished by bikaverin which was confirmed by Realtime Quantitative PCR analysis of SOD and CAT genes. Bikaverin pretreatment efficiently potentiated the H₂O₂-induced neuronal markers, such as BDNF, TH, and AADC expression, which orchestrate the neuronal damage of the cell. The H₂O₂-induced damage to cells, nuclear, and mitochondrial integrity was also restored by bikaverin. Bikaverin could be developed as a preventive agent against neurodegeneration and as an alternative to some of the toxic synthetic antioxidants.     

Neuroprotective Effects of Theaflavins Against Oxidative Stress-Induced Apoptosis in PC12 Cells

Oxidative stress can induce neuronal apoptosis via the production of superoxide and hydroxyl radicals. This process is as a major pathogenic mechanism in neurodegenerative disorders. In this study, we aimed to clarify whether theaflavins protect PC12 cells from oxidative stress damage induced by H₂O₂. A cell model of PC12 cells undergoing oxidative stress was created by exposing cells to 200 μM H₂O₂ in the presence or absence of varying concentrations of theaflavins (5, 10, and 20 μM). Cell viability was monitored using the MTT assay and Hoechst 33258 staining, showing that 10 μM theaflavins enhanced cell survival following 200 μM H₂O₂ induced toxicity and increased cell viability by approximately 40?%. Additionally, we measured levels of intracellular reactive oxygen species (ROS) and antioxidant enzyme activity. This suggested that the neuroprotective effect of theaflavins against oxidative stress in PC12 cells is derived from suppression of oxidant enzyme activity. Furthermore, Western blot analyses indicated that theaflavins downregulated the ratio of pro-apoptosis/anti-apoptosis proteins Bax/Bcl-2. Theaflavins also downregulated the expression of caspase-3 compared with a H₂O₂-treated group that had not been treated with theaflavins. Interestingly, this is the first study to report that the four main components of theaflavins found in black tea can protect neural cells (PC12) from apoptosis induced by H₂O₂. These findings provide the foundations for a new field of using theaflavins or its source, black tea, in the treatment of neurodegenerative diseases caused by oxidative stress.     

Understanding apoptotic signaling pathways in cytosine deaminase-uracil phosphoribosyl transferase-mediated suicide gene therapy in vitro

The present work was carried out to evaluate the antioxidant activity of hesperidin and to study its protective effect on H₂O₂ induced oxidative damage on pBR322 DNA and RBC cellular membrane. The in vitro assays were performed with different concentrations (2, 4, 6, 8, and 10 μg/ml, which were equivalent to 3.27, 6.55, 9.83, 13.10, and 16.38 μM) of hesperidin and the results clearly indicate that hesperidin at 10 μg/ml exhibited radical scavenging activity greater than that of standards like ascorbic acid and trolox. The protective effect of hesperidin on pBR322 DNA and RBC cellular membrane on treatment with different concentrations of H₂O₂ shows that hesperidin at 2.5 mM converts the open circular form (oc) of pBR322 DNA that is an indication of damage to super coiled (ccc) form and at 10 μg/ml it prevents membrane damage. Thus, our result proves hesperidin to be a valuable antioxidant that protects pBR322 DNA and RBC cellular membrane from free radical induced oxidative damage.     

Oxidative stress in rheumatoid arthritis patients: relationship to diseases activity

The aim of this study was to assess the oxidative stress status in rheumatoid arthritis (RA) by measuring markers of free radical production, systemic activity of disease, and levels of antioxidant. 52 RA patients and 30 healthy controls were included in the study, and clinical examination and investigations were performed and disease activity was assessed. Peripheral blood samples were used for all the assays. We assessed the markers of oxidative stress, including plasma levels of index of lipid peroxidation-thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H₂O₂), superoxide anion radical (O₂ ^?), nitric oxide (NO), and superoxide dismutase activity (SOD), catalase activity (CAT) and glutathione levels in erythrocytes. In the RA group, levels of H₂O₂, O₂ ^?, and TBARS were significantly higher than in controls (4.08 ± 0.31 vs. 2.39 ± 0.13 nmol/l, p < 0.01; 8.90 ± 1.28 vs. 3.04 ± 0.38 nmol/l, p < 0.01, 3.65 ± 0.55 vs. 1.06 ± 0.17 μmol/l, p < 0.01). RA patients had significantly increased SOD activity compared with healthy controls (2,918.24 ± 477.14 vs. 643.46 ± 200.63UgHbx103, p < 0.001). Patients had significantly higher levels of pro-oxidants (O₂ ^?, H₂O₂, and TBARS) compared to controls, despite significantly higher levels of SOD. Significant differences were also observed in serum levels of NO in patients with high-diseases activity. Our findings support an association between oxidative/nitrosative stress and RA. Stronger response in samples with higher diseases activity suggests that oxidative/nitrosative stress markers may be useful in evaluating the progression of RA as well as in elucidating the mechanisms of disease pathogenesis.     

