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Characterisation of antibacterial Australian medicinal plant extracts by investigation of the mechanism of action and the effect of interfering substances
Author(s) -
Tomlinson Steven,
Palombo Enzo A.
Publication year - 2005
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.200410534
Subject(s) - propidium iodide , chemistry , membrane permeability , antibacterial activity , mechanism of action , bacteria , staphylococcus aureus , traditional medicine , food science , membrane , biochemistry , biology , apoptosis , medicine , programmed cell death , in vitro , genetics
Propidium iodide (PI) uptake and salt tolerance assays were used to investigate the mechanism of antibacterial action of an extract of the leaves of Eremophila duttonii, a traditional Australian medicinal plant previously shown to have potent bactericidal activity against Gram positive bacteria. The extract compromised the integrity of the cytoplasmic membrane of Staphylococcus aureus , leading to increased membrane permeability (indicated by uptake of PI) and a decrease in ability to exclude NaCl. The bactericidal action of the E. duttonii extract was concluded to be due to its membrane‐active properties. The effect of contaminants on the efficacy of this extract and other medicinal plant extracts was also investigated. Organic contaminants (bakers' yeast and skim milk powder) decreased the efficacy of all extracts investigated, while hard water had no effect. Greater understanding of the biocidal properties of the plant extracts investigated may determine if they have medical, industrial or environmental applications. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)