Pathise Souto Oliveira

Antioxidant capacity and environmentally friendly synthesis of dihydropyrimidin-(2H)-ones promoted by naturally occurring organic acids

The Biginelli reaction is a multicomponent reaction involving the condensation between an aldehyde, a β‐ketoester, and urea or thiourea, in the presence of an acid catalyst, producing dihydropyrimidinones (DHPMs). Owing to their important pharmacological properties, the DHPMs have been studied by many authors. However, most of the methodologies used for the synthesis of these compounds require drastic reaction conditions. In the current study, we report an efficient and clean procedure for preparing DHPMs by the use of citric acid or tartaric acid as a promoter of the Biginelli synthesis in ethanol as solvent. In addition, we have evaluated the antioxidant capacity of the compounds synthesized by the 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging assay and the thiobarbituric acid‐reactive species test. Two compounds presented antioxidant activity and also reduced lipid peroxidation at concentrations of 200 and 300 µM. In summary, we report an environmentally friendly procedure for the preparation of DHPMs and demonstrate the antioxidant capacity of some of the compounds.

Eugenol derivatives as potential anti-oxidants: is phenolic hydroxyl necessary to obtain an effect?

Eugenol, obtained from clove oil (Eugenia caryophyllata), possess several biological activities. It is anti‐inflammatory, analgesic, anaesthesic, antipyretic, antiplatelet, anti‐anaphylactic, anticonvulsant, anti‐oxidant, antibacterial, antidepressant, antifungal and antiviral. The anti‐oxidant activity of eugenol have already been proven. From this perspective testing, a series of planned structural derivatives of eugenol were screened to perform structural optimization and consequent increase of the potency of these biological activities.

Green juice as a protector against reactive species in rats

INTRODUCTION Green juice is popularly known for introducing antioxidants, improving intestinal function and reducing weight gain. OBJECTIVES In the present study we determine the antioxidant effect of green juice comparing it with orange juice. METHODS Rats were divided into three experimental groups and submitted to supplementation for 15 days: the (GJ) group received green juice, the (OJ) group received orange juice and the control group received water. We evaluated the antioxidant activity and total phenolic content of green and orange juices, as well as rat weight gain. We also investigated some oxidative stress parameters, namely thiobarbituric acid-reactive substances (TBARS), superoxide dismutase and catalase in rat cerebral cortex. RESULTS AND DISCUSSION Results showed that GJ had significantly less weight gain than the control group. With respect to antioxidant activity screening, the remaining percentage of DPPH at dilutions 1:10, 1:100 and 1:1000 of green juice was 22.8%, 58% and 78%, and orange juice, at the same dilutions, was 5.6%, 5.6% and 77.2%, respectively. The ability of juices to reduce the ABTS radical was 3.5 mmol trolox/L for green juice and 5.2 mmol trolox/L for orange juice. Additionally, the green juice did not present any difference in total phenolic acid content when compared to orange juice. TBARS were reduced in GJ and OJ. Besides, GJ supplementation decreased catalase activity. In conclusion, our data showed that green juice reduced weight gain, lipoperoxidation and catalase activity, suggesting that this supplementation may have a protective effect against reactive species.

Vaccinium virgatum fruit extract as an important adjuvant in biochemical and behavioral alterations observed in animal model of metabolic syndrome

The aim of this study was to investigate the effect of blueberry (Vaccinium virgatum) fruit extract on metabolic, behavioral and oxidative stress parameters in the hippocampus and cerebral cortex of mice submitted to an experimental model of metabolic syndrome induced by a highly palatable diet (HPD). Mice C57BL/6 were divided into 4 experimental groups: (1) received standard chow and saline orally, (2) received standard chow and blueberry hydroalcoholic extract, (3) received HPD and saline orally, (4) received HPD and blueberry hydroalcoholic extract. The animals were treated for 150days. Our results showed that the animals fed with HPD presented insulin resistance, increased body weight, visceral fat, glucose, triglycerides, and total cholesterol when compared to the control group. The blueberry extract prevented the increase of these metabolic parameters. Also, the extract was able to reduce the levels of thiobarbituric acid reactive substances in the cerebral cortex and hippocampus of animals submitted to HPD. In contrast, no differences were observed in the total thiol content, activity of the antioxidant enzymes catalase and superoxide dismutase. In addition, the HPD fed animals showed a significant increase in immobility time in the forced swimming test and blueberry prevented this alteration, although no changes were observed in the ambulatory behavior, as well as in the anxiolytic profile of these animals. Overall, our findings suggest that chronic consumption of blueberry extract exhibits hypoglycemic, hypolipidemic, antidepressant-like and antiperoxidative effects in an animal model of metabolic syndrome.