Nanoparticle-mediated catalase delivery protects human neurons from oxidative stress

Several neurodegenerative diseases and brain injury involve reactive oxygen species and implicate oxidative stress in disease mechanisms. Hydrogen peroxide (H₂O₂) formation due to mitochondrial superoxide leakage perpetuates oxidative stress in neuronal injury. Catalase, an H₂O₂-degrading enzyme, thus remains an important antioxidant therapy target. However, catalase therapy is restricted by its labile nature and inadequate delivery. Here, a nanotechnology approach was evaluated using catalase-loaded, poly(lactic co-glycolic acid) nanoparticles (NPs) in human neuronal protection against oxidative damage. This study showed highly efficient catalase encapsulation capable of retaining∼99% enzymatic activity. NPs released catalase rapidly, and antioxidant activity was sustained for over a month. NP uptake in human neurons was rapid and nontoxic. Although human neurons were highly sensitive to H₂O₂, NP-mediated catalase delivery successfully protected cultured neurons from H₂O₂-induced oxidative stress. Catalase-loaded NPs significantly reduced H₂O₂-induced protein oxidation, DNA damage, mitochondrial membrane transition pore opening and loss of cell membrane integrity and restored neuronal morphology, neurite network and microtubule-associated protein-2 levels. Further, catalase-loaded NPs improved neuronal recovery from H₂O₂ pre-exposure better than free catalase, suggesting possible applications in ameliorating stroke-relevant oxidative stress. Brain targeting of catalase-loaded NPs may find wide therapeutic applications for oxidative stress-associated acute and chronic neurodegenerative disorders.     

Effect of acetone extract from stem bark of Acacia species (A. dealbata,A. ferruginea and A. leucophloea) on antioxidant enzymes status in hydrogen peroxide-induced HepG2 cells

Acacia species are multipurpose trees, widely used in the traditional systems of medicine to treat various ailments. The major objective of the present study was to determine the gene expression of enzymatic antioxidants by acetone extract from the stem bark of three Acacia species (Acacia dealbata, Acacia ferruginea and Acacia leucophloea) in hydrogen peroxide (H₂O₂)-induced human hepatoma (HepG2) cells. The expression of antioxidant enzymes such as superoxide dismutase containing copper–zinc (CuZnSOD)/manganese (MnSOD), catalase (CAT) and glutathione peroxidase (GPx) in HepG2 cells was evaluated by real-time PCR. The results of antioxidant enzyme expression in real-time PCR study revealed that the H₂O₂ (200 μM) challenged HepG2 cells reduced the expression of enzymes such as SOD, GPx and CAT. However, the cells pre-treated with acetone extracts of all the three Acacia species significantly (P > 0.05) up-regulated the expression of antioxidant enzymes in a concentration dependent manner (25, 50 and 75 μg/mL). In conclusion, the findings of our study demonstrated that the acetone extract of Acacia species effectively inhibited H₂O₂ mediated oxidative stress and may be useful as a therapeutic agent in preventing oxidative stress mediated diseases.     

