Syzygium cumini leaf extract protects macrophages against the oxidized LDL-induced toxicity: A promising atheroprotective effect.

Oxidized LDL (oxLDL) plays a pivotal role on atherosclerosis development, mainly in the formation of lipid-laden macrophage "foam cells". As a consequence, substances that can modulate LDL oxidation have a pharmacological and therapeutic relevance. Based in previous findings showing the ability of Syzigium cumini leaf extract (ScExt) in preventing LDL oxidation in vitro, this study was aimed to assess the effects of ScExt on oxLDL-mediated toxicity in murine J774 macrophages-like cells. For biochemical analyses, LDL isolated from fresh human plasma and oxidized with CuSO4 was incubated with ScExt pre-treated macrophages. Our results demonstrated that ScExt was efficient in preventing the overproduction of reactive oxygen/nitrogen species (ROS/RNS), the loss of macrophage's viability and the foam cells formation induced by oxLDL. These protective effects of ScExt make it a promising antioxidant for future trials toward atherogenesis.

Atorvastatin Improves Mitochondrial Function and Prevents Oxidative Stress in Hippocampus Following Amyloid-ß1-40 Intracerebroventricular Administration in Mice.

Amyloid-ß (Aß) peptides play a significant role in the pathogenesis of Alzheimer's disease (AD). Neurotoxic effects promoted by Aß peptides involve glutamate transmission impairment, decrease of neurotrophic factors, mitochondrial dysfunction, oxidative stress, synaptotoxicity, and neuronal degeneration. Here, we assessed the early events evoked by Aß1-40 on the hippocampus. Additionally, we sought to unravel the molecular mechanisms of atorvastatin preventive effect on Aß-induced hippocampal damage. Mice were treated orally (p.o.) with atorvastatin 10 mg/kg/day during 7 consecutive days before the intracerebroventricular (i.c.v.) infusion of Aß1-40 (400 pmol/site). Twenty-four hours after Aß1-40 infusion, a reduced content of mature BDNF/proBDNF ratio was observed in Aß-treated mice. However, there is no alteration in synaptophysin, PSD-95, and doublecortin immunocontent in the hippocampus. Aß1-40 promoted an increase in reactive oxygen species (ROS) and nitric oxide (NO) generation in hippocampal slices, and atorvastatin prevented this oxidative burst. Mitochondrial OXPHOS was measured by high-resolution respirometry. At this time point, Aß1-40 did not alter the O2 consumption rates (OCR) related to phosphorylating state associated with complexes I and II, and the maximal OCR. However, atorvastatin increased OCR of phosphorylating state associated with complex I and complexes I and II, maximal OCR of complexes I and II, and OCR associated with mitochondrial spare capacity. Atorvastatin treatment improved mitochondrial function in the rodent hippocampus, even after Aß infusion, pointing to a promising effect of improving brain mitochondria bioenergetics. Therefore, atorvastatin could act as an adjuvant in battling the symptoms of AD to preventing or delaying the disease progression.

Potential neuroprotective and anti-inflammatory effects provided by omega-3 (DHA) against Zika virus infection in human SH-SY5Y cells.

Zika virus (ZIKV) has a strong tropism for the nervous system and has been related to post-infection neurological syndromes. Once neuronal cells are infected, the virus is capable of modulating cell metabolism, leading to neurotoxicity and cellular death. The negative effect of ZIKV in neuron cells has been characterized. However, the description of molecules capable of reversing these cytotoxic effects is still under investigation. In this context, it has been largely demonstrated that docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, is highly neuroprotective. Here, we hypothesized that DHA's neuroprotective proprieties could have an influence on ZIKV-induced neurotoxicity in SH-SY5Y cells. Our data showed that pre-treatment of SH-SY5Y cells with DHA increased the cell viability and proliferation in ZIKV-infected cells. Moreover, DHA triggered an anti-inflammatory response in those infected cells. Besides, DHA was capable of restoring mitochondria function and number in ZIKV-infected SH-SY5Y cells. In addition, cells pre-treated with DHA prior to ZIKV infection presented a lower viral load at different times of infection. Taking together, these results demonstrated that DHA has a potential anti-inflammatory and neuroprotective effect against ZIKV infection in these neuron-like cells and could be a useful tool in the treatment against this virus.

Neuroprotective effect of the proanthocyanidin-rich fraction in experimental model of spinal cord injury.

