Virginia C. Rech

Trypanocidal activity of the essential oils in their conventional and nanoemulsion forms: in vitro tests.

The aim of this study was to investigate the susceptibility in vitro of Trypanosoma evansi to the essential oils of andiroba (Carapa guaianensis) and aroeira (Schinus molle), in their conventional and nanostructured forms. For that, pure oils at concentrations of 0.5%, 1.0% and 2.0% were used. A negative control (untreated) and a positive control (diminazene aceturate 0.5%) were used as comparative parameters. Later, the same tests were performed, using nanoemulsions oils at concentrations of 0.5% and 1.0%. The tests were carried out in triplicates and the numbers of parasites were quantified on 1, 3 and 6 h from onset of the study. A dose-dependent reduction in the number of parasites to the forms of two oils tested was observed after 1 h. The concentration of parasites was significantly reduced at low concentrations after 3 h, as well as at 6 h no alive parasites were observed for the essential oils tested. Ours findings indicate, for the first time, that oils of andiroba and aroeira (in their conventional and nanoemulsion forms) have high activity against T. evansi in vitro, leading to the suggestion that these oils may be applied as an alternative treatment for this disease.

Treatment with essential oil of Achyrocline satureioides in rats infected with Trypanosoma evansi: relationship between protective effect and tissue damage.

The aim of this study was to evaluate the effects of treatment with free and nanoencapsulated essential oil of Achyrocline satureioides on trypanosomosis and its oxidative/antioxidants variables in liver and kidney of rats infected experimentally with Trypanosoma evansi. For that, 48 rats were divided into six groups (A-F), eight animals each group. Groups A, C and D were composed of uninfected animals, while animals in groups B, E and F were inoculated intraperitoneally with T. evansi. Groups A and B were used as controls, negative and positive, respectively. Groups C and E receive oil (orally), as well as the animals in groups D and F were treated with nanoencapsulated essential oil. The treatment was not able to eliminate the parasites, but it remained the levels of parasitemia low. The carbonyl levels in liver and kidney did not differ between groups. Infected animals (group B) showed an increase in the TBARS levels and a decrease in the CAT activity and NPSH levels in liver and kidney, compared with the same parameters in the control (group A). Treatment with A. satureioides (groups C and D) did not influence the TBARS levels and CAT activity in the liver, but it increased the CAT activity in kidneys of the animals of group C. NPSH levels decreased in liver in the groups treated with nanoencapsulated essential oil (groups D and F). An interesting result observed was that the animals infected and then treated with essential oil of A. satureioides (groups E and F) did not differ from animals of group A for TBARS, CAT and NPSH, unlike what happened with the animals of group B. Therefore, the treatment with essential oil did not eliminate the parasites from the bloodstream, but it reduced the number of trypanosomes, mainly by its nanoencapsulated form. The same occurred with the lipid peroxidation in the liver. However, the treatments reduced the oxidative damage, and it led to the activation of the antioxidant enzymes. We believe that the association of this natural product with a trypanocidal drug may enhance its curative effect.

Activity of cholinesterases, pyruvate kinase and adenosine deaminase in rats experimentally infected by Fasciola hepatica: Influences of these enzymes on inflammatory response and pathological findings

The aim of this study was to investigate acetylcholinesterase (AChE) in total blood and liver tissue; butyrylcholinesterase (BChE) in serum and liver tissue; adenosine deaminase (ADA) in serum and liver tissue; and pyruvate kinase (PK) in liver tissue of rats experimentally infected by Fasciola hepatica. Animals were divided into two groups with 12 animals each, as follows: group A (uninfected) and group B (infected). Samples were collected at 20 (A1 and B1;n=6 each) and 150 (A2 and B2; n=6 each) days post-infection (PI). Infected animals showed an increase in AChE activity in whole blood and a decrease in AChE activity in liver homogenates (P<0.05) at 20 and 150 days PI. BChE and PK activities were decreased (P<0.05) in serum and liver homogenates of infected animals at 150 days PI. ADA activity was decreased in serum at 20 and 150 days PI, while in liver homogenates it was only decreased at 150 days PI (P<0.05). Aspartate aminotransferase and alanine aminotransferase activities in serum were increased (P<0.05), while concentrations of total protein and albumin were decreased (P<0.05) when compared to control. The histological analysis revealed fibrous perihepatitis and necrosis. Therefore, we conclude that the liver fluke is associated with cholinergic and purinergic dysfunctions, which in turn may influence the pathogenesis of the disease.

Effect of Leucine Administration to Female Rats During Pregnancy and Lactation on Oxidative Stress and Enzymes Activities of Phosphoryltransfer Network in Cerebral Cortex and Hippocampus of the Offspring

Maple Syrup Urine Disease is an inborn error of metabolism caused by severe deficiency in the activity of branched-chain α-keto acid dehydrogenase complex. Neurological disorder is common in patients with maple syrup urine disease. Although leucine is considered the main toxic metabolite, the mechanisms underlying the neuropathology of brain injury are poorly understood. In the present study, we evaluated the possible preventive effect of the co-administration of creatine plus pyruvate on the effects elicited by leucine administration to female Wistar rats during pregnancy and lactation on some oxidative stress parameters as well as the activities of some enzymes involved in the phosphoryltransfer network in the brain cortex and hippocampus of the offspring at 21xa0days of age. Leucine administration induced oxidative stress and altered the activities of pyruvate kinase, adenylate kinase, mitochondrial and cytosolic creatine kinase. Co-administration of creatine plus pyruvate was partially effective in the prevention of some alterations provoked by leucine administration on the oxidative stress but not in the enzymes of phosphoryltransfer network. These results suggest that non-treated maternal hyperleucinemia may be toxic to the brain of the offspring.