Effects of Selenium and Topiramate on Cytosolic Ca2+ Influx and Oxidative Stress in Neuronal PC12 Cells

It has been widely suggested that selenium (Se) deficiency play an important role in the pathophysiology of epilepsy. It has been reported that Se provides protection against the neuronal damage in patients and animals with epilepsy by restoring the antioxidant defense mechanism. The neuroprotective effects of topiramate (TPM) have been reported in several studies but the putative mechanism of action remains elusive. We investigated effects of Se and TPM in neuronal PC12 cell by evaluating Ca²⁺ mobilization, lipid peroxidation and antioxidant levels. PC12 cells were divided into eight groups namely control, TPM, Se, H₂O₂, TPM + H₂O₂, Se + H₂O₂, Se + TPM and Se + TPM + H₂O₂. The toxic doses and times of H₂O₂, TPM and Se were determined by cell viability assay which is used to evaluate cell viability. Cells were incubated with 0.01 mM TPM for 5 h and 500 nM Se for 10 h. Then, the cells were exposed to 0.1 mM H₂O₂ for 10 h before analysis. The cells in all groups except control, TPM and Se were exposed to H₂O₂ for 15 min before analysis. Cytosolic Ca²⁺ release and lipid peroxidation levels were higher in H₂O₂ group than in control, Se and TPM combination groups although their levels were decreased by incubation of Se and TPM combination. However, there is no difference on Ca²⁺ release in TPM group. Glutathione peroxidase activity, reduced glutathione and vitamin C levels in the cells were lower in H₂O₂ group than in control, Se and TPM groups although their values were higher in the cells incubated with Se and TPM groups than in H₂O₂ groups. In conclusion, these results indicate that Se induced protective effects on oxidative stress in PC12 cells by modulating cytosolic Ca²⁺ influx and antioxidant levels. TPM modulated also lipid peroxidation and glutathione and vitamin C concentrations in the cell system.     

Response of Pteris vittata to different cadmium treatments

Pteris vittata is known as an arsenic hyperaccumulator, but there is little information about its tolerance to cadmium and on its ability to accumulate this heavy metal. Our aim was to analyse the accumulation capacity, oxidative stress and antioxidant response of this fern after cadmium treatments. Cadmium content, main markers of oxidative stress and antioxidant response were detected in leaves of plants grown in hydroponics for both short- (5 days) and long- (15 days) term exposure to 0 (control) 60 and 100 μM CdCl₂. In leaves, the concentration of cadmium and oxidative stress were parallel with the increase of cadmium exposure. In the short-term exposure, antioxidant response was sufficient to contrast cadmium phytotoxicity only in 60 μM cadmium-treated plants. In the long-term exposure all treated plants, in spite of the increase in activity of some peroxide-scavenging enzymes, showed a significant increase in oxidative damage. As in the long-term stress markers were comparable in all treated plants, with no clear correlation with hydrogen peroxide content, at least part of cadmium-induced oxidative injury seems not mediated by H₂O₂. Based on our studies, P. vittata, able to uptake relatively high concentrations of cadmium, is only partially tolerant to this heavy metal.     

Optimization of the alkaline comet assay for easy repair capacity quantification of oxidative DNA damage in PBMC from human volunteers using aphidicolin block

Assessment of DNA repair capacity (DRC) upon ex vivo challenge of peripheral blood mononuclear cells (PBMC) with oxidative damage inducing agents, as evaluated by the comet assay, is widely used as biomarker to assess the antioxidant status in human studies. Here, the alkaline comet assay was now optimized for easy and time saving detection of repair capacity upon oxidative stress-induced DNA damage using the DNA polymerase inhibitor aphidicolin (APC) to block repair of hydrogen peroxide (H₂O₂) induced DNA damage. Addition of a DMSO-containing DNA damage stop solution was found suitable to replace washing steps for H₂O₂ removal before APC block. Cell treatment with APC at 6 μM did not impact baseline DNA damage but could reliably block DNA repair after H₂O₂ challenge in both fresh and cryopreserved samples thus omitting the use of a starting time point control. Under the conditions used, frozen cells, with or without an additional 4 h rest, showed the same repair capacity as their fresh counterpart. The intra assay coefficient of variation (CV) was 3.3%. To provide proof of principle, the modified assay was applied to cryopreserved PBMC from 19 participants of a short-term Brassica diet intervention study investigating potential health promoting effects of the food intervention. Then, a 33% increase in DRC (p ≤ 0.01) could be shown in samples after intervention (mean ± SD: 5.82 ± 1) as compared to baseline (mean ± SD: 4.38 ± 1.21). Individual samples from baseline and intervention showed an inter-individual CV of 27.65% (baseline) and 17.26% (intervention). Taken together this modified comet assay protocol allows the facilitated detection of DNA repair in fresh or cryopreserved human PBMC samples with a good sensitivity and reliability and could be useful in human studies addressing the antioxidant status and repair capacity of PBMC.     

