Assis Ecker

High-sucrose diet induces diabetic-like phenotypes and oxidative stress in Drosophila melanogaster: Protective role of Syzygium cumini and Bauhinia forficata

Diet is a key component for development and longevity of organisms. Here, the fruit fly was used to evaluate the detrimental effects caused by consumption of high-sucrose diets (HSD), namely phenotypic responses linked to insulin signaling and oxidative stress. The protective effects of extracts from medicinal plants Syzygium cumini and Bauhinia forficata were investigated. HSD intake (15% and 30%) delayed the time to pupation and reduced the number of white pupae. In adult flies, the intake of diets was associated with mortality and increased levels of glucose+trehalose, triacylglycerols and hydrogen peroxide. Indeed, 30% HSD induced body-weight loss, mitochondrial dysfunction and changes in acetylcholinesterase, δ-aminolevulinate dehydratase and antioxidant enzymes activity. Catalase, superoxide dismutase, keap1, HSP70, dILP-5 and Insulin receptor mRNA levels were over-expressed in flies emerged from 30% HSD. The extract treatments blunted the developmental alterations elicited by diets. Syzygium cumini extract was more efficient than B. forficata in reducing hyperglycaemia, redox disturbances and the changes in mRNA expression of insulin receptor.

Effect of Syzygium cumini and Bauhinia forficata aqueous-leaf extracts on oxidative and mitochondrial parameters in vitro.

Aqueous-leaf extract of Syzygium cumini and Bauhinia forficata are traditionally used in the treatment of diabetes and cancer, especially in South America, Africa, and Asia. In this study, we analyzed the effects of these extracts on oxidative and mitochondrial parameters in vitro, as well as their protective activities against toxic agents. Phytochemical screenings of the extracts were carried out by HPLC analysis. The in vitro antioxidant capacities were compared by DPPH radical scavenging and Fe2+ chelating activities. Mitochondrial parameters observed were swelling, lipid peroxidation and dehydrogenase activity. The major chemical constituent of S. cumini was rutin. In B. forficata were predominant quercetin and gallic acid. S. cumini reduced DPPH radical more than B. forficata, and showed iron chelating activity at all tested concentrations, while B. forficata had not similar property. In mitochondria, high concentrations of B. forficata alone induced a decrease in mitochondrial dehydrogenase activity, but low concentrations of this extract prevented the effect induced by Fe2++H2O2. This was also observed with high concentrations of S. cumini. Both extracts partially prevented the lipid peroxidation induced by Fe2+/citrate. S. cumini was effective against mitochondrial swelling induced by Ca2+, while B. forficata alone induced swelling more than Ca2+. This study suggests that leaf extract of S. cumini might represent a useful therapeutic for the treatment of diseases related with mitochondrial dysfunctions. On the other hand, the consumption of B. forficata should be avoided because mitochondrial damages were observed, and this possibly may pose risk to human health.

Peumus boldus attenuates copper-induced toxicity in Drosophila melanogaster

Peumus boldus (P. boldus) is a medicinal plant popularly used in the treatment of gastrointestinal disorders. P. boldus aqueous extract is rich in phenolic compounds and alkaloids that possess antiinflammatory and antioxidant effects. In the present study, the potential protective effect of P. boldus against Cu2+-induced toxicity was investigated. Adult Drosophila melanogaster were exposed to Cu2+ (1mM and 3mM) and/or P. boldus aqueous extract (5mg/mL) in the food during 4days. Cu2+-fed flies had impairment in the negative geotaxis performance (i.e. motor climbing capability) as well as a higher incidence of mortality when compared to the control group. P. boldus co-treatment afforded protection against the Cu2+-induced toxicity. Acetylcholinesterase (AChE) and glutathione S-transferase (GST) activity decreased significantly in D. melanogaster after Cu2+ exposure. P. boldus co-exposure for 4days restored enzyme activities to control levels. In addition, Cu2+ exposure caused a significant increase in the mRNA levels of antioxidant enzymes, superoxide dismutase (Sod1), catalase (Cat), thioredoxin reductase (TrxR1) and nuclear factor erythroid 2-related factor 2 (Nrf2), as well as increased the mRNA levels of acetylcholinesterase (Ace). The expression of P-type ATPase (Atp7A) and copper uptake protein 1 (Ctr1A) mRNAs were up-regulated in D. melanogaster exposed to Cu2+. The co-treatment with P. boldus blunted Cu2+-induced up-regulation of Atp7A and down-regulated Ctr1A mRNA expression. These findings suggest that P. boldus extracts reduce Cu2+-induced toxicity but not Cu2+ absorption in D. melanogaster. Consequently, P. boldus can be a potential therapeutical alternative for modulating Cu2+-associated toxicity.