OBJECTIVES: In this study, we evaluated the effect of the proanthocyanidins-rich fraction (PRF) obtained from Croton celtidifolius bark in an experimental animal model of spinal cord injury and cell death induced by glutamate. METHODS: Experiments were conducted using adult male Wistar rats (10 weeks old and weighing 270-300g). Experimental groups were randomly allocated into the following groups: spinal cord injury (SCI) + vehicle group: rats were subjected to SCI plus intraperitoneal administration of vehicle (saline 10 ml/kg); SCI + PRF: rats were subjected to SCI plus intraperitoneal administration of PRF (10 mg/kg) at 1 and 6 h after injury and sham operated. KEY FINDINGS: The treatment with the proanthocyanidin-rich fraction significantly improved not only motor recovery and grip force but also H2 O2 or glutamate-induced cell death and reactive oxygen species generation induced by glutamate in dorsal root ganglion cells. In this study we demonstrate that the neuroprotective effect triggered by the proanthocyanidins-rich fraction appears to be mediated in part by the inhibition of N-methyl-D-aspartate-type glutamate receptors. CONCLUSIONS: Taken together, our results demonstrate that PRF treatment ameliorates spinal cord injury and glutamatergic excitotoxicity and could have a potential therapeutic use.

Diphenyl diselenide supplementation reduces biochemical alterations associated with oxidative stress in rats fed with fructose and hydrochlorothiazide.

The study evaluated whether a diet containing diphenyl diselenide (PhSe)2, a synthetic antioxidant, could reduce the biochemical alterations induced by chronic consumption of highly enriched fructose diet and/or hydrochlorothiazide (HCTZ). Rats were fed a control diet (CT) or a high fructose diet (HFD), supplemented with or not HCTZ (4.0g/kg) and/or (PhSe)2 (3ppm) for 18weeks. HFD intake increased significantly plasma glucose, fructosamine, triglycerides and cholesterol levels. (PhSe)2 supplementation significantly reduced triglycerides and cholesterol but could not restore them to control levels. The combination of HFD and HCTZ significantly altered plasma glucose, fructosamine, triglycerides and cholesterol levels which were not restore by (PhSe)2 supplementation. Lipid peroxidation, protein carbonyl formation, vitamin C level and catalase activity decreased after HFD, HCTZ or HFD plus HCTZ ingestion. Remarkably (PhSe)2 supplementation restored the oxidative stress parameters. HCTZ decreased renal superoxide dismutase (SOD) activity, which was restored to control levels by (PhSe)2. Furthermore, the association of HFD and HCTZ decreased plasma potassium levels and aggravated HCTZ-induced hypomagnesemia and hypertriglyceridemia. Here we provided evidence of the involvement of oxidative stress and metabolic disorders in a rat model of HFD associated or not with HTCZ. (PhSe)2 supplementation reduced the oxidative stress and this compound should be considered for the treatment of biochemical disturbances and oxidative stress in other animal models of metabolic disorders.

Cardioprotective effects of a proanthocyanidin-rich fraction from Croton celtidifolius Baill: focus on atherosclerosis.

Proanthocyanidins are the most abundant polyphenols in human diets. Epidemiological studies have pointed to proanthocyanidins as promising molecules that could prevent the development of several coronary syndromes by inhibiting the atherogenic process. The present study was designed to investigate the antiatherogenic effects of a proanthocyanidin-rich fraction (PRF) obtained from Croton celtidifolius Baill (Euphorbiaceae) barks. In isolated human LDL, PRF caused a concentration-dependent inhibition of Cu2+-induced oxidative modifications, evidenced by the increasing of the lag phase of lipid peroxidation and decreasing in the oxidation rate (Vmax), moreover, the protein moieties from LDL were protected against Cu2+-induced oxidation. In human umbilical vein endothelial cells (HUVECs), PRF reduced the ROS production stimulated by oxidized LDL. Herein, we demonstrate that oral treatment with PRF improved endothelium-dependent vasorelaxation in hypercholesterolemic LDL receptor knockout mice (LDLr-/-), however, the fraction did not modify plasma lipids and atherosclerotic lesion size in this experimental model. Finally, our results showed for the first time that PRF prevent isolated LDL oxidation, decrease oxidative stress in endothelial cells and improve endothelial function in mice.

Differential effects of insulin on peripheral diabetes-related changes in mitochondrial bioenergetics: involvement of advanced glycosylated end products.

