Purple pitanga extract (Eugenia uniflora) attenuates oxidative stress induced by MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely used due to its specific and reproducible neurotoxic effect on the nigrostriatal system, being considered a convenient model of dopaminergic neurodegeneration to study interventions therapeutics. The purple pitanga (Eugenia uniflora) is a polyphenol-rich fruit with antioxidant and antidepressant properties, among others. Therefore, this study investigated the effect of purple pitanga extract (PPE) on acute early oxidative stress induced by intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in rats. Male Wistar rats were pre-treated orally with PPE (1000 mg/kg) or vehicle. After 24 h, MPTP (0.1 mg/10µL/nostril) or vehicle was administered bilaterally into the animal's nostrils, and 6 h later, the olfactory bulb (OB), striatum (ST), and substantia nigra (SN) were collected to evaluate the oxidative stress parameters. Our findings revealed that OB and SN were the most affected areas after 6 h of MPTP infusion; an early increase in reactive oxygen species (ROS) levels was observed, while pretreatment with a single dose of PPE prevented this increment. No differences in thiobarbituric acid reactive species (TBARS) and 3-nitrotyrosine (3-NT) formation were observed, although 4-hydroxy-2-nonenal (4-HNE) levels increased, which is the most toxic form of lipid peroxidation, in the MPTP group. The PPE pretreatment could prevent this increase by increasing the NPSH levels previously decreased by MPTP. Furthermore, PPE prevents the Na+/K + ATPase strongly inhibited by MPTP, showing the neuroprotective capacity of the PPE by inhibiting the MPTP-generated oxidation. Thus, we demonstrated for the first time the antioxidant and neuroprotective effects of PPE against the early MPTP neurotoxicity.

The Endocannabinoid System in Caenorhabditis elegans.

The existence of a formal Endocannabinoid System in C. elegans has been questioned due to data showing the absence of typical cannabinoid receptors in the worm; however, the presence of a full metabolism for endocannabinoids, alternative ligands, and receptors for these agents and a considerable number of orthologous and homologous genes regulating physiological cannabinoid-like signals and responses - several of which are similar to those of mammals - demonstrates a well-structured and functional complex system in nematodes. In this review, we describe and compare similarities and differences between the Endocannabinoid System in mammals and nematodes, highlighting the basis for the integral study of this novel system in the worm.

Caffeic acid and caffeine attenuate toxicity associated with malonic or methylmalonic acid exposure in Drosophila melanogaster.

The deficiency in the activity of the mitochondrial enzyme methylmalonyl-CoA mutase (MCM, EC 5.4.99.2) leads to a condition called methylmalonic academia, which is characterised by the accumulation of methylmalonic (MMA), malonic (MA) or other organic acids. Importantly, we have recently found that supplementation with Ilex paraguariensis aqueous extract offered protection against toxicity associated with MMA or MA exposure to Drosophila melanogaster. Of note, caffeic acid (CA) and caffeine (CAF) were the major phytochemicals found in our Ilex paraguariensis crude extract. Therefore, here, we have exploited CA and/or CAF to test the hypothesis that supplementation with the isolated compounds (either alone or combined) could exert a protective effect against MMA or MA-induced toxicity in flies. Therefore, flies were exposed to MA (5 mM) or MMA (5 mM) and concomitantly treated with CA (1.39 µg/mL), CAF (1.27 µg/mL) or CA + CAF for 10 days for survival, and for 4 days for behavioural and biochemical assays. CA, CAF and CA + CAF treatments completely abolished the mortality associated with either MMA or MA exposure. Moreover, CA and CAF, either alone or combined, completely abolished behavioural changes, and completely protect against changes in thiobarbituric acid reactive substances (TBARS) levels, catalase (CAT) activity and MTT reduction ability, associated with MA or MMA exposure. In turn, CAF restored SOD activity in the head of flies exposed to MA or MMA. However, CA and CAF (either alone or combined) significantly decreased acetylcholinesterase (AChE) activity per se, while CAF alone protected from changes in AChE activity (in head tissue) associated with MA or MMA. Finally, CA and/or CAF were able to protect from a decrease in glucose and triglyceride levels associated with both MA and MMA exposures in haemolymph. Together, our data confirm the hypothesis that supplementation with CA and/or CAF offers protection against detrimental changes associated with MMA or MA exposure in flies, being responsible, at least in part, for the protective effect of I. paraguariensis crude extract which was reported previously.

