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Secondary metabolites produced by solid-state fermentation of a neotropical Aspergillus flavus strain confer anti-mosquito activity with long shelf-life

Abstract:

Fungal metabolites have shown promising potential as alternative tools for controlling mosquito larvae. Here, we evaluated the insecticidal activities of secondary metabolites (smAf) obtained by solid-state fermentation (SSF) of maize substrate inoculated with spores of the fungi Aspergillus flavus and evaluated the smAf toxicity against Aedes aegypti larvae. We further applied computational approaches to pbkp_redict the interactions of three potential constituents of smAf with the A. aegypti acetylcholinesterases, which consists of a relevant physiological target for insecticides. Our results revealed that esters [Hexadecenoic acid, methyl ester; (E, E) − 9,12-octadecadienoic acid, methyl ester; (E, E) - 11,14-eicosadecanoic acid, methyl ester; (Z, Z) − 9,12-octadecadienoic acid, ethyl ester]; chromene [2,5,5,8a-tetramethyloctahydro-2Hchromene]; fatty acids [Hexadecenoic acid] and aromatic compounds [2-hydroxy-5-methoxybenzaldehyde, propyl ether; 3-hydroxy-4-propionylphenyl acetate; N-(2,4-dimethoxyphenyl) acetamide] were present in smAf. Toxicological bioassays demonstrated that smAf exhibited similar mosquitocidal activities against A. aegypti mosquito larvae just after obtention and after 48 storage months. Our computational pbkp_redictions revealed the 2,5,5,8a-tetramethyloctahydro-2 H-chromene and acetylcholinesterase as the interaction with the highest binding energy (−7.3 kcal/mol). Our findings reinforce the mosquitocidal potential of smAf and demonstrate its efficacy, even after a long storage period.