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1.
Genet. mol. res. (Online) ; 4(1): 94-99, Mar. 2005.
Artículo en Inglés | LILACS | ID: lil-417405

RESUMEN

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


Asunto(s)
Antimutagênicos/farmacología , Carotenoides/farmacología , Daño del ADN/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Bixaceae/química , ADN Bacteriano/efectos de los fármacos , ADN Bacteriano/efectos de la radiación , Daño del ADN/efectos de la radiación , Escherichia coli/citología , Peróxido de Hidrógeno/toxicidad , Respuesta SOS en Genética , Superóxidos/toxicidad , Pruebas de Mutagenicidad/métodos , Rayos Ultravioleta
2.
Braz. j. med. biol. res ; 27(11): 2551-5, Nov. 1994. graf
Artículo en Inglés | LILACS | ID: lil-153974

RESUMEN

The iron chelator o-phenanthroline enhances the lethal effect of H2O2 about four hundred times in Escherichia coli when both substances are added simultaneously to the culture mediu. If o-phenanthroline is added for increasing periods of time prior to the addition of H2O2, there is a shift from this lethal interaction to protection by the chelator about seven hundred times. It is known that the Fe2+ -o-phenanthroline(I) and Fe2+ -o-phenanthroline(II) complexes are formed quickly whereas the final and more stable Fe2+ -o-phenanthroline(III) complex is formed slowly, Moreover, the mono and bis complexes react with H2O2 to produce OH., whereas the tris complex is stable towards H2O2. Therefore, the lethal effect could be explained by the kinetics of reaction of o-phenanthroline with intracellular Fe2+, i.e., the mono and bis complexes are more reactive than intracellular Fe2+


Asunto(s)
Escherichia coli/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Fenantrolinas/farmacología , 2,2'-Dipiridil/farmacología , ADN/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Radical Hidroxilo/farmacología , Quelantes del Hierro/farmacología , Factores de Tiempo
3.
Braz. j. med. biol. res ; 20(6): 873-5, 1987. ilus
Artículo en Inglés | LILACS | ID: lil-77470

RESUMEN

The present study analyzes the possible scavenger capacity of several anti-inflammatory drugs on growth of Escherichia coli K12, Bw9109, a strain hypersensitive to H2O2, in medium containing H2)2. although all cyclo-oxygenase and/or lipoxygenase inhibitors protected the cells against H2O2, no correlation was found between their relative protective abilities and reported anti-inflammatory potencies


Asunto(s)
Cloranfenicol/farmacología , Daño del ADN , Escherichia coli/efectos de la radiación , Peróxido de Hidrógeno/farmacología , Rayos Ultravioleta
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