Biological activities and phytochemical screening of leaf extracts from Zanthoxylum caribaeum L. (Rutaceae) / Atividades biológicas e prospecção fitoquímica de extratos vegetais das folhas de Zanthoxylum caribaeum L. (Rutaceae)

The Brazilian flora is known for its vast biodiversity; however, many species have been still little studied regarding to their chemical composition and biological potential. Thus, this study aimed to determine the antimicrobial, antioxidant and acaricidal activity of the extracts of leaves of Zanthoxylum caribaeum L. In addition, phytochemical screening of these extracts was carried out to determine the main classes of secondary metabolites present in Z. caribaeum. Using the Z. caribaeum leaves, aqueous and organic extracts were obtained using the following solvents (ethanol, methanol, hexane, acetone, dichloromethane and ethyl acetate). The antimicrobial activity of extracts was determined by broth microdilution method, and to detect antioxidant activity the method of capturing the free radical 2,2-diphenyl-1-picryl hydrazyl (DPPH) was used. The acaricidal activity of the extracts was tested on Dermanyssus gallinae (De Geer) (Acari: Dermanissidae). Ethanolic and methanolic extracts presented antimicrobial activity for most of the bacterial strains tested, as well as for yeast Candida albicans. The ethanolic extract presented high free radical sequestration potential (71.2%) and antioxidant capacity (the lowest IC50 value - 24.39 µg mL-1). The crude extracts obtained with methanol and acetone were the most promising. In general, phytochemical screening indicated the presence of steroids, flavanones, flavones, flavonols, saponins, tannins, triterpenoids and xanthones.

A flora brasileira é conhecida pela sua vasta biodiversidade, no entanto, muitas espécies ainda são pouco estudadas quanto à composição química e ao potencial biológico. Assim, esse trabalho teve como objetivo determinar a atividade antimicrobiana, antioxidante e acaricida dos extratos vegetais das folhas de Zanthoxylum caribaeum L. Adicionalmente, foi realizada triagem fotoquímica desses extratos para determinar as principais classes de metabólitos secundários presentes em Z. caribaeum. Empregando-se as folhas de Z. caribaeum foram obtidos o extrato aquoso e orgânicos, utilizando os seguintes solventes (etanol, metanol, hexano, acetona, diclorometano e acetato de etila). A atividade antimicrobiana dos extratos foi determinada pelo método de microdiluição em caldo, e para detecção da atividade antioxidante foi empregado o método de captura do radical livre 2,2-difenil-1-picril hidrazil (DPPH). A atividade acaricida dos extratos foi avaliada frente a Dermanyssus gallinae (De Geer) (Acari: Dermanissidae). Os extratos brutos etanólico e metanólico apresentaram atividade antimicrobiana para a maioria das cepas bacterianas testadas, e também para a levedura Candida albicans. O extrato etanólico apresentou elevado potencial de sequestro de radicais livres (71,2%) e o menor valor de IC50 (24,39µg mL-1), revelando, portanto, sua capacidade antioxidante. No que se refere à atividade acaricida, os extratos obtidos com metanol e acetona foram os mais promissores. De modo geral, a triagem fitoquímica indicou a presença de esteroides, flavanonas, flavonas, flavonóis, saponinas, taninos, triterpenóides e xantonas.

The sensitivity of Demodex canis (Acari: Demodicidae) to the essential oil of Melaleuca alternifolia - an in vitro study / A sensibilidade do Demodex canis (Acari: Demodicidae) ao óleo essencial de Melaleuca alternifolia - um estudo in vitro

Abstract The essential oil of the Melaleuca alternifolia (Maiden & Betche) (tea tree oil) has been effective in previous studies, in the treatment of infestation by Demodex mites in humans. The present study aimed at evaluating the in vitro acaricidal effect of this herbal medicine on Demodex canis. For the parasitological examination, samples were collected from a dog's skin and examined using optical microscopy. Only samples with intact mites and with evident movement of chelicerae and tarsi were selected. Twenty-one samples were tested with the oil, in seven different concentrations: 100%; 50%; 25%; 12.5%; 6.25%; 5.0% and 3.13%. Three samples were tested with the positive control amitraz, and three with the negative control neutral shampoo. The interval between the time the solution was added and the moment the movement of the last mite ceased defined the survival time in the sample. By comparing the times at different concentrations and controls, the results showed that the higher the concentration of the oil, the more quickly its lethal effect occurred, and that the survival times in the controls were longer than in the different concentrations of melaleuca oil.

