Browsing by Subject "Antimicrobial activity"

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    3-Acyl dihydroflavonols from poplar resins collected by honey bees are active against the bee pathogens Paenibacillus larvae and Ascosphaera apis
    (Elsevier, 2017) Wilson, Michael B.; Pawlus, Alison D.; Brinkman, Doug; Gardner, Gary; Hegeman, Adrian D.; Spivak, Marla; Cohen, Jerry D.
    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 dihydro-flavonols 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 ¼ 17e68 mM) and Ascosphaera apis (IC50 ¼ 8e23 mM), 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.
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    Evaluating the chemical diversity and biological activity of plant extracts for commercialization
    (2014-11) Martin, Amanda C.
    Perennial plants are a manageable natural resource with the potential to provide both highly valuable biologically active chemicals and ecosystem services. Ecosystem services include various benefits that are provided by an ecosystem such as food, fuel, recreation, as well as water, air, and land quality for society. Biologically active chemicals from plants have a long history of use by humans in botanical medicines and pharmaceuticals, food and dietary supplements, agricultural inputs, and home and personal care products. There are different strategies that can be used to incorporate plants into an economic and ecosystem service role. Method development and application studies were used to facilitate use of plant derived bioactive compounds for commercial use. Methodological studies, using the technique of metabolic fingerprinting, resulted in the determination of extraction conditions that maximize chemical diversity and yield. Maximum chemical diversity in a plant extract was most efficiently approached if solvent partitioning was performed on an extract made with 70 percent ethanol. Additionally, strategies to integrate extract chemical analysis with information regarding extract quality, such as cytotoxicity measurements, were developed and used to evaluate commercial kava samples obtained from multiple sources. These approaches were then applied to two different perennial plant species (Comptonia peregrina, and (Glycyrrhiza lepidota,) with the aim of developing their commercial value based on their extractable chemical composition. These studies resulted in the isolation of two small molecules from (C. peregrina, with strong antimicrobial activity and the identification of two (G. lepidota, populations with the potential to be developed into a cultivar with optimal characteristics for the cultivation of biologically active compounds.