Lipid Peroxidation In Brain Homogenates Research Articles

Comparative study of the antioxidant and anti-inflammatory effects of the natural coumarins 1,2-benzopyrone, umbelliferone and esculetin: in silico, in vitro and in vivo analyses.

The aim of this work was to compare the anti-inflammatory and antioxidant effects of three natural coumarins: 1,2-benzopyrone, umbelliferone and esculetin. The antioxidant capacity of coumarins was evaluated using both chemical and biological in vitro assays. Chemical assays included DPPH and ABTS∙+ radical scavenging as well as ferric ion reducing ability power (FRAP) assay. Inhibition of mitochondrial ROS generation and lipid peroxidation in brain homogenates were used as biological in vitro assays. The experimental method of carrageenan-induced pleurisy in rats was used for the in vivo investigation of the anti-inflammatory activity. In silico molecular docking analysis was undertaken to predict the affinity of COX-2 to the coumarins. Considering the antioxidant capacity, esculetin was the most efficient one as revealed by all employed assays. Particularly, the mitochondrial ROS generation was totally abolished by the compound at low concentrations (IC50 = 0.57μM). As for the anti-inflammatory effects, the COX-2 enzyme presented good affinities to the three coumarins, as revealed by the molecular docking analyses. However, considering the in vivo anti-inflammatory effects, 1,2-benzopyrone was the most efficient one in counteracting pleural inflammation and it potentiated the anti-inflammatory actions of dexamethasone. Umbelliferone and esculetin treatments failed to reduce the volume of pleural exudate. Overall, therefore, our results support the notion that this class of plant secondary metabolites displays promising effects in the prevention and/or treatment of inflammation and other diseases associated with oxidative stress, although the singularities regarding the type of the inflammatory process and pharmacokinetics must be taken into account.

KI Essence extract (a spleen-tonifying formula) promotes neurite outgrowth, alleviates oxidative stress and hypomyelination, and modulates microbiome in maternal immune activation offspring.

Mushrooms and Chinese traditional herbs have bioactive nutraceuticals with multiple therapeutic functions, including antioxidant and antibacterial activities and microbiome modulation properties. Mushroom-derived bioactive compounds are used in medicines for the treatment of neurological disorders with abnormal brain–gut–microbiome axis. This study examined the effects of KI Essence extract, a spleen-tonifying formula, on neurite growth, antioxidant activity, hypomyelination modulation, and the microbiome profile in lipopolysaccharide (LPS)-induced maternal immune activation (MIA) offspring. The KI Essence extract induced PC12 cell neurite growth by increasing extracellular signal–regulated kinase (ERK) phosphorylation, promoting 2,2′-diphenyl-1-picrylhydrazyl radical scavenging activity, reducing the level of tert-butylhydroperoxide–induced lipid peroxidation in brain homogenates, protecting PC12 cells from H2O2-induced cell death (through the inhibition of ERK phosphorylation), alleviating hypomyelination, and downregulating interleukin‐1β through LPS-activated microglia production; moreover, the numbers of Enterobacteriaceae, Actinobacteria, Peptostreptococcaceae, Erysipelotrichaceae, and Bifidobacterium bacteria in MIA offspring increased. In summary, the KI Essence extract promotes neurite outgrowth, alleviates oxidative stress and hypomyelination, and modulates microbiota dysbiosis in MIA offspring.

