Toxicity of squamocin on Aedes aegypti larvae, its predators and human cells

Abstract

Background: The mosquito Aedes aegypti transmits a virus that causes diverse human diseases, and control of the vector is an important strategy to avoid disease propagation. Plants in the family Annonaceae are recognised as sources of molecules with uses in the medical and agriculture fields. Molecules of secondary metabolites of Annonaceae plants exhibit insecticidal potential against insect pests and vectors, especially acetogenins, showing high toxicity at low doses, which has encouraged research into producing new insecticide molecules. Herein, we identify an acetogenin from Annona mucosa seeds (chemical analysis) and provide the results of toxicity tests against larvae of A. aegypti (target insect) and its predators Culex bigoti and Toxorhynchites theobaldi (non-target insects) and cytotoxicity to human leukocytes.

Results: We identified squamocin (C₃₇ H₆₆ O₇ ), a fatty acid with a bis-tetrahydrofuran ring. In A. aegypti, this compound caused behavioural disturbance before larval death and high mortality at low concentrations (LC₅₀ = 0.01 µg mL^-1 and LC₉₀ = 0.11 µg mL^-1 ). However, in predators and human leukocytes, squamocin showed no toxicity effect, indicating the selectivity of this molecule for non-target organisms.

Conclusion: We identified squamocin from A. mucosa seeds, which exhibited lethal action against A. aegypti and showed selectivity for non-target insects and low cytotoxicity to human cells. © 2016 Society of Chemical Industry.

Keywords: Annona mucosa; acetogenin; non-target insect; selectivity; target insect.