Geographical variation in the surface flavonoids of Pulicaria dysenterica

Four chemical races were detected in Pulicaria dysenterica, when sampled wi thin Europe, on the basis of the surface flavonoids present. One race uniqu ely contained quercetagetin 3,7-dimethyl ether and another B-hydroxykaempfe rol 3,4'-dimethyl ether. A third race was based on plants having 6-hydroxyk aempferol 3,7-dimethyl ether together with quercetagetin 3,7,3'-trimethyl e ther. The fourth race contained the above two compounds, as well as quercet agetin 3,7,3',4'-tetramethyl ether and 6-hydroxykaempferol 3,7,4'-trimethyl ether. These lipophilic constituents were variously present on the surface s of leaf, ray floret, disc floret and fruit. By contrast, the vacuolar fla vonoid of all tissues and all races was uniformly quercetin 3-glucuronide. The kaempferol 3-glucoside previously reported in flowers was not detected. Of the lipophilic flavonoids newly reported from this plant, one 6-hydroxy kaempferol 3,7,4'-trimethyl ether is new to nature. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.