Artículos de revistas
Singlet oxygen quenching by anthocyanin's flavylium cations
Registro en:
Free Radical Research. Informa Healthcare, v. 42, n. 10, n. 885, n. 891, 2008.
1071-5762
WOS:000260641600006
10.1080/10715760802506349
Autor
De Rosso, VV
Vieyra, FEM
Mercadante, AZ
Borsarelli, CD
Institución
Resumen
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The quenching of singlet molecular oxygen (1O2) by the flavylium cation form of six widespread anthocyanin derivatives: cyanidin 3-glucoside (CG), cyanidin 3-rutinoside (CR), cyanidin 3-galactoside (CGL), malvidin (M), malvidin 3-glucoside (MG) and malvidin 3,5-diglucoside (MDG) was studied in 1% HCl methanol solution by time-resolved phosphorescence detection (TRPD) of 1O2 and photostationary actinometry using perinaphthenone and methylene blue as sensitizers, respectively. The average value of the total (k 0) and chemical (k c) quenching rate constants were 4108 m-1 s-1 and 3106 m-1 s-1, respectively, indicating the good performance of the studied anthocyanins as catalytic quenchers of 1O2. The quenching efficiency was larger for malvidin than for cyanidin derivatives, probably by the extra electron-donating methoxy group in ring B of the malvidin derivatives; and it was also dependent on the number and type of glycosylated substitution. As observed for other phenolic-like derivatives, the quenching of 1O2 by anthocyanins was mediated by a charge-transfer mechanism, which was modulated by the total number of -OR substituents that increases the electron-donating ability of these compounds. 42 10 885 891 CICyT-UNSE CONICET (Argentina) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)