Simultaneous comparison of relative reactivities of twelve major anthocyanins in bilberry towards reactive nitrogen species.

The reactivities of twelve major anthocyanins identified in bilberry extracts towards nitric oxide (NO.) and peroxynitrite (ONOO-) were studied in vitro using capillary zone electrophoresis (CZE). The reactivities of the anthocyanins towards NO. were slightly weak compared with that of (+)-catechin as a reference antioxidant under anaerobic conditions except delphinidin glycosides (Dp3glys). The reactivities of other anthocyanins were not significantly affected by either the aglycon structure or the type of sugar moiety. Under aerobic conditions, all anthocyanins and catechin showed significant enhancement of the reactivity, indicating that they reacted with other reactive species secondarily generated from NO. . Dp3glys showed rather extraordinally high reactivity towards ONOO- compared to other anthocyanins which showed approximately two times low reactivity than catechin when compared with IC50. Structural divergence in the reactivity was also small for all these anthocyanins.