De Rosso Veridiana V, Morán Vieyra Faustino E, Mercadante Adriana Z, Borsarelli Claudio D
Department of Food Science, Faculty of Food Engineering, University of Campinas, Campinas, Sao Paulo, Brazil.
Free Radic Res. 2008 Oct;42(10):885-91. doi: 10.1080/10715760802506349.
The quenching of singlet molecular oxygen ((1)O(2)) 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 (1)O(2) 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 approximately 4 x 10(8) M(-1) s(-1) and 3 x 10(6) M(-1) s(-1), respectively, indicating the good performance of the studied anthocyanins as catalytic quenchers of (1)O(2). 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 (1)O(2) 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.
采用时间分辨磷光检测（TRPD）法检测单线态分子氧（(1)O(2)），并分别以苊醌和亚甲基蓝为敏化剂，通过光稳态光度法，在1%盐酸甲醇溶液中研究了六种广泛存在的花青素衍生物（矢车菊素3 - 葡萄糖苷（CG）、矢车菊素3 - 芸香糖苷（CR）、矢车菊素3 - 半乳糖苷（CGL）、锦葵色素（M）、锦葵色素3 - 葡萄糖苷（MG）和锦葵色素3,5 - 二葡萄糖苷（MDG））的黄烊盐阳离子形式对(1)O(2)的猝灭作用。总猝灭速率常数（k(0)）和化学猝灭速率常数（k(c)）的平均值分别约为4×10(8) M(-1) s(-1)和3×10(6) M(-1) s(-1)，这表明所研究的花青素作为(1)O(2)的催化猝灭剂具有良好的性能。锦葵色素的猝灭效率高于矢车菊素衍生物，这可能是由于锦葵色素衍生物B环上额外的供电子甲氧基所致；并且它还取决于糖基化取代的数量和类型。正如对其他酚类衍生物所观察到的那样，花青素对(1)O(2)的猝灭是通过电荷转移机制介导的，该机制受增加这些化合物供电子能力的 -OR取代基总数的调节。
