RESUMO
A chemical investigation and bioassays against fifth-instar nymphae of the hematophagous insect Rhodnius prolixus, vector of Chagas disease, were conducted with the essential oil from Zanthoxylum caribaeum. The main results may be summarized as follows: (i) 54 components were identified, corresponding to 90.4% of the relative composition; sesquiterpenes (47.3%) and monoterpenes (41.2%) are the major constituents; (ii) muurola-4,5-trans-diene and isodaucene are described for the first time as chemical constituents of the essential oil from leaves of this species; (iii) topical treatment with the crude essential oil induced high levels of paralysis (from 18.88 to 33.33%) and mortality (from 80 to 98.9%) depending on the dose applied (0.5 to 5.0 µl per insect); (iv) feeding treatment with the crude essential oil also induced high levels of mortality (from 48.8 to 100%) but low levels of paralysis (from 2.22 to 7.77%) depending on the dose applied (0.5 to 5.0 µl/ml of blood); (v) in the continuous treatment, only the dose of 5.0 µl/cm(2) was able to promote statistical significant levels of mortality (63.3%) but no paralysis were detected. However in this group, occasionally, only few insects displayed malformations of legs and wings after treatment; and (vi) any treatment was able to disrupt the metamorphosis process since the low adult stage emergence observed to all groups was due the high insect mortality. These observations suggest the interference of Z. caribaeum compounds on the triatomine neuroendocrine system. The significance of these results in relation to the relevant biological events in R. prolixus as well as the possible use of insect growth regulators present in Z. caribaeum oil in integrated vector control programs against hematophagous triatomine species is herein discussed.
Assuntos
Inseticidas , Óleos Voláteis/farmacologia , Rhodnius/efeitos dos fármacos , Zanthoxylum/química , Animais , Insetos Vetores/efeitos dos fármacos , Monoterpenos/química , Monoterpenos/farmacologia , Ninfa/efeitos dos fármacos , Óleos Voláteis/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Sesquiterpenos/química , Sesquiterpenos/farmacologiaRESUMO
Polonium-210 ((210)Po) concentration was quantified in the muscle tissue and organs of two predatory marine fishes (Genypterus brasiliensis and Cynoscion microlepidotus) from Cabo Frio, Rio de Janeiro, Brazil. The species C. microlepidotus, a benthic carnivore, registered higher (210)Po in its tissue. The organs associated with digestion displayed the maximum radionuclide compared with other organs. The average activity was 2 mBq kg(-1) for G. brasiliensis and it was 6 mBq kg(-1) for C. microlepidotus. The activity concentrations varied significantly between the species and among organs.
Assuntos
Exposição Ambiental , Peixes/metabolismo , Polônio/metabolismo , Poluentes Radioativos da Água/metabolismo , Animais , Brasil , Monitoramento de Radiação , Especificidade da EspécieRESUMO
Ácido oleanólico apresenta no barbeiro Rhodnius prolixus, vetor da doença de Chagas, toxicidade dosedependente e drástica inibição da muda nas doses de 1, 10 e 100 mg/ml. Eugenol induz uma letargia que persiste por vários dias, apresenta forte fagorrepelência, toxicidade média e inibição total da muda nas doses de 10 e 100 mg/ml.
RESUMO
A study of the phagoinhibitor and anti-moulting activities of the Brazilian Melia azedarach, collected in the State of Rio de Janeiro, Brazil, allowed the isolation of four lignanes identified as pinoresinol (1), bis-epi-pinoresinol (2), the hemicetal (3) and the diacid (4). These substances are devoid of anti-moulting activity.