An approach to the characterization of bee pollens via their flavonoid/phenolic profiles

Bee pollen is a mix of bee-collected floral pollens which varies widely in composition. A systematic method for characterising bee pollens in terms of their constituent pollens is needed in view of the growing phytotherapeutic interest in bee pollen products. Studies involving three bee pollen samples collected from Portugal and New Zealand are reported, An approach based on flavonoid/phenolics profiles derived from high pressure liquid chromatography is demonstrated to be more precise and informative than traditional microscopy. This method provides a convenient means for identifying the contributing pollens, and for characterising bee pollens in terms of their predominant constituent pollens. The flavonoid/phenolics profiles obtained in the course of this work also highlight other observations of interest. For example: bees are shown to be highly selective pollen gatherers from the finding that bee pollens comprise pollen from only a few of the available species; pollen from only one floral source is found in each bee pollen pellet; and flavonoids are normally found as glycosides in pollens but are shown to occur naturally as aglycones in Eucalyptus globulus pollen, Two of these aglycones, tricetin and 3-O-methylquercetin, are reported as pollen constituents for the first time. (C) 1997 by John Wiley & Sons, Ltd.