Resumo O óleo essencial de Melaleuca alternifolia (Maiden & Betche) (óleo da árvore do chá) foi eficaz em estudos anteriores, no tratamento da infestação por ácaros Demodex em humanos. O presente estudo teve por objetivo avaliar o tempo do efeito acaricida, in vitro, desse fitoterápico sobre Demodex canis. Para o exame parasitológico, amostras foram coletadas da pele de um cão e examinadas por microscopia óptica. Apenas amostras com ácaros íntegros e com evidente movimentação de quelíceras e tarsos foram selecionadas. Vinte e uma amostras foram direcionadas para teste com o óleo, em sete concentrações diferentes: 100%; 50%; 25%; 12,5%; 6,25%; 5,0% e 3,13%. Três amostras foram testadas com o controle positivo, amitraz, e três com o controle negativo, xampu neutro. O intervalo entre o momento em que a solução foi adicionada e o instante em que cessou o movimento do último ácaro definiu o tempo de sobrevivência na amostra. Os tempos nas diferentes concentrações e nos controles foram comparados. Quanto mais alta a concentração do óleo, mais rapidamente ocorreu seu efeito letal. Os tempos de sobrevivência nos controles foram maiores que nas diferentes concentrações do óleo de melaleuca.

Acaricidal potential of volatile oils from Croton species on Rhipicephalus microplus

ABSTRACT The objective of this study was to evaluate the acaricidal activity of the volatile oils of three species of Croton, Euphorbiaceae, against the cattle tick Rhipicephalus microplus. The volatile oils were obtained by hydrodistillation, analyzed by GC-MS and GC-FID and their acaricidal activity was evaluated by the larval packet test and adult immersion test. The volatile oils from Croton conduplicatus Kunth, Croton pulegiodorus Baill., and two different collections of Croton grewioides Baill. (CG1 and CG2) showed eucalyptol (24.09%), p-cymene (23.13%) and methyl chavicol (83.59% and 95.38%) as the major compounds, respectively. All the volatile oils tested in this study showed efficacy against larvae and engorged females of Rhipicephalus microplus. Therefore, Croton pulegiodorus volatile oil is promising for a potential acaricidal formulation because of the best activity against both stages of the cattle tick.

Comparative Acaricidal Bioefficacy Of Spilanthes Acmella And Calotropis Procera Of Eastern Himalayan Region Against Cattle Tick

In this study, relative toxicity of Spilanthes acmella and Calotropis procera wasevaluated against adults and larvae of Rhipicephalus (Boophilus) microplus. The aerial part ofboth plants materials were collected from Eastern Himalayan Region (West Bengal) of India.Plant materials were washed, shade dried, coarsely ground, methanol extracted and dried byrotary evaporator and collected proper yield of extracts. The crude methanolic extracts werefurther fractionated using solvents (hexane, ethyl acetate, chloroform) of different polarity andfinally aqueous fraction was collected and dried. Methanolic crude extracts and their fractions(hexane, ethyl acetate, chloroform and aqueous) concentrations of both the plants weretested against the engorged adult females and cultured larvae of Rhipicephalus (Boophilus)microplus. The bioefficacy observations are shown in table 3 and mentioned LC50, LC90 andtheir related statistics. Adult and larval stages were significantly affected by the chloroformextract of both the plants selected and observed the most potent with LC50 50.22 and 13.86mg/ml of Calotropis procera and LC50 60.94 and 25.82 mg/ml of Spilanthes acmella.