Strobilanthes crispus attenuates renal carcinogen, iron nitrilotriacetate (Fe-NTA)-mediated oxidative damage of lipids and DNA

This study was aimed to evaluate the effect of Strobilanthes crispus extract for possible protection against lipid peroxidation and DNA damage induced by iron nitrilotriacetate (Fe-NTA) and hydrogen peroxide (H₂O₂). Fe-NTA is a potent nephrotoxic agent and induces acute and subacute renal proximal tubular necrosis by catalyzing the decomposition of H₂O₂-derived production of hydroxyl radicals, which are known to cause lipid peroxidation and DNA damage. Incubation of postmitochondrial supernatant and/or calf thymus DNA with H₂O₂ (40 mM) in the presence of Fe-NTA (0.1 mM) induces lipid peroxidation and DNA damage to about 2.3-fold and 2.9-fold, respectively, as compared to control (P < 0.05). In lipid peroxidation protection studies, S. crispus treatment showed a dose-dependent inhibition (45–53% inhibition, P < 0.05) of Fe-NTA and H₂O₂ induced lipid peroxidation. Similarly, in DNA damage protection studies, S. crispus treatment also showed a dose-dependent inhibition (18–30% inhibition, P < 0.05) of DNA damage. In addition, the protection was closely related to the content of phenolic compounds as evident by S. crispus extract showing the value of 124.48 mg/g total phenolics expressed as gallic acid equivalent (GAE, mg/g of extract). From these studies, it is concluded that S. crispus inhibits peroxidation of membrane lipids and DNA damage induced by Fe-NTA and H₂O₂ and possesses the potential to be used to treat or prevent degenerative diseases where oxidative stress is implicated.     

Protective effects of cyclosativene on H2O2-induced injury in cultured rat primary cerebral cortex cells

Sesquiterpenes have attracted much interest with respect to their protective effect against oxidative damage that may be the cause of many diseases including several neurodegenerative disorders and cancer. Our previous unpublished work suggested that cyclosativene (CSV), a tetracyclic sesquiterpene, has antioxidant and anticarcinogenic features. However, little is known about the effects of CSV on oxidative stress induced neurotoxicity. We used hydrogen peroxide (H₂O₂) exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of CSV in H₂O₂-induced toxicity in new-born rat cerebral cortex cell cultures for the first time. For this aim, MTT and lactate dehydrogenase release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC) and total oxidative stress (TOS) parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG) levels, the single cell gel electrophoresis (or Comet assay) was also performed for measuring the resistance of neuronal DNA to H₂O₂-induced challenge. Our results showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage (Comet assay) increased in the H₂O₂ alone treated cultures. But pre-treatment of CSV suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H₂O₂. On the basis of these observations, it is suggested that CSV as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative disorders.     

Evaluation of diphlorethohydroxycarmalol isolated from Ishige okamurae for radical scavenging activity and its protective effect against H2O2-induced cell damage

In this study, the antioxidant activities of 21 species of marine algae were assessed via an ABTS free radical scavenging assay. The Ishige okamurae extract tested herein evidenced profound free radical scavenging activity, compared to that exhibited by other marine algae extracts. Thus, I. okamurae was selected for use in further experiments, and was partitioned with different organic solvents. Profound radical scavenging activity was detected in the ethyl acetate fraction, and the active compound was identified as the carmalol derivative, diphlorethohydroxycarmalol, which evidenced higher levels of activity than that of commercial antioxidants. Moreover, the protective effects of diphlorethohydroxycarmalol against H₂O₂-induced cell damage were evaluated. Intracellular reactive oxygen species (ROS) were overproduced as the result of the addition of H₂O₂, but this ROS generation was reduced significantly after diphlorethohydroxycarmalol treatment; this corresponds to a significant enhancement of cell viability against H₂O₂-induced oxidative damage. The inhibitory effects of diphlorethohydroxycarmalol against cell damage were determined via comet assay and Hoechst staining assay, and diphlorethohydroxycarmalol was found to exert a positive dose-dependent effect. These results clearly indicate that the diphlorethohydroxycarmalol isolated from I. okamurae exerts profound antioxidant effects against H₂O₂-mediated cell damage, and treatment with this compound may be a potential therapeutic modality for the treatment or prevention of several diseases associated with oxidative stress.     