Antidepressant-like effect of (3Z)-5-Chloro-3-(hydroxyimino)indolin-2-one in rats exposed to malathion: Involvement of BDNF-Trkß pathway and AChE.

BACKGROUND: Organophosphorus pesticides exert their toxic effects mainly by the inhibition of acetylcholinesterase (AChE), which is related to emotional disorders, such as depression. Atropine-oximes therapy is commonly used; however, the efficacy of oximes in the reactivation of AChE has been inconsistent. The objective of this study was to investigate the possible neuroprotective effect of (3Z)-5-Chloro-3-(hydroxyimino)indolin-2-one (Cℓ-HIN), a compound that combines the isatin and oxime functional groups, in rats exposed to malathion. The effect of Cℓ-HIN on the AChE activity and the BDNF-Trkß pathway in the prefrontal cortex of malathion-exposed rats were tested. METHODS: Wistar male rats were co-treated with Cℓ-HIN [50 mg/kg (p.o.) (3 mL/kg)] and/or malathion [250 mg/kg (i.p.) (5 mL/kg)] and performed behavioral tests twelve hours after these exposures. RESULTS: The Cℓ-HIN reversed the increased immobility time in the forced swimming test and the decreased grooming time in the splash test induced by malathion, but any significant difference was observed in locomotion analysis. These results demonstrate the antidepressant-like effect of Cℓ-HIN. The cortical AChE activity was reactivated by Cℓ-HIN in rats exposed to malathion. Malathion induced an increase in Trkß and a decrease in BDNF levels in the prefrontal cortex of rats, which were avoided by Cℓ-HIN. CONCLUSION: These findings support the hypothesis that Cℓ-HIN is an AChE reactivator with antidepressant-like properties, which is related to the improvement of BDNF-Trkß signaling after acute exposure to malathion in rats. Thus, the results allow suggesting the potential use of Cℓ-HIN as an oxime-based therapy against the neurotoxic effects of malathion.

Butiá fruit extract (Butia eriospatha) protects against oxidative damage and increases lifespan on Caenorhabditis elegans.

Butiá (Butia eriospatha) is a fruit of a palm tree belonging to the family Arecaceae, native to South America. The aim of this study was to evaluate the antioxidant potential of butiá extract using Caenorhabditis elegans as animal model. Initially, we performed survival experiments, reproduction, resistance to oxidative stress (post or pre-treatment with paraquat or hydrogen peroxide), longevity, superoxide dismutase, and catalase GFP reporters' expression. We observed that butiá extract did not affect the worms' survival. Similarly, egg laying also showed no significant difference between treatments. None of the extract concentrations tested was able to significantly protect or reverse paraquat-induced oxidative stress. However, they were able to reverse the oxidative damage induced by hydrogen peroxide. In addition, butiá extract increased C. elegans lifespan under stress and not per se. Our results demonstrate that the Butiá is able to extend the lifespan of the nematode C. elegans and that this effect may be mediated by an induced resistance to oxidative stress. PRACTICAL APPLICATIONS: The practical applications of this research are to expand and bring scientific knowledge to the population about the benefits of the consumption of this native fruit from the southern region of Brazil. Many fruits and other plant foods are consumed and spread with benefits without proper scientific proof of these benefits. This fruit is widely cultivated and its production and consumption can be expanded from these results. Still, we point out that this is the first time that the benefits of this fruit are studied.

Purple pitanga fruit (Eugenia uniflora L.) protects against oxidative stress and increase the lifespan in Caenorhabditis elegans via the DAF-16/FOXO pathway.