Acaricidal activity of ethanolic extracts of Stryphnodendron adstringens and Lafoensia pacari and oil resins from Copaifera sp. and Pterodon emarginatus against Sarcoptes scabiei var. suis / Atividade acaricida dos extratos etanólicos de Stryphnodendron adstringens Mart. e Lafoensia pacari A. St Hil., bem como das óleo-resinas de Copaifera sp. e Pterodon emarginatus Vogel, 1837 contra Sarcoptes scabiei var. suis

In vitro bioassay using Sarcoptes scabiei as a test microorganism is a viable method of study for diverse drugs with acaricidal properties. A great amount of assays proves the diverse and efficient biological activity of extracts and compounds from Brazilian savanna plants. This study had as main object, test and compare the acaricidal activity of four Brazilian Cerrado bioproducts: Stryphnodendron adstringens Mart., Copaifera sp., Lafoensia pacari A. St Hil. and Pterodon emarginatus Vogel, 1837. To perform this test S. scabiei mites were collected from crusts removed on ears of highly infected sows. The mites were selected and separated in Petri dishes with three different concentrations (25, 50 and 75%) of each bioproduct, to evaluate their potential acaricidal activity. The mortality of the mites was counted in each Petri dish every hour, during five hours. The statistical analyses demonstrated differences between the bioproducts tested. The oleoresin of Copaifera sp. and P. emarginatus presented the best results with 100% of mites mortality after treatment. The ethanolic extracts of S. adstringens and L. pacari demonstrated lower acaricidal activity when compared to the oleoresins, with little or no difference among the control groups tested. This bioassay demonstrated to be efficient, reliable, low cost and easy accomplishment. Oil resins from Copaifera sp. and P. emarginatus have in vitro acaricidal activity against adult females of S. scabiei var. suis.(AU)

O uso de Sarcoptes scabiei como microrganismo teste para bioensaio in vitro é um método de estudo viável para diversas drogas acaricidas. Muitos ensaios comprovam a diversidade e eficiência de atividade biocida de extratos e componentes presentes em plantas do cerrado brasileiro. Este trabalho objetivou testar e comparar a atividade acaricida de quatro bioprodutos do cerrado brasileiro: Stryphnodendron adstringens Mart., Lafoensia pacari A. St Hil., Copaifera sp. e Pterodon emarginatus Vogel, 1837. Para este estudo, ácaros S. scabiei foram colhidos em crostas removidas de orelhas de fêmeas suínas altamente infestadas. Os ácaros foram selecionados, separados e colocados em placas de Petri com três diferentes concentrações (25, 50 e 75%) de bioprodutos, para avaliar o potencial de atividade acaricida de cada um. Foi realizada a contagem da mortalidade dos ácaros em cada placa de Petri a cada hora, durante cinco horas. As análises estatísticas demonstraram diferenças entre os bioprodutos testados. As óleo-resinas de Copaifera sp. e P. emarginatus apresentaram os melhores resultados, com 100% de mortalidade dos ácaros após tratamento. Os extratos etanólicos de S. adstringens Mart. e L. pacari demonstraram menor atividade acaricida quando comparados as óleo-resinas, com pequena ou nenhuma diferença entre os resultados dos grupos controle. Este ensaio demonstrou ser uma ferramenta eficiente, confiável, de baixo custo e de fácil realização. As óleo-resinas Copaifera sp. e P. emarginatus possuem atividade acaricida in vitro sobre fêmeas adultas de S. scabiei var. suis.(AU)

Comparative toxicity of essential oil and blends of selected terpenes of Ocotea species from Pernambuco, Brazil, against Tetranychus urticae Koch

ABSTRACT Essential oils from the leaves of two species of the genus Ocotea that occur in the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry. The acaricidal activity of these oils as well as 11 selected components and blends were evaluated in fumigation and residual contact tests against the two-spotted spider mite (Tetranychus urticae). Sixty-seven constituents were identified, totaling 97.3 ± 0.3% and 97.8 ± 0.5% of the oils from O. duckei and O. glomerata, respectively. Sesquiterpene was the dominant class. The compounds β-caryophyllene (18.6 ± 0.1%) and aromadendrene (17.3 ± 0.6%) were the main constituents of the oils from O. duckei and O. glomerata, respectively. Acaricidal action varied depending on the method employed, species and chemical nature of the selected constituents. The mites were susceptible to the oils and chemical constituents using the fumigation method. The O. duckei oil was respectively 2.5-fold and 1.5-fold more toxic than the O. glomerata oil using the fumigation and residual contact methods. Among the selected constituents, β-caryophyllene was the most toxic, independently of the method employed. The individual toxicity of the selected compounds and their blends as well as the role of these constituents in the overall toxicity of the essential oils are also discussed.

