Nitric oxide release from the S-nitrosothiol zinc phthalocyanine complex by flash photolysis

Autor(es)

J.C.G. Rotta ^[1] ; C.N. Lunardi ^[2] ; A.C. Tedesco ^[3]

Afiliação do(s) autor(es)

^[1] Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto. Departamento de Química - Brasil

^[2] Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto. Departamento de Química - Brasil

^[3] Universidade de São Paulo. Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto. Departamento de Química - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 36, n. 5, p. 587-594, 2003-05-00.

Resumo

The photogeneration of nitric oxide (NO) using laser flash photolysis was investigated for S-nitroso-glutathione (GSNO) and S-nitroso-N-acetylcysteine (NacySNO) at pH 6.4 (PBS/HCl) and 7.4 (PBS). Irradiation of S-nitrosothiol with light (lambda = 355 nm followed by absorption spectroscopy) resulted in the homolytic decomposition of NacySNO and GSNO to generate radicals (GS· and NacyS·) and NO. The release of NO from donor compounds measured with an ISO-Nometer apparatus was larger at pH 7.4 than pH 6.4. NacySNO was also incorporated into dipalmitoyl-phosphatidylcholine liposomes in the presence and absence of zinc phthalocyanine (ZnPC), a well-known photosensitizer useful for photodynamic therapy. Liposomes are usually used as carriers for hydrophobic compounds such as ZnPC. Inclusion of ZnPC resulted in a decrease in NO liberation in liposomal medium. However, there was a synergistic action of both photosensitizers and S-nitrosothiols resulting in the formation of other reactive species such as peroxynitrite, which is a potent oxidizing agent. These data show that NO release depends on pH and the medium, as well as on the laser energy applied to the system. Changes in the absorption spectrum were monitored as a function of light exposure. (AU)

• Processo FAPESP: 99/01394-3 - Síntese e estudos fotofísicos de S-nitrosotióis Ftalocianinas, úteis em terapia fotodinâmica de neoplasias
• Beneficiário: Jeane Cristina Gomes Rotta
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 00/00431-1 - Síntese e caracterização fotofísica e fotobiologica de zinco ftalocianina substituída do composto 3-nitro-4-[N, N-di(metilenocarboxilato de metila]-amino-fenoxi
• Beneficiário: Claure Nain Lunardi Gomes
• Modalidade de apoio: Bolsas no Brasil - Doutorado