Bis-γ-carbolines as new potential multitarget agents for Alzheimer’s disease

Abstract A new series of homobivalent Dimebon analogs, bis-γ-carbolines with alkylene, phenylenedialkylene, and triazole-containing spacers, was synthesized. Doubling the γ-carboline pharmacophore increased inhibitory potency against acetylcholinesterase (AChE) compared with Dimebon, while keeping Dimebon’s anti-butyrylcholinesterase activity; therefore, leading to inversion of selectivity. Molecular docking revealed the reasons for the increased anti-AChE activity and ability to block AChE-induced aggregation of β-amyloid for bis-γ-carbolines, which became double-site inhibitors of AChE. Conjugates with ditriazole-containing spacers were the most active antioxidants in both the ABTS-test and prevention of lipid peroxidation in brain homogenates without inhibiting the mitochondrial permeability transition (MPT). Conjugates with alkylene (4a–d), phenylenedialkylene (4e), and monotriazole (8) spacers were less active as antioxidants but prevented induction of the MPT and increased the calcium retention capacity of mitochondria. Lead compound 4e showed neuroprotective potential in a cellular calcium overload model of neurodegeneration. Computational studies showed that all the bis-γ-carbolines were expected to have high values for intestinal absorption and very good blood-brain barrier permeability along with good drug-likeness. Overall, the results showed that new homobivalent Dimebon analogs exhibit an expanded spectrum of biological activity and improved pharmacological properties, making them promising candidates for further research and optimization as multitarget agents for Alzheimer’s disease treatment.

Gallic Acid Attenuated LPS-Induced Neuroinflammation: Protein Aggregation and Necroptosis.

Gallic acid (3,4,5-trihydroxybenzoic acid, GA), a phenolic acid, is ubiquitous in almost all parts of the plant. In the present study, a neuroinflammatory rat model using intranigral infusion of lipopolysaccharides (LPS, 4μg/μL) was employed to study the neuroprotective effect of GA which was orally administered daily. Compared with the vehicle-treated rats, systemic administration of GA (100mg/kg) significantly attenuated LPS-induced increases in glial fibrillary acidic protein (a biomarker of activated astrocytes) and ED-1 (a biomarker of activated microglia), as well as inducible nitric oxide synthase (iNOS, a proinflammatory enzyme) and interleukin-1β (a proinflammatory cytokine), in the LPS-infused substantia nigra (SN) of rat brain. At the same time, GA attenuated LPS-induced elevation in heme oxygenase-1 level (a redox-regulated protein) and α-synuclein aggregation (a hallmark of CNS neurodegeneration), suggesting that GA is capable of inhibiting LPS-induced oxidative stress and protein conjugation. Furthermore, GA prevented LPS-induced caspase 3 activation (a biomarker of programmed cell death) and LPS-induced increases in receptor-interacting protein kinase (RIPK)-1 and RIPK-3 levels (biomarkers of necroptosis), indicating that GA inhibited LPS-induced apoptosis and necroptosis in the nigrostriatal dopaminergic system of rat brain. Moreover, an in vitro study was employed to investigate the anti-inflammatory effect of GA on BV2 microglial cells which were subjected to LPS (1μg/mL) treatment. Consistently, co-incubation of GA diminished LPS-induced increases in iNOS mRNA and iNOS protein expression in the treated BV-2 cells as well as NO production in the culture medium. The anti-oxidative activity of GA was evaluated using iron-induced lipid peroxidation of brain homogenates. After 3-h incubation at 37°C, GA was more potent than glutathione and less potent than trolox in inhibiting iron-induced lipid peroxidation. Conclusively, the present study suggests that GA is anti-inflammatory via attenuating LPS-induced neuroinflammation, oxidative stress, and protein conjugation. Furthermore, GA prevented LPS-induced programmed cell deaths of nigrostriatal dopaminergic neurons of the rat brain, suggesting that GA may be neuroprotective by attenuating neuroinflammation in CNS neurodegenerative diseases.

Bioactive Properties of Tabebuia impetiginosa-Based Phytopreparations and Phytoformulations: A Comparison between Extracts and Dietary Supplements.

Tabebuia impetiginosa (Mart. ex DC.) Standl. has been used in traditional medicine for many centuries, being nowadays marketed as dried plant material (inner bark) for infusions, pills, and syrups. The main objective of the present work was to validate its popular use through the bioactivity evaluation of the inner bark (methanolic extract and infusion) and of two different formulations (pills and syrup) also based on the same plant-material. The antioxidant activity was evaluated by in vitro assays testing free radical scavenging activity, reducing power and inhibition of lipid peroxidation in brain homogenates. The cytotoxicity was determined in four human tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2, and also in non-tumor cells (porcine liver primary cells, PLP2)). Furthermore, the sample was chemically characterized regarding free sugars, organic acids, fatty acids, and tocopherols. Syrup and methanolic extract showed the highest antioxidant activity, related to their highest amount of phenolics and flavonoids. Methanolic extract was the only sample showing cytotoxic effects on the tested human tumor cell lines, but none of the samples showed toxicity in PLP2. Glucose and oxalic acid were, respectively, the most abundant sugar and organic acid in the sample. Unsaturated predominated over the saturated fatty acids, due to oleic, linoleic, and linolenic acids expression. α- and γ-Tocopherols were also identified and quantified. Overall, T. impetiginosa might be used in different phytoformulations, taking advantage of its interesting bioactive properties and chemical composition.

