Isoflavone Content and Antioxidant Activity of Ethanol Extract from Flowers of Pueraria lobata

The ethanol extract from flowers of Pueraria lobata were divided into four fractions:chloroform extract,ethyl acetate extract,n-butanol extract and water extract.They were used to determine isoflavone content with Kakkalide as standard compound.Then the four fractions were prepared to different mass concentration and their free radical scavenging activities were measured with DPPH· method.The results show that:(1) the isoflavone contents of chloroform extract,ethyl acetate extract,n-butanol extract and water extract are 35.27%,53.42%,52.13% and 2.34% respectively.(2)The DPPH· scavenging value of IC50 are 252,49,197 and 344 μg/mL.(3)The correlation study showed that the powerful antioxidative activity of flowers of Pueraria lobata was mainly resulted from high contents of isoflavonoids,The research indicates that the isoflavone content of ethyl acetate extract and n-butanol extract is higher than that of chloroform extract and water extract;Four fractions have DPPH free radical scavenging activities.The ethyl acetate extract is the best,showed that the isoflavone of flowers of Pueraria lobata is a natural antioxidant,and it has strong antioxidant activity.