title: In vitro activity of essential oils of free and nanostructured Melaleuca alternifolia and of terpinen-4-ol on eggs and larvae of Haemonchus contortus.
abstract: Haemonchus contortus is one of the major gastrointestinal nematodes responsible for significant economic and production losses of sheep. Diseases caused by this species lack effective anthelmintic products, and the search for new compounds to replace synthetic anthelmintics has been extensive. The present investigation assesses the in vitro activity of the essential oil of melaleuca (Melaleuca alternifolia), both free (TTO) and nanostructured (nanoTTO), and terpinen-4-ol (terp-4-ol) on eggs and larvae of H. contortus. Tests of egg hatching (EHT) and inhibition of larval migration (LMIT) were used to assess the in vitro efficacy of TTO, nanoTTO and terp-4-ol. Using EHT, at a concentration of 3.5 mg/ml, 100% inhibition occurred using TTO and terp-4-ol, with LC50 values of 0.43 and 0.63 mg/ml, and LC90 values of 1.75 mg/ml and 3.12 mg/ml, respectively. NanoTTO had lower activity, with 82.6% inhibition at the same concentration. Using LMIT, TTO and nanoTTO had a similar activity with 88.0% and 84.8% inhibition, respectively, at a concentration of 56 mg/ml. Terp-4-ol had a greater effect on larvae, with 85.7% inhibition at a concentration of 56 mg/ml and 82.4% at 3.5 mg/ml, demonstrating high activity at the lowest concentration tested. Therefore, the results indicate that all substances tested showed ovicidal and larvicidal activity against H. contortus. TTO, terp-4-ol and, mainly, nanoTTO may be targeted in in vivo studies, besides being a promising line of research into the control and treatment of veterinary important helminths.
authors.affiliation: Department of Microbiology and Parasitology,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: T H
authors.initials: TH
authors.lastname: Grando
authors.affiliation: Department of Microbiology and Parasitology,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: M F
authors.initials: MF
authors.lastname: de Sá
authors.affiliation: Department of Microbiology and Parasitology,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: M D
authors.initials: MD
authors.lastname: Baldissera
authors.affiliation: Department of Microbiology and Parasitology,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: C B
authors.initials: CB
authors.lastname: Oliveira
authors.affiliation: Department of Microbiology,Centro Universitário Franciscano - Unifra - Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: M E
authors.initials: ME
authors.lastname: de Souza
authors.affiliation: Department of Microbiology,Centro Universitário Franciscano - Unifra - Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: R P
authors.initials: RP
authors.lastname: Raffin
authors.affiliation: Department of Microbiology,Centro Universitário Franciscano - Unifra - Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: R C V
authors.initials: RC
authors.lastname: Santos
authors.affiliation: Animal Health Laboratory, Empresa Brasileira de Pesquisa Agropecuária - Embrapa, Bagé,Rio Grande do Sul,Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Domingues
authors.affiliation: Animal Health Laboratory, Empresa Brasileira de Pesquisa Agropecuária - Embrapa, Bagé,Rio Grande do Sul,Brazil.
authors.forename: A P
authors.initials: AP
authors.lastname: Minho
authors.affiliation: Department of Large Animal,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: M L R
authors.initials: ML
authors.lastname: Leal
authors.affiliation: Department of Microbiology and Parasitology,Universidade Federal Santa Maria - UFSM, Santa Maria,Rio Grande do Sul,Brazil.
authors.forename: S G
authors.initials: SG
authors.lastname: Monteiro
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000302:isolation & purification / Q000494:pharmacology*; D001681:Biological Assay; D006189:Haemonchus / Q000187:drug effects* / Q000254:growth & development; D007814:Larva / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects; D031650:Melaleuca / Q000737:chemistry*; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology*; D016019:Survival Analysis; D013729:Terpenes / Q000302:isolation & purification / Q000494:pharmacology*; D015053:Zygote / Q000187:drug effects*
chemical_list: D000871:Anthelmintics; D009822:Oils, Volatile; D013729:Terpenes; C034019:terpinenol-4