Pitanga, a fruit of the pitangueira tree (Eugenia uniflora L.), is native to Brazil and has a high antioxidant capacity due to the elevated amount of anthocyanins. The present study aimed to investigate the chemical composition of the purple pitanga fruit and to evaluate its antioxidant effect in the nematode Caenorhabditis elegans. We observed that the ethanolic extract of purple pitanga did not cause any toxic effects but notably increased worm lifespan. The extract improved the survival, reproduction and lifespan of the worms in pre- and post-exposure to stressors H2O2 and juglone, as well as improved the lifespan of the oxidative stress hypersensitive strain mev-1. Notably, PPE extract decreased reactive oxygen species by DCF-DA probe and protein carbonyl content from worms stressed with H2O2. The extract also affected the expression of superoxide dismutase SOD-3 and heat shock protein HSP-16.2 levels, daf 16 target genes that modulate lifespan and antioxidant metabolism. In addition, we demonstrate that these effects are dependent on DAF-16, as PPE extract did not provide protection in daf-16 mutants. Therefore, these results suggest that PPE significantly protected against oxidative stress modulating daf-16 target genes.

Antiulcerogenic activity of Scutia buxifolia on gastric ulcers induced by ethanol in rats.

Gastric ulcers affect many people around the world and their development is a result of the imbalance between aggressive and protective factors in the gastric mucosa. Scutia buxifolia, commonly known as coronilha, has attracted the interest of the scientific community due to its pharmacological properties and its potential therapeutic applications. In this study, the preventive effects of the crude extract of Scutia buxifolia (ceSb) against gastric ulcer induced by 70% ethanol were evaluated in male Wistar rats. In addition, the composition of ceSb was clarified by high-performance liquid chromatography (HPLC). S. buxifolia extract (100, 200 and 400 mg/kg body weight) attenuated oxidative and histopathological features induced by ethanol. Moreover, all evaluated doses of ceSb caused significant (P<0.001 and P<0.0001) and dose-dependent increase in sulfhydryl groups (NPSH) levels, catalase (CAT) and superoxide dismutase (SOD) activities. Furthermore, the administration of ceSb reversed the increase in lipid peroxidation produced by ethanol. The protective effect of the extract could be attributed to antioxidant compounds present in the ceSb, such as flavonoids and phenolic acids, which were quantified by HPLC. Thus, an antioxidant effect of the extract leads to a protection on gastric tissue. These results indicate that S. buxifolia could have a beneficial role against ethanol toxicity by preventing oxidative stress and gastric tissue injury.

Cooperation of non-effective concentration of glutamatergic system modulators and antioxidant against oxidative stress induced by quinolinic acid.

Excessive formation of reactive oxygen species (ROS) and disruption of glutamate uptake have been hypothesized as key mechanisms contributing to quinolinic acid (QA)-induced toxicity. Thus, here we investigate if the use of diphenyl diselenide (PhSe)(2), guanosine (GUO) and MK-801, alone or in combination, could protect rat brain slices from QA-induced toxicity. QA (1 mM) increased ROS formation, thiobarbituric acid reactive substances (TBARS) and decreased cell viability after 2 h of exposure. (PhSe)(2) (1 µM) protected against this ROS formation in the cortex and the striatum and also prevented decreases in cell viability induced by QA. (PhSe)(2) (5 µM) prevented ROS formation in the hippocampus. GUO (10 and 100 µM) blocked the increase in ROS formation caused by QA and MK-801 (20 and 100 µM) abolished the pro-oxidant effect of QA. When the noneffective concentrations were used in combination produced a decrease in ROS formation, mainly (PhSe)(2) + GUO and (PhSe)(2) + GUO + MK-801. These results demonstrate that this combination could be effective to avoid toxic effects caused by high concentrations of QA. Furthermore, the data obtained in the ROS formation and cellular viability assays suggest different pathways in amelioration of QA toxicity present in the neurodegenerative process.

High-fat diet and hydrochlorothiazide increase oxidative stress in brain of rats.

