Study on the antioxidation activity of flavonoids in Myricaria germanica

OBJECTIVE To study antioxidant activity in vitro from the 11 kinds of flavonoids in Myricaria germanica. METHODS Several methods were employed,including DPPH free radical scavenging activity test,total antioxidant capacity of FRAP experiment,total antioxidant capacity of ABTS test and the inhibition of tyrosinase activity. The capacity of free radical scavenging and antioxidant activity of the 11 kinds of flavonoids in vitro were evaluated. RESULTS 3,5,4'- trihydroxy- 7- methoxyflavone,3,5,7-trihydroxy- 4'- methoxyflavone,tamarixetin,kaempferol and quercetrin had stronger activity on DPPH free radical scavenging activity( IC50 lower than that of Vitamin C). Compared to Trolox standard,ABTS total antioxidant value was higher than 0. 01 mmol·L- 1. The total anti- oxidative capacity of these flavonoids was measured by FRAP,but the value was lower than the positive control Trolox. The11 kinds of flavonoids could inhibit the activity of tyrosinase activity,but IC50 was higher than that of the positive control of kojic acid.CONCLUSION 3,5,4'- trihydroxy- 7- methoxyflavone,3,5,7- trihydroxy- 4'- methoxyflavone,tamarixetin,kaempferol and quercetrin of 11 kinds of flavonoids have relatively strong antioxidant activity.