Acaricidal activity of Derris floribunda essential oil and its main constituent

Objective To evaluate the acaricidal activity of the essential oil obtained from roots of Derris floribunda (D. floribunda) (Miq.) Benth, and its main constituent nerolidol against the Mexican mite Tetranychus mexicanus (T. mexicanus) (McGregor). Methods The essential oil from the roots of D. floribunda collected in the Amazon region (Brazil) was obtained by hydrodistillation. Its chemical composition was determined by GC–MS analysis. The acaricidal activities of this essential oil and nerolidol, were evaluated by recording the number of dead females (mortality) and eggs (fertility). Results The essential oil showed sesquiterpenes as major volatile components. Nerolidol, the main component, represented 68.5% of the total composition of the essential oil. D. floribunda essential oil and nerolidol showed acaricidal activity, with LC

Acaricidal activity of Derris floribunda essential oil and its main constituent

Objective:To evaluate the acaricidal activity of the essential oil obtained from roots of Derrisfloribunda (D.floribunda) (Miq.) Benth,and its main constituent nerolidol against the Mexican mite Tetranychus mexicanus (T.mexicanus) (McGregor).Methods:The essential oil from the roots of D.floribunda collected in the Amazon region (Brazil) was obtained by hydrodistillation.Its chemical composition was determined by GC-MS analysis.The acaricidal activities of this essential oil and nerolidol,were evaluated by recording the number of dead females (mortality) and eggs (fertility).Results:The essential oil showed sesquiterpenes as major volatile components.Nerolidol,the main component,represented 68.5％ of the total composition of the essential oil.D.floribunda essential oil and nerolidol showed acaricidal activity,with LC50 of 9.61 μg/mL air and 9.2 μg/mL air,respectively,over a 72 h period.In addition,both the essential oil and nerolidol significantly reduced the fecundity of T.mexicanus.Contusions:Due to the economic importance of T.mexicanus and the lack of new pesticides,our data are very promising in the search for efficient and safer acaricidal products.Furthermore,this is the first report about the chemical composition and bioactivity of the essential oil of the Amazon plant species D.floribunda.

Assessment of different Lippia sidoides genotypes regarding their acaricidal activity against Rhipicephalus (Boophilus) microplus / Avaliação da atividade carrapaticida do óleo essencial de diferentes genótipos de Lippia sidoides sobre Rhipicephalus (Boophilus) microplus

Abstract The aim of this study was to select different genotypes of Lippia sidoides with the highest activity against larvae and engorged females of the tick Rhipicephalus (Boophilus) microplus. The germplasms studied were LSID006, LSID102, LSID103 and LSID104. The LSID104 genotype, that presented carvacrol as a major constituent, was the germplasm with the worst larvicide effect (LC50 2.99 mg/mL). The LSID006 genotype was the least effective against engorged females (LC50 12.46 mg/mL), and it was chemically similar to the LSID102 genotype, which presented the highest acaricide activity (LC50 2.81 mg/mL). We conclude that chemical similarity of the germplasms was not correlated with acaricide activity against R. (B.) microplus. The essential oil of L. sidoides is a potent natural agent. However, the findings of this work provide a better understanding for product development based on this natural product, which must consider synergic effects or the action of minor compounds.

Resumo O objetivo deste trabalho foi selecionar genótipos de Lippia sidoides que apresentem maiores atividades em larvas e fêmeas ingurgitadas do carrapato Rhipicephalus (Boophilus) microplus. Os genótipos estudados foram LSID006, LSID102, LSID103 e LSID104. O genótipo LSID104, o único a conter o monoterpeno carvacrol como um dos principais constituintes, foi o que apresentou o menor efeito larvicida (CL50 2,99 mg/mL). O genótipo LSID006 apresentou menor efeito sobre fêmeas ingurgitadas (CL50 12,46 mg/mL), entretanto foi quimicamente similar ao genótipo LSID102, que apresentou a maior atividade carrapaticida (CL50 2,81 mg/mL). Conclui-se que a semelhança química dos genótipos não se correlaciona com a atividade carrapaticida contra R. (B.) microplus. O óleo essencial de L. sidoides é um agente natural potente e os resultados deste trabalho proporcionam um melhor entendimento para o desenvolvimento de produtos com base neste produto natural, devendo ser considerado os efeitos sinérgicos ou a ação de compostos presentes em menores concentrações.

