Chemical diversity of propolis and the problem of standardization

Chemical variability of propolis is discussed with respect to the problem of standardization. Several chemical types of propolis arc formulated, based on their plant source Reliable criteria for chemical standardization of different propolis types are needed but such generally accepted criteria do not vet exist. The chemical profile of "poplar" propolis. typical for the temperate zone, can be characterized by the following parameters: total flavone and flavonol content, total flavanone and dihydroflavonol content, and total phenolics content. These parameters correlate better with the biological activity and are more informative that the quantification of individual components. There is still a lot of work to be done to achieve standardization of other propolis type. Working with standardized material will allow scientists to connect a particular chemical propolis type to a specific type of biological activity and formulate recommendations for mainstream practitioners. (C) 2005 Published by Elsevier Ireland Ltd.