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In vitro Growth Inhibition by Hypericum Extracts and Isolated Pure Compounds of Paenibacillus larvae , a Lethal Disease Affecting Honeybees Worldwide
Author(s) -
HernándezLópez Javier,
Crockett Sara,
Kunert Olaf,
Hammer Elfe,
Schuehly Wolfgang,
Bauer Rudolf,
Crailsheim Karl,
RiessbergerGallé Ulrike
Publication year - 2014
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201300399
Subject(s) - american foulbrood , hypericum perforatum , hypericum , spore , chemistry , microbiology and biotechnology , safrole , biology , in vitro , pathogen , traditional medicine , botany , biochemistry , pharmacology , chromatography , medicine
The in vitro inhibitory potential of 50 extracts from various species of the flowering plant genus Hypericum was investigated using the KirbyBauer disk diffusion susceptibility test against Paenibacillus larvae , a spore‐forming, Gram ‐positive bacterial pathogen that causes American foulbrood (AFB), a lethal disease affecting honeybee brood worldwide. Of the tested extracts, 14 were identified as highly active against P. larvae as compared to the activity of the positive control, indicating the presence of highly potent antibacterial compounds in the extracts. Examination of these extracts using TLC and HPLC/MS analyses revealed the presence of acylphloroglucinol and filicinic‐acid derivatives. Six pure compounds isolated from these extracts, viz. , hyperforin ( 1 ), uliginosin B ( 2 ), uliginosin A ( 3 ), 7‐epiclusianone ( 4 ), albaspidin AA ( 5 ), and drummondin E ( 6 ), displayed strong antibacterial activity against the vegetative form of P. larvae ( MIC ranging from 0.168–220 μ M ). Incubation of P. larvae spores with the lipophilic extract of Hypericum perforatum and its main acylphloroglucinol constituent 1 led to the observation of significantly fewer colony forming units as compared to the negative control, indicating that the acylphloroglucinol scaffold represents an interesting lead structure for the development of new AFB control agents.