Antiradical and reductant activities of anthocyanidins and anthocyanins, structure–activity relationship and synthesis
2015; Elsevier BV; Volume: 194; Linguagem: Inglês
10.1016/j.foodchem.2015.09.003
ISSN1873-7072
AutoresHussein M. Ali, Wafaa Almagribi, Mona N. Al-Rashidi,
Tópico(s)Antioxidant Activity and Oxidative Stress
ResumoEight anthocyanidins, seven anthocyanins and two synthesized 4'-hydroxy flavyliums were examined as hydrogen donors to DPPH, ABTS and hydroxyl radicals, and as electron donors in the FRAP assay. Most compounds gave better activities than trolox and catechol. A structure-activity relationship (SAR) study showed that, in the absence of the 3-OH group, radicals of the 4, 5 or 7-OH groups can only be stabilized by resonance through pyrylium oxygen, while 3-OH group improved hydrogen atom donation because of the stabilization by anthocyanidin semiquinone-like resonance. Electron donation was also enhanced by the 3-OH group. Both anthocyanidins and their respective anthocyanins showed similar trends and close activities. Different types of sugar unit bonded to the 3-OH group or counter ion had minor effect on activities. The catechol structure improved both hydrogen and electron donation. Compounds lacking the catechol structure had a decreasing order of H-atom and electron donation (Mv>Pn>Pg>Ap>4'-OH-flavylium) consistent with the decreasing number of their hydroxyl and/or methoxy groups.
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