Mosquito larvicidal activities of Solanum villosum berry extract against the dengue vector Stegomyia aegypti

<p>Abstract</p> <p>Background</p> <p>Vector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. Although several plants have been reported for mosquitocidal activity, only a few botanicals have moved from the laboratory to field use, because they are poorly characterized, in most cases active principals are not determined and most of the works are restricted to preliminary screening. <it>Solanum villosum </it>is a common weed distributed in many parts of India with medicinal properties, but the larvicidal activity of this plant has not been reported so far.</p> <p>Methods</p> <p>Aqueous and polar/non-polar solvent extract of fresh, mature, green berries of <it>S. villosum </it>was tested against <it>Stegomyia aegypti</it>, a common vector of dengue fever. A phytochemical analysis of chloroform:methanol extract was performed to search for the active toxic ingredient. The lethal concentration was determined (log probit analysis) and compared with Malathion. The chemical nature of the active substance was also evaluated following ultraviolet-visual (UV-Vis) and infrared (IR) analysis.</p> <p>Results</p> <p>In a 72 hour bioassay experiment with the aqueous extract, the highest mortality was recorded in 0.5% extract. When the mortality of different solvent extracts was compared, the maximum (<it>p </it>< 0.05) mortality was recorded at a concentration of 50 ppm of chloroform:methanol extract (1:1, v/v). The larvicidal activity was lower when compared with the chemical insecticide, Malathion (<it>p </it>< 0.05). Results of regression analysis revealed that the mortality rate (<it>Y</it>) was positively correlated with the period of exposure (<it>X</it>) and the log probit analysis (95% confidence level) recorded lowest value (5.97 ppm) at 72 hours of exposure. Phytochemical analysis of the chlororm:methanol extract reported the presence of many bioactive phytochemicals. Two toxic compounds were detected having <it>R</it>_f= 0.82 (70% and 73.33% mortality in 24 and 48 hours, respectively) and <it>R</it>_f= 0.95 (40% and 50% mortality in 24 and 48 hours, respectively). IR analysis provided preliminary information about the steroidal nature of the active ingredient.</p> <p>Conclusion</p> <p><it>S. villosum </it>offers promise as potential bio control agent against <it>S. aegypti </it>particularly in its markedly larvicidal effect. The extract or isolated bioactive phytochemical could be used in stagnant water bodies for the control of mosquitoes acting as vector for many communicable diseases.</p

Adubação orgânica na produção, rendimento e composição do óleo essencial da alfavaca quimiotipo eugenol Organic fertilization in the production, yield and chemical composition of basil chemotype eugenol

Este trabalho foi realizado na UFPR, município de Pinhais-PR, de outubro de 2005 a junho de 2006. Avaliou-se a resposta do Ocimum gratissimum à adubação orgânica com composto de esterco de carneiro, verificando a viabilidade dessa prática para o aumento no rendimento de biomassa, na quantidade e qualidade de seu óleo essencial. As mudas foram plantadas com espaçamento de 0,5 m entre plantas dentro das parcelas e 1 m entre as parcelas. Testaram-se 3 doses de adubação com composto orgânico (4; 8 e 12 kg m-2) e uma testemunha, com 5 repetições e 8 plantas por parcela. As colheitas foram realizadas aos 150 e 226 dias após o plantio, sendo avaliado o rendimento de massa fresca e massa seca total e de folhas, flores e caule, o teor de óleo essencial das folhas e flores e a sua composição por cromatógrafo a gás acoplado a um detector de massas (CG-MS). Houve diferença entre os tratamentos, quanto ao rendimento de biomassa na primeira colheita, onde o tratamento com 8 kg m-2 de composto orgânico foi superior à testemunha sem adubação, para a massa fresca de flores por planta e massa seca total e de flores por planta, mas não diferiu dos outros níveis de adubação. Na segunda colheita não houve diferença entre os tratamentos. Quanto ao rendimento de óleo essencial não houve diferença entre os tratamentos nas duas colheitas. Também não foram observadas grandes variações nos componentes do óleo essencial decorrente dos tratamentos aplicados. Entretanto, ocorreram variações na composição do óleo essencial quando extraído das folhas e das flores, sendo o teor médio de eugenol de 90,4% nas folhas e 80,8% nas flores, na colheita em março. Já na colheita em junho, houve uma redução do teor de eugenol nas folhas e uma elevação dos teores, principalmente de alfa trans trans farneseno, beta bisaboleno, beta cariofileno, germacrene D e alfa selineno.<br>This work was carried out at the Universidade Federal do Parana, Paraná State, Brazil, from October 2005 to June 2006. The effect of organic fertilization with sheep manure was evaluated on Ocimum gratissimum development and the viability of this practice was determined to increase biomass and essential oil yield and quality. The plants were spaced 0.5 m from each other in the experimental units which were separated in 1 m. Three rates of organic fertlization (4; 8 and 12 kg m-2) were compared to control (without fertilizers), with 5 replications and 8 plants by experimental unit. Plants were harvested 150 and 226 days after planting, and the total, leaves, flowers and stems fresh and dried biomass, essential oil yield from leaves and flowers and composition by GC/MS beign evaluated. There was significant difference among the treatments on biomass production at the first harvest, where the plants treated with 8 kg m-2 of organic fertilizer presented higher flowers fresh biomass, and flowers and total dry biomass than plants without fertilizer (control plants), but with no difference compared to other organic fertilization levels. At the second harvest there were no differences among treatments. Regarding the essential oil yield no differences were found comparing the organic fertilization levels in both harvest times. In addition, the essential oil composition was similar on plants from all treatments. However, some variations in composition were observed when the essential oil was extracted from flowers and leaves, where the eugenol percentage was 90.4% on leaves and 80.8% on flowers at the first harvest. At the second harvest, a reduction of eugenol content and an increase of alpha trans trans farnesene, beta bisabolene, beta cariophilene, germacrene D and alfa selineno was found

