title: Rapid, Bioassay-Guided Process for the Detection and Identification of Antibacterial Neem Oil Compounds.
abstract: Bioassay guidance was used along the whole process including method development, isolation and identification of antibacterial neem (Azadirachta indica) oil compounds. The biomonitoring was performed by direct bioautography (DB), a combination of thin-layer chromatography (TLC) and antimicrobial detection. DB of neem oil showed one antibacterial zone that was not UV-active; therefore, the TLC separation was improved under DB control. The chromatographic zone that exhibited activity against Bacillus subtilis, Xanthomonas euvesicatoria, Aliivibrio fischeri, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus was characterized by TLC reagents, indicating a lipophilic, fatty acid-like chemical feature. Two compounds were found and identified in the active zone by high-performance liquid chromatography-electrospray ionization mass spectrometry as linoleic and oleic acids. Both fatty acids inhibited B. subtilis, but A. fischeri was sensitive only against linoleic acid.
authors.affiliation: Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman O. út 15, 1022 Budapest, Hungary.
authors.forename: Dániel
authors.initials: D
authors.lastname: Krüzselyi
authors.affiliation: Institute of Biology, Eötvös Lóránd University, Pázmány P. stny. 1/c, 1117 Budapest, Hungary.
authors.forename: Róbert
authors.initials: R
authors.lastname: Nagy
authors.affiliation: Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman O. út 15, 1022 Budapest, Hungary.
authors.forename: Péter G
authors.initials: PG
authors.lastname: Ott
authors.affiliation: Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman O. út 15, 1022 Budapest, Hungary moricz.agnes@agrar.mta.hu.
authors.forename: Ágnes M
authors.initials: ÁM
authors.lastname: Móricz
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects / Q000254:growth & development; D000900:Anti-Bacterial Agents / Q000302:isolation & purification* / Q000494:pharmacology; D031601:Azadirachta / Q000737:chemistry*; D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D015373:Bacterial Typing Techniques; D001681:Biological Assay; D002855:Chromatography, Thin Layer; D005989:Glycerides / Q000737:chemistry*; D019787:Linoleic Acid / Q000302:isolation & purification* / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development; D019301:Oleic Acid / Q000302:isolation & purification* / Q000494:pharmacology; D021241:Spectrometry, Mass, Electrospray Ionization; D013729:Terpenes / Q000737:chemistry*; D014974:Xanthomonas / Q000187:drug effects / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D005989:Glycerides; D013729:Terpenes; D019301:Oleic Acid; C002443:neem oil; D019787:Linoleic Acid