Singlet molecular oxygen quenching, O2(1Dg), ability of water soluble chitosan (WSCh).

VANDEN BRABER, NOELIA; VAZQUEZ, MARÍA EMILIA; MONTENEGRO MARIANA; MORÁN EDUARDO; RICARDO A. MIGNONE; BORSARELLI CLAUDIO

Córdoba

Congreso; 16th International Congress on Photobiology; 2014

International Union of Photobiology

Chitosan (Ch) is a nontoxic biopolymer produced by the deacetylation of chitin, a major component of the shells of crustaceans. The biological activities of Ch include hypocholesterolemic, antimicrobial, immunostimulating, anticancer effect, anti-inflammatory and antioxidant. This biomolecule contains three types of reactive functional groups, an amino/acetamido group and both primary and secondary hydroxyl groups at the C-2, C-3 and C-6 positions, respectively. Ch is only soluble in the acid pH range. Hence, improving its solubility is crucial if it is to be utilized across a wide pH range. WSCh, produced through Maillard reaction with glucosamine, is a feasible way to increase solubility, because glucosamine, like Ch, possesses active amino and hydroxyl groups. In this work, we study the O2(1Dg) quenching by Ch and WSCh. O2(1Dg) was generated by photosensitization with tris(bipyridine)ruthenium(II) dichloride (Ru(bpy)3Cl2). The rate constants for total and reactive deactivation were measured using a time-resolved phosphorescence detection method (TRPD) to 1270 nm and oxygen consumption, respectively. The obtained rate constant values for the total and reactive quenching of O2(1Dg) shown that both Ch and WSCh could deactivate this specie mainly through a reactive via with values in the order of 107 M-1s-1, which could correspond to the iteration of the primaries amino groups of Ch.