Antioxidant, antihyperglycemic, and antidyslipidemic effects of Brazilian-native fruit extracts in an animal model of insulin resistance

ABSTRACT Objective: Insulin resistance (IR) plays an important role in the development of many diseases, such as diabetes mellitus. Therefore, the aim of the present study was to evaluate the effects of the extracts from fruits native to Brazil on metabolic parameters and hepatic oxidative markers in an animal model of insulin resistance induced by dexamethasone (DEX). Methods: Wistar rats received water or extracts of Eugenia uniflora or Psidium cattleianum, once a day for 21 days. For the last 5 days, the rats received an intraperitoneal injection of saline or DEX. Results: DEX caused a reduction in body weight gain and relative pancreatic weight, as well as glucose intolerance, and an increase in serum glucose and triacylglycerol levels. The extracts were found to prevent hyperglycemia and hypertriglyceridemia. DEX caused an increase in the levels of thiobarbituric acid-reactive substances and reactive oxygen species production in the liver of rats, and both extracts prevented these changes. In addition, hepatic glutathione peroxidase activity was reduced by DEX. However, total thiol content and activities of catalase, superoxide dismutase, and delta-aminolevulinate dehydratase were not altered in any of the tested groups. Conclusion: Fruit extracts of E. uniflora and P. cattleianum exhibited considerable antihyperglycemic, antidyslipidemic, and antioxidant effects, and may be useful in the therapeutic management of alterations due to IR.

Synthesis and antioxidant activity of 3-(Pyridin-2-ylmethyl)-1,3-thiazinan(thiazolidin)-4-ones.

The antioxidant properties of two series of thiazolidinones and thiazinanones were reported. The novel six‐membered thiazinanones were synthesized from the efficient multicomponent reaction of 2‐picolylamine (2‐aminomethylpyridine), arenaldehydes, and the 3‐mercaptopropionic acid in moderate to excellent yields. These novel compounds were fully identified and characterized by NMR and GC‐MS techniques. In vitro antioxidant activities of all compounds were evaluated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azinobis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) tests. The antioxidant assays of thiobarbituric acid reactive species and total thiol content levels in the cerebral cortex and liver of rats were also performed. Thiazinanone 5a showed the best radical scavenging activity in DPPH and ABTS tests, as well as reduced lipid peroxidation and increased total thiol group in biological systems. Altogether, the results may be considered a good starting point for the discovery of a new radical scavenger.

Eugenia uniflora fruit (red type) standardized extract: a potential pharmacological tool to diet-induced metabolic syndrome damage management

The aim of this study was to investigate the effect of Eugenia uniflora fruit (red type) extract on metabolic status, as well as on neurochemical and behavioral parameters in an animal model of metabolic syndrome induced by a highly palatable diet (HPD). Rats were treated for 150days and divided into 4 experimental groups: standard chow (SC) and water orally, SC and E. uniflora extract (200mg/kg daily, p.o), HPD and water orally, HPD and extract. Our data showed that HPD caused glucose intolerance, increased visceral fat, weight gain, as well as serum glucose, triacylglycerol, total cholesterol and LDL cholesterol; however, E. uniflora prevented these alterations. The extract decreased lipid peroxidation and prevented the reduction of superoxide dismutase and catalase activities in the prefrontal cortex, hippocampus and striatum of animals submitted to HPD. We observed a HPD-induced reduction of thiol content in these cerebral structures. The extract prevented increased acetylcholinesterase activity in the prefrontal cortex caused by HPD and the increase in immobility time observed in the forced swim test. Regarding chemical composition, LC/MS analysis showed the presence of nine anthocyanins as the major compounds. In conclusion, E. uniflora extract showed benefits against metabolic alterations caused by HPD, as well as exhibited antioxidant and antidepressant-like effects.

