title: Pro-oxidant activity of oleuropein determined in vitro by electron spin resonance spin-trapping methodology.
abstract: In this work, the pro-oxidant behavior of oleuropein (OLP, 1) is characterized in a Fenton-like experiment by means of ESR spectroscopy using the spin trap system DMSO and 4-(pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) in phosphate buffer (PB) solution. Ferrous ions in the absence of hydrogen peroxide cause the formation of the stable nitroxide species 4 and 5 through the intermediate perferryl species. OLP displays its antioxidant activity in vitro blocking the oxidation path that leads to methoxyl radicals hence to the formation of the stable radical species 5. The role of the catechol moiety was proved when the perferryl experiments were repeated in the presence of the dimethylated oleuropein homologue (OLP-Met2, 2). The dual behavior of oleuropein, similar to that ascertained for other catechol and non-catechol natural active species, should provide warnings for its use as nutraceutical or as drug with manifold healing effects.
authors.affiliation: Dipartimento di Chimica, Università della Calabria, I-87036 Arcavacata di Rende (CS), Italy.
authors.forename: Armando
authors.initials: A
authors.lastname: Mazziotti
authors.forename: Fabio
authors.initials: F
authors.lastname: Mazzotti
authors.forename: Manuela
authors.initials: M
authors.lastname: Pantusa
authors.forename: Luigi
authors.initials: L
authors.lastname: Sportelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Sindona
mesh_terms: D000975:Antioxidants; D003497:Cyclic N-Oxides; D004121:Dimethyl Sulfoxide; D004578:Electron Spin Resonance Spectroscopy; D057888:Iridoid Glucosides; D039823:Iridoids; D031658:Olea / Q000737:chemistry; D016877:Oxidants / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D011714:Pyrans / Q000494:pharmacology*; D011725:Pyridines
chemical_list: D000975:Antioxidants; D003497:Cyclic N-Oxides; D057888:Iridoid Glucosides; D039823:Iridoids; D016877:Oxidants; D011714:Pyrans; D011725:Pyridines; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; C002769:oleuropein; C034445:1-oxyl-2,2,6,6-tetramethyl 4-piperidinyl nicotinate; D004121:Dimethyl Sulfoxide