Actividad acaricida del aceite esencial de la corteza de Croton malambo H. Karst, metil-eugenol y metil-isoeugenol contra Dermatophagoides farinae Hughes, 1961 / Acaricide activity of essential oil of Croton malambo H. Karst, methyl-eugenol and methyl-isoeugenol against Dermatophagoides farinae Hughes, 1961

Dermotophagoides farinae lives in the indoor environment of houses, where it is source of allergens; therefore its control is a priority in preventing respiratory allergies. The aim of this study was to evaluate the acaricidal activity of essential oil of Croton malambo H. Karst bark and their components methyl-eugenol and methyl-isoeugenol against Dermatophagoides farinae. The essential oil was obtained through hydro-distillation assisted by microwave radiation and analyzed by GC-MS. Acaricidal activity was assessed by dose- response bioassay, at different times, using benzyl benzoate as a positive control. The relative amount of methyl-eugenol and methyl- isoeugenol in the essential oil was 68.4 percent and 4.9 percent, respectively. The acaricidal activity was: essential oil > methyl-eugenol > benzyl benzoate > methyl-isoeugenol. The acaricidal properties of essential oil of Croton malambo bark and methyl-eugenol against Dermatophagoides farinae were established...

Dermatophagoides farinae habita en el interior de las casas, donde es fuente importante de alérgenos, por tanto su control es una prioridad en la prevención de alergias respiratoria. El objetivo de este estudio fue evaluar la actividad acaricida del aceite esencial de la corteza de Croton malambo H. Karst y sus componentes metil-eugenol y metil-isoeugenol contra Dermatophagoides farinae. El aceite esencial se obtuvo por hidrodestilación asistida por radiación de microondas y se analizó por CG-EM. La actividad acaricida se evaluó mediante bioensayo de dosis-respuesta a diferentes tiempos, usando benzoato de bencilo como control. La cantidad relativa de metil-eugenol y metil-isoeugenol en el aceite fue 68.4 por ciento y 4.9 por ciento, respectivamente. La actividad acaricida fue: aceite esencial > metil-eugenol > benzoato de bencilo > metil-isoeugenol. Se establecieron las propiedades acaricidas del aceite esencial de la corteza de Croton malambo y metil-eugenol contra Dermatophagoides farinae...

Avaliação in vitro do extrato alcoólico da própolis para o controle do Rhipicephalus (Boophilus) microplus / An in vitro assessment of the alcoholic extract in propolis for the control of Rhipicephalus (Boophilus) microplus / Evaluación in vitro de extracto alcoholico de propóleos para el control del Rhipicephalus (Boophilus) microplus

Própolis é uma substância resinosa obtida pelas abelhas de diversas partes da planta e vem sendo utilizada desde a antiguidade devido seu amplo espectro de atividade biológica. A infestação em animais de grande porte por Rhipicephalus (Boophilus) microplus é uma problemática nos dias atuais, em que se utiliza para sua eliminação medicamentos que causam a contaminação do animal, e dos seus subprodutos. O presente trabalho teve por objetivo avaliar in vitro a atividade do extratoalcoólico da própolis no combate ao carrapato da espécie Rhipicephalus (Boophilus) microplus em vacas leiteiras da raça holandesa pertencentes a uma propriedade rural no município de Icaraíma- Paraná. O experimento foi inteiramente casualisado, os testes consistiram na comparação da postura e eclosão dos ovos de animais tratados com extrato alcoólico de própolis nas concentrações de 50%, 25%, 12,5% e 6,25%, no qual a concentração de 50% foi a mais eficiente, obtendo uma margem de 99,10% de eficácia; enquanto as concentrações de 25%, 12,5% e 6,25%, obtiveram uma eficácia de 73,53%, 77,07% e 50,93% respectivamente. Os resultados mostraram uma maior sensibilidade dos carrapatos à concentrações mais elevadas. A própolis pode ser uma opção de tratamento, podendo ser utilizado como uma fonte para atividade carrapaticida devido às suas inúmeras substâncias funcionais.

