Determination, Antioxidant Activity and Reaction Kinetics of Eriodictyol and Luteolin in Xerochrysum Bracteatum

OBJECTIVE To establish a method for the determination of eriodictyol and luteolin in Xerochrysum braeteatum, and to evaluate their antioxidant activities in vitro. METHODS UPLC was used to investigate the coutent determination methodologically. Vitamin C and Trolox were used as the control, the IC₅₀ values of eriodictyol and luteolin for scaving DPPH free radical were determined, and the antioxidant activity was compared. The kinetic characteristics of free radical scavenging reaction were preliminarily explained by the change of free radical scavenging rate within 4 h. RESULTS There was a good linear relationship (R=0.999 7) between the peak area and the concentration of eriodictyol in the range of 0.005 4-0.545 0 mg·mL^-1 and luteolin in the range of 0.005 3-0.535 0 mg·mL^-1. The precision, stability and recovery of the method were satisfactory. The scavenging ability of the 4 compounds from high to low was luteolin>eriodictyol>vitamin C>Trolox. Different from vitamin C and Trolox, the free radical scavenging process of eriodictyol and luteolin showed three stages:first fast and then slow. CONCLUSION The content determination method is simple and rapid, and can be used for the determination of eriodictyol and luteolin in Xerochrysum braeteatum. The resources of Xerochrysum braeteatum are worth further development because of their excellent antioxidant activities.