This study evaluated the effect of possible synergic interaction between high fat diet (HF) and hydrochlorothiazide (HCTZ) on biochemical parameters of oxidative stress in brain. Rats were fed for 16 weeks with a control diet or with an HF, both supplemented with different doses of HCTZ (0.4, 1.0, and 4.0 g kg(-1) of diet). HF associated with HCTZ caused a significant increase in lipid peroxidation and blood glucose levels. In addition, HF ingestion was associated with an increase in cerebral lipid peroxidation, vitamin C and non-protein thiol groups (NPSH) levels. There was an increase in vitamin C as well as NPSH levels in HCTZ (1.0 and 4.0 g kg(-1) of diet) and HF plus HCTZ groups. Na(+)-K(+)-ATPase activity of HCTZ (4.0 g kg(-1) of diet) and HCTZ plus HF-fed animals was significantly inhibited. Our data indicate that chronic intake of a high dose of HCTZ (4 g kg(-1) of diet) or HF change biochemical indexes of oxidative stress in rat brain. Furthermore, high-fat diets consumption and HCTZ treatment have interactive effects on brain, showing that a long-term intake of high-fat diets can aggravate the toxicity of HCTZ.

Additive anticonvulsant effects of creatine supplementation and physical exercise against pentylenetetrazol-induced seizures.

Although physical activity and creatine supplementation have been a documented beneficial effect on neurological disorders, its implications for epilepsy are still controversial. Thus, we decided to investigate the effects of 6 weeks swimming training, creatine supplementation (300 mg/kg; p.o.) or its combination seizures and neurochemical alterations induced by pentylenetetrazol (PTZ). We found that 6 weeks of physical training or creatine supplementation decreased the duration of PTZ-induced seizures in adult male Wistar rats, as measured by cortical and hippocampal electroencephalography and behavioral analysis. Importantly, the combination between physical training and creatine supplementation had additive anticonvulsant effects, since it increased the onset latency for PTZ-induced seizures and was more effective in decrease seizure duration than physical training and creatine supplementation individually. Analysis of selected parameters of oxidative stress and antioxidant defenses in the hippocampus revealed that physical training, creatine supplementation or its combination abrogated the PTZ-elicited increase in levels of thiobarbituric acid-reactive substances (TBARS) and protein carbonylation, as well as decrease in non-protein-thiols content, catalase (CAT) and SOD activities. In addition, this protocol of physical training and creatine supplementation prevented the PTZ-induced decrease in hippocampal Na+,K+-ATPase activity. Altogether, these results suggest that protection elicited physical training and creatine supplementation of selected targets for reactive species-mediated damage decrease of neuronal excitability and consequent oxidative damage elicited by PTZ. In conclusion, the present study shows that physical training, creatine supplementation or its combination attenuated PTZ-induced seizures and oxidative damage in vivo, and provide evidence that combination between creatine supplementation and physical exercise may be a useful strategy in the treatment of convulsive disorders.

Swimming training prevents pentylenetetrazol-induced inhibition of Na+, K+-ATPase activity, seizures, and oxidative stress.

PURPOSE: In the present study we decided to investigate whether physical exercise protects against the electrographic, oxidative, and neurochemical alterations induced by subthreshold to severe convulsive doses of pentyltetrazole (PTZ). METHODS: The effect of swimming training (6 weeks) on convulsive behavior induced by PTZ (30, 45, and 60 mg/kg, i.p.) was measured and different electrographic electroencephalography (EEG) frequencies obtained from freely moving rats. After EEG recordings, reactive oxygen species (ROS) generation, nonprotein sulfhydryl (NPS), protein carbonyl, thiobarbituric acid-reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), Na(+), K(+)-ATPase activity, and glutamate uptake were measured in the cerebral cortex of rats. RESULTS: We showed that physical training increased latency and attenuated the duration of generalized seizures induced by administration of PTZ (45 mg/kg). EEG recordings showed that physical exercise decreased the spike amplitude after PTZ administration (all doses). Pearson's correlation analysis revealed that protection of physical training against PTZ-induced seizures strongly correlated with NPS content, Na(+), K(+)-ATPase activity, and glutamate-uptake maintenance. Physical training also increased SOD activity, NPS content, attenuated ROS generation per se, and was effective against inhibition of Na(+), K(+)-ATPase activity induced by a subthreshold convulsive dose of PTZ (30 mg/kg). In addition, physical training protected against 2',7'-dichlorofluorescein diacetate (DCFH-DA) oxidation, TBARS and protein carbonyl increase, decrease of NPS content, inhibition of SOD and catalase, and inhibition glutamate uptake induced by PTZ. CONCLUSIONS: These data suggest that effective protection of selected targets for free radical damage, such as Na(+), K(+)-ATPase, elicited by physical training protects against the increase of neuronal excitability and oxidative damage induced by PTZ.