Relationship between behavioral alterations and activities of adenylate kinase and creatine kinase in brain of rats infected by Trypanosoma evansi

The aim of this study was to investigate the behavioral assessment and activities of important enzymes involved in the phosphoryl transfer network in rat brains that were experimentally infected with Trypanosoma evansi. Behavioral assessment (cognitive performance), pro-inflammatory cytokines in serum and activities of adenylate kinase (AK), pyruvate kinase (PK), and creatine kinase (CK) in brain were evaluated at 5 and 15 days post-infection (PI). Here we demonstrate a cognitive impairment in the rats infected with T.u2009evansi. At 5 and 15 days PI, a memory deficit and a depressant activity were demonstrated by an inhibition avoidance test and increase in the immobility time in a tail suspension test, respectively. On day 5 PI, a decrease in the CK activity and an increase in the AK activity were observed. On day 15 PI, an increase in the CK activity and a decrease in the AK activity were observed. Considering the importance of energy metabolism for brain functioning, it is possible that the changes in the activity of enzymes involved in the cerebral phosphotransfer network and an increase in the proinflammatory cytokines (TNF and IFN) may be involved at least in part in the cognitive impairment in infected rats with T.u2009evansi.

Effects of sulfamethoxazole-trimethoprim associated to resveratrol on its free form and complexed with 2-hydroxypropyl-β-cyclodextrin on cytokines levels of mice infected by Toxoplasma gondii

The aim of this study was to investigate the effects of resveratrol on its free form and complexed with 2-hydroxypropyl-β-cyclodextrin (HPβCD) when associated with sulfamethoxazole-trimethoprim (ST) on cytokines levels of mice (n = 60) experimentally infected by Toxoplasma gondii. Groups A and E were used as controls (untreated): negative and positive, respectively. The onset of treatment started 20 days post-infection (PI), and it lasted for 10 consecutive days. ST was administered orally in doses of 0.5 mg kg(-1) for groups B and F, while 100 mg kg(-1) was the dose for resveratrol in its free form (groups C - G), inclusion complex (groups D and H), and on free and inclusion complex together (groups I - J). On day 31 PI, blood samples were collected in order to evaluate the cytokine profile. The mice that received drug combination (I and J) showed a significant (P < 0.05) reduction in the number of cysts in the brain compared to other infected groups (E - H). The results showed that mice from the Group E had increased (P < 0.001) levels of pro-inflammatory cytokines, while IL-10 levels were reduced when compared to the Group A. Additionally, there were increased levels of IL-4 and IFN-γ in animals of groups C and D, respectively (P < 0.05). Animals of the Group B showed reduced levels of IL-1, IL-4, IL-6, TNF-α, and IFN-γ (P < 0.05). Mice infected and treated (groups F - J) showed increased levels of pro-inflammatory cytokines along with a reduction of IL-10. Treatment with the combination of drugs (the Group J) led to a protective effect, i.e. reduction in pro-inflammatory cytokines. Therefore, resveratrol associated with ST was able to modulate seric cytokine profile and moderate the tissue inflammatory process caused by T. gondii infection, as well as to reduce parasite multiplication.

Enzymatic activities linked to cardiac energy metabolism of Trypanosoma evansi-infected rats and their possible functional correlations to disease pathogenesis.

The aim of this study was to investigate the activities of important enzymes involved in the phosphoryl transfer network (adenylate kinase and creatine kinase (CK)), lactate dehydrogenase (LDH), respiratory chain complexes and biomarkers of cardiac function in rat experimentally infected by Trypanosoma evansi. Rat heart samples were evaluated at 5 and 15 days post-infection (PI). At 5 day PI, there was an increase in LDH and CK activities, and a decrease in respiratory chain complexes II, IV and succinate dehydrogenase activities. In addition, on day 15 PI, a decrease in the respiratory chain complex IV activity was observed. Biomarkers of cardiac function were higher in infected animals on days 5 and 15 PI. Considering the importance of the energy metabolism for heart function, it is possible that the changes in the enzymatic activities involved in the cardiac phosphotransfer network and the decrease in respiratory chain might be involved partially in the role of biomarkers of cardiac function of T. evansi-infected rats.

Sulfamethoxazole-trimethoprim associated with resveratrol for the treatment of toxoplasmosis in mice: Influence on the activity of enzymes involved in brain neurotransmission.

