Evaluation of cytotoxicity, genotoxicity, antigenotoxicity and expression of Tp53 and Ephx2 genes in rats treated with Caryocar villosum

Author(s)

Mara Ribeiro de Almeida

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC)
• Defense date: 2013-03-01

Examining board members

Maria de Lourdes Pires Bianchi; Elaine Cristina Pereira de Martinis; Danielle Palma de Oliveira; Maria Lucia Pedrosa; Valdo José Dias da Silva

• Advisor: Maria de Lourdes Pires Bianchi

Abstract

Fruit and vegetables intake has been related to the promotion of health because it has been associated to reduced risk of chronic diseases development such as cancer, and cardiovascular and degenerative diseases. Thus, the study of the biological effects of these foods has increased in recent years. Piquiá (Caryocar villosum) is a fruit native of the Amazon and it is rich in antioxidant compounds such as phenolic compounds. Therefore, the aim of this study was to evaluate the in vivo genotoxicity and antigenotoxicity effects of the piquiá lyophilized pulp fruit and its ethanolic extract. Moreover, the phytochemical characterization of pulp and extract was determined. Wistar rats were treated by gavage, for 14 days, with three doses of piquiá pulp (75, 150 or 300 mg/kg b.w.) or with its ethanolic extract (75 mg/kg b.w.). On 14th day, the animals received saline (0.9% i.p.) or doxorubicin (DXR, 15 mg/kg b.w.) and after 24 hours they were euthanized. Bone marrow and peripheral blood were used in micronucleus (MN) test, and the liver, kidney and heart were used in comet assay, thiobarbituric acid reactive substances (TBARS), reduced gluthatione (GSH), and in the evaluation of mRNA expression of epoxide hydrolase (Ephx2) and tumor protein p53 (Tp53) genes. The piquiá pulp was not genotoxic nor mutagenic, demonstrated antigenotoxic effects and reduced the TBARS levels induced by DXR in heart. The ethanolic extract had opposite effects, whereas it was genotoxic, but not mutagenic, and increased the TBARS levels in heart. Ephx2 mRNA levels in kidney and heart were increased after treatment with the higher dose of piquiá pulp, however, in kidney the lowest dose decreased the transcription of this gene induced by DXR. In liver, the 75 and 300 mg/kg b.w. doses of piquiá pulp decreased the Ephx2 mRNA levels induced by DXR. The piquiá pulp 300 mg/kg + DXR group, presented lower levels of Tp53 mRNA in liver, kidney and heart. The ethanolic extract of piquiá pulp modulated the mRNA Ephx2 expression only in the liver, increasing the levels of this transcript, while in the heart decreased the transcription of Tp53 gene. There was a difference on phytochemical composition between the pulp and its ethanolic extract. The extract presented 1.4-fold more phenolic compounds and 3-fold less carotenoids than piquiá pulp. Furthermore, gallic acid was the predominant phenol in the pulp, whereas in the ethanolic extract the most abundant phenol was the ellagic acid. The difference in the biological effects between piquiá pulp and is ethanolic extract may be due the change of the phytochemical composition. (AU)

• FAPESP's process: 09/15692-0 - Evaluation of citotoxicity, genotoxicity, antigenotoxicity and gene expression of Tp53 and Ephx2 in rats treated with Caryocar villosum
• Grantee: Mara Ribeiro de Almeida
• Support type: Scholarships in Brazil - Doctorate