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Mechanistic Insight into the Photodynamic Effect Mediated by Neutral Red and a New Azine Compound in Staphylococcus aureus Cells
Author(s) -
Urrutia María Noel,
Ortiz Cristina S.,
Alovero Fabiana L.
Publication year - 2019
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201900262
Subject(s) - chemistry , sodium azide , mannitol , singlet oxygen , staphylococcus aureus , azine , photosensitizer , neutral red , reactive oxygen species , azide , sodium , oxygen , photochemistry , biochemistry , bacteria , medicinal chemistry , organic chemistry , cytotoxicity , biology , in vitro , genetics
Abstract The photodynamic activity of Neutral Red and the new monobrominated Neutral Red was studied in suspensions of Staphylococcus aureus . The effect of mannitol and sodium azide in the presence of 25 μ m photosensitizer on lethal photosensitization were investigated. The results of the mechanistic evaluation of Neutral Red showed that both mannitol and sodium azide produced a completed protective effect after irradiation without significant differences between them. The evaluation of monobrominated Neutral Red also showed a protective effect of microorganisms with the addition of mannitol. Although sodium azide produced a protective effect of the photoinactivation, it was incomplete and less than that exhibited by mannitol. The results indicate that the starting reagent, Neutral Red, is a producer of radical species, acting through a type I mechanism, whereas the halogenated derivative of Neutral Red produced reactive oxygen species and a contribution of singlet molecular oxygen cannot be discarded in the photoinactivation of Staphylococcus aureus cells. These results, analyzed together with the previously evaluated properties of the dyes, allow us to explain the differences observed in the photoinactivation of Staphylococcus aureus mediated by both azine photosensitizers.