title: Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae).
abstract: Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (-)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (-)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (-)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H₂DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound.
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. orlando_neto.88@hotmail.com.
authors.forename: Orlando
authors.initials: O
authors.lastname: Salvador-Neto
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. simoneazgomes@yahoo.com.br.|Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil. simoneazgomes@yahoo.com.br.
authors.forename: Simone Azevedo
authors.initials: SA
authors.lastname: Gomes
authors.affiliation: Grupo de Produtos Naturais de Organismos Aquáticos (GPNOA), Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. angelica.r.soares@gmail.com.
authors.forename: Angélica Ribeiro
authors.initials: AR
authors.lastname: Soares
authors.affiliation: Grupo de Produtos Naturais de Organismos Aquáticos (GPNOA), Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. fernandanupem@yahoo.com.br.
authors.forename: Fernanda Lacerda da Silva
authors.initials: FL
authors.lastname: Machado
authors.affiliation: Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil. richardiansamuels@gmail.com.
authors.forename: Richard Ian
authors.initials: RI
authors.lastname: Samuels
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. rodrigo.nunes.da.fonseca@gmail.com.|Laboratório Integrado de Ciências Morfofuncionais (LICMF), Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. rodrigo.nunes.da.fonseca@gmail.com.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. rodrigo.nunes.da.fonseca@gmail.com.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Nunes da Fonseca
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. jacksonmenezes@gmail.com.|Laboratório Integrado de Ciências Morfofuncionais (LICMF), Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. jacksonmenezes@gmail.com.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. jacksonmenezes@gmail.com.
authors.forename: Jackson
authors.initials: J
authors.lastname: Souza-Menezes
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. jorgemoraes@bioqmed.ufrj.br.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. jorgemoraes@bioqmed.ufrj.br.
authors.forename: Jorge Luiz da Cunha
authors.initials: JL
authors.lastname: Moraes
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. eldocampos@yahoo.com.br.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. eldocampos@yahoo.com.br.
authors.forename: Eldo
authors.initials: E
authors.lastname: Campos
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. flaviamury@gmail.com.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. flaviamury@gmail.com.
authors.forename: Flávia Borges
authors.initials: FB
authors.lastname: Mury
authors.affiliation: Laboratório Integrado de Bioquímica Hatisaburo Masuda (LIBHM); Núcleo em Pesquisas Ecológicas e Desenvolvimento Sócio-Ambiental de Macaé (NUPEM), Universidade Federal do Rio de Janeiro, Macaé, Rio de Janeiro 27965-045, Brazil. joseroberto@macae.ufrj.br.|Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, (INCT-EM), Rio de Janeiro 21941-590, Brazil. joseroberto@macae.ufrj.br.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Silva
mesh_terms: D000330:Aedes; D000818:Animals; D001938:Brazil; D003715:Dengue / Q000635:transmission; D007300:Insect Control / Q000379:methods; D007303:Insect Vectors; D007306:Insecticides / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D044722:Laurencia / Q000737:chemistry*; D007928:Lethal Dose 50; D017382:Reactive Oxygen Species / Q000378:metabolism; D012717:Sesquiterpenes / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D017382:Reactive Oxygen Species; D012717:Sesquiterpenes; C000611956:obtusol
keywords: (+)-obtusol; (−)-elatol; Aedes aegypti; Laurencia dendroidea; larvicide; oxidative stress; sesquiterpenes
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