Propolis is a resinous substance obtained by bees from several parts of the plants and it has been used since ancient times due to its broad biological activity spectrum. Large-sized animals infested with Rhipicephalus (Boophilus) microplus are nowadays considered a problem, and in order to eliminate the infestation, medicines and byproducts are used, which can cause animal contamination. The present study has the purpose of evaluating the in vitro activity of the alcohol extract in propolis in combating ticks from Rhipicephalus (Boophilus) microplus species in Holstein cows belonging to a small farm in Icaraima- Paraná. The experiment was completely randomized, the assays consisted in the comparison of the laying and hatching of eggs in animals treated with the alcoholic extract from propolis in the concentrations of 50%, 25%,12. 5% and 6.25%. The concentration of 50% was the most efficient, yielding a margin of 99.10% efficiency. Meanwhile, the concentrations of 25%, 12,5% and 6.25%, had an efficiency of 73.53%, 77.07% and 50.93%, respectively. The results showed a greater sensitivity of ticks to the higher concentrations. Propolis, therefore, can be an treatment option, and can be used as a source of acaricide activity because of its several functional substances.

Propóleos es una sustancia resinosa obtenida por las abejas a partir de diferentes partes de la planta y se ha utilizado desde la antigüedad debido a su amplio espectro de actividad biológica. La infestación en animales de gran porte por Rhipicephalus (Boophilus) microplus es un problema hoy en día, porque el tratamiento consiste en el uso de medicamentos que causan la contaminación del animal, y de sus derivados. Este estudio tuvo como objetivo evaluar la actividad in vitro del extracto alcohólico de propóleos para combatir la especie de garrapata Rhipicephalus (Boophilus) microplus en vacas lecheras de la raza holandesa pertenecientes e una propiedad rural en el municipio de Icaraíma-Paraná. El experimento fue totalmente aleatorizado, pruebas consistieron en la comparación de la postura y eclosión de los huevos de animales tratados con extracto alcohólico de propóleos en concentraciones de 50%, 25%, 12. 5% y 6,25%, donde la concentración de 50% fue la más eficiente, obteniendo un margen de 99,10% de eficacia; mientras que las concentraciones de 25%, 12,5% y 6,25%, alcanzaron una eficacia de 73,53%, 77,07% y 50 93%, respectivamente. Los resultados mostraron mayor sensibilidad de las garrapatas a concentraciones más elevadas. Propóleos puede ser una opción de tratamiento, pudiendo ser utilizado como una fuente para actividad acaricida debido a sus numerosas sustancias funcionales.

Influence of essential oil fractionation by vacuum distillation on acaricidal activity against the cattle tick

The aim of this work was to study the influence of essential oil fractionation on acaricidal activity against the cattle tick Rhipicephalus (Boophilus) microplus. The citronella (Cymbopogon winterianus J.) and pepper tree (Schinus molle L.) essential oils were fractionated by vacuum distillation yielding fractions that were analyzed by the GC/MS. Laboratory tests were carried out to determine the effect of the total essential oil and fractions on larvae of the cattle tick R. (B.) microplus. The fractions 04 and 05 of the C. winterianus essential oil were the most active showing LC50 values of 1.20 and 1.34 μL/mL, respectively. The LC50 of the total oil was 3.30 μL/mL while the effect of the fractions 01, 02 and 03 was less pronounced, with LC50 values of 4.37, 4.24 and 3.49 μL/mL, respectively. The fraction 03 of the S. molle essential oil was the most active showing LC50 value of 8.80 μL/mL while the fractions 01 and 02 did not show toxic effects on the larvae.

Acaricidal activity of Cymbopogon citratus and Azadirachta indica against house dust mites

