title: Repellent activity of fractioned compounds from Chamaecyparis nootkatensis essential oil against nymphal Ixodes scapularis (Acari: Ixodidae).
abstract: Preliminary repellent activity of 14 natural products isolated from essential oil components extracted from the heartwood of Alaska yellow cedar, Chamaecyparis nootkatensis (D. Don) Spach., were evaluated against nymphal Ixodes scapularis Say in a laboratory bioassay and compared with technical grade N,N-diethyl-3-methylbenzamide (deet). Four hours after treatment, nootkatone and valencene-13-ol had repellent concentration (RC)50 values of 0.0458 and 0.0712% (wt:vol), respectively; two additional Alaska yellow cedar compounds, nootkatone 1 --> 10 epoxide and carvacrol had reported RC50 values of 0.0858 and 0.112%, respectively. The observed RC50 value for deet was 0.0728% (wt:vol). Although not statistically significantly more active than deet, the ability of these natural products to repel ticks at relatively low concentrations may represent a potential alternative to synthetic commercial repellents.
authors.affiliation: Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80524, USA. eid7@cdc.gov
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Dietrich
authors.forename: Marc C
authors.initials: MC
authors.lastname: Dolan
authors.forename: Javier
authors.initials: J
authors.lastname: Peralta-Cruz
authors.forename: Jason
authors.initials: J
authors.lastname: Schmidt
authors.forename: Joseph
authors.initials: J
authors.lastname: Piesman
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Eisen
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Karchesy
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods; D029780:Chamaecyparis / Q000737:chemistry*; D003671:DEET / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D007302:Insect Repellents / Q000494:pharmacology; D018884:Ixodes / Q000187:drug effects*; D009758:Nymph / Q000187:drug effects; D009822:Oils, Volatile / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D007302:Insect Repellents; D009822:Oils, Volatile; D003671:DEET