title: Synergistic larvicidal effect and morphological alterations induced by ethanolic extracts of Annona muricata and Piper nigrum against the dengue fever vector Aedes aegypti.
abstract: BACKGROUND
  Phytopesticide combinations of different botanical sources are seldom reported. Annona muricata seed and Piper nigrum fruit ethanolic extracts enriched in acetogenins and piperamides, respectively, were synergistically used as larvicides against the dengue fever vector Aedes aegypti.
  
  
  RESULTS
  Individual bioassays of A. muricata and P. nigrum indicated respective LC50 values of 93.48 and 1.84 µg mL(-1) against third-instar larvae. Five combinations of different proportions of plant extracts pointed to synergism between the extracts. The best A. muricata:P. nigrum extract combination was 90:10, which showed 5.12 times the amount of synergism, as confirmed by statistical equations and total concentration log versus combination proportions. Concerning the morphology, A. muricata caused larvae body elongation, mainly in the abdomen, along with the appearance of a cervix. Conversely, P. nigrum induced abdomen and whole body shortening. The morphological effects of A. muricata were prevalent in all of the combinations tested, irrespective of its proportion in the combination.
  
  
  CONCLUSIONS
  It is suggested that the different mechanisms of action of the larvicidal actives A. muricata acetogenins and P. nigrum piperamides explain the observed synergism. The combination of inexpensive botanicals and a low-cost organosolvent such as ethanol leads to a simple and efficient phytolarvicidal formulation.
authors.affiliation: Department of Pharmacy/Coordination for Graduation on Pharmaceutical Sciences, Federal University of Parana (UFPR), Curitiba, PR, Brazil.
authors.forename: Adelia
authors.initials: A
authors.lastname: Grzybowski
authors.forename: Marcela
authors.initials: M
authors.lastname: Tiboni
authors.forename: Mário A N
authors.initials: MA
authors.lastname: Silva
authors.forename: Rodrigo F
authors.initials: RF
authors.lastname: Chitolina
authors.forename: Maurício
authors.initials: M
authors.lastname: Passos
authors.forename: José D
authors.initials: JD
authors.lastname: Fontana
mesh_terms: D000330:Aedes / Q000187:drug effects*; D000818:Animals; D031041:Annona / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D003715:Dengue / Q000635:transmission; D004357:Drug Synergism; D005260:Female; D007306:Insecticides / Q000032:analysis* / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D029222:Piper nigrum / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D051381:Rats
chemical_list: D007306:Insecticides; D010936:Plant Extracts