Free-radical scavenging activities of silybin and its analogues; A Pulse radiolysis study

Fu, H. Y.*; Lin, M.; Katsumura, Yosuke*; Muroya, Yusa*

Free radical scavenging and antioxidant activities of four natural flavonoids, namely silybin, naringenin, naringin and hesperetin, have been studied using nanosecond pulse radiolysis techniques. The kinetics and mechanisms of the reactions of silybin and analogues with various oxidizing radicals have been investigated. Further, the transient species has been assigned and radical scavenging rate constants have also been measured. Moreover, the structure-activity relationships (SAR) between chemical structures of the flavonoids and their radical scavenging activities are further analyzed by theoretical calculation. Combined our previous observation of the fast reparation of DNA damage and efficient DNA protection against radiation damage in vitro, it can be confirmed that test flavonoids are promising molecules to be used for their potential antioxidant properties.