Peripheral blood mononuclear cells from rat model of pleurisy: The effects of hesperidin on ectoenzymes activity, apoptosis, cell cycle and reactive oxygen species production

The present study investigates the effect of hesperidin; a flavonone commonly found in citrus fruits, on the ectoenzymes (ectonucleotidase and ecto-adenosine deaminase) activity, cell viability, apoptosis, cell cycle arrest and reactive oxygen species production in peripheral blood mononuclear cells (PBMCs) from rat model of pleurisy. Wistar rats were pretreated with either saline or hesperidin (80mg/kg) by oral gavage for 21days and injected intrapleurally with 2% carrageenan or saline on the 22nd day. PBMCs were subsequently prepared after 4h of carrageenan induction. The results revealed that hesperidin may exhibit its anti-inflammatory effects through possible modulation of ectonucleotidase (E-NTPDase) and ecto-adenosine deaminase (E-ADA) activities, reduction of intracellular reactive oxygen species, prevention of DNA damage and modulation of apoptosis as well as activation of cell cycle arrest. This study suggests some possible underlying anti-inflammatory mechanisms of hesperidin on PBMCs in acute inflammatory condition. Furthermore, hesperidin may minimize oxidative injury mediated pleurisy in rat.

Syzygium cumini leaf extract inhibits LDL oxidation, but does not protect the liproprotein from glycation

ETNOPHARMACOLOGICAL RELEVANCE Syzygium cumini (L.) Skeels is a plant widely used in folk medicine to treat diabetes mellitus (DM). The tea from its leaves is frequently used by diabetics for lowering hyperglycemia. There is a close relationship between DM and atherosclerosis, a chronic immuno-inflammatory disease, were the early stages encompass oxidative and glycative modifications in the structure of low density lipoprotein (LDL). AIM OF THIS STUDY To investigate the potential protective effects of aqueous-leaf extract from Syzygium cumini (S.cExt) against CuSO4-induced oxidation and methylglyoxal (MG)-induced glycation of human LDL in vitro. MATERIALS AND METHODS LDL oxidative changes were evaluated by measuring conjugated dienes (CD) formation, thiobarbituric acid reactive substances (TBARS) levels, quenching of tryptophan (Trp) fluorescence and structural modifications in LDL particle. In LDL glycated by MG (glyLDL), we determined the levels of fluorescent advanced glycation end products (AGEs) and mobility by agarose gel electrophoresis. RESULTS S.cExt blocked oxidative events induced by CuSO4 in human LDL, plasma and serum. Fourier transform infrared spectroscopy (FT-IR) revealed that specific regions of apoB100 were oxidized by CuSO4 in human LDL and that S.cExt reduced these oxidations. Unlike, the increased AGEs levels and eletrophoretic mobility observed in LDL MG-glycated were not modified by S.cExt. CONCLUSION The findings herein indicate that S.cExt could be tested in atherogenesis models as potential protective agent against LDL oxidation.

Protective effect of (−)-α-bisabolol on rotenone-induced toxicity in Drosophila melanogaster

(-)-α-Bisabolol (BISA) is a sesquiterpene alcohol, which has several recognized biological activities, including anti-inflammatory, anti-irritant, and antibacterial properties. In the present study, we investigated the influence of BISA (5, 25, and 250 μmol/L) on rotenone (500 μmol/L)-induced toxicity in Drosophila melanogaster for 7 days. BISA supplementation significantly decreased rotenone-induced mortality and locomotor deficits. The loss of motor function induced by rotenone correlated with a significant change in stress response factors; it decreased thiol levels, inhibited mitochondria complex I, and increased the mRNA expression of antioxidant marker proteins such as superoxide dismutase (SOD), catalase (CAT), and the keap1 gene product. Taken together, our findings indicate that the toxicity of rotenone is likely due to the direct inhibition of complex I activity, resulting in a high level of oxidative stress. Dietary supplementation with BISA affected the expression of SOD mRNA only at a concentration of 250 μmol/L, and did not affect any other parameter measured. Our results showed a protective effect of BISA on rotenone-induced mortality and locomotor deficits in Drosophila; this effect did not correlate with mitochondrial complex I activity, but may be related to the antioxidant protection afforded by eliminating superoxide generated as a result of rotenone-induced mitochondrial dysfunction.