The protective effect of Aloysia triphylla aqueous extracts against brain lipid-peroxidation

In a normal diet, the use of herbs may contribute significantly to the total intake of plant antioxidants and even be a better source of dietary antioxidants than many other food groups. Therefore, the aims of this study were to evaluate the protective effect of aqueous extracts of Aloysia triphylla (infusion and decoction) against lipid-peroxidation of brain homogenates and to determine changes in the prooxidant/antioxidant balance when the plant material is added. In order to elucidate a possible antioxidant mechanism in vitro evaluation of total antioxidant capacity, oxygen species scavenging ability and reducing power (RP) were studied. Tested extracts had shown a strong inhibition of lipid-peroxidation measured as thiobarbituric acid-reactive products of lipid-peroxidation (TBARS) and chemiluminescence. Furthermore, infusion and decoction exhibited free radical trapping ability, expressed by the capacity to scavenge superoxide and hydrogen peroxide. Additionally, both aqueous extracts presented antioxidant activity measured as total reactive antioxidant potential (TRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS) scavenging activity and RP. These results suggest that the lipid-peroxidation inhibition mechanism proposed is that the antioxidants present in Aloysia triphylla could act as strong scavengers of reactive oxygen species not only at the initiation of the lipid-peroxidation chain reaction, but also at the propagation step. Therefore, they could be used as prophylactic and therapeutic agents for those diseases where the occurrence of oxidative stress and lipid-peroxidation contributes to the progression of damage.

Antioxidant properties of diorganoyl diselenides and ditellurides: modulation by organic aryl or naphthyl moiety

Diorganoyl dichalcogenide compouds can have antioxidant activity in different in vitro and in vivo models. Here, we have compared the potential antioxidant activity of 1-dinaphthyl diselenide (1-NapSe)(2), 2-dinaphthyl diselenide (2-NapSe)(2), 1-dinaphthyl distelluride (1-NapTe)(2), 2-dinaphthyl ditelluride (2-NapTe)(2) with their well-studied analogs diphenyl diselenide ((PhSe)(2)) and diphenyl telluride ((PhTe)(2)). (PhSe)(2), (PhTe)(2), and naphthalene analogs-inhibited Fe(II)-induced lipid peroxidation, catalytically decomposed hydrogen peroxide and oxidized thiols, such as dithiothreitol (DTT), Cysteine (CYS), dimercaptopropionic acid (DMPS), and thiophenol (PhSH). (PhSe)(2) was the less potent of the tested compounds against Fe(II)-induced lipid peroxidation in brain homogenates and the change in the organic moiety from an aryl to naphthyl group increased considerably the antioxidant potency of diselenide compounds. However, the change from aryl to naphthyl had little effect on the thio-peroxidase-like activity of diorganoyl dichalcogenides. These results suggest that minor changes in the organic moiety of aromatic diselenide compounds can modify profoundly their capacity to inhibit iron-induced lipid peroxidation. The pharmacological properties of organochalcogens are thought to be linked to their capacity of modulating oxidative stress. Consequently, it becomes important to explore the toxicological properties of dinaphthyl diselenides and ditellurides.

