Bee pollen is a granule-type material of agglutinated flower pollen made by worker honey bees with nectar and bee secretions. The resulting pollen is higher in nutritional value than untreated pollen, and is used as the primary source of protein for the bee hive. Bee pollen has been used in folk medicine from ancient times in many regions of the world for its medical properties to alleviate or cure conditions such as colds, flu, ulcers, and anemia [1]. Recently, biological effects such as antiox- [7], and antimutagenic [8] activities were also reported. Like other apicultural products, royal jelly, honey, and propolis, the chemical composition of bee pollen depends on the plant source, regional vegetation, season, and honeybee races at the site of collection. It is rich in carbohydrates, proteins, lipids, minerals, vitamins, and various organic compounds, including phenolic acids and flavonoids. Most flavonoids from bee pollen exist as glycosides and contain kaempferol or quercetin as aglycone parts. Other phenolic acids usually found in
Abstract
!The active constituents of Korean Papaver rhoeas bee pollen conferring neuraminidase inhibitory activities (H1N1, H3N2, and H5N1) were investigated. Six flavonoids and one alkaloid were isolated and characterized by nuclear magnetic resonance and mass spectrometry data. These included kaempferol-3-sophoroside (1), kaempferol-3-neohesperidoside (2), kaempferol-3-sambubioside (3), kaempferol-3-glucoside (4), quercetin-3-sophoroside (5), luteolin (6), and chelianthifoline (7). All compounds showed neuraminidase inhibitory activities with IC 50 values ranging from 10.7 to 151.1 µM. The most potent neuraminidase inhibitor was luteolin, which was the dominant content in the ethyl acetate fraction. All tested compounds displayed noncompetitive inhibition of H3N2 neuraminidase. Furthermore, compounds 1-7 all reduced the severity of virally induced cytopathic effects as determined by the Madin-Darby canine kidney cell-based assay showing antiviral activity with IC 50 values ranging from 10.7 to 33.4 µM (zanamivir: 58.3 µM). The active compounds were quantified by highperformance liquid chromatography, and the total amount of compounds 1-7 made up about 0.592 g/100 g bee pollen, contributing a rich resource of a natural antiviral product.
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