Diethyl 2-phenyl-2 tellurophenyl vinylphosphonate: an organotellurium compound with low toxicity.

It is well-known that organotellurium compounds can have antioxidant activity in vitro, but in vivo these compounds can be potentially toxic to rodents. Here we investigated the potential in vitro and ex vivo toxicity of a new beta-organochalcogenyl vinylphosphonate, the diethyl 2-phenyl-2 tellurophenyl vinylphosphonate. The in vitro antioxidant activity of this organotellurium compound was also investigated. In vitro, the rate of dithiotreitol (DTT) oxidation was increased and the activity of cerebral, renal and hepatic delta-aminolevulinate dehydratase (delta-ALA-D) was decreased by diethyl 2-phenyl-2-tellurophenyl vinylphosphonate (120-1200 microM), indicating that this compound oxidize-SH groups. The antioxidant activity was also observed in brain, liver and kidney, in very low concentrations (0.4, 1.0, 4.0, 10.0 and 40.0 microM), and this capacity was comparable to the antioxidant standard organotellurium compound, diphenyl ditelluride. In vivo, delta-ALA-D activity in liver, kidney and brain of mice treated for 12 days with dimethylsulfoxide (DMSO) as vehicle, 25, 75 or 250 micromol/kg of diethyl 2-phenyl-2-tellurophenyl vinylphosphonate was not affected. Furthermore, only one animal treated with the highest dose died, whereas all animals treated with diphenyl ditteluride died in the fourth day. These results suggest that this novel organotellurium compound interacts with the sulfhydryl groups, however only at higher doses when compared with diphenyl ditelluride. Since diethyl 2-phenyl-2 tellurophenyl vinylphosphonate had low toxicity to mice after sub-chronic exposure, it becomes important to investigate its possible pharmacological properties.

alpha-Tocopherol protects against pentylenetetrazol- and methylmalonate-induced convulsions.

Increased excitatory amino acid transmission and decreased GABAergic inhibitory responses seem to be important mechanisms in the genesis of convulsions, where reactive oxygen species (ROS) have recently been suggested to play a critical role. Therefore, administration of antioxidants may be potentially beneficial for the treatment of convulsive states. In the current study we investigated the effect of the systemic Vitamin E administration, an antioxidant, on the convulsions and oxidative damage induced by two convulsant agents with different mechanisms of action: methylmalonic acid (MMA), which induces convulsions through energy depletion and secondary activation of glutamatergic mechanisms and ROS production and pentylenetetrazol (PTZ), which is a chemical convulsant that causes convulsions by blocking the GABAA receptor-coupled chloride ionophore. Adult male Wistar rats (270-300 g) were injected with vehicle (5% Tween 80 in 0.9% NaCl; 1 ml/kg, i.p.) or alpha-tocopherol (25, 75 or 225 mg/kg, i.p.), once a day for 7 days. On the seventh day of antioxidant treatment, the animals were injected with the antioxidant (or vehicle) and, 30 min later, they were intrastriatally injected with NaCl (9 micromol/2 microl) or with MMA (6 micromol/2 microl) or PTZ (3.26 mmicromol/2 microl). The animals were observed for the appearance of convulsive behavior and the striatal content of thiobarbituric acid-reactive substances (TBARS) and total protein carbonylation were determined. Intrastriatal injection of increasing amounts of PTZ and of MMA caused the appearance of convulsive behavior. PTZ- and MMA-induced convulsions, TBARS production and total protein carbonylation were attenuated by alpha-tocopherol in a dose-dependent manner.