Chemotaxonomy of the genus Citrus based on polymethoxyflavones.

Abstract

The contents of seven polymethoxylflavones [5, 6, 7, 8, 4'-pentamethoxy- (1), 5, 6, 7, 8, 3', 4'-hexamethoxy- (2), 5, 7, 4'-trimethoxy- (3), 5, 6, 7, 3', 4'-pentamethoxy- (4), 5, 7, 3', 4'-tetramethoxy- (5), 5, 7, 8, 4'-tetramethoxy- (6) and 5, 7, 8, 3', 4'-pentamethoxyflavones (7)] in the fruit peels of Citrus species (Rutaceae) were determined by use of high performance liquid chromatography. On the basis of their composition, relative ratio and the total contents, seven distinct flavone-patterns (types I-VII) were designated. These flavonone-patterns facilitate the chemotaxonomy of the genus Citrus. The results obtained in the present study support the morphological classification systems presented by Swingle or Tanaka except several taxa.