Correlation of Polyphenolics Content to Antioxidant Activity of Forsythia Suspensa Leaves

Dried ripe fruit of Forsythia suspensa is widely used as traditional Chinese medicine including antifebrile, antiphlogistic, diuretic, drainage and analgesic for tumor and skin diseases. In this research, polyphenols in Forsythia suspensa, which is considered to participate in these physiological functions, were analyzed and the antioxidant activities were also investigated. Forsythia suspensa samples harvested in March 2008 - October 2008 were extracted with 60 % methanol and the polyphenol contents in the extract were investigated by the Folin-ciocalteu method, and the flavonoid contents were investigated by the AlCl3 coloring method. Their anti-oxidization activities were estimated by DPPH radical scavenging activity and ABTS radical scavenging activity. As results, the polyphenol content and the flavonoid content in leaves were higher than those in the flower and the fruit, and DPPH radical scavenging activity and ABTS radical scavenging activity of the leaves were also higher. Changes of polyphenolic contents in the leaves accompanying growth was determined and it turned out that the leaves picked in March had highest polyphenol and flavonoid contents, and highest DPPH and ABTS radical scavenging activities. High correlativity was observed in the polyphenol and flavonoid content, and the radical scavenging activities of the leaves extract, and it was suggested to leaves of Forsythia suspensa that polyphenols with high antioxidant activity were containedOtherShinshu University International Symposium 2010 : Sustainable Agriculture and Environment : Asian Networks II 信州大学国際シンポジウム2010 : 持続的農業と環境 : アジアネットワークII ― アジアネットワークの発展をめざして―. 信州大学農学部, 2010, 79-84conference pape