Neuroprotective Effects of Longan (Dimocarpus longan Lour.) Flower Water Extract on MPP+-Induced Neurotoxicity in Rat Brain

In this study, the neuroprotective effect of Dimocarpus longan Lour. flower water extract (LFWE) was investigated. First, an in vitro study showed that LFWE concentration-dependently inhibited lipid peroxidation of brain homogenates incubated at 37 °C. The antioxidative activity of LFWE was more potent than that of glutathione or Trolox. Furthermore, an ex vivo study found that the basal lipid peroxidation (0 °C) and lipid peroxidation incubated at 37 °C were lower in the brain homogenates of LFWE-treated (500 mg/day) rats, indicating that the brain of LFWE-treated rats was more resistant to oxidative stress. Moreover, a Parkinsonian animal model was employed to demonstrate that oral administration of LFWE (125-500 mg/kg/day) dose-dependently attenuated 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in the nigrostriatal dopaminergic system of rat brain. In conclusion, this study suggests that LFWE is antioxidative, anti-inflammatory, and anti-apoptotic. Furthermore, oral administration of LFWE appears to be useful in preventing and/or treating central nervous system neurodegenerative diseases, including Parkinsonism.

Antioxidant Effect of Stryphnodendron rotundifolium Martius Extracts from Cariri-Ceará State (Brazil): Potential Involvement in Its Therapeutic Use

Stryphnodendron rotundifolium is a phytotherapic used in the northeast of Brazil for the treatment of inflammatory processes which normally are associated with oxidative stress. Consequently, we have tested the antioxidant properties of hydroalcoholic (HAB) and aqueous extracts (AB) from the bark and aqueous extract (AL) from the leaves of Stryphnodendron rotundifolium to determine a possible association between antioxidant activity and the popular use of this plant. Free radical scavenger properties were assessed by the quenching of 1′,1′-diphenil-2-picrylhydrazyl (DPPH) and the calculated IC50 were: HAB = 5.4 ± 0.7, AB = 12.0 ± 2.6, and AL = 46.3 ± 12.3 µg/mL. Total phenolic contents were: HAB = 102.7 ± 2.8, AB = 114.4 ± 14.6, and AL = 93.8 ± 9.1 µg/mg plant). HPLC/DAD analyses indicated that gallic acid, catechin, rutin and caffeic acid were the major components of the crude extracts of S. rotundifolium. Plant extracts inhibited Fe(II)-induced lipid peroxidation in brain homogenates. Iron chelation was also investigated and only HBA exhibited a weak activity. Taken together, the results suggest that S. rotundifolium could be considered an effective agent in the prevention of diseases associated with oxidative stress.

Neuroprotective effect of oral S/B remedy (Scutellaria baicalensis Georgi and Bupleurum scorzonerifolfium Willd) on iron-induced neurodegeneration in the nigrostriatal dopaminergic system of rat brain

S/B remedy prepared from Scutellaria baicalensis Georgi and Bupleurum scorzonerifolfium Willd, two herbals of Xiao-Tsai-Hu-Tang or Sho-Saiko-To (TJ-9), contains active flavonoids. In this study, the protective effect of S/B remedy on iron-induced neurodegeneration was investigated in the nigrostriatal dopaminergic system of rat brain. The antioxidative activity of S/B remedy was studied using brain homogenates incubated with ferrous citrate (iron, 1M), S/B remedy, Trolox and melatonin. Furthermore, a Parkinsonian animal model by an intranigral infusion of iron in the anesthetized rats was employed to investigate the protective effect of S/B remedy in the nigrostriatal dopaminergic system. Our in vitro studies showed that S/B remedy was more potent than melatonin and equal to trolox in inhibiting iron-induced lipid peroxidation of brain homogenates. Our in vivo studies found that oral administration of S/B remedy dose-dependently attenuated iron-elevated lipid peroxidation in the infused substantia nigra (SN) and iron-depleted dopamine levels in the ipsilateral striatum. Furthermore, iron-induced reductions in glutathione (GSH) content and increases in GSSG (oxidized GSH)/GSH ratio in the infused SN were inhibited in S/B remedy-treated rats. Systemic S/B remedy attenuated the iron-induced increases in heme-oxygenase-1 levels and α-synuclein aggregation in the infused SN. Moreover, S/B remedy reduced iron-induced apoptosis via attenuating mitochondrial and endoplasmic reticulum stress. In addition, S/B remedy was anti-inflammatory as indicated by the attenuation of iron-induced elevations in inducible nitric oxide synthase and cyclo-oxygenase II levels as well as glial fibrillary acidic protein (a biological marker of astrocytes) and ED-1 (a protein indicative of activated microglia) levels in the infused SN of S/B remedy-treated rats. These findings suggest that oral administration of S/B remedy is protective against iron-induced neurodegeneration in the nigrostriatal dopaminergic system of rat brain. Therefore, S/B remedy may be therapeutically useful for the treatment of CNS neurodegenerative diseases.