Objective: To examine the acaricidal effects of the essential oil of Cymbopogon citratus leaf extract (lemongrass) and ethanolic Azadirachta indica leaf extract (neem) against house dust mites Dermatophagoides farinae (D. farinae) and Dermatophagoides pteronyssinus (D. pteronyssinus). Methods: Twenty-five adults mites were placed onto treated filter paper that is soaked with plant extract and been tested at different concentrations (50.00%, 25.00%, 12.50%, 6.25% and 3.13%) and exposure times (24hrs, 48hrs, 72hrs and 96 hrs). All treatments were replicated 7 times, and the experiment repeated once. The topical and contact activities of the two herbs were investigated.Results:Mortalities from lemongrass extract were higher than neem for both topical and contact activities. At 50 % concentration, both 24 hrs topical and contact exposures to lemongrass resulted in more than 91% mortalities for both species of mites. At the same concentration and exposure time, neem resulted in topical mortalities of 40.3% and 15.7% against D. pteronyssinus and D.farinae respectively; contact mortalities were 8.0% and 8.9% against the 2 mites, respectively. There was no difference in topical mortalities of D. pteronyssinus from exposure to concentrations of lemongrass and neem up to 12.50%; lemongrass was more effective than neem at the higher concentrations. Conclusions: Generally, topical mortalities of D. farinae due to lemongrass are higher than that due to neem. Contact mortalities of lemongrass are always higher that neem against both species of mites.

Acaricidal activity of Cymbopogon citratus and Azadirachta indica against house dust mites

<p><b>OBJECTIVE</b>To examine the acaricidal effects of the essential oil of Cymbopogon citratus leaf extract (lemongrass) and ethanolic Azadirachta indica leaf extract (neem) against house dust mites Dermatophagoides farinae (D. farinae) and Dermatophagoides pteronyssinus (D. pteronyssinus).</p><p><b>METHODS</b>Twenty-five adults mites were placed onto treated filter paper that is soaked with plant extract and been tested at different concentrations (50.00%, 25.00%, 12.50%, 6.25% and 3.13%) and exposure times (24hrs, 48hrs, 72hrs and 96 hrs). All treatments were replicated 7 times, and the experiment repeated once. The topical and contact activities of the two herbs were investigated.</p><p><b>RESULTS</b>Mortalities from lemongrass extract were higher than neem for both topical and contact activities. At 50 % concentration, both 24 hrs topical and contact exposures to lemongrass resulted in more than 91% mortalities for both species of mites. At the same concentration and exposure time, neem resulted in topical mortalities of 40.3% and 15.7% against D. pteronyssinus and D. farinae respectively; contact mortalities were 8.0% and 8.9% against the 2 mites, respectively. There was no difference in topical mortalities of D. pteronyssinus from exposure to concentrations of lemongrass and neem up to 12.50%; lemongrass was more effective than neem at the higher concentrations.</p><p><b>CONCLUSIONS</b>Generally, topical mortalities of D. farinae due to lemongrass are higher than that due to neem. Contact mortalities of lemongrass are always higher that neem against both species of mites.</p>

Composición quíiica y actividad acaricida del aeite esencial de cymbopongon ciitratus stapf contra el acaro intradomiciliario dermatophagoides farinae (acari:pyroglyphidae) / Cheical composittion and acaricidal activity of essntial oil cymboopongon citratus stapf against house dust mite dermatophagoides farinae (acari: pyroglyphidae)

Los ácaros del polvo son fuente importante de alérgenos intradomiciliarios, por lo que su control biológico es una prioridad en la prevención y control de la sensibilización alérgica. El propósito de este trabajo fue obtener el aceite esencial de hojas de Cymbopongon citratus Stapf y evaluar su actividad acaricida sobre Dermatophagoides farinae. El aceite esencial se obtuvo por hidrodestilación y extracción con diclorometano. La composición química relativa del aceite fue determinada por CG-EM. Se realizaron bioensayos de concentración- respuesta en papeles filtros tratados con 5; 0,5; 0,05 y 0,005 µL del aceite esencial/cm² de papel. La ausencia de movimiento del ácaro al contacto con una aguja fina se tomó como indicador de muerte. El rendimiento de extracción del aceite fue 1,22% v/p de hojas frescas. El análisis de CG-EM reveló el citral (41,8% de geranial y 34,9% de neral) como componente mayoritario. El efecto tóxico del aceite esencial del C. citratus Stapf sobre el ácaro D. farinae fue proporcional a la concentración y tiempo de exposición. A una concentración de 0,5 µL/cm² de aceite esencial, el 46,67% de los ácaros murieron después de 60 minutos de exposición. Estos resultados permitieron comprobar una alta actividad tóxica del aceite esencial de C. citratus Stapf sobre el ácaro D. farinae, este efecto puede estar relacionado con la presencia del geranial y neral, monoterpenos análogos a la octopamina, un neurotransmisor periférico de insectos.

