Antioxidant flavonoid glycosides from the leaves of Ficus pumila L.

The Okinawan folks in Japan use Ficus pumila L. as a beverage or herbal medicine to treat diabetes and high blood pressure. Four flavonoid glycosides were isolated and identified as rutin (1 and 3), apigenin 6-neohesperidose (2), kaempferol 3-robinobioside (4) and kaempferol 3-rutinoside (5). Among these compounds, rutin exhibited the strongest antioxidant activity in DPPH radical scavenging assay and superoxide radical inhibition assay. The preparation of Ooitabi leaves in water provide sufficient amount of flavonoid glycosides to the Okinawan although 50% of aqueous ethanol extracted these flavonoid glycosides more effectively. These results show the potential of Ooitabi leaves as a natural source of antioxidant for health management.