title: Lethal and sublethal effects of essential oil of Lippia sidoides (Verbenaceae) and monoterpenes on Chagas' disease vector Rhodnius prolixus.
abstract: The aim of this study was to identify the composition of the essential oil from leaves of Lippia sidoides (EOLS), a typical shrub commonly found in the dry northeast of Brazil, popularly known as "alecrim-pimenta". Additionally, we investigated the nymphicidal, ovicidal, phagoinhibitory and excretion effects of EOLS, its major constituent thymol and its isomer carvacrol, on fourth instar nymphs and eggs of Rhodnius prolixus, the Chagas' disease vector. The nymphicidal and ovicidal activity of thymol, carvacrol, and EOLS was assessed by tests using impregnated Petri dishes. The lethal concentration values (LC50) for EOLS, carvacrol, and thymol were 54.48, 32.98, and 9.38 mg/cm2, respectively. The ovicidal test showed that both carvacrol and thymol (50 mg/cm2) inhibited hatching (50% and 23.3%, respectively), while treatments with 10 mg/cm2 or 50 mg/cm2 EOLS did not affect the hatching rate at all (80% and 90%, respectively). We observed an anti-feeding effect in insects fed with blood containing natural products at the higher concentrations (100 µg/mL). Finally, excretion rate was affected by EOLS and carvacrol, but not by thymol. These findings offer novel insights into basic physiological processes that make the tested natural compounds interesting candidates for new types of insecticides.
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, Seropédica, RJ, Brasil.|Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica e Fisiologia de Insetos, Rio de Janeiro, RJ, Brasil.
authors.forename: Marcela B
authors.initials: MB
authors.lastname: Figueiredo
authors.affiliation: Universidade Estadual Vale do Acaraú, Centro de Ciências Exatas e Tecnologia, Sobral, CE, Brasil.
authors.forename: Geovany A
authors.initials: GA
authors.lastname: Gomes
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Florestas, Departamento de Ciências Ambientais, Seropédica, RJ, Brasil.
authors.forename: Jayme M
authors.initials: JM
authors.lastname: Santangelo
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, Seropédica, RJ, Brasil.
authors.forename: Emerson G
authors.initials: EG
authors.lastname: Pontes
authors.affiliation: Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica e Fisiologia de Insetos, Rio de Janeiro, RJ, Brasil.
authors.forename: Patricia
authors.initials: P
authors.lastname: Azambuja
authors.affiliation: Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Laboratório de Bioquímica e Fisiologia de Insetos, Rio de Janeiro, RJ, Brasil.
authors.forename: Elói S
authors.initials: ES
authors.lastname: Garcia
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, Seropédica, RJ, Brasil.
authors.forename: Mário G de
authors.initials: MG
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000635:transmission; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D007928:Lethal Dose 50; D032411:Lippia / Q000737:chemistry*; D039821:Monoterpenes / Q000008:administration & dosage*; D009822:Oils, Volatile / Q000008:administration & dosage*; D012239:Rhodnius / Q000187:drug effects*; D013943:Thymol / Q000008:administration & dosage*
chemical_list: D000081007:Cymenes; D039821:Monoterpenes; D009822:Oils, Volatile; D013943:Thymol; C073316:carvacrol