Burchellin: study of bioactivity against Aedes aegypti.
BACKGROUND
The dengue mosquito Aedes aegypti Linnaeus, 1762 is a widespread insect pest of serious medical importance. Since no effective vaccine is available for treating dengue, the eradication or control of the main mosquito vector is regarded as essential. Since conventional insecticides have limited success, plants may be an alternative source of larvicidal agents, since they contain a rich source of bioactive chemicals. The aim of this study was to evaluate the larvicidal activity of the neolignan burchellin isolated from Ocotea cymbarum (Lauraceae), a plant from the Amazon region, against third instar larvae of A. aegypti.


METHODS
Burchellin obtained from O. cymbarum was analyzed. The inhibitory activity against A. aegypti eggs and larvae and histological changes in the digestive system of treated L3 larvae were evaluated. In addition, nitric oxide synthase activity and nitric oxide levels were determined, and cytotoxicity bioassays performed.


RESULTS
The data showed that burchellin interfered with the development cycle of the mosquito, where its strongest toxic effect was 100% mortality in larvae (L3) at concentrations ≥ 30 ppm. This compound did not show target cell toxicity in peritoneal macrophages from BALB/c mice, and proved to have molecular stability when dissolved in water. The L3 and L4 larvae treated with the compound showed cellular destruction and disorganization, cell spacing, and vacuolization of epithelial cells in small regions of the midgut.


CONCLUSIONS
The neolignan burchellin proved to be a strong candidate for a natural, safe and stable phytolarvicidal to be used in population control of A. aegypti.
Juliana Oliveira Abreu
JO
Narciso
Renata Oliveira de Araújo
RO
Soares
Jacenir
J
Reis dos Santos Mallet
Anthony Érico
AÉ
Guimarães
Maria Célia
MC
de Oliveira Chaves
José Maria
JM
Barbosa-Filho
Laboratório de Diptera, Instituto Oswaldo Cruz, FIOCRUZ, Av, Brazil 4365, Rio de Janeiro 21045-900, Brazil. mmaleck@oi.com.br.
Marise
M
Maleck
D000330:Aedes / Q000187:drug effects*; D000818:Animals; D001572:Benzofurans / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D003715:Dengue / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D007303:Insect Vectors / Q000187:drug effects; D007306:Insecticides / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva; D017737:Macrophages, Peritoneal / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D015394:Molecular Structure
D001572:Benzofurans; D007306:Insecticides; C053585:burchellin