Large scale clinical trials have demonstrated that an intensive antihyperglycemic treatment in diabetes mellitus (DM) in individuals reduces the incidence of micro- and macrovascular complications, e.g. nephropathy, retinopathy, DM-accelerated atherosclerosis, myocardial infarction, or limb amputations. Here, we investigated the effect of short- and long-term insulin administration on mitochondrial function in peripheral tissues of streptozotocin (STZ)-induced hyperglycemic rats. In addition, the in vitro effect of methylglyoxal (MG), advanced glycation end products (AGEs) and human diabetic plasma on mitochondrial activity was investigated in skeletal muscle and liver mitochondria and in rat skin primary fibroblasts. Hyperglycemic STZ rats showed tissue-specific patterns of energy deficiency, evidenced by reduced activities of complexes I, II and/or IV after 30 days of hyperglycemia in heart, skeletal muscle and liver; moreover, cardiac tissue was found to be the most sensitive to the diabetic condition, since energy metabolism was impaired after 10 days of the hyperglycemia. Insulin-induced tight glycemic control was effective in protecting against the hyperglycemia-induced inhibition of mitochondrial enzyme activities. Furthermore, the long-term hormone replacement (30 days) also increased these activities in kidney from STZ-treated animals, where the hyperglycemic state did not modify the electron transport activity. Results from in vitro experiments indicate that mitochondrial impairment could result from oxidative stress-induced accumulation of MG and/or AGEs. Further investigations demonstrated that human plasma AGE accumulation elicits reduced mitochondrial function in skin fibroblast. These data suggest that persistent hyperglycemia results in tissue-specific patterns of energy deficiency and that early and continuous insulin therapy is necessary to maintain proper mitochondrial metabolism.

Acute exposure of rabbits to diphenyl diselenide: a toxicological evaluation.

The simple organoselenium compound diphenyl diselenide (PhSe)(2) is a promising new pharmacological agent. However, few toxicological evaluations of this molecule have been reported. We evaluated the effects of acute administration of (PhSe)(2) on toxicological parameters in rabbits. Adult New Zealand rabbits were exposed to (PhSe)(2) (5-500 micromol kg(-1) , intraperitoneally) once a day for 5 days. Exposure to 500 micromol kg(-1) caused 85% mortality. Exposure to 50 micromol kg(-1) of (PhSe)(2) increased the glutathione levels in the hippocampus, kidney, heart, muscle and blood, whereas lipoperoxidation (TBARS) decreased in the cerebellum and kidney after exposure to 5 micromol kg(-1) . The activity of glutathione peroxidase increased in the heart and muscle of rabbits treated with 50 micromol kg(-1) of (PhSe)(2) and glutathione reductase activity was reduced in the cerebellum, cerebral cortex and kidney. Treatment with (PhSe)(2) reduced the activity of δ-aminolevulinate dehydratase in the hippocampus and increased this activity in the heart, but did not alter the activity of complexes I and II of the respiratory chain in the liver and brain. Hepatic and renal biochemical and histological parameters were not modified by (PhSe)(2) and apoptosis was not detected in these tissues; however, the hepatic cells tended to accumulate fat vacuoles. These results indicated that acute toxicology to (PhSe)(2) in rabbit is dependent on the dose, which should motivate further experiments on the therapeutic properties of this compound.

Diphenyl diselenide decreases serum levels of total cholesterol and tissue oxidative stress in cholesterol-fed rabbits.

Hypercholesterolaemia and oxidative stress are well-known risk factors in coronary artery diseases. Diphenyl diselenide is a synthetic organoselenium compound that has been shown to have in vitro and in vivo antioxidant properties. In this study, we investigated whether diphenyl diselenide could reduce the hypercholesterolaemia and diminish the tissue oxidative stress in cholesterol-fed rabbits. Twenty-four New Zealand white male rabbits were randomly divided into four groups. Each group was fed a different diet as follows: Control group--regular chow; Cholesterol group--1% cholesterol-enriched diet; diphenyl diselenide group--regular diet supplemented with 10 ppm diphenyl diselenide; and Chol/diphenyl diselenide group--the same cholesterol-rich supplemented with 10 ppm diphenyl diselenide. After 45 days of treatment, the rabbits were killed and the blood, liver, and brain were used for laboratory analysis. The results showed that the serum levels of total cholesterol were markedly increased in cholesterol-fed rabbits and the consumption of diphenyl diselenide decreased these levels approximately twofold in Chol/diphenyl diselenide rabbits (P < 0.05). The intake of diphenyl diselenide by hypercholesterolaemic rabbits diminished the serum and hepatic thiobarbituric acid reactive substances levels as well as the production of reactive oxygen species in the blood and brain (P < 0.05) when compared to the cholesterol group. In addition, diphenyl diselenide supplementation increased hepatic and cerebral delta-aminolevulinic dehydratase activity and hepatic non-protein thiol groups levels despite hypercholesterolaemia (P < 0.05). In summary, the results showed that diphenyl diselenide reduced the hypercholesterolaemia and the oxidative stress in cholesterol-fed rabbits.

A single high dose of ascorbic acid and iron is not correlated with oxidative stress in healthy volunteers.

