Phomalactone as the Active Constituent against Mosquitoes from <i>Nigrospora spherica</i>

Abstract

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.

Synthesis and insecticidal activity of novel pyrimidine derivatives containing urea pharmacophore against Aedes aegypti

“…Bioassays were conducted following standard protocols . Test compounds were initially diluted in DMSO or ethanol, as appropriate, to make 100 µg µL −1 stock solutions.…”

“…25,26 Bioassays were conducted following standard protocols. 27,28 Test compounds were initially diluted in DMSO or ethanol, as appropriate, to make 100 μg μL −1 stock solutions. For larval bioassays, stocks were diluted in a final volume of 200 μL of larval rearing media that contained five first-instar Ae.…”

Sarniensine, a mesembrine-type alkaloid isolated from Nerine sarniensis, an indigenous South African Amaryllidaceae, with larvicidal and adulticidal activities against Aedes aegypti

“…aegypti larva were exposed to final concentrations of 1.0, 0.5, 0.25 and 0.1 g L -1 in 96-well tissue culture plates. The detailed larval bioassay has been described previously [21]. Mortality was assessed at 24 hours.…”

Phylogenetic reassessment of Nigrospora: ubiquitous endophytes, plant and human pathogens

“…Nigrospora is regarded as extremely interesting as a source of natural products and because of its potential industrial applications ( Chen et al 2016 ). Metabolites produced by N. sacchari showed remarkable herbicidal activity in the treatment of intact greenhouse-grown plants ( Fukushima et al 1998 ), while Phomalactone produced by N. spherica was found to be an active constituent against mosquitoes ( Meepagala et al 2015 ) . Moreover, some extrolites produced by N. sphaerica exhibited antibacterial activities against the growth of methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella pneumonia cells ( Ibrahim et al 2015 ).…”