Exotic fruits as a source of important phytochemicals: Improving the traditional use of Rosa canina fruits in Portugal

Several exotic fruits are used in folk medicine as potential sources of healthy compounds. Rosa canina L. (dog rose) fruits and other parts used to be widely consumed in rural areas from Portugal. The present work intends to highlight the presence of bioactive compounds in those different parts, in order to improve their use based on scientific studies. The antioxidant activity was screened through: radical scavenging effects, reducing power, and inhibition of lipid peroxidation in brain homogenates. Phytochemical characterization included determination of sugars by HPLC-RI, fatty acids by GC-FID, tocopherols by HPLC-fluorescence, phenolics, flavonoids, carotenoids, chlorophylls and ascorbic acid, by spectrophotometric techniques. Galls revealed the highest antioxidant potential, ripen hips showed the highest tocopherols and β-carotene contents, as also the most adequate n-6/n-3 fatty acids ratios. Unripe hips gave the highest levels of ascorbic acid and petals revealed the highest concentration of sugars. Ethnobotanical studies conducted have mentioned different use-reports for seeds, petals, flowers and galls, as well as for fruits in different stages of maturity and, therefore, the comparison between chemical compounds and antioxidant properties of those different parts is a key-point of the present study. Furthermore, the levels of antioxidants found would make them suitable sources of compounds to be used commercially to retard rancidity in fatty materials in food manufacturing, to reduce the effects of ageing and to help to prevent oxidative-stress related diseases such as cancer and heart disease.

Antioxidant activity and inhibitory effect of L. viridis extract on Fe2+-induced lipid peroxidation in brain homogenates

Antioxidant activity and inhibitory effect of L. viridis extract on Fe2+-induced lipid peroxidation in brain homogenates

In vitro antioxidant properties and characterization in nutrients and phytochemicals of six medicinal plants from the Portuguese folk medicine

Traditional ethnomedical use of plants is recognized as an important potential source of compounds used in mainstream medicine. Herein, the i n vitro antioxidant properties, nutrients and phytochemical composition of six medicinal plants widely used in the north-eastern Portuguese region were evaluated. The antioxidant activity was screened through: radical scavenging effects, reducing power, and inhibition of lipid peroxidation in brain homogenates. Nutrients and phytochemical characterization included determination of sugars by HPLC-RI, fatty acids by GC-FID, tocopherols by HPLC-fluorescence, phenolics, flavonoids, carotenoids and ascorbic acid, by spectrophotometric techniques. Rubus ulmifolius flowers revealed the highest antioxidant activity, and the highest contents in phenolics, flavonoids, ascorbic acid and lycopene. Castanea sativa flowers revealed the highest concentration of individual and total tocopherols, and total sugars, including the reducing sugars glucose and fructose. Helichrysum stoechas aerial parts gave the highest levels of β-carotene, Matricaria recutita aerial parts revealed the highest PUFA levels, including linoleic acid. The studied medicinal plants have interesting antioxidant properties and a phytochemical composition that could provide scientific evidence for some folk uses in the treatment of diseases related to the production of ROS and oxidative stress, but further experiments are required to explore the mechanisms of action.

