title: The antibacterial activity of fragrance ingredients against Legionella pneumophila.
abstract: In the current study we investigated the antibacterial activity of fragrance ingredients against Legionella pneumophila, a causative agent of severe pneumonia. Among the 41 different fragrance ingredients tested, we found that the natural fragrance ingredients oakmoss (OM) and birch tar oil (BT), which contain many components, exhibit potent antibacterial activity. The minimum inhibitory concentration (MIC, % (v/v)) of OM and BT were 0.0020 and 0.0024, respectively and were lower than that of cinnamic aldehyde (0.0078), which has been previously shown to possess high antimicrobial activity. In a time-kill assay of OM and BT at MIC and two times MIC, the colony forming units (CFU) of the microbe were reduced to between 10(-3) to 10(-4) of the original CFU after 1 h co-incubation. After this time, the CFU gradually decreased in number, but remained above detection levels even after a 48-h co-incubation, except for BT at two times MIC. In contrast, at a concentration of 0.1% OM and BT (approximately 50 times MIC), CFU were not detected after co-incubation for 1 h. Another 18 fragrance ingredients including ketone, aldehyde, lactone, acid, phenol derivative, aliphatic alcohol and quinoline also exhibited a lesser degree of antibacterial activity against L. pneumophila at a MIC of less than 0.10.
authors.affiliation: Department of Microbiology, School of Pharmaceutical Sciences, Josai University, Saitama, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Shimizu
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Isshiki
authors.forename: Harue
authors.initials: H
authors.lastname: Nomura
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sakuda
authors.forename: Katsuya
authors.initials: K
authors.lastname: Sakuma
authors.forename: Seiichi
authors.initials: S
authors.lastname: Kondo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D029662:Betula / Q000737:chemistry; D016952:Legionella pneumophila / Q000187:drug effects* / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D010476:Perfume / Q000737:chemistry* / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology*; D012116:Resins, Plant / Q000494:pharmacology*; D013638:Tars / Q000737:chemistry; D013729:Terpenes / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010476:Perfume; D010938:Plant Oils; D012116:Resins, Plant; D013638:Tars; D013729:Terpenes; C044724:oakmoss