Clarissa Marques Moreira dos Santos

Locomotor damage and brain oxidative stress induced by lead exposure are attenuated by gallic acid treatment

We investigated the antioxidant potential of gallic acid (GA), a natural compound found in vegetal sources, on the motor and oxidative damages induced by lead. Rats exposed to lead (50 mg/kg, i.p., once a day, 5 days) were treated with GA (13.5mg/kg, p.o.) or EDTA (110 mg/kg, i.p.) daily, for 3 days. Lead exposure decreased the locomotor and exploratory activities, reduced blood ALA-D activity, and increased brain catalase (CAT) activity without altering other antioxidant defenses. Brain oxidative stress (OS) estimated by lipid peroxidation (TBARS) and protein carbonyl were increased by lead. GA reversed the motor behavior parameters, the ALA-D activity, as well as the markers of OS changed by lead exposure. CAT activity remained high, possibly as a compensatory mechanism to eliminate hydroperoxides during lead poisoning. EDTA, a conventional chelating agent, was not beneficial on the lead-induced motor behavior and oxidative damages. Both GA (less) and EDTA (more) reduced the lead accumulation in brain tissue. Negative correlations were observed between the behavioral parameters and lipid peroxidation and the lead levels in brain tissue. In conclusion, GA may be an adjuvant in lead exposure, mainly by its antioxidant properties against the motor and oxidative damages resulting from such poisoning.

Microwave-assisted diluted acid digestion for trace elements analysis of edible soybean products.

A new method for the decomposition of soybean based edible products (soy extract, textured soy protein, transgenic soybeans, and whole soy flour) was developed to essential (Co, Cr, Cu, Fe, Mn, Ni, Se, V, and Zn) and non-essential (As, Ba, Cd, Pb, and Sr) trace elements determination by ICP OES and ICP-MS respectively. Effects related to the concentration of HNO3 (2.1-14.5 mol L(-1)) and the use of hydrogen peroxide on the efficiency of decomposition was evaluated based on the residual carbon content (RCC). It was demonstrated that 2.1 mol L(-1) HNO3 plus 1.0 mL H2O2 was suitable for an efficient digestion, since RCC was lower than 18% and the agreement with certified values and spike recoveries were higher than 90% for all analytes. The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: The concentrations of analytes in the samples (minimum-maximum in mgkg(-1)) were: As (<0.007-0.040), Ba (0.064-10.6), Cd (<0.006-0.028), Co (0.012-102), Cr (0.56-5.88), Cu (6.53-13.9), Fe (24.9-126), Mn (16.4-35.2), Ni (0.74-4.78), Se (<2.90-25), Sr (2.48-20.1), Pb (<0.029-0.11), V (<0.027-20), and Zn (30.1-47.3). Soy-based foods investigated in this study presented variable composition in terms of essential and potentially toxic elements, which can be attributed to different methods of processing.

Investigation of major and trace element distribution in the extraction-transesterification process of fatty acid methyl esters from microalgae Chlorella sp.

This work reports, for the first time, the determination of major and trace elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Se, Sn, Sr, Ti, Tl, U, V, and Zn) in the fractions of the synthesis of fatty acid methyl esters (FAMEs). These include fresh microalgae, residual biomass, lipid fraction, crude FAMEs, insoluble fraction and purified FAMEs from microalgae Chlorella sp. A microwave-assisted digestion procedure in closed vessels was applied for sample digestion and subsequent element determination by inductively coupled plasma-based techniques. The proposed method was suitable for the multielement determination in FAMEs and its fractions obtained from microalgae. The element concentration was compared with results found in the literature and a careful discussion about the use of residual biomass for different applications was performed.

Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS.

