Insigths in the phenolic composition of portuguese própolis

The chemical composition of propolis is highly variable, depending strongly on thc plant sources available to the bees at different locations, the geographic and climatic characteristics of these locations, I n the temperate zone, propol is originates mostly Ii'om bud exudates of poplar trees (Populus spp .. section Aigciros), For this reason, European propolis contains the typical 'poplar bud' phenolics: flavonoid aglicones (flavones and flavanones), phenolic acids and their esters.