Caffeine prevents high-intensity exercise-induced increase in enzymatic antioxidant and Na+-K+-ATPase activities and reduction of anxiolytic like-behaviour in rats

ABSTRACT Objective: Here we investigated the impact of chronic high-intensity interval training (HIIT) and caffeine consumption on the activities of Na+-K+-ATPase and enzymes of the antioxidant system, as well as anxiolytic-like behaviour in the rat brain. Methods: Animals were divided into groups: control, caffeine (4 mg/kg), caffeine (8 mg/kg), HIIT, HIIT plus caffeine (4 mg/kg) and HIIT plus caffeine (8 mg/kg). Rats were trained three times per week for 6 weeks, and caffeine was administered 30 minutes before training. We assessed the anxiolytic-like behaviour, Na+-K+-ATPase, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, levels of reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) in the brain. Results and discussion: HIIT-induced anxiolytic-like behaviour increased Na+-K+-ATPase and GPx activities and TBARS levels, altered the activities of SOD and CAT in different brain regions, and decreased GSH levels. Caffeine, however, elicited anxiogenic-like behaviour and blocked HIIT effects. The combination of caffeine and HIIT prevented the increase in SOD activity in the cerebral cortex and GPx activity in three brain regions. Our results show that caffeine promoted anxiogenic behaviour and prevented HIIT-induced changes in the antioxidant system and Na+-K+-ATPase activities.

Acute administration of methionine and/or methionine sulfoxide impairs redox status and induces apoptosis in rat cerebral cortex

High plasma levels of methionine (Met) and its metabolites such as methionine sulfoxide (MetO) may occur in several genetic abnormalities. Patients with hypermethioninemia can present neurological dysfunction; however, the neurotoxicity mechanisms induced by these amino acids remain unknown. The aim of the present work was to study the effects of Met and/or MetO on oxidative stress, genotoxicity, cytotoxicity and to evaluate whether the cell death mechanism is mediated by apoptosis in the cerebral cortex of young rats. Forty-eight Wistar rats were divided into groups: saline, Met 0.4 g/Kg, MetO 0.1 g/Kg and Met 0.4 g/Kg + MetO 0.1 g/Kg, and were euthanized 1 and 3 h after subcutaneous injection. Results showed that TBARS levels were enhanced by MetO and Met+MetO 1 h and 3 h after treatment. ROS was increased at 3 h by Met, MetO and Met+MetO. SOD activity was increased in the Met group, while CAT was reduced in all experimental groups 1 h and 3 h after treatment. GPx activity was enhanced 1 h after treatment by Met, MetO and Met+MetO, however it was reduced in the same experimental groups 3 h after administration of amino acids. Caspase-3, caspase-9 and DNA damage was increased and cell viability was reduced by Met, MetO and Met+MetO at 3 h. Also, Met, MetO and Met+MetO, after 3 h, enhanced early and late apoptosis cells. Mitochondrial electrochemical potential was decreased by MetO and Met+MetO 1 h and 3 h after treatment. These findings help understand the mechanisms involved in neurotoxicity induced by hypermethioninemia.

High levels of methionine and methionine sulfoxide: Impact on adenine nucleotide hydrolysis and redox status in platelets and serum of young rats: SOARES et al.

We investigated acute and chronic effects administration of methionine (Met) and/or methionine sulfoxide (MetO) on ectonucleotidases and oxidative stress in platelets and serum of young rats. Wistar rats were divided into four groups: control, Met, MetO, and Met + MetO. In acute treatment, the animals received a single subcutaneous injection of amino acid(s) and were euthanized after 1 and 3 hours. In chronic protocol, Met and/or MetO were administered twice a day with an 8‐hour interval from the 6th to the 28th day of life. Nucleoside triphosphate phosphohydrolase and 5′‐nucleotidase activities were reduced in platelets and serum by Met, MetO, and Met + MetO after 3 hours and 21 days. Adenosine deaminase activity reduced in platelets at 3 hours after MetO and Met + MetO administration and increased after 21 days in animals treated with Met + MetO. Superoxide dismutase and catalase activities decreased in platelets in MetO and Met + MetO groups after 3 hours, while reactive oxygen species (ROS) levels increased in same groups. Catalase activity in platelets decreased in all experimental groups after chronic treatment. Met, MetO, and Met + MetO administration increased plasmatic ROS levels in acute and chronic protocols; glutathione S‐transferase activity increased by MetO and Met + MetO administration at 3 hours, and ascorbic acid decreased in all experimental groups in acute and chronic protocols. Thiobarbituric acid reactive substances increased, superoxide dismutase and catalase activities reduced in the Met and/or MetO groups at 3 hours and in chronic treatment. Our data demonstrated that Met and/or MetO induced changes in adenine nucleotide hydrolysis and redox status of platelets and serum, which can be associated with platelet dysfunction in hypermethioninemia.