Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes ...Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes has increased the importance for the search for novel mosquito control agents. Natural products, particularly plant and microbe derived secondary metabolites, are good sources in the search for such compounds. Ammi visnaga (Lam.) Lamarck is a plant in the Apiaceae family native to North Africa, Europe, and Asia. In the search for environmentally benign and effective insecticides as part of an ongoing joint effort between the USDA (US Department of Agriculture) and the DWFP (Deployed War Fighter Protection) program sponsored by the Department of Defense, we have investigated ethyl acetate extract of A. visnaga seeds. Two furanochromones, khellin and visnagin that exhibited larvicide activity against Aedes aegypti mosquito larvae were isolated from the ethyl acetate extract of the seeds by bioassay-guided fractionation. This is the first report of mosquito larvicidal activity of khellin and visnagin.展开更多
The identification of natural, plant-derived compounds with pesticidal properties is crucial for developing environmentally sustainable alternatives to synthetic pesticides. In this study, four major lignans—dihydroc...The identification of natural, plant-derived compounds with pesticidal properties is crucial for developing environmentally sustainable alternatives to synthetic pesticides. In this study, four major lignans—dihydroclusin, cubebin, clusin, and yatein—were isolated from the crude extract of Piper cubeba fruit. Phytotoxicity assays revealed herbicidal activity against Agrostis stolonifera, with dihydroclusin and clusin exhibiting the highest efficacy, inhibiting seed germination by 50% and showing IC50 values of 2.9 µM and 45 µM, respectively, against Lemna paucicostata. Additionally, all compounds, except dihydroclusin, demonstrated fungicidal activity against the strawberry anthracnose pathogen Colletotrichum fragariae. Moreover, only dihydroclusin exhibited larvicidal activity against Aedes aegypti, causing 96% mortality of mosquito larvae at the 100-ppm concentration tested. These findings highlight the broad-spectrum bioactivity of Piper cubeba lignans, suggesting their potential as alternative agents of synthetic pesticides for managing agricultural pests.展开更多
The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pat...The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pathogenic effects on Zinnia elegans and Hydrangea macrophylla plants had been identified as Nigrospora spherica by molecular techniques. The mosquito adulticidal constituent in the culture filtrate was identified as phomalactone by spectroscopic techniques. Laboratory bioassays showed that phomalactone had larvicidal activity against permethrin susceptible and resistant Aedes aegypti larvae and topical adulticide activities on permethrin susceptible and resistant Aedes aegypti and Anopheles quadrimaculatus mosquitoes. Phomalactone was effective as a topical adulticide against the standard Orlando reference strain of Ae. aegypti with an LD50 of 0.64 μg/org. Activity against An. quadrimaculatus was 0.20 μg/org.展开更多
文摘Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes has increased the importance for the search for novel mosquito control agents. Natural products, particularly plant and microbe derived secondary metabolites, are good sources in the search for such compounds. Ammi visnaga (Lam.) Lamarck is a plant in the Apiaceae family native to North Africa, Europe, and Asia. In the search for environmentally benign and effective insecticides as part of an ongoing joint effort between the USDA (US Department of Agriculture) and the DWFP (Deployed War Fighter Protection) program sponsored by the Department of Defense, we have investigated ethyl acetate extract of A. visnaga seeds. Two furanochromones, khellin and visnagin that exhibited larvicide activity against Aedes aegypti mosquito larvae were isolated from the ethyl acetate extract of the seeds by bioassay-guided fractionation. This is the first report of mosquito larvicidal activity of khellin and visnagin.
文摘The identification of natural, plant-derived compounds with pesticidal properties is crucial for developing environmentally sustainable alternatives to synthetic pesticides. In this study, four major lignans—dihydroclusin, cubebin, clusin, and yatein—were isolated from the crude extract of Piper cubeba fruit. Phytotoxicity assays revealed herbicidal activity against Agrostis stolonifera, with dihydroclusin and clusin exhibiting the highest efficacy, inhibiting seed germination by 50% and showing IC50 values of 2.9 µM and 45 µM, respectively, against Lemna paucicostata. Additionally, all compounds, except dihydroclusin, demonstrated fungicidal activity against the strawberry anthracnose pathogen Colletotrichum fragariae. Moreover, only dihydroclusin exhibited larvicidal activity against Aedes aegypti, causing 96% mortality of mosquito larvae at the 100-ppm concentration tested. These findings highlight the broad-spectrum bioactivity of Piper cubeba lignans, suggesting their potential as alternative agents of synthetic pesticides for managing agricultural pests.
文摘The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pathogenic effects on Zinnia elegans and Hydrangea macrophylla plants had been identified as Nigrospora spherica by molecular techniques. The mosquito adulticidal constituent in the culture filtrate was identified as phomalactone by spectroscopic techniques. Laboratory bioassays showed that phomalactone had larvicidal activity against permethrin susceptible and resistant Aedes aegypti larvae and topical adulticide activities on permethrin susceptible and resistant Aedes aegypti and Anopheles quadrimaculatus mosquitoes. Phomalactone was effective as a topical adulticide against the standard Orlando reference strain of Ae. aegypti with an LD50 of 0.64 μg/org. Activity against An. quadrimaculatus was 0.20 μg/org.