Evaluation of methylglyoxal toxicity in human erythrocytes, leukocytes and platelets

Abstract Methylglyoxal (MG) is a reactive dicarbonyl metabolite originated mainly from glucose degradation pathway that plays an important role in the pathogenesis of diabetes mellitus (DM). Reactions of MG with biological macromolecules (proteins, DNA and lipids) can induce cytotoxicity and apoptosis. Here, human erythrocytes, leukocytes and platelets were acutely exposed to MG at concentration ranging from 0.025 to 10 mM. Afterwards, hemolysis and osmotic fragility in erythrocytes, DNA damage and cell viability in leukocytes, and the activity of purinergic ecto-nucleotidases in platelets were evaluated. The levels of glycated products from leukocytes and free amino groups from erythrocytes and platelets were also measured. MG caused fragility of membrane, hemolysis and depletion of amino groups in erythrocytes. DNA damage, loss of cell viability and increased levels of glycated products were observed in leukocytes. In platelets, MG inhibited the activity of enzymes NTPDase, 5′-nucleotidase and adenosine deaminase (ADA) without affecting the levels of free amino groups. Our findings provide insights for understanding the mechanisms involved in MG acute toxicity towards distinct blood cells.

Safety profile of AZT derivatives: Organoselenium moieties confer different cytotoxic responses in fresh human erythrocytes during in vitro exposures

INTRODUCTION The incorporation of selenium in the structure of nucleosides is a promising strategy to develop novel therapeutic molecules. OBJECTIVE To assess the toxic effects of three AZT derivatives containing organoselenium moieties on human erythrocytes. METHODOLOGY Freshly human erythrocytes were acutely treated with AZT and selenium derivatives SZ1 (chlorophenylseleno), SZ2 (phenylseleno) and SZ3 (methylphenylseleno) at concentrations ranging from 10 to 500 μM. Afterwards, parameters related to membrane damage, redox dyshomeostasis and eryptosis were determined in the cells. RESULTS The effects of AZT and derivatives toward erythrocytes differed considerably. Overall, the SZ3 exhibited similar effect profiles to the prototypal AZT, without causing cytotoxicity. Contrary, the derivative SZ1 induced hemolysis and increased the membrane fragility of cells. Reactive species generation, lipid peroxidation and thiol depletion were also substantially increased in cells after exposure to SZ1. δ-ALA-D and Na+/K+-ATPase activities were inhibited by derivatives SZ1 and SZ2. Additionally, both derivatives caused eryptosis, promoting cell shrinkage and translocation of phosphatidylserine at the membrane surface. The size and granularity of erythrocytes were not modified by any compound. CONCLUSION The insertion of either chlorophenylseleno or, in a certain way, phenylseleno moietes in the structure of AZT molecule was harmful to erythrocytes and this effect seems to involve a pro-oxidant activity. This was not true for the derivative encompassing methylphenylseleno portion, making it a promising candidate for pharmacological studies.

Safety evaluation of supratherapeutic dose of Maytenus ilicifolia Mart. ex Reissek extracts on fertility and neurobehavioral status of male and pregnant rats

ABSTRACT Maytenus ilicifolia Mart. ex Reissek is a plant commonly used in folklore medicine in the management of gastric diseases in South America. This study explores the effects of a supratherapeutic dose of aqueous and ethanol extracts of M. ilicifolia (1360 mg/kg) on fertility and neurobehavioral status in male and pregnant rats. A battery of sensory‐motor developmental endpoints was carried out to assess impairments on pups of dams orally treated with the aqueous extract of M. ilicifolia during the organogenesis period of pregnancy (GD 9 through GD 14). The neuromotor maturation reflexes and physical developments of the offspring were not significantly different between the groups (p < 0.05). Also, the hippocampal morphology revealed no indices of cell loss in the CA1, CA2, CA3 and CA4 areas. As second protocol, some fertility aspects were investigated in young post pubertal male Wistar rats treated with the ethanol extract for 30 days. The semen quality and testicular tissue morphology of male rats treated with the ethanol extract of M. ilicifolia remained unaffected upon treatment. Thus, the results indicate that the high‐dose of M. ilicifolia extracts have no neurotoxic potential on offspring and seem not to affect the sperm quality of male rats. HighlightsGradual acceptance has been given to the use of Maytenus ilicifolia medicinal herb for gastric diseases in South America.Fertility and neurobehavioral assessments of M. ilicifolia extractions on pregnant and male rats were investigated here.Aqueous extract exhibited no neurotoxic potential on offspring exposed gestationally during the organogenesis.Ethanol extract did not affect the sperm quality of male rats treated for 30 days.The reproductive endpoints were not modified by the supratherapeutic dose of M. ilicifolia extracts.