3-Acyl dihydroflavonols from poplar resins collected by honey bees are active against the bee pathogens Paenibacillus larvae and Ascosphaera apis

This work investigates the identity and botanical sources of propolis compounds important to bee health in North America. Six 3-acyl dihydroflavonols from Populus fremontii with differential activity against Ascosphera apis and Paenibacillus larvae were isolated from Fallon, NV, propolis. Further analysis showed these compounds have a variable distribution among other North American poplar species.232