Genotoxic effect of Lippia alba (Mill.) N. E. Brown essential oil on fish (Oreochromis niloticus) and mammal (Mus musculus)

•We tested the genotoxic effect of essential oil (EO) of Lippia alba as anesthetic for Oreochromis niloticus and Mus musculus.•We administrated the EO by gavage in fish and in mice and by inhalation in fish.•The EO present a low genotoxic effect in fish and no genotoxic effect in mice. “Erva cidreira” (Lippia alba (Mill.) N. E. Brown) is popular for its therapeutic properties, especially its sedative properties. Such properties led to the discovery of the anesthetic action of Lippia alba essential oil in fish culture. The objective of this study was to evaluate the genotoxic effect of Lippia alba essential oil in fish and mammals. The oil was extracted by hydrodistillation with a Clevenger apparatus and analyzed by gas chromatography coupled to mass spectrometry (GC–MS), where the compounds linalool, eucalyptol, γ-muurolene, and caryophyllene were identified as the most abundant compounds. Lippia alba essential oil showed inhibitory activity on LPS-stimulated Nitric Oxide (NO) production (77% at 20 μg mL−1) in RAW 264.7 macrophages without influence cellular viability. Genotoxic action was observed by micronucleus and comet assay in the doses 100, 200 and 300 mg Kg−1, showing greater damage to fish than mammals. When we compared the treatment modes, greater damage was observed in the treatment by inhalation, but this was still not toxic. The oxidative stress measured by quantification of advanced oxidation protein products revealed low oxidation but significantly more harm than the control. These findings support the use of Lippia alba essential oil as an anesthetic for fish without harm to consumers.