Superoxide anion radicals are produced by a number of
cellular reactions, including various enzyme systems, such
as lipoxygenases, peroxidase, NADPH oxidase and xanthine
oxidase. Superoxide anion plays an important role
in plant tissues and is involved in the formation of other
cell-damaging free radicals (Bloknina et al., 2003). In the
present study, superoxide radical was generated by illuminating
a solution containing riboflavin. The relative scavenging
effects of litchi anthocyanins on superoxide radical
are shown in Fig. 4. As with the reducing power, anthocyanins
exhibited an excellent superoxide anion-scavenging
activity, which was much higher than those of ascorbic acid
and BHT. At 50 lg/ml, the scavenging activity of anthocyanins,
ascorbic acid and BHT were 91.4%, 12.4% and
13.3%, respectively.