Distribution of Surface Flavonoids in Bulgarian Plants

Abstract

The review describes the distribution of surface flavonoids in Bulgarian plants. More than 100 species of Asteraceae, Lamiaceae, Scrophulariaceae, Geraniaceae and other families have been checked for external flavonoid aglycones. The flavonoid profiles of Asteraceae species are composed of a wide array of flavones and flavonols, mainly based upon 6-substituted derivatives. Flavone aglycones are predominant in the exudates of Lamiaceae species. Apigenin, luteolin and their derivatives were most commonly found in the studied species of Scropulariaceae and Lamiaceae. It has been shown that species of Geraniaceae, Ranunculaceae, and Solanaceae contain flavonoids of the flavonol class as surface constituents. Surface distributed flavonoids appear to have been well studied and useful for chemotaxonomy. If there is not too much infraspecific variation, flavonoid profiles can be used as taxonomic characters to distinguish species. Correlations between external flavonoid formation and local environment are apparent.