Characterization of Neuraminidase Inhibitors in Korean Papaver rhoeas Bee Pollen Contributing to Anti-Influenza Activities In Vitro

Planta Med. 2016 Apr;82(6):524-9. doi: 10.1055/s-0041-111631. Epub 2016 Feb 5.


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 IC50 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 IC50 values ranging from 10.7 to 33.4 µM (zanamivir: 58.3 µM). The active compounds were quantified by high-performance 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / chemistry*
  • Antiviral Agents / pharmacology*
  • Bees
  • Dogs
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical / methods
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Flavonoids / chemistry
  • Flavonoids / isolation & purification
  • Flavonoids / pharmacology
  • Influenza A Virus, H1N1 Subtype / drug effects
  • Influenza A Virus, H3N2 Subtype / drug effects
  • Influenza A Virus, H5N1 Subtype / drug effects
  • Madin Darby Canine Kidney Cells / drug effects
  • Madin Darby Canine Kidney Cells / virology
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Neuraminidase / antagonists & inhibitors*
  • Papaver / chemistry*
  • Pollen / chemistry*


  • Antiviral Agents
  • Enzyme Inhibitors
  • Flavonoids
  • Neuraminidase