Artículos de revistas
UV-light effects on cytochrome c modulated by the aggregation state of phenothiazines
Fecha
2013-10Registro en:
PLOS One,San Francisco : Public Library of Science - PLOS, v. 8, n. 10, p. e76857-1-e76857-10, Oct. 2013
1932-6203
10.1371/journal.pone.0076857.g001
Autor
Santos, Carolina G.
Silva, André L.
Souza, Flavio L.
Lanfredi, Alexandre J. C.
Di Mascio, Paolo
Nascimento, Otaciro Rangel
Rodrigues, Tiago
Nantes, Iseli L.
Institución
Resumen
The present study shows the factors that modulate the photodamage promoted by phenothiazines. Cytochrome c was irradiated with UV light for 120 min, over a pH range from 4.0 to 8.0, in the absence and in the presence of different concentrations of thioridazine (TR) and fluphenazine (FP). In the absence of phenothiazines, the maximal rate of a Soret band blue shift (nm/min) from 409 to 406 nm was obtained at pH 4.0 (0.028 nm/min). The presence of phenothiazines at the concentration range 10-25 μmol/L amplified and accelerated a cytochrome c blue shift (409 to 405 nm, at a rate = 0.041 nm/min). Above 25 μmol/L, crescent concentrations of phenothiazines contributed to cytochrome c protection with (maximal at 2500 μmol/L). Scanning electronic microscopy revealed the formation of nanostructures. The pH also influenced the effect of low phenothiazine concentrations on cytochrome c. Thus, the predominance of phenothiazine-promoted cytochrome c damage or protection depends on a balance of the following factors: the yield of photo-generated drug cation radicals, which is favored by acidic pH; the stability of the cation radicals, which is favored by the drug aggregation; and the cytochrome c structure, modulated by the pH.