Determinação da atividade antioxidante e avaliação do efeito genotóxico e/ou antigenotóxico do óleo fixo da Castanha do Brasil (Bertholletia excelsa) em eritrócitos de camundongos swiss

Abstract

Bertholletia excelsa belongs to the Lecitidaceae family, popularly known as Brazil nut and Chestnut. Its geographic distribution extends to the states of Maranhão, Pará, Acre, Amapá, Roraima and Amazonas, and in countries Neighbors such as Bolivia, Peru and Guyana. This species has been applied in the fight against reactive oxygen species, due to its antioxidant activity. The present work had as objective the determination of the antioxidant activity and evaluation of the genotoxic and/or antigenotoxic effect of the fixed oil of Chestnut Brazil (Bertholletia excelsa) in erythrocytes of swiss mice. The fixed oil of B. excelsa was obtained by cold hydraulic pressing. For the determination of the antioxidant activity, the β-carotene/linoleic acid method was used, using the concentrations of 10,000 and 15,000 ppm, and the DPPH method, using concentrations of 50,000, 70,000 and 100,000 ppm. For the analysis of the genotoxic and antigenotoxic effects, healthy Swiss male mice with 6-7 weeks of life were used, from the State University of Campinas, being six animals in each treatment group. The genotoxic effect groups were treated with different concentrations of B. excelsa (500, 1,000 and 2,000 mg/kg bw), negative control (water) and dimethylsulfoxide solvent (DMSO 200 μL) in 0.5 ml orally. For the antigenotoxic effect the animals were treated with the pre-established concentrations, followed by intraperitoneal injection of doxorubicin (DXR, 15 mg/kg b.w.) in 0.3 ml. Peripheral blood samples were collected 24h and 48h after treatment. The frequency of micronucleated polychromatic erythrocytes (PCEMNs) was obtained from the analysis of 2000 PCEMNs/animal and the Nuclear Division Index was established by counting 400 polychromatic erythrocytes PCEs/animal, with a total of 2,400 PCEs/group. In the β- carotene/linoleic acid method, the results of 87 and 92% were obtained, in concentrations of 15,000 and 10,000, and in the DPPH method, the results were 14.53, 25.57 and 40.33% for the concentrations Of 50,000, 70,000 and 100,000. In the comparison between the groups treated with the different concentrations of the fixed oil of B. excelsa and the negative control and DMSO groups, no statistically significant differences were observed in the frequency of PCEMNs, demonstrating absence of genotoxic effect. In order to analyze the antigenotoxic effect, statistically significant differences were observed in the frequency of PCEMNs in the comparison between the groups treated with the different concentrations of the fixed oil of B. excelsa + DXR with the positive control group, being the rates of reduction in the frequency of PCEMNs from 52.08 to 67.36% in 24 hours and from 76.78 to 87.89% in 48 hours. With the analysis of the data, it was concluded that the fixed oil of B. excelsa did not show a genotoxic effect, however, it presented an antigenotoxic effect, according to the protocols and treatments performed in this work