title: Effect of Moringa oleifera flower extract on larval trypsin and acetylcholinesterase activities in Aedes aegypti.
abstract: Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality.
authors.affiliation: Departamento de Bioquímica, CCB, Universidade Federal de Pernambuco, Cidade Universitária, Recife, Pernambuco, Brasil.
authors.forename: Emmanuel Viana
authors.initials: EV
authors.lastname: Pontual
authors.forename: Thiago Henrique
authors.initials: TH
authors.lastname: Napoleão
authors.forename: Caio Rodrigo
authors.initials: CR
authors.lastname: Dias de Assis
authors.forename: Ranilson
authors.initials: R
authors.lastname: de Souza Bezerra
authors.forename: Haroudo Satiro
authors.initials: HS
authors.lastname: Xavier
authors.forename: Daniela Maria do Amaral Ferraz
authors.initials: DM
authors.lastname: Navarro
authors.forename: Luana Cassandra Breitenbach Barroso
authors.initials: LC
authors.lastname: Coelho
authors.forename: Patrícia Maria Guedes
authors.initials: PM
authors.lastname: Paiva
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000201:enzymology; D000818:Animals; D002417:Cattle; D002800:Cholinesterase Inhibitors / Q000032:analysis; D004593:Electrophorus; D035264:Flowers / Q000737:chemistry; D007306:Insecticides / Q000032:analysis*; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D029588:Moringa oleifera / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D014361:Trypsin Inhibitors / Q000032:analysis*
chemical_list: D002800:Cholinesterase Inhibitors; D007306:Insecticides; D010936:Plant Extracts; D014361:Trypsin Inhibitors