Dos_2025_Ecotoxicology__

Geraniol, a monoterpene essential oils, has been investigated as a sustainable alternative to conventional pesticides. Its action may benefit from using the nanoencapsulation technique, which could enhance its properties. In this study, we assessed the effects of acute exposures to geraniol and nanoencapsulated geraniol on biomarkers of the Neotropical teleost Prochilodus lineatus. For this, juveniles of P. lineatus were exposed to a control group containing water and the solvent (CTR - Pluronic F-68(a)), zein nanocapsules (NANO), nanoencapsulated geraniol (nGER), or geraniol in its conventional form (GER), all at a concentration of 5 mg L(-1). After exposures (24 and 96 h), biochemical, genotoxic, physiological, and histological biomarkers were analyzed in blood, brain, muscle, liver, and gills. When compared to respective controls, our results showed a significant increase in DNA damage in the erythrocytes of fish exposed to GER and increased acetylcholinesterase activity in the brain of animals exposed to nGER and GER, as well as a significant decrease in glutathione content in the gills of animals exposed to nGER. However, empty zein nanocapsules were toxic to the animals, given the total mortality of the NANO group after 24 h exposure. Thus, compared to NANO, nGER was less harmful, suggesting that the interaction of geraniol with the nanocapsules attenuated the effects induced by the empty NANOs. Overall, nanoencapsulated geraniol caused fewer effects in P. lineatus than geraniol. However, further studies should be carried out before its use as an alternative to more sustainable agriculture.