Antioxidant properties of polyphenol-rich cocoa products industrially processed

Abstract Fermentation and roasting are the main causes of polyphenol degradation during the process for obtaining cocoa products. In the present study, a process for obtaining polyphenol-rich cocoa products on an industrial scale is described. The process avoids the fermentation and roasting steps and includes a step for the inactivation of the enzyme Polyphenol Oxidase (PPO), which helps preserve the polyphenol content present in the raw cocoa bean. In addition, our study evaluates the antioxidant capacity and characterizes the flavonoid profile of the polyphenol-rich cocoa products obtained from the natural polyphenol-rich cocoa cake. Using different protocols, we have obtained three cocoa extracts with high polyphenol content, namely extracts A (167 mg/g), B (374 mg/g) and C (787 mg/g). The scavenging capacity of the extracts was measured as their ability to bleach the stable radicals DPPH and ABTS + while their antioxidant effect was evaluated with the FRAP assay. The results for A, B and C in the DPPH test expressed as Trolox equivalent (μmol)/mg dry weight of extract were 0.2, 1.4 and 3.0, respectively; in the ABTS test the results were 1.0, 4.7 and 9.8. The antioxidant capacity expressed as ascorbic acid equivalent (μmol)/mg dry weight of each product were 17.2, 76.1 and 207.7, respectively. The scavenging properties of cocoa powder against the superoxide anion, H 2 O 2 , HClO, and peroxynitrite were also determined. The IC 50 (μg/mL) values in the hypoxanthine/xanthine oxidase test were 77.5, 12.3 and 10.3, for A, B and C, respectively, while as an HOCl scavenger the IC 50 (μg/mL) values were 225.4, 73.2 and 21.5. As a peroxynitrite anion scavenger, only extract C had a relevant effect, with IC 50 (μg/mL) values of 76.1 or 110.0 in the absence or presence of bicarbonate. None of the extracts tested showed activity in the hydrogen peroxide test, but B and C significantly increased the deoxyribose degradation in the absence of ascorbate. Likewise, none of the extracts inhibited the ferrous or copper chelating activity at 100 μg/mL, but they inhibited the lipid peroxidation in brain homogenates and human plasma through non-enzymatic generation systems, with extract C giving the best IC 50 (μg/mL) values: 17.4 and 8.1 against lipid peroxidation in brain homogenates and human plasma, respectively. In conclusion, if the extractive protocol is well characterized, defined and optimized, cocoa could constitute a source of polyphenols for enriching foods, nutraceuticals and alimentary supplements.

Ameliorating reactive oxygen species-induced in vitro lipid peroxidation in brain, liver, mitochondria and DNA damage by Zingiber officinale Roscoe.

Iron is an essential nutrient for a number of cellular activities. However, excess cellular iron can be toxic by producing reactive oxygen species (ROS) such as superoxide anion (O(2) (-)) and hydroxyl radical (HO(·)) that damage proteins, lipids and DNA. Mutagenic and genotoxic end products of lipid peroxidation can induce the decline of mitochondrial respiration and are associated with various human ailments including aging, neurodegenerative disorders, cancer etc. Zingiber officinale Roscoe (ginger) is a widely used spice around the world. The protective effect of aqueous ethanol extract of Z. officinale against ROS-induced in vitro lipid peroxidation and DNA damage was evaluated in this study. The lipid peroxidation was induced by hydroxyl radical generated from Fenton's reaction in rat liver and brain homogenates and mitochondrial fraction (isolated from rat liver). The DNA protection was evaluated using H(2)O(2)-induced changes in pBR-322 plasmid and Fenton reaction-induced DNA fragmentation in rat liver. The results indicated that Z. officinale significantly (P<0.001) protected the lipid peroxidation in all the tissue homogenate/mitochondria. The extract at 2 and 0.5 mg/ml could protect 92 % of the lipid peroxidation in brain homogenate and liver mitochondria respectively. The percent inhibition of lipid peroxidation at 1mg/ml of Z. officinale in the liver homogenate was 94 %. However, the extract could partially alleviate the DNA damage. The protective mechanism can be correlated to the radical scavenging property of Z. officinale. The results of the study suggest the possible nutraceutical role of Z. officinale against the oxidative stress induced human ailments.

