ABSTRACT
O principal mecanismo de controle do dengue tem sido por meio da eliminação do Aedes aegypti, seu transmissor mais competente. Este mecanismo consiste, principalmente, na destruição dos criadouros potenciais, na educação sanitária e no uso de inseticidas sintéticos. Estes inseticidas apresentam eficiência, mas são altamente tóxicos aos vertebrados e ao meio ambiente. Com o aparecimento da resistência dos mosquitos a essas substâncias, abre-se uma oportunidade aos inseticidas de origem botânica. Neste estudo, apresentam-se os mecanismos da atividade larvicida do ácido 3-Beta-acetoxylabdan-8(17)-13-dien-15-oico, extraído da planta medicinal Copaifera reticulata Ducke (Leguminosae), sobre larvas de terceiro estádio de Ae. aegypti. As larvas foram submetidas a uma solução do ácido a 9ppm, por até 24 horas. Aquelas que atingiram estado letárgico foram coletadas e fixadas em paraformaldeído a 4 por cento, em tampão cacodilato de sódio 0.1M pH 7.2, incluídas em resina, e as lâminas, coradas pela técnica de hematoxilina-eosina e analisadas por microscopia de luz. O ácido causou a morte das larvas pela destruição celular do intestino médio, por meio de vacuolização citoplasmática, hipertrofia celular e nuclear, degeneração do bordo em escova, formação vesicular apical com liberação de conteúdo citoplasmático, estratificação do epitélio e dobras na matriz peritrófica.
The main mechanism of control of dengue has been through the fight against Aedes aegypti, the most competent vector. The fight primarily consists of elimination of its potential breeding sites, health education and use of synthetic insecticides. These insecticides are effective but are highly toxic to vertebrates and the environment. With the emergence of resistance of mosquitoes to them, insecticides of botanical origin are being explored. This study looks at the larvicidal activity of a solution of a solution of 3-Beta-acetoxylabdan-8(17)-13-dien-15-óico acid extracted from the medicinal plant Copaifera reticulata Ducke (Leguminosae) on the 3rd stage larvae of Ae. aegypti. Larvae were subjected to 9 ppm acid for up to 24 h. Those that reached lethargic state were collected and fixed in 4 percent paraformaldhyde in 0.1 M sodium cacodilate buffer, pH 7.2, included in resin and the slides stained with the hematoxylin-eosin technique and examined by light microscopy. This acid caused the death of the Ae. aegypti larvae by cell destruction in the midgut, by the high cytoplasmic vacuolation, cell and nuclear hypertrophy, degeneration of the brush edge, apical vesicular formation with release of cytoplasmic contents of cells, stratification of the epithelium and folds in the peritrophic matrix.
Subject(s)
Aedes , Dengue , Larvicides , Plants, Medicinal , Yellow FeverABSTRACT
The purpose of this study was to assess the in vitro antimicrobial activity of alkaloid-enriched extracts from Prosopis juliflora (Fabaceae) pods in order to evaluate them as feed additives for ruminants. As only the basic chloroformic extract (BCE), whose main constituents were juliprosopine (juliflorine), prosoflorine and juliprosine, showed Gram-positive antibacterial activity against Micrococcus luteus (MIC = 25 µg/mL), Staphylococcus aureus (MIC = 50 µg/mL) and Streptococcus mutans (MIC = 50 µg/mL), its influence on ruminal digestion was evaluated using a semi-automated in vitro gas production technique, with monensin as the positive control. Results showed that BCE has decreased gas production as efficiently as monensin after 36 h of fermentation, revealing its positive influence on gas production during ruminal digestion. Since P. juliflora is a very affordable plant, this study points out this alkaloid enriched extract from the pods of Prosopis juliflora as a potential feed additive to decrease gas production during ruminal digestion.
