RESUMO
Carotenoids are 40-carbon molecules with conjugated double bonds, making them particularly effective for quenching free radicals. They have always been believed to possess anticancer properties, which could be due to their antioxidant potential. Norbixin is an unusual dicarboxylic water-soluble carotenoid present as a component in the pericarp of the seeds of Bixa orellana L. (from the Bixaceae family), a tropical shrub commonly found in Brazil. The main carotenoids present in these seeds, bixin and norbixin, form a coloring material, known as annatto, which is mainly used in the food industry. As annatto is only used as a coloring material, most studies of annatto pigments have focused on the determination of annatto levels in food. However, little attention has been given to the biological properties of bixin and norbixin. We evaluated the effect of norbixin on the response of Escherichia coli cells to DNA damage induced by UV radiation, hydrogen peroxide (H2O2) and superoxide anions (O2*-)) and found that norbixin protects the cells against these agents. Norbixin enhanced survival at least 10 times. The SOS induction by UVC was inhibited 2.3 times more when cells were grown in the presence of norbixin. We also found that norbixin has antimutagenic properties, with a maximum inhibition of H2O2-induced mutagenic activity of 87%, based on the Salmonella mutagenicity test
Assuntos
Antimutagênicos/farmacologia , Carotenoides/farmacologia , Dano ao DNA/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Bixaceae/química , DNA Bacteriano/efeitos dos fármacos , DNA Bacteriano/efeitos da radiação , Dano ao DNA/efeitos da radiação , Escherichia coli/citologia , Peróxido de Hidrogênio/toxicidade , Resposta SOS em Genética , Superóxidos/toxicidade , Testes de Mutagenicidade/métodos , Raios UltravioletaRESUMO
1. Peptide growth factors and products of some oncogenes are likely to be active in common regulatory pathways that control the cell cycle. 2. Cell transformation by DNA -mediated transfections with cloned oncogenes is an approach that can provide insight into the mechanisms of both growth factor action and cell cycle regulation. 3. This paper deals with this approach, summarizing and discussing transfection experiments of mouse c-myc- and human c-Ha-ras-1 cloned oncogenes into mouse embryo Balb-3T3 cells