Abstract
Honey bees, Apis mellifera, collect antimicrobial plant resins from the environment and deposit them in their nests as propolis. This behavior is of practical concern to beekeepers since the presence of propolis in the hive has a variety of benefits, including the suppression of disease symptoms. To connect the benefits that bees derive from propolis with particular resinous plants, we determined the identity and botanical origin of propolis compounds active against bee pathogens using bioassay-guided fractionation against the bacterium Paenibacillus larvae, the causative agent of American foulbrood. Eleven dihydroflavonols were isolated from propolis collected in Fallon, NV, including pinobanksin-3-octanoate. This hitherto unknown derivative and five other 3-acyl-dihydroflavonols showed inhibitory activity against both P. larvae (IC50 = 17–68 μM) and Ascosphaera apis (IC50 = 8–23 μM), the fungal agent of chalkbrood. A structure-activity relationship between acyl group size and antimicrobial activity was found, with longer acyl groups increasing activity against P. larvae and shorter acyl groups increasing activity against A. apis. Finally, it was determined that the isolated 3-acyl-dihydroflavonols originated from Populus fremontii, and further analysis showed these compounds can also be found in other North American Populus spp.
Original language | English (US) |
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Pages (from-to) | 83-92 |
Number of pages | 10 |
Journal | Phytochemistry |
Volume | 138 |
DOIs | |
State | Published - Jun 1 2017 |
Bibliographical note
Publisher Copyright:© 2017 Elsevier Ltd
Keywords
- Antimicrobial activity
- Ascospharea apis
- Dihydroflavonol
- Honey bees (Apis mellifera)
- Paenibacillus larvae
- Plant resins
- Populus
- Propolis
- Salicaceae