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Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron

BACKGROUND: Plants are traditionally used for medicinal treatment of numerous human disorders including infectious diseases caused by microorganisms. Due to the increasing resistance of many pathogens to commonly used antimicrobial agents, there is an urgent need for novel antimicrobial compounds. P...

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Autores principales: Rezk, Ahmed, Nolzen, Jennifer, Schepker, Hartwig, Albach, Dirk C, Brix, Klaudia, Ullrich, Matthias S
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367927/
https://www.ncbi.nlm.nih.gov/pubmed/25879877
http://dx.doi.org/10.1186/s12906-015-0596-5
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author Rezk, Ahmed
Nolzen, Jennifer
Schepker, Hartwig
Albach, Dirk C
Brix, Klaudia
Ullrich, Matthias S
author_facet Rezk, Ahmed
Nolzen, Jennifer
Schepker, Hartwig
Albach, Dirk C
Brix, Klaudia
Ullrich, Matthias S
author_sort Rezk, Ahmed
collection PubMed
description BACKGROUND: Plants are traditionally used for medicinal treatment of numerous human disorders including infectious diseases caused by microorganisms. Due to the increasing resistance of many pathogens to commonly used antimicrobial agents, there is an urgent need for novel antimicrobial compounds. Plants of the genus Rhododendron belong to the woody representatives of the family Ericaceae, which are typically used in a range of ethno-medical applications. There are more than one thousand Rhododendron species worldwide. The Rhododendron-Park Bremen grows plants representing approximately 600 of the known Rhododendron species, and thus enables research involving almost two thirds of all known Rhododendron species. METHODS: Twenty-six bacterial species representing different taxonomic clades have been used to study the antimicrobial potential of Rhododendron leaf extracts. Agar diffusion assay were conducted using 80% methanol crude extracts derived from 120 Rhododendron species. Data were analyzed using principal component analysis and the plant-borne antibacterial activities grouped according the first and second principal components. RESULTS: The leaf extracts of 17 Rhododendron species exhibited significant growth-inhibiting activities against Gram-positive bacteria. In contrast, only very few of the leaf extracts affected the growth of Gram-negative bacteria. All leaf extracts with antimicrobial bioactivity were extracted from representatives of the subgenus Rhododendron, with 15 from the sub-section Rhododendron and two belonging to the section Pogonanthum. The use of bacterial multidrug efflux pump mutants revealed remarkable differences in the susceptibility towards Rhododendron leaf extract treatment. CONCLUSIONS: For the first time, our comprehensive study demonstrated that compounds with antimicrobial activities accumulate in the leaves of certain Rhododendron species, which mainly belong to a particular subgenus. The results suggested that common genetic traits are responsible for the production of bioactive secondary metabolite(s) which act primarily on Gram-positive organisms, and which may affect Gram-negative bacteria in dependence of the activity of multidrug efflux pumps in their cell envelope. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12906-015-0596-5) contains supplementary material, which is available to authorized users.
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spelling pubmed-43679272015-03-21 Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron Rezk, Ahmed Nolzen, Jennifer Schepker, Hartwig Albach, Dirk C Brix, Klaudia Ullrich, Matthias S BMC Complement Altern Med Research Article BACKGROUND: Plants are traditionally used for medicinal treatment of numerous human disorders including infectious diseases caused by microorganisms. Due to the increasing resistance of many pathogens to commonly used antimicrobial agents, there is an urgent need for novel antimicrobial compounds. Plants of the genus Rhododendron belong to the woody representatives of the family Ericaceae, which are typically used in a range of ethno-medical applications. There are more than one thousand Rhododendron species worldwide. The Rhododendron-Park Bremen grows plants representing approximately 600 of the known Rhododendron species, and thus enables research involving almost two thirds of all known Rhododendron species. METHODS: Twenty-six bacterial species representing different taxonomic clades have been used to study the antimicrobial potential of Rhododendron leaf extracts. Agar diffusion assay were conducted using 80% methanol crude extracts derived from 120 Rhododendron species. Data were analyzed using principal component analysis and the plant-borne antibacterial activities grouped according the first and second principal components. RESULTS: The leaf extracts of 17 Rhododendron species exhibited significant growth-inhibiting activities against Gram-positive bacteria. In contrast, only very few of the leaf extracts affected the growth of Gram-negative bacteria. All leaf extracts with antimicrobial bioactivity were extracted from representatives of the subgenus Rhododendron, with 15 from the sub-section Rhododendron and two belonging to the section Pogonanthum. The use of bacterial multidrug efflux pump mutants revealed remarkable differences in the susceptibility towards Rhododendron leaf extract treatment. CONCLUSIONS: For the first time, our comprehensive study demonstrated that compounds with antimicrobial activities accumulate in the leaves of certain Rhododendron species, which mainly belong to a particular subgenus. The results suggested that common genetic traits are responsible for the production of bioactive secondary metabolite(s) which act primarily on Gram-positive organisms, and which may affect Gram-negative bacteria in dependence of the activity of multidrug efflux pumps in their cell envelope. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12906-015-0596-5) contains supplementary material, which is available to authorized users. BioMed Central 2015-03-18 /pmc/articles/PMC4367927/ /pubmed/25879877 http://dx.doi.org/10.1186/s12906-015-0596-5 Text en © Rezk et al.; licensee BioMed Central. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Rezk, Ahmed
Nolzen, Jennifer
Schepker, Hartwig
Albach, Dirk C
Brix, Klaudia
Ullrich, Matthias S
Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title_full Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title_fullStr Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title_full_unstemmed Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title_short Phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus Rhododendron
title_sort phylogenetic spectrum and analysis of antibacterial activities of leaf extracts from plants of the genus rhododendron
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367927/
https://www.ncbi.nlm.nih.gov/pubmed/25879877
http://dx.doi.org/10.1186/s12906-015-0596-5
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