The ameliorating effect of Acadian marine plant extract against ionic liquids-induced oxidative stress and DNA damage in marine macroalga Ulva lactuca

Ionic liquids (ILs) are generally considered as the green replacement for conventional volatile organic solvents. Nonetheless, their high solubility in water with proven toxic effects on aquatic biota has questioned their green credentials. In the present study, the detoxification potential of Acadian marine plant extract powder (AMPEP) prepared from the brown alga Ascophyllum nodosum was investigated against the 1-alkyl-3-methylimidazolium bromide [C₁₂mim]Br ionic liquid-induced toxicity and oxidative stress in marine macroalga Ulva lactuca. The IL ([C₁₂mim]Br) at LC₅₀ (70 μM) exposure triggered the generation of reactive oxygen species (ROS) such as O ₂ ^·? , H₂O₂ and OH· causing membrane and DNA damage together with inhibition of antioxidant systems in the alga. The supplementation of AMPEP (150 μg mL^?1) to the culture medium significantly reduced the accumulation of ROS and lipid peroxidation together with the inhibition of lipoxygenase (LOX) activity specially LOX-2 and LOX-3 isoforms. This is for the first time wherein comet assay was performed to ascertain the protective role of AMPEP against DNA damage in algal tissue grown in medium supplemented with IL and AMPEP. The AMPEP showed protective role against DNA damage (5–45 % tail DNA) when compared to those of grown in IL alone (45–70 % tail DNA). Further, specific isomorphs of different antioxidant enzymes such as superoxide dismutase (Mn-SOD-1, ~150 kDa), ascorbate peroxidase (APX-4, ~55 kDa), glutathione peroxidase (GSH-Px-2, ~55 kDa) and glutathione reductase (GR-1, ~180 kDa) responded specifically to AMPEP supplementation. It is evident from these findings that AMPEP could possibly be used for circumventing the negative effects arising from ILs-induced toxicity in marine ecosystem.     

Endogenous Expression of ODN-Related Peptides in Astrocytes Contributes to Cell Protection Against Oxidative Stress: Astrocyte-Neuron Crosstalk Relevance for Neuronal Survival

Astroglial cells are important actors in the defense of brain against oxidative stress injuries. Glial cells synthesize and release the octadecaneuropeptide ODN, a diazepam-binding inhibitor (DBI)-related peptide, which acts through its metabotropic receptor to protect neurons and astrocytes from oxidative stress-induced apoptosis. The purpose of the present study is to examine the contribution of the endogenous ODN in the protection of astrocytes and neurons from moderate oxidative stress. The administration of H₂O₂ (50 μM, 6 h) induced a moderate oxidative stress in cultured astrocytes, i.e., an increase in reactive oxygen species, malondialdehyde, and carbonyl group levels, but it had no effect on astrocyte death. Mass spectrometry and QPCR analysis revealed that 50 μM H₂O₂ increased ODN release and DBI mRNA levels. The inhibition of ODN release or pharmacological blockage of the effects of ODN revealed that in these conditions, 50 μM H₂O₂ induced the death of astrocytes. The transfection of astrocytes with DBI siRNA increased the vulnerability of cells to moderate stress. Finally, the addition of 1 nM ODN to culture media reversed cell death observed in DBI-deficient astrocytes. The treatment of neurons with media from 50 μM H₂O₂-stressed astrocytes significantly reduced the neuronal death induced by H₂O₂; this effect is greatly attenuated by the administration of an ODN metabotropic receptor antagonist. Overall, these results indicate that astrocytes produce authentic ODN, notably in a moderate oxidative stress situation, and this glio- and neuro-protective agent may form part of the brain defense mechanisms against oxidative stress injury.