In vitro studies of the dual properties of Allopurinol anti- and photo-oxidants Mechanisms
The objective of this study was to investigate the ability of allopurinol (1) to inhibit free radical or reactive oxygen species (.OH, ¹O2, H2O2) as well as the study of its photochemical activity. We investigated the ability of 1 to scavenge oxygen metabolites generated by cell-free systems using luminol enhanced-chemiluminescence and electronic absorption spectra as monitors. Both absorbance and fluorescence scans reveal that 1 is able to react with equimolar quantities of H2O2. In the presence of 1 a dose-dependent inhibition period was observed in this system as assayed by isoluminol-enhanced chemiluminescence (ILCL) in the presence of horseradish peroxidase (HRP), as well as by luminol-enhanced chemiluminescence (LCL) in the presence of H2O2 or ferrous ion. On the other hand, 1 did not show an efficient scavenging activity of galvanoxyl radical in ethanolic solutions. Furthermore, in a separate experiment, it was not observed trapping of singlet oxygen (¹O2) generated by Rose Bengal, in the presence of 1. The activity of 1 was compared with that of vitamins E and C. In vitro experiments of photohemolysis in presence of 1 and cinoxacin, a phototoxic antibacterial quinolone, the photohemolytic effect of cinoxacin was diminished. Allopurinol alone did not show any phototoxic effect under irradiation with UV-A or visible light but was photo-unstable and phototoxic in vitro with UV-B light.
| Main Authors: | , , , , , , , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Departamento de Farmácia, Facultad de Ciencias, Universidade Nacional da Colombia
2008
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| Online Access: | http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0034-74182008000100005 |
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| Summary: | The objective of this study was to investigate the ability of allopurinol (1) to inhibit free radical or reactive oxygen species (.OH, ¹O2, H2O2) as well as the study of its photochemical activity. We investigated the ability of 1 to scavenge oxygen metabolites generated by cell-free systems using luminol enhanced-chemiluminescence and electronic absorption spectra as monitors. Both absorbance and fluorescence scans reveal that 1 is able to react with equimolar quantities of H2O2. In the presence of 1 a dose-dependent inhibition period was observed in this system as assayed by isoluminol-enhanced chemiluminescence (ILCL) in the presence of horseradish peroxidase (HRP), as well as by luminol-enhanced chemiluminescence (LCL) in the presence of H2O2 or ferrous ion. On the other hand, 1 did not show an efficient scavenging activity of galvanoxyl radical in ethanolic solutions. Furthermore, in a separate experiment, it was not observed trapping of singlet oxygen (¹O2) generated by Rose Bengal, in the presence of 1. The activity of 1 was compared with that of vitamins E and C. In vitro experiments of photohemolysis in presence of 1 and cinoxacin, a phototoxic antibacterial quinolone, the photohemolytic effect of cinoxacin was diminished. Allopurinol alone did not show any phototoxic effect under irradiation with UV-A or visible light but was photo-unstable and phototoxic in vitro with UV-B light. |
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