Resumo (PT):
In the present work, a fluorimetric automatic method based on multisyringe flow injection analysis (MSFIA) was developed for in vitro evaluation of scavenging capacity against nitric oxide (NO) using 4,5-diaminofluorescein (DAF-2) as an NO-selective fluorogenic probe. The MSFIA manifold was assembled to perform the in-line generation of NO and the competitive reaction of putative scavenger molecules and DAF-2 with NO at conditions close to those found in vivo regarding temperature (37°C), pH (7.4), and concentration of NO (less than 1 μM). This approach allowed the evaluation of scavenging capacity against NO by endogenous antioxidant molecules, pharmaceutical compounds, and human plasma. IC<sub>50</sub> values were calculated for rutin (1.30 ± 0.02 μM, positive control), cysteine (321 ± 8 μM), reduced glutathione (1106 ± 93 μM), uric acid (134 ± 12 μM), dipyrone (1.36 ± 0.06 μM), and captopril (363 ± 28 μM). A high degree of automation was attained as the successive dilution of antioxidant standard solutions required for IC<sub>50</sub> assessment was performed automatically, in a dilution chamber placed in the flow system. A determination throughput of 16 h<sup>-1</sup> and a good precision were attained (relative standard deviation between 1.6 and 9.0%), fostering the application of the proposed method to routine/screening analysis of scavenging capacity against NO
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Abstract (EN):
In the present work, a fluorimetric automatic method based on multisyringe flow injection analysis (MSFIA) was developed for in vitro evaluation of scavenging capacity against nitric oxide (NO) using 4,5-diaminofluorescein (DAF-2) as an NO-selective fluorogenic probe. The MSFIA manifold was assembled to perform the in-line generation of NO and the competitive reaction of putative scavenger molecules and DAF-2 with NO at conditions close to those found in vivo regarding temperature (37 degrees C), pH (7.4), and concentration of NO (less than 1 mu M). This approach allowed the evaluation of scavenging capacity against NO by endogenous antioxidant molecules, pharmaceutical compounds, and human plasma. IC(50) values were calculated for rutin (1.30+/-0.02 mu M, positive control), cysteine (321+/-8 mu M), reduced glutathione (1106+/-93 mu M), uric acid (134+/-12 mu M), dipyrone (1.36+/-0.06 mu M), and captopril (363+/-28 mu M). A high degree of automation was attained as the successive dilution of antioxidant standard solutions required for IC(50) assessment was performed automatically, in a dilution chamber placed in the flow system. A determination throughput of 16 h(-1) and a good precision were attained (relative standard deviation between 1.6 and 9.0%), fostering the application of the proposed method to routine/screening analysis of scavenging capacity against NO.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
10