Dust mites are an important source of intradomiciliary allergens reason why their the biological control is a priority in the prevention and control of allergic sensitization. The purpose of this work was to obtain the essential oil of leaves of Cymbopongon citratus Stapf and evaluate its acaricidal activity on Dermatophagoides farinae mite. The essential oil was obtained through hydrodistillation and extraction with dichloromethane. The relative chemical composition of the oil was determined by GC-MS. Concentration-response bio essays were carried out in filter paper treated with 5, 0.5, 0.05, and 0.005 µL of essential oil/cm². The absence of dust mite movement when they touched with a fine needle was considered as an indicator of death. The oil extraction yield was 1.22 % v/w of fresh leaves. The GC-MS analysis revealed citral (41.8% of geranial over 34.9% of neral) as a major component. The toxic effect of the C. citratus Stapf essential oil on dust mites D. farinae was proportional to concentration and time exposure. Using a 0.5 µL/cm² concentration of essential oil, 46.67% of dust mites died after 60 minutes exposure. These results allowed the verification of a high toxic activity of C. citrates Stapf essential oil on D. farinae mites; this effect may be related to the presence of geranial and neral monoterpenes analogue to octopamine, an peripheral neurotransmitter in insect.

Chemical composition and acaricidal activity of the leaf and fruit essential oils of Protium heptaphyllum (Aubl. ) Marchand (Burseraceae)

Essential oils from leaves and fruits of Protiumheptaphyllum collected in Tamandaré beach Pernambuco/Brazil were analysed by GC/MS and tested for toxicity and repellent effect against the two spotted spider mite (Tetranychus urticae). The major constituent identified in the fruits was alpha-terpinene (47.6 percent) whereas oil from leaf contained mainly sesquiterpenes such as 9-epi-caryophyllene (21.4 percent), trans-isolongifolanone (10.7 percent) and 14-hydroxi-9-epi-caryophyllene (16.7 percent). The fruit oil was found to be more effective against the mite when compared to the leaf oil. Both showed mortality properties and oviposition deterrence in higher concentration (10 µl.l-1 air), but only the essential oil from fruits induced repellence on T. urticae.

O óleo essencial das folhas e frutos de Protiumheptaphyllum coletada em Tamandaré-Pernambuco foi analisado por CG/EM e testado sua toxicidade e efeito repelente contra ácaro rajado (Tetranychus urticae). O constituinte majoritário identificado nos frutos foi alfa-terpineno (47,6 por cento) enquanto que nas folhas foram os sesquiterpenos 9-epi-cariofileno (21,4 por cento), trans-isolongifolanona (10,7 por cento) and 14-hidroxi-9-epi-cariofileno (16,7 por cento). O óleo dos frutos foi mais eficiente contra o ácaro, comparado com o óleo das folhas. Ambos os óleos revelaram propriedades de mortalidade e deterrência de oviposição na maior concentração (10 µl.l-1 air) e apenas o óleo essencial dos frutos induziu repelência no T. urticae.

Acaricidal effects of herb essential oils against Dermatophagoides farinae and D. pteronyssinus(Acari: Pyroglyphidae) and qualitative analysis of a herb Mentha pulegium(pennyroyal)

This experiment was undertaken to screen the acaricidal effects of herb essential oils (pennyroyal, ylang ylang, citronella, lemon grass, tea tree, and rosemary) at different doses (0.1, 0.05, 0.025, 0.0125, and 0.00625 microliter/cm2) and exposure times (5, 10, 20, 20, 30 and 60 min) on house dust mites Dermatophgoides farinae and D. pteronyssinus. The most effective acaricidal components of pennyroyal (Mentha pulegium) were analyzed using a gas chromatography-mass spectrometer (GC-MS). Of these essential oils, the most effective was pennyroyal, which is composed essentially of pulegone (> 99%), at a dose of 0.025 microliter/cm2, which at an exposure time of 5 min killed more than 98% of house dust mites. In the pennyroyal fumigation test, the closed method was more effective than the open method and maximum acaricidal effect was 100% at 0.025 microliter/cm2, 60 min. The results show that herb essential oils, in particular, pennyroyal was proved to have potent acaricidal activity