Luísa Zuravski

Evaluation of genotoxic and cytotoxic effects of hydroalcoholic extract of Euphorbia tirucalli (Euphorbiaceae) in cell cultures of human leukocytes

Euphorbia tirucalli (L.), commonly known as aveloz, has been indiscriminately used in popular medicine to treat various illnesses. However, some components can have devastating consequences. Injury to a cells genetic material can cause mutations, cancer, and cell death. Our main goal in this work was to evaluate the genotoxic and cytotoxic effects of E. tirucalli extract on human leukocytes. For this purpose, we performed a phytochemical analysis to evaluate the plants components. In the second step, we treated cultured human leukocytes with different concentrations of the dry extract of the plant and then evaluated the oxidative and genotoxic profiles of these leukocytes. We found that at 1% and 10% concentrations, the aveloz extract acted as a genotoxic agent that could damage DNA and increase oxidative damage. We conclude that despite its popular use, aveloz can act as a genotoxic agent, especially when it contains phorbol ester. Avelozs indiscriminate use might actually promote tumors and therefore carry a considerable genetic risk for its users.

Oxidative stress and labile plasmatic iron in anemic patients following blood therapy.

AIM To determine the plasmatic iron content and evaluate the oxidative stress (OS) markers in subjects receiving blood therapy. METHODS Thirty-nine individuals with unspecified anemia receiving blood transfusions and 15 healthy subjects were included in the study. Anemic subjects were divided into three subgrouP: (1) those that received up to five blood transfusions (n = 14); (2) those that received from five to ten transfusions (n = 11); and (3) those that received more than ten transfusions (n = 14). Blood samples were collected by venous arm puncture and stored in tubes containing heparin. The plasma and cells were separated by centrifugation and subsequently used for analyses. Statistical analyses were performed using Kruskal-Wallis analysis of variance followed by Dunns multiple comparison tests when appropriate. RESULTS The eletrophoretic hemoglobin profiles of the subjects included in this study indicated that no patients presented with hemoglobinopathy. Labile plasmatic iron, ferritin, protein carbonyl, thiobarbituric acid-reactive substances (TBARS) and dichlorofluorescein diacetate oxidation were significantly higher (P < 0.05), whereas total thiol levels were significantly lower (P < 0.05) in transfused subjects compared to controls. Additionally, the activity of catalase, superoxide dismutase and glutathione peroxidase were significantly lower in the transfused subjects (P < 0.05). Antioxidant enzyme activities and total thiol levels were positively correlated (P < 0.05), and negatively correlated with the levels of protein carbonyl and TBARS (P < 0.05). In contrast, protein carbonyl and TBARS were positively correlated (P < 0.05). Altogether, these data confirm the involvement of OS in patients following therapy with repeated blood transfusions. CONCLUSION Our data reveal that changes in OS markers are correlated with levels of labile plasmatic iron and ferritin and the number of transfusions.

Is tartrazine really safe? In silico and ex vivo toxicological studies in human leukocytes: a question of dose

The use of food colorings has a long-recorded history. Tartrazine (TRZ) is a dye that confers a lemon-yellow color to food and is widely used in the manufacture of numerous food products, as well as in pharmaceuticals and cosmetics. However, few studies have addressed the toxicology of TRZ in human cells or tissues. Considering the frequent consumption of the TRZ dye in food products and the lack of toxicological data, the present study aimed to evaluate the cytotoxicity and genotoxicity of the TRZ dye in human leukocyte cultures and perform theoretical studies to predict its toxicity in silico. Leukocyte cultures were treated with TRZ at concentrations of 5, 17.5, 35, 70, 100, 200, 300, 400, and 500 μg mL-1. All groups were assayed in triplicates. The mutagenicity was evaluated using the micronucleus test, the nuclear division index, and the nuclear division cytotoxicity index, and the chromosomal instability was quantitatively evaluated by band cytogenetics. Genotoxicity was evaluated using the alkaline comet test. Viability was assessed using the Trypan Blue method. Statistical analyses were performed using analysis of variance followed by Tukeys post hoc test, with a p value <0.05 reflecting statistical significance. No mutagenicity or cytotoxicity was found for the dye at the concentrations evaluated. However, DNA damage was induced by TRZ at a concentration of 70 μg mL-1. These results were confirmed by the predictive data from the in silico evaluations. Further studies are required to confirm our data, considering the frequency of the use of TRZ in the diet of the population, including that of children, as well as the exposure to TRZ through drugs, cosmetics, and other non-food products.