Abstract: Leaves of sixteen H. cordata cultivars including H. emeiensis Z.Y. Zhu et S. L. Zhang were extracted with 95% ethanol by ultrasonic-assisted method. The contents of total phenolic acids and flavonoids were determined spectrometrically, and their antioxidant capacities were evaluated. The results showed that total phenol contents in dried leaves of H. cordata were in the range of 7.01－15.0 mg/g, and flavonoid contents varied from 3.56 to 11.0 mg/g. DPPH radical scavenging rates of the leaf extracts of H. cordata varied from 84.7 to 248 μmol/g, and ABTS radical scavenging rates from 78.4 to 218 μmol/g. Cluster analysis based on the contents of polyphenol and flavonoid as well as antioxidant activity in vitro indicated that 16 H. cordata cultivars could be classified into two subgroups. The group I included 11 H. cordata cultivars with relatively low total phenol content, flavonoid content, and DPPH and ABTS radical scavenging capacity, while group Ⅱ showed higher contents of polyphenol, flavonoid, and antioxidant activity in vitro. The chromosome number did not show any significant correlation with the contents of polyphenol and flavonoid or antioxidant activity in vitro, while total phenolic acid and flavonoids contents had an obvious correlation with antioxidant activity.

Key words: Houttuynia cordata Thunb., total phenol, flavonoid, antioxidant activity, cluster analysis