title: Plant Phenols as Antibiotic Boosters: In Vitro Interaction of Olive Leaf Phenols with Ampicillin.
abstract: The antimicrobial properties of olive leaf extract (OLE) have been well recognized in the Mediterranean traditional medicine. Few studies have investigated the antimicrobial properties of OLE. In this preliminary study, commercial OLE and its major phenolic secondary metabolites were evaluated in vitro for their antimicrobial activities against Escherichia coli and Staphylococcus aureus, both individually and in combination with ampicillin. Besides luteolin 7-O-glucoside, OLE and its major phenolic secondary metabolites were effective against both bacteria, with more activity on S. aureus. In combination with ampicillin, OLE, caffeic acid, verbascoside and oleuropein showed additive effects. Synergistic interaction was observed between ampicillin and hydroxytyrosol. The phenolic composition of OLE and the stability of olive phenols in assay medium were also investigated. While OLE and its phenolic secondary metabolites may not be potent enough as stand-alone antimicrobials, their abilities to boost the activity of co-administered antibiotics constitute an imperative future research area.
authors.affiliation: School of Dentistry & Health Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia.
authors.forename: Anxy
authors.initials: A
authors.lastname: Lim
authors.affiliation: School of Biomedical Sciences & Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia.
authors.forename: Nusrat
authors.initials: N
authors.lastname: Subhan
authors.affiliation: School of Biomedical Sciences & Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia.
authors.forename: Jalal A
authors.initials: JA
authors.lastname: Jazayeri
authors.affiliation: School of Biomedical Sciences & Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia.
authors.forename: George
authors.initials: G
authors.lastname: John
authors.affiliation: School of Biomedical Sciences & Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia.
authors.forename: Thiru
authors.initials: T
authors.lastname: Vanniasinkam
authors.affiliation: School of Biomedical Sciences & Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, 2678, Australia.
authors.forename: Hassan K
authors.initials: HK
authors.lastname: Obied
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002109:Caffeic Acids / Q000494:pharmacology; D004357:Drug Synergism; D004926:Escherichia coli / Q000187:drug effects; D047309:Flavones / Q000494:pharmacology; D005960:Glucosides / Q000494:pharmacology; D041743:Herb-Drug Interactions; D057888:Iridoid Glucosides; D039823:Iridoids / Q000494:pharmacology; D008519:Medicine, Traditional; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000494:pharmacology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000494:pharmacology; D010936:Plant Extracts / Q000378:metabolism / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects; D059808:Polyphenols; D047311:Luteolin
chemical_list: D000667:Ampicillin; D000900:Anti-Bacterial Agents; D002109:Caffeic Acids; D047309:Flavones; D005960:Glucosides; D057888:Iridoid Glucosides; D039823:Iridoids; D010636:Phenols; D010626:Phenylethyl Alcohol; D010936:Plant Extracts; C005975:3,4-dihydroxyphenylethanol; C002769:oleuropein; C058956:acteoside; D059808:Polyphenols; C066408:luteolin-7-glucoside; D047311:Luteolin; C040048:caffeic acid
keywords: MIC; biophenols; drug interaction; polyphenols; synergism