Antioxidant activity of three polyphenol-enriched cocoa products obtained on an industrial scale

Using different protocols we have obtained three cocoa extracts with a high content in polyphenols: A (167mg/g), B (374mg/g) and C (787mg/g). The scavenging capacity of the extracts was measured as the ability to bleach the stable radicals DPPH· and ABTS·+, and the antioxidant effect of them by the FRAP assay [1]. The results in the DPPH test were 0.2, 1.4 and 3.0 (expressed as Trolox equivalent, µmol/mg dry weight of each extract), and in the ABTS test were 1.0, 4.7 and 9.8, for A, B and C, respectively. The antioxidant capacity expressed as ascorbic acid equivalent were 17.2, 76.1 and 207.7, respectively. The scavenging properties of cocoa powder against the superoxide anion, H2O2, HClO [1], and peroxynitrite [2] were determined and the IC50 (µg/mL) values were 77.5, 12.3 and 10.3, for A, B and C, respectively, in the hypoxanthine/xanthine oxidase test, and 225.4, 73.2 and 21.5 as HOCl scavenger, respectively. Only extract C gave relevant effect as scavenger of peroxynitrite anion, with IC50 (µg/mL) of 76.1 and 110.0 in absence or presence of bicarbonate. None of the tested extract was active in the hydrogen peroxide test, but B and C significantly increased the deoxyribose degradation in the absence of ascorbate. None of the extracts inhibited the ferrous or copper chelating activity at 100µg/mL, but they inhibited the lipid peroxidation in brain homogenates and human plasma using non-enzymatic generation systems [3], giving the extract C the best IC50 (µg/mL) values, 17.4 and 8.1 against to lipid peroxidation in brain homogenates and human plasma, respectively. We conclude that cocoa may constitute a source of polyphenols which could serve for enriching foods, nutraceuticals and alimentary supplements.

Autoxidation of brain homogenates from various animals as measured by thiobarbituric acid assay

Introduction The TBARS assay has been well recognized for determination of lipid peroxidation and oxidative injury in biological samples including brain homogenates. In general, the homogenates are freshly prepared using rat brains as the tissue sources. In this study, we compared the rates of spontaneous lipid peroxidation in brain homogenates obtained from bovine, canine, hen, rat, and swine. In addition, the influences of lyophilization process and storage time up to six months at − 20 °C without the freeze–thaw cycle were also determined in the swine brain preparations. Methods The standard assay for thiobarbituric acid-reactive substances (TBARS) was performed at 37 °C, using spectrophotometry to quantify the malondialdehyde (MDA) content. Results Rat brain homogenate exhibited the highest autoxidation rate (0.128 ± 0.002 μM/min) whereas the bovine brain exhibited the lowest rate (0.032 ± 0.001 μM/min). Swine brain homogenate could be kept at − 20 °C up to 3 months without a significant increase in rate of autoxidation. Lyophilization caused a significant increase in the autoxidation rate of brain homogenate. However, the autoxidation rates of the lyophilized preparation were quite comparable throughout the six-month freezing time. Discussion Swine brain was a good candidate for tissue source in the TBARS reaction. The homogenate could be kept in the lyophilized form under the storage condition at − 20 °C without the freeze–thaw cycle in the dark for at least six months.

Neuroprotection by tamoxifen in focal cerebral ischemia is not mediated by an agonist action at estrogen receptors but is associated with antioxidant activity

We have previously shown that tamoxifen can induce marked neuroprotection after middle cerebral artery occlusion (MCAo) in rats and have described two possible mechanisms of action: namely, inhibition of EAA release and inhibition of nNOS activity. In this study we tested other potential mechanisms. Namely, agonist action at estrogen receptors and an antioxidative action. Tamoxifen-treated rats had significantly improved neurobehavioral deficit scores after 24 h and showed ∼ 75% reduced infarct volumes. These were unaffected by ICI 182,780 (a high affinity and pure receptor antagonist) administered intravenously, or intracisternally to avoid possible lack of brain penetration, 15 min before intravenous administration of tamoxifen. In rats subjected to 2 h MCAo followed by 22 h reperfusion, 1.8-fold and 2.9-fold increases of F 2-IsoPs and F 4 neuroprostanes, respectively, as relatively stable markers of oxidative damage, were measured in the ischemic hemisphere compared with the corresponding contralateral hemisphere or sham controls. Tamoxifen given at 3 h after the start of ischemia reduced the IsoPs and NeuroPs to sham control levels, and also inhibited their production by chemically induced lipid peroxidation in brain homogenates. These data are consistent with at least part of tamoxifen's marked neuroprotection in focal cerebral ischemic injury being due to its antioxidant activity but not by an acute action on estrogen receptors (212 words).

