André Sousa, Paula Araújo, Luís Cruz, Natércia F. Brás, Nuno Mateus, and Victor De Freitas
Abstract
The aim of this study was to investigate interactions possibly taking place in red wine between oaklins, which are deoxyanthocyanidin derivatives (guaiacylcatechin-pyrylium and syringylcatechin-pyrylium), and several copigments: catechin (CP1), epicatechin (CP2), chlorogenic acid (CP3), epigallocatechin (CP4), and procyanidin B3 (CP5). The results show that oaklins, like common anthocyanins, also present copigmentation interactions that further stabilize the flavylium cation in hydroalcoholic solutions. Molecular dynamics simulations were also performed to interpret the binding data, to specify the relative arrangement of the pigment and copigment molecules within the complexes, and to interpret their absorption properties in the visible range.
(-)Epigallocatechin (EGC) was purchased from Biopurify Phytochemicals Ltd. (Sichuan, China).