Fe (II) is a potential prooxidant in vivo and can induce cellular oxidative stress. Ascorbic acid (AA) is a powerful physiological antioxidant and, in the presence of free Fe (II), can exhibit prooxidant effects in vitro. However, in vivo prooxidant effects of Fe (II) and AA have not yet been indisputably demonstrated. Here we evaluate the potential toxic effect of supplementation of Fe (II) associated with AA. Nine healthy, nonsmoking male volunteers (20-31 years old) participated in the crossover study design. The volunteers were supplemented with either a dose of 2 g of AA, 150 mg of iron carbonyl or 2 g of AA plus 150 mg of iron carbonyl with a washout period of 15 days between each treatment. AA, iron, ferritin, thiobarbituric acid-reactive substances, catalase, delta-aminolevulinic dehydratase and SH thiol groups were measured in the blood of the volunteers. Plasma AA levels were increased at 2, 5 and 24 h after AA or AA plus iron ingestion. Plasma Fe levels were increased at 2 and 5 h in the AA plus iron group. Erythrocyte malondialdehyde levels decreased at 5 and 24 h after AA and 5 h after AA plus iron ingestion. Catalase activity from erythrocytes was increased 5 h after supplementation with AA plus iron. There was no significant difference between groups in the other biochemical parameters evaluated. Thus, the present study does not support the hypothesis that the combination of high plasma concentrations of AA and iron, or iron alone, could cause in vivo oxidative damage after a single supplementation dose.

Low toxicity of diphenyl diselenide in rabbits: a long-term study.

Selenium compounds, like diphenyl diselenide (Ph(2)Se(2)), possess glutathione peroxidase (GSHPx)-like activities and other antioxidant properties. The aim of this study was to evaluate the effects of a long-term oral supplementation with Ph(2)Se(2) on various toxicological parameters in rabbits. Adult New Zealand male rabbits were divided into four groups: Group I served as control; Groups II, III and IV received 0.3, 3.0 and 30 p.p.m. of Ph(2)Se(2) pulverized in the chow for 8 months. A number of toxicological parameters were examined in liver, kidney, cerebral cortex and hippocampus, such as delta-aminolaevulinic acid dehydratase (delta-ALA-D), catalase (CAT), GSHPx activities, non-protein thiol (-SH), lipid peroxidation and ascorbic acid levels. The results indicated that supplementation 30 p.p.m. Ph(2)Se(2 )significantly increased delta-ALA-D activity in liver and in cerebral cortex. Non-protein -SH levels were significantly increased in liver but not in kidney, cerebral cortex and hippocampus of rabbits. Ascorbic acid content was significantly lower in the liver and cerebral cortex after supplementation with 30 p.p.m. Ph(2)Se(2). Conversely, no alterations in GSHPx and CAT activities, nor in thiobarbituric acid reactive substances levels were observed in rabbit tissues. These results indicate that oral supplementation with Ph(2)Se(2) is relatively secure in rabbits after 8 months of exposure. The findings encourage further experiments on the potential therapeutic effects of such compound.

Changes in biochemical parameters in rabbits blood after oral exposure to diphenyl diselenide for long periods.

The concept that selenium-containing molecules may be better antioxidants than classical antioxidants, has led to the design of synthetic organoselenium compounds. The present study was conducted to evaluate the potential toxicity of long time oral exposure to diphenyl diselenide (PhSe)2 in rabbits. Male adult New Zealand rabbits were divided into four groups, group I served as control; groups II, III and IV received 0.3, 3.0 and 30 ppm of (PhSe)2 pulverized in the chow for 8 months. A number of parameters were examined in blood as indicators of toxicity, including delta-aminolevulinate dehydratase (delta-ALA-D), catalase, glutathione peroxidase (GPx), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, TBARS, non-protein-SH, ascorbic acid and selenium. The results demonstrated that 6 and 8 months of 30 ppm (PhSe)2 intake caused a significant increase in blood delta-ALA-D activity. Erythrocyte non-protein thiol levels were significantly increased after 2 months of 30 ppm (PhSe)2 intake and then return to control levels after prolonged periods of intake. Ingestion of 3.0 ppm of (PhSe)2 for 8 months significantly increased catalase activity in erythrocytes. Conversely, no alterations in GPx, ALT, AST, TBARS and selenium levels were observed in rabbit serum, conversely, selenium levels in peri-renal adipose tissue were significantly increased after 8 months of 30 ppm (PhSe)2 intake, indicating its great lipophylicity. The present results suggest that diphenyl diselenide was not hepato- or renotoxic for rabbits, but caused some biochemical alterations that can be related to some pro-oxidant activity of the compound (particularly the reduction in Vitamin C).