This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L(-1), respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

Antioxidant protection of gallic acid against toxicity induced by Pb in blood, liver and kidney of rats

The effect of the antioxidant gallic acid (GA) on Pb toxicity in blood, liver and kidney was investigated in the present study. Rats Wistar received Pb nitrate (50 mg/Kg/day, i.p., 5 days) followed by GA (13.5 mg/Kg, p.o., 3 days) or a chelating agent (EDTA, 55 mg/Kg, i.p.). As result, Pb decreased body weight, hematocrit and blood δ-aminolevulinic acid dehydratase (ALA-D) activity. In addition, high Pb levels were observed in blood and tissues, together with increased (1) lipid peroxidation in erythrocytes, plasma and tissues, (2) protein oxidation in tissues and (3) plasma aspartate transaminase (AST) levels. These changes were accompanied by decreasing in antioxidant defenses, like superoxide dismutase (SOD) activity in tissues and catalase (CAT) activity and reduced glutathione (GSH) in liver. GA was able to reverse Pb-induced decrease in body weight and ALA-D activity, as well as Pb-induced oxidative damages and most antioxidant alterations, however it did not decrease Pb bioaccumulation herein as EDTA did. Furthermore, EDTA did not show antioxidant protection in Pb-treated animals as GA did. In conclusion, GA decreased Pb-induced oxidative damages not by decreasing Pb bioaccumulation, but by improving antioxidant defenses, thus GA may be promising in the treatment of Pb intoxications.

Acute Exposure to Low Lead Levels and its Implications on the Activity and Expression of Cytosolic Thioredoxin Reductase in the Kidney

Renal thioredoxin reductase‐1 (TrxR‐1) activity is stimulated at lead doses lower than that necessary to inhibit δ‐aminolevulinate dehydratase activity (δ‐ALA‐D), which is a classical early biomarker of lead effects. Thus, we hypothesized that the activity of TrxR‐1 could be a more sensitive early indicator of lead effects than is δ‐ALA‐D. To evaluate this hypothesis, we assessed the blood and renal TrxR‐1 activity and its gene expression along with biomarkers of oxidative damage, antioxidant enzyme activities and biomarkers of lead exposure in rats acutely exposed to lead. A histopathological analysis was performed to verify renal damage. The increase in renal TrxR‐1 activity paralleled the increase in the blood and renal lead levels at 6, 24 and 48 hr after the exposure to 25 mg/kg lead acetate (p < 0.05), whereas its expression was increased 24 and 48 hr after exposure. These effects were not accompanied by oxidative or tissue damage in the kidneys. Blood TrxR‐1 activity was not affected by lead exposure (up to 25 mg/kg). Erythrocyte δ‐ALA‐D activity was inhibited 6 hr after the exposure to 25 mg/kg lead acetate (p < 0.05) but recovered thereafter. Renal δ‐ALA‐D activity decreased 24 and 48 hr after the exposure to 25 mg/kg lead acetate. There were no changes in any parameters at lead acetate doses <25 mg/kg. Our results indicate that blood TrxR‐1 activity is not a suitable indicator of lead effects. In contrast, the increase in renal TrxR‐1 expression and activity is implicated in the early events of lead exposure, most likely as a protective cellular mechanism against lead toxicity.

Influence of Rangelia vitalii (Apicomplexa: Piroplasmorida) on Copper, Iron, and Zinc Bloodstream Levels in Experimentally Infected Dogs

Abstract: The aim of this study was to evaluate the concentrations of copper, iron, and zinc in blood serum of dogs experimentally infected with Rangelia vitalii (n  =  7) compared with uninfected controls (n  =  5). Serum metal levels were determined in blood samples collected at days 0, 10, 15, and 20 post-infection (PI). Inductively coupled plasma optical emission spectrometry was used to measure the levels of copper, iron, and zinc. Significant differences (P < 0.05) were observed among groups PI. Increased levels of copper and decreased levels of iron and zinc were observed in the infected animals. The infection by R. vitalii may, therefore, alter the serum metal levels, resulting in metabolic disorders in dogs. These metals are directly involved in many enzymatic systems; accordingly, alterations in their blood concentrations may also influence the pathogenesis of disease.