title: Effects of oakmoss and its components on Acanthamoeba castellanii ATCC 30234 and the uptake of Legionella pneumophila JCM 7571 (ATCC 33152) into A. castellanii.
abstract: Acanthamoeba castellanii, a ubiquitous organism in water environments, is pathogenic toward humans and also is a host for bacteria of the genus Legionella, a causative agent of legionellosis. Oakmoss, a natural fragrance ingredient, and its components are antibacterial agents specifically against the genus Legionella. In the present study, oakmoss and its components were investigated for their amoebicidal activity against A. castellanii ATCC 30234 and the inhibitory effect on the uptake of L. pneumophila JCM 7571 (ATCC 33152) into A. castellanii. The oakmoss and its components 3-hydroxy-5-methylphenyl 2,4-dihydroxy-6-methylbenzoate(5), and 6,8-dihydroxy-3-pentyl-1H-isochromen-1-one (12) exhibited high amoebicidal activity (IC50 values; 10.5 ± 2.3, 16.3 ± 4.0 and 17.5 ± 2.8 μg/mL, respectively) after 48 h of treatment, which were equivalent to that of the reference compound, chlorhexidine gluconate. Pretreatment of L. pneumophila with sub-minimal inhibitory concentration of oakmoss, compound 5, 3-hydroxy-5-methylphenyl 2-hydroxy-4-methoxy-6-methylbenzoate (10) and 8-(2,4-dihydroxy-6-pentylphenoxy)-6-hydroxy-3-pentyl-1H-isochromen-1-one (14) obviously reduced the uptake of L. pneumophila into A.castellanii (p < 0.05).The inhibitory effect of compound 5 on the uptake of L. pneumophila was almost equivalent to that of ampicillin used as a reference. Thus, the oakmoss and its components were considered to be good candidates for disinfectants against not only genus Legionella but also A. castellanii.
authors.affiliation: Department of Microbiology, School of Pharmaceutical Sciences, Josai University.
authors.forename: Harue
authors.initials: H
authors.lastname: Nomura
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Isshiki
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: D048248:Acanthamoeba castellanii / Q000187:drug effects* / Q000382:microbiology* / Q000502:physiology; D000981:Antiprotozoal Agents / Q000737:chemistry / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D016952:Legionella pneumophila / Q000254:growth & development*; D012116:Resins, Plant / Q000737:chemistry / Q000494:pharmacology*; D013729:Terpenes / Q000737:chemistry / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000981:Antiprotozoal Agents; D012116:Resins, Plant; D013729:Terpenes; C044724:oakmoss