Abstract
This study presents for the first time a microwave-assisted method used to extract useful components from dried peels of Citrus yuko Hort. Polymethoxyflavones were extracted from dried peels of C. yuko for 2.5 to 5min under reflux with stirring in methanol. Tangeretin (4′,5,6,7,8-pentamethoxyflavone) and nobiletin (3′,4′,5,6,7,8-hexamethoxyflavone) were isolated in 0.12% and 0.10% (w/w) yields, respectively. Hesperidin, which has been isolated previously from peels of C. yuko, was also isolated in this study and hydrolyzed to give hesperetin. The structures of these polymethoxyflavones were confirmed on the basis of spectroscopic, elemental and HPLC analyses. The microwave-assisted extraction is a more rapid and efficient method than conventional thermal heating extraction.
