Background
The use of synthetic insecticides is one of the most common strategies for controlling disease vectors such as mosquitos. However, their overuse can result in serious risks to human health, to the environment, as well as to the selection of insecticidal resistant insect strains. The development of efficient and eco-friendly insect control is urgent, and essential oils have been presented as potential alternatives to synthetic insecticides. Moreover, nanoencapsulation techniques can enhance their efficiency by protecting from degradation and providing a controlled release rate.
Results
We assessed the potential of chitosan nanoparticles in encapsulating
Siparuna guianensis
essential oil, and maintaining its efficiency and prolonging its activity for the control of
Aedes aegypti
larvae. The encapsulation was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), with an encapsulation efficiency ranging from 84.8% to 88.0%. Toxicity studies have demonstrated efficacy against mosquito larvae over 50% for 19 days with 100% mortality during the first week. This persistent action is presumably due to the enhanced contact and slow and maintained release conferred by chitosan nanoparticles. Furthermore, the exposure of aquatic non-target organisms (e.g. embryos and small adult fishes) revealed adequate selectivity of these nanoparticles.
Conclusions
The encapsulation of
S
.
guianensis
essential oil in chitosan nanoparticles showed promising potential as a larvicide control alternative and should be considered within strategies for fighting
Ae
.
aegypti
.
A cerveja é uma bebida alcoólica não destilada, obtida da fermentação alcoólica do mosto de cereal maltado, geralmente malte de cevada. O presente trabalho apresenta as etapas da produção de cerveja, mostrando as matérias-primas que são utilizadas durante o processamento, as quais passam pela fabricação do mosto, fermentação, maturação, filtração e engarrafamento. Este material possibilita uma introdução ao conhecimento de indústria de produção de cerveja, fazendo um apanhado geral das etapas do processo produtivo.Palavras-chave: cerveja, fermentação, processamento.
The plant Siparuna guianensis is used in traditional medicine and has been the target of studies on the development of new drugs for the control of pests and vector insects. The present study was aimed to evaluate the seasonal influence on the content and composition of the essential oil of S. guianensis. The experiment was conducted for 12 months evaluating the yield of the essential oil of leaves throughout the seasons (autumn, winter, spring and summer). The chemical composition of the essential oil was obtained by gas chromatography-mass spectrometry (GC-MS). The highest oil yield was in autumn and winter, comprising 0.33 and 0.29% (w/w), respectively. The major compound identified was β-myrcene (48.59-24.2%), followed by epicurzerenone (27.24-13.7%) being the most abundant; germacrene D showed lower values of 9.93% in autumn and 13.5-14.34% in the other seasons, besides curzerene that had no production in autumn. The ɣ-elemene component had a higher production of 7.29% in autumn. Compound 2-undecanone did not show significant seasonal changes, with percentages being between 7.26 and 5.43%. The monoterpenes and sesquiterpenes showed similar levels in autumn; however, in the other seasons (winter, spring, and summer), the sesquiterpenes presented higher concentration, reaching 68.54% in summer. The components identified in the essential oil of S. guianensis exhibit interesting biological activities, making this essential oil a promising compound for the development of new biodegradable drugs, repellents, and insecticides. The knowledge about the yield and seasonal composition is fundamental to optimize and maximize the obtainment of compounds of interest for the production of new drugs.
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