Subject(s)
Animal Feed/analysis , Anti-Bacterial Agents/chemistry , Prosopis/chemistry , Rumen/drug effects , Rumen/physiology , Alkaloids/administration & dosage , Animals , Anti-Bacterial Agents/administration & dosage , Cattle , Digestion , Fermentation , Food Additives/administration & dosage , Food Additives/chemistry , In Vitro Techniques , Indolizines/administration & dosage , Methane/biosynthesis , Microbial Sensitivity Tests , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Rumen/microbiologyABSTRACT
INTRODUCTION: Dengue is an important public health problem in many countries and its main vector Aedes aegypti, is the mosquito most adapted to urban areas. For the first time, the mechanism of action of labdane diterpenoid extracted from Copaifera reticulata and the fraction enriched of catechin tannins extracted from Magonia pubescens is demonstrated through ultrastructural alterations of Aedes aegypti larvae. METHODS: Experiments were performed using a 0.9 ppm solution of diterpenoid and 3.7 ppm of the fraction as the main catechin tannin of molecular mass 846 Da. The compounds were obtained by thin layer chromatography and identified by nuclear magnetic resonance of hydrogen and mass spectrometry. Larvae that achieved lethargic state were collected and dissected. Next, they were contrasted with 1% uranyl acetate, dehydrated, embedded and polymerized. Ultrathin sections were made, mixed with 3% uranyl acetate and lead citrate and placed in an electron microscope. RESULTS: The main ultrastructural alterations caused by the diterpenoid and by tanins in larvae of Aedes aegypti were: cytoplasmic vacuolation, alteration of microvilli, cellular aging, cell disruption and degeneration, formation of secretion vesicles and structural changes in microvilli, irregular nuclei and displacement of cells in the basal lamina. CONCLUSIONS: The fraction containing tannins and the diterpenoid caused the death of Aedes aegypti larvae by cell destruction in the midgut.
Subject(s)
Aedes/drug effects , Diterpenes/pharmacology , Fabaceae/chemistry , Insecticides , Plant Extracts/pharmacology , Sapindaceae/chemistry , Tannins/pharmacology , Aedes/growth & development , Aedes/ultrastructure , Animals , Diterpenes/isolation & purification , Insecticides/isolation & purification , Intestines/diagnostic imaging , Intestines/drug effects , Larva/drug effects , Larva/ultrastructure , Magnetic Resonance Spectroscopy , Mass Spectrometry , Tannins/isolation & purification , UltrasonographyABSTRACT
INTRODUÇÃO: Dengue é um importante problema de saúde pública, em vários países, e tem como principal vetor o Aedes aegypti, mosquito mais adaptado às áreas urbanizadas. Apresenta-se, pela primeira vez, as alterações ultraestruturais em larvas de 3º estádio, desse mosquito, causadas pelos larvicidas naturais, um diterpeno labdano, extraído de Copaifera reticulata, e uma fração rica em taninos catéquicos, extraída de Magonia pubescens, evidenciando o mecanismo de ação dessas substâncias. MÉTODOS: Os experimentos foram realizados com larvas de 3º estádio em solução de 0,9ppm, do diterpeno (3-β-acetoxylabdan-8(17)-13-dien-15-óico) e de 3,7ppm, da fração majoritária de tanino catéquico de massa molecular 864Da. Obtiveram-se as substâncias através de fracionamentos cromatográficos sucessivos, identificadas por ressonância magnética nuclear de hidrogênio e espectrometria de massas. As larvas que atingiram estado letárgico foram coletadas e dissecadas e seus tubos digestórios fixados, desidratados, emblocados e polimerizados. Cortes ultrafinos foram feitos e contrastados com acetato de uranila 3 por cento e citrato de chumbo, posteriormente, levados ao microscópio eletrônico. RESULTADOS: As principais alterações ultraestruturais provocadas pelos diterpeno e tanino sobre larvas de Aedes aegypti foram vacuolização citoplasmática, desorganização e degeneração celular, mudança estrutural dos microvilos e deslocamento das células da lâmina basal. CONCLUSÕES: O diterpeno e a fração rica em taninos catéquicos provocaram a morte das larvas de Aedes aegypti através da destruição celular no intestino médio.
INTRODUCTION: Dengue is an important public health problem in many countries and its main vector Aedes aegypti, is the mosquito most adapted to urban areas. For the first time, the mechanism of action of labdane diterpenoid extracted from Copaifera reticulata and the fraction enriched of catechin tannins extracted from Magonia pubescens is demonstrated through ultrastructural alterations of Aedes aegypti larvae. METHODS: Experiments were performed using a 0.9ppm solution of diterpenoid and 3.7ppm of the fraction as the main catechin tannin of molecular mass 846Da. The compounds were obtained by thin layer chromatography and identified by nuclear magnetic resonance of hydrogen and mass spectrometry. Larvae that achieved lethargic state were collected and dissected. Next, they were contrasted with 1 percent uranyl acetate, dehydrated, embedded and polymerized. Ultrathin sections were made, mixed with 3 percent uranyl acetate and lead citrate and placed in an electron microscope. RESULTS: The main ultrastructural alterations caused by the diterpenoid and by tanins in larvae of Aedes aegypti were: cytoplasmic vacuolation, alteration of microvilli, cellular aging, cell disruption and degeneration, formation of secretion vesicles and structural changes in microvilli, irregular nuclei and displacement of cells in the basal lamina. CONCLUSIONS: The fraction containing tannins and the diterpenoid caused the death of Aedes aegypti larvae by cell destruction in the midgut.
