title: In vitro antioxidant and photo-oxidant properties of dipyridamole.
abstract: The in vitro antioxidant and photo-oxidant activity of dipyridamole was studied by its effect on superoxide- and singlet oxygen-mediated photohemolysis and viability of neutrophils. Dipyridamole was found to be phototoxic when examined by the photohemolysis on human erythrocytes and on linoleic acid as lipid peroxidation model at concentrations above 3.0 x 10(-5) M. On the contrary, when lower concentrations (1.0 x 10(-5) to 1.0 x 10(-6) M) were used, dipyridamole showed a protector action against singlet oxygen-mediated photohemolysis by other phototoxic compounds like triamterene. This antioxidant property is proposed to result from quenching of triamterene mediated by fluorescence energy transfer. Auto-oxidation and fluorescence-energy transfer is clearly an important mechanism for protection for this drug.
authors.affiliation: Laboratorio de Fotoquimica, Centro de Química, Instituto Venezolano de Investigaciones Científicas IVIC, Caracas, Venezuela. fvargas@ivic.ve
authors.forename: F
authors.initials: F
authors.lastname: Vargas
authors.forename: A T
authors.initials: AT
authors.lastname: Cheng
authors.forename: G
authors.initials: G
authors.lastname: Velutini
authors.forename: E
authors.initials: E
authors.lastname: Marcano
authors.forename: Y
authors.initials: Y
authors.lastname: Sánchez
authors.forename: G
authors.initials: G
authors.lastname: Fraile
authors.forename: M
authors.initials: M
authors.lastname: Velásquez
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D004176:Dipyridamole / Q000494:pharmacology* / Q000633:toxicity*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D019787:Linoleic Acid; D010782:Photolysis; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology* / Q000633:toxicity*; D026082:Singlet Oxygen; D013056:Spectrophotometry, Ultraviolet; D013481:Superoxides; D014223:Triamterene / Q000633:toxicity; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010975:Platelet Aggregation Inhibitors; D013481:Superoxides; D026082:Singlet Oxygen; D004176:Dipyridamole; D019787:Linoleic Acid; D014223:Triamterene