Flavonoids occur widely in the plant kingdom with the exception of the algae and fungi. About half of mosses and liverworts accumulate such compounds and they are ubiquitous in the vascular plants. They consist in a group of about 4000 different compounds in the form glycosides and aglycones (400 flavone, 450 flavonol, 350 flavanone aglycones, 300 isoflavones, 20 anthocyanidins, and 250 chalcones) (1). It is estimated that about 2% of all carbon photosynthesized by plants, is converted into flavonoids or related compounds