Subject(s)
Animals , Aedes/drug effects , Diterpenes/pharmacology , Fabaceae/chemistry , Insecticides , Plant Extracts/pharmacology , Sapindaceae/chemistry , Tannins/pharmacology , Aedes/growth & development , Aedes/ultrastructure , Diterpenes/isolation & purification , Insecticides/isolation & purification , Intestines/drug effects , Intestines , Larva/drug effects , Larva/ultrastructure , Magnetic Resonance Spectroscopy , Mass Spectrometry , Tannins/isolation & purificationABSTRACT
Oil-resin fractions from Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) were evaluated for larvicidal activity on third larval instars of Aedes aegypti, in searching for alternative control methods for this mosquito. The bioactive fractions were chemically monitored by thin-layer chromatography, (1)H and 13C nuclear magnetic resonance and mass spectrometry. Bioassays were performed using five repetitions, at a temperature of 28+/-1 degrees C, relative humidity of 80+/- 5% and light and dark cycles of 12h. Mortality was indicated by darkening of the cephalic capsule after 24h of exposure of the larvae to the solutions. The most active fractions were CRM1-4 (sesquiterpenes) and CRM5-7 (labdane diterpenes), which showed LC50 values of 0.2 and 0.8 ppm, respectively.
Subject(s)
Aedes , Balsams/chemistry , Insecticides , Animals , Brazil , Chromatography, Thin Layer , Larva/drug effects , Lethal Dose 50 , Magnetic Resonance Spectroscopy , Mass SpectrometryABSTRACT
Oil-resin fractions from Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) were evaluated for larvicidal activity on third larval instars of Aedes aegypti, in searching for alternative control methods for this mosquito. The bioactive fractions were chemically monitored by thin-layer chromatography, ¹H and 13C nuclear magnetic resonance and mass spectrometry. Bioassays were performed using five repetitions, at a temperature of 28 ± 1°C, relative humidity of 80 ± 5 percent and light and dark cycles of 12h. Mortality was indicated by darkening of the cephalic capsule after 24h of exposure of the larvae to the solutions. The most active fractions were CRM1-4 (sesquiterpenes) and CRM5-7 (labdane diterpenes), which showed LC50 values of 0.2 and 0.8ppm, respectively.
A atividade larvicida das frações do óleo-resina de Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae) foi avaliada em larvas de 3° estádio de Aedes aegypti, na busca de alternativas para o controle desse mosquito. As frações bioativas foram monitoradas quimicamente através de cromatografia de camada delgada, analisada por ressonância magnética nuclear de hidrogênio (¹H e 13C) e espectrometria de massas. Os bioensaios foram realizados à temperatura de 28±1°C, 80±5 por cento de umidade relativa e fotofase de 12h, com cinco repetições. A mortalidade foi determinada através do escurecimento da cápsula cefálica, após 24h de exposição das larvas às soluções. As frações mais ativas foram CRM1-4 (sesquiterpenos) e CRM5-7 (diterpeno labdano), que mostraram os valores de CL50 de 0,2 e 0,8ppm, respectivamente.
Subject(s)
Animals , Aedes , Balsams , Insecticides , Brazil , Chromatography, Thin Layer , Larva/drug effects , Magnetic Resonance Spectroscopy , Mass SpectrometryABSTRACT
O óleo-resina de Copaifera reticulata Ducke foi utilizado para verificar sua toxicidade e as alterações morfológicas estruturais provocadas em larvas de terceiro estádio de Aedes aegypti. A partir de 15 minutos de contato da larva com a solução a 30 ppm, houve diminuição em sua mobilidade e após 20 horas, destruição total ou parcial das células, elevada vacuolização citoplasmática, aumento do espaço intercelular e da liberação de secreções celulares e alterações nos nervos periféricos, nas microvilosidades, no núcleo, nucléolo e no epitélio que sofre pavimentação e estratificação. Este estudo elucida os mecanismos de ação do óleo-resina de C. reticulata sobre larvas de A. aegypti. As CL50 e CL90 foram de 8,9 e 59,4 ppm, respectivamente. Tais concentrações evidenciam o potencial larvicida da planta, ampliando as possibilidades de seu uso no controle deste mosquito.