Protective effects of ursolic acid and luteolin against oxidative DNA damage include enhancement of DNA repair in Caco-2 cells

• Autor(a) principal: Ramos, Alice A.
• Data de Publicação: 2010
• Outros Autores: Wilson, Cristina Pereira, Collins, Andrew R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/18405
• topic: Ursolic acid; Luteolin; DNA oxidation; Antioxidants; DNA repair; Comet assay; Science & Technology

Consumption of fruits and vegetables is associated with a reduced risk of developing a wide range of cancers including colon cancer. In this study, we evaluated the effects of two compounds present in fruits and vegetables, ursolic acid, a triterpenoid, and luteolin, a flavonoid, on DNA protection and DNA repair in Caco-2 cells using the comet assay. Ursolic acid and luteolin showed a protective effect against H2O2-induced DNA damage. Repair rate (rejoining of strand breaks) after treatment with H2O2 was increased by pre-treatment of Caco-2 cells for 24 h with ursolic acid or luteolin. To evaluate effects on induction of base oxidation, we exposed cells to the photosensitizer Ro 19-8022 plus visible light to induce 8-oxoguanine. Luteolin protected against this damage in Caco-2 cells after a short period of incubation. We also measured the incision activity of a cell extract from Caco-2 cells treated for 24 h with test compounds, on a DNA substrate containing specific damage (8-oxoGua), to evaluate effects on base excision repair activity. Preincubation for 24 h with ursolic acid enhanced incision activity in Caco-2 cells. In conclusion, we demonstrated for the first time that ursolic acid and luteolin not only protect DNA from oxidative damage but also increase repair activity in Caco-2 cells. These effects of ursolic acid and luteolin may contribute to their anti-carcinogenic effects.