This study aimed to investigate the influence of sulfamethoxazole-trimethoprim (ST) associated with resveratrol on the enzymatic activities of acetylcholinesterase (AChE), adenylate kinase (AK), pyruvate kinase (PK), and creatine kinase (CK) in the brain of mice experimentally infected by Toxoplasma gondii. For that, 60 mice were divided into ten groups with 6 animals each: groups A to D composed by healthy mice and groups E to J consisting of animals infected by T. gondii (VEG strain). Animals started treatment 20 days post-infection for 10 consecutive days with oral doses of 0.5 mg kg(-1) of ST (groups B and F), 100 mg kg(-1) of free resveratrol (groups C and G) and inclusion complex of resveratrol (nanoparticles containing resveratrol) (groups D and H), as well as with an association of both drugs (groups I and J). The results showed increased (P < 0.001) AChE activity on infected animals (groups E-J) when compared to not-infected (A) animals, and also uninfected animals treated with ST (group B) had increased AChE activity. AK activity decreased (P < 0.001) in the infected and untreated (group E), differently from the other groups that did not differ. PK activity did not differ between groups (P > 0.05). When comparing control groups (uninfected (A) and infected (E)), we verified a significant (P < 0.001) increase in CK activity in the brain, and it is noteworthy that the animals treated with resveratrol associated with ST (group I and J) had similar CK activity to those animals from the group A. Treatment with the combination of ST and resveratrol was able to reduce (P < 0.05) the number of parasitic cysts in the brain, thus reduced inflammatory infiltrates in the liver, and prevented the occurrence of hepatocytes lesions due to toxoplasmosis in mice. Based on these results, it is possible to conclude that increased AChE and CK activities after T. gondii infection did not change with the treatment of ST-resveratrol association. In addition, decreased AK activity caused by T. gondii infection was normalized by ST-resveratrol treatment. T. gondii infection and treatment does not affect PK activity in brain.

Effect of the treatment with Achyrocline satureioides (free and nanocapsules essential oil) and diminazene aceturate on hematological and biochemical parameters in rats infected by Trypanosoma evansi.

This study aimed to verify the effect of the treatment with A.u2009satureioides essential oil (free and nanoencapsulated forms) and diminazene aceturate on hematological and biochemical variables in rats infected by Trypanosoma evansi. The 56 rats were divided into seven groups with eight rats each. Groups A, C and D were composed by uninfected animals, and groups B, E, F and G were formed by infected rats with T.u2009evansi. Rats from groups A and B were used as negative and positive control, respectively. Rats from the groups C and E were treated with A.u2009satureioides essential oil, and groups D and F were treated with A.u2009satureioides nanoencapsulated essential oil. Groups C, D, E and F received one dose of oil (1.5u2009mLu2009kg(-1)) during five consecutive days orally. Group G was treated with diminazene aceturate (D.A.) in therapeutic dose (3.5u2009mgu2009kg(-1)) in an only dose. The blood samples were collected on day 5 PI for analyses of hematological (erythrocytes and leukocytes count, hemoglobin concentration, hematocrit, mean corpuscular and mean corpuscular hemoglobin concentration) and biochemical (glucose, triglycerides, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, urea and creatinine) variables. A.u2009satureioides administered was able to maintain low parasitemia, mainly the nanoencapsulated form, on 5 days post infection. On the infected animals with T.u2009evansi treated with A.u2009satureioides essential oil (free and nanocapsules) the number of total leucocytes, lymphocytes and monocytes present was similar to uninfected rats, and different from infected and not-treated animals (leukocytosis). Treatment with A.u2009satureioides in free form elevated levels of ALT and AST, demonstrating liver damage; however, treatment with nanoencapsulated form did not cause elevation of these enzymes. Finally, treatments inhibited the increase in creatinine levels caused by infection for T.u2009evansi. In summary, the nanoencapsulated form showed better activity on the trypanosome; it did not cause liver toxicity and prevented renal damage.

Relationship between pathological findings and enzymes of the energy metabolism in liver of rats infected by Trypanosoma evansi.

The aim of this study was to investigate the activities of important enzymes involved in the energetic metabolism in the liver of rats experimentally infected by Trypanosoma evansi. Adenylate kinase (AK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) in liver homogenate, as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT), and clotting time in plasma were evaluated at 5 and 15 days post-infection (PI). The activities of the respiratory chain complexes and of Na(+), K(+)-ATPase were also evaluated. This study demonstrates energetic metabolism impairment in rats infected by T. evansi. A reduced energy metabolism in the liver of rats infected by T. evansi was observed, demonstrated by AK decreased and PK increased activities at 5 days PI, a mechanism known as energetic compensation. However, at 15 days PI a decrease of AK and PK activities were observed. In addition, an increase in the activities of respiratory chain complexes II, II-III and IV in infected rats at 15 days PI, and a decrease of Na(+), K(+)-ATPase activities in infected rats on days 5 and 15 PI were verified. In the plasma, we observed an increase in ALT and AST activities on days 5 and 15 PI, and increase in clotting time in infected rats. The changes caused by T. evansi infection on the activity of enzymes of hepatic energy metabolism can corroborate to elucidate the mechanisms that lead to liver injury and inflammatory infiltration verified in T. evansi infected rats. Therefore, these alterations are directly related to disease pathogenesis.