Abstract: The total flavonoids,rutin and hyperoside extraction process of four Crataegus L fruits were optimized by single factor experiment and Orthogonal Test.And antioxidant activities of four Crataegus L fruits were determined by ABTS,DPPH scavenging rate.The optimal extraction process was as follows:90 ℃,30 min,40% ethanol,solidtoliquid ratio of 1:40 (g/mL).Under this condition,the extraction rate of flavonoids and antioxidant activity of the four Crataegus L fruits decreased in the following order:Crataegus pinnatifida var.major N.E.Brown >Crataegus pinnatifida Bge.>Crataegus chlorocarpa Lenne et C.Koch.>Crataegus sanguine Pall..There was a good linear relationship between total flavonoids extraction rate and ABTS,DPPH scavenging activity (R=0.955 and 0.922,respectively),and they showed a significant positive correlation.These results demonstrated that the four CrataegusL.fruits are potential sources of natural antioxidants,and their flavonoids and biological activities are worth further research.

Key words: Crataegus L., total flavonoids, rutin, hyperoside, antioxidant activity