Hypoxic preconditioning prevents cortical infarction by transient focal ischemia-reperfusion.

One of the proposed pathologic actions underlying brain infarction is excess free radicals resulting from reoxygenation. In this paper we report an investigation of the neuroprotective effect of hypoxic preconditioning on transient focal ischemia-reperfusion injuries in rat brain. Female Wistar rats were subjected to 380 mmHg in an altitude chamber for 15 hours/day. Our ex vivo studies showed that auto-oxidation and iron-induced lipid peroxidation of brain homogenates of the four-week hypoxia-preconditioned rats were significantly lower than those of the normoxic rats. A focal infarction in the cerebral cortex of normoxic rats was consistently observed 24 hours after a 60-minute transient ischemic occlusion of the right middle cerebral artery and bilateral common carotid arteries. Hypoxic preconditioning in fact attenuated cortical infarction in a duration-dependent manner. Induction of the neuroprotection required two weeks of hypoxic preconditioning. Four weeks of hypoxic preconditioning significantly reduced the cortical infarcted area, the elevated lipid peroxidation, and resulted in an acute increase in cytosolic cytochrome c in the infarcted cortex of normoxic rats. The protective effect of four weeks of hypoxic preconditioning lasted seven days under a renormoxic condition. Our data suggest that oxidative stress may result in apoptosis in the transient focal ischemia-reperfusion injuries. Furthermore, hypoxic preconditioning attenuated cortical infarction in the rat brain. Although supplementation of antioxidants may encounter difficulty at the blood-brain barrier, hypoxic preconditioning is very likely to protect CNS targets from oxidative injuries without any barrier.

Angeli's Salt Induces Neurotoxicity in Dopaminergic Neurons In Vivo and In Vitro

In this study, we investigated the hypothesis that the pro-oxidative properties of Angeli's salt (AS), a nitroxyl anion (HNO/NO m ) releasing compound, cause neurotoxicity in dopaminergic neurons. The pro-oxidative properties were demonstrated in vitro by measuring hydroxylation products of salicylate and peroxidation of lipids under various redox conditions. AS (0-1000 w M) released high amounts of hydroxylating species in a concentration dependent manner. AS also increased lipid peroxidation in brain homogenates at concentrations below 100 w M, while inhibiting it at 1000 w M concentration. The AS induced pro-oxidative effects were completely suppressed by copper (II), which converts nitroxyl anion to nitric oxide, as well as by a potent nitroxyl anion scavenger glutathione. Neurotoxicity towards dopaminergic neurons was tested in rat nigrostriatal dopaminergic system in vivo and by using primary mesencephalic dopaminergic neuronal cultures in vitro. Intranigral infusion of AS (0-400 nmol) caused neurotoxicity reflected as a dose dependent decrease of striatal dopamine seven days after treatment. The effect of the 100 nmol dose was more pronounced when measured 50 days after the infusion. Neurotoxicity was also confirmed as a decrease of tyrosine hydroxylase positive neurons in the substantia nigra. Neither sulphononoate, a close structural analog of AS, nor sodiumnitrite caused changes in striatal dopamine, thus reflecting lack of neurotoxicity. In primary dopaminergic neuronal cultures AS reduced [ 3 H] dopamine uptake with concentrations over 200 w M confirming neurotoxicity. In line with the quite low efficacy to increase lipid peroxidation in vitro, infusion of AS into substantia nigra did not cause increased formation of fluorescent products of lipid peroxidation. These results support the hypothesis that AS derived species oxidize critical thiol groups, rather than membrane lipids, potentially leading to protein oxidation/dysfunction and demonstrated neurotoxicity. These findings may have pathophysiological relevance in case of excess formation of nitroxyl anion.