Antioxidant properties of anthocyanins in Azolla imbricata under cadmium stress
满江红花青素在镉胁迫下的抗氧化作用

To investigate the physiological function of anthocyanins which are induced by cadmium in Azolla imbricata,the in vitro antioxidant properties of anthocyanins were investigated using different testing indexes,including reducing power,superoxide anion radical(O2·-)scavenging,hydrogen peroxide(H2O2)scavenging and hydroxyl radical(·OH)scavenging.The scavenging activity of reactive oxygen species,as well as the reducing power increased with increasing concentrations of anthocyanin extracts.Thus,anthocyanins induced under Cd stress have an inherent potential to function as effective antioxidants by scavenging reactive oxygen species.We also investigated the effects of Cd on active oxygen metabolism in the fronds of A.imbricata.The results showed that 0.5 mg·L-1 Cd treatment resulted in excessive accumulation of O2·- and H2O2,by imposing active oxygen stress.The data here suggest that anthocyanins might partially protect the fronds from oxidative damage.Based on these results,an increase in the content of anthocyanins is considered one of the resistance mechanisms of A.imbricata toward Cd toxicity.