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- Title
UV-Light Effects on Cytochrome <i>C</i> Modulated by the Aggregation State of Phenothiazines.
- Authors
dos Santos, Carolina G.; Silva, André L.; Souza, Flavio L.; Lanfredi, Alexandre J. C.; Di Mascio, Paolo; Nascimento, Otaciro R.; Rodrigues, Tiago; Nantes, Iseli L.
- Abstract
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.
- Subjects
ULTRAVIOLET radiation; CYTOCHROME c; PHENOTHIAZINE; FLUPHENAZINE; PH effect; CATIONS; DRUG analysis
- Publication
PLoS ONE, 2013, Vol 8, Issue 10, p1
- ISSN
1932-6203
- Publication type
Article
- DOI
10.1371/journal.pone.0076857