title: Micellar effect on the scavenging of singlet molecular oxygen by hydroxybenzenes.
abstract: The antioxidative effectiveness of three hydroxyaromatic derivatives (OHAD), namely phenol, resorcinol and phloroglucinol, as reflected by their scavenging ability of the photochemically generated species singlet molecular oxygen [O(2)((1)Delta(g))], was studied in aqueous solution and micellar media. Kinetic results, obtained through time-resolved phosphorescence detection of O(2)((1)Delta(g)) emission and polarographic methods, at pH 7 and 12 in homogeneous and CTAB micellar media, were compared. Calculated photooxidation quantum efficiencies (phi(r)), ranging from very low values ( approximately 0.01) to relatively high ones (approximately 0.3), depend on the preferential solubilization sites of the hydroxyaromatic derivatives either in the micellar or homogeneous media. OHAD in water pH 7 and in CTAB 0.02 M pH 12 exhibit their highest antioxidative efficiency as O(2)((1)Delta(g)) scavengers. In these conditions, they present the best degree of self protection against O(2)((1)Delta(g))-mediated photooxidation with relatively high values for the overall quenching rate constant and, simultaneously, the lowest phi(r).
authors: Departamento de Química, Facultad de Ciencias Naturales, Universidad Nacional de La Patagonia SJB, Comodoro Rivadavia, Argentina.
authors: Marta
authors: M
authors: Luiz
authors: Alicia
authors: A
authors: Biasutti
authors: Norman A
authors: NA
authors: García
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D055592:Biophysical Phenomena; D001703:Biophysics; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D008823:Micelles; D008956:Models, Chemical; D010100:Oxygen / Q000378:metabolism*; D019800:Phenol / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D008823:Micelles; D019800:Phenol; D010100:Oxygen