In vitro efficacy of Coriandrum sativum, Lippia sidoides and Copaifera reticulata against Leishmania chagasi Eficácia in vitro de Coriandrum sativum, Lippia sidoides e Copaifera reticulata sobre Leishmania chagasi

The increased incidence of visceral leishmaniasis (VL) in Brazil is due to a lack of effective disease control measures. In addition to that, no effective treatment exists for canine VL in response to synthetic drugs. Thus, the objective of this study was to evaluate the effect of the essential oils of Coriandrum sativum and Lippia sidoides, and oleoresin from Copaifera reticulata, on Leishmania chagasi promastigotes and amastigotes. We also examined the toxicity of these treatments on the murine monocyte cell line RAW 264.7. To determine the IC50 a MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed on promastigotes, and an in situ ELISA assay was conducted on amastigotes. Here, we demonstrate that oleoresin from C. reticulata was effective against both promastigotes (IC50 of 7.88 µg.mL-1) and amastigotes (IC50 of 0.52 µg.mL-1), and neither of the two treatments differed significantly (p > 0.05) from pentamidine (IC50 of 2.149 µg.mL-1) and amphotericin B (IC50 of 9.754 µg.mL-1). Of the three plant oils tested, only oleoresin showed no toxicity toward monocyte, with 78.45% viability after treatment. Inhibition of promastigote and amastigote growth and the lack of cytotoxicity by C. reticulata demonstrate that oleoresin may be a viable option for analyzing the in vivo therapeutic effects of leishmanicidal plants<br>O aumento na incidência da Leishmaníase Visceral (LV) no Brasil deve-se à ineficácia das medidas de controle da doença. Além disso, não há tratamento efetivo para LV canina com drogas sintéticas. Assim, o objetivo deste trabalho foi avaliar o efeito dos óleos essenciais de Coriandrum sativum e de Lippia sidoides e do óleo-resina de Copaiferareticulata sobre promastigotas e amastigotas de Leishmania chagasi e analisar o grau de toxicidade sobre células monocíticas murinas RAW 264.7. Para determinar a CI50 sobre promastigotas foi usado teste MTT (brometo de 3-[4,5-dimetil-tiazol-2-il]-2,5-difeniltetrazólio) e sobre amastigotas foi realizado imunoensaio in situ pela técnica de ELISA. Os resultados obtidos comprovaram que o óleo-resina de C. reticulata foi o mais eficaz contra as formas promastigotas (CI50 de 7,88 µg.mL-1) e amastigotas (CI50 de 0,52 µg.mL-1) e em nenhum dos dois testes diferiu do controle pentamidina que obteve CI50 de 2,149 µg.mL-1, no teste sobre promastigotas, e anfotericina B que obteve CI50 de 9,754 µg.mL-1, nos testes com amastigotas (p > 0.05). Quanto à citotoxicidade apenas o óleo-resina não apresentou toxicidade com 78,45% de monócitos viáveis. Os resultados obtidos sobre promastigotas e amastigotas e a ausência de citotoxicidade do óleo-resina de C. reticulata evidenciam que este óleo-resina pode ser viável para a análise de seus efeitos terapêuticos em testes in vivo