Toxicological effects of aqueous extract of Genipa americana L. leaves on adult zebrafish (Danio rerio): Chemical profile, histopathological effects and lack of genotoxicity

Genipa americana is a native plant of Brazil with potential applications in folk medicine. Whereas most of the phytochemical and pharmacological studies on this plant have focused on its fruits, the crude extracts of its leaves contain chemical metabolites that may have toxicity to organisms, which have yet to be investigated. This study aimed to determine the main groups of secondary metabolites in the aqueous extract of the leaves of G. americana by phytochemistry and qualitative HPLC, and to evaluate the possible toxicological effects and histopathological changes caused by this extract in zebrafish (Danio rerio) adults, through micronucleus test, nuclear abnormalities and histopathological analyses of gills and liver. While three metabolites of high intensity (phenolic compounds, flavonoids and triterpenes) were found in the phytochemical evaluation, the HPLC showed results compatible with flavonoids and iridoids, all belonging to common classes for this species and the Rubiaceae family. The acute toxicity test did not induce mortality or genotoxicity in zebrafish, but after exposure for 96 h, it was possible to observe injuries to the fish gill tissue, such as lamellar fusion, vasodilation and telangiectasia; in the liver, necrosis was visualized at 40 mg/L, and at higher concentrations (80 and 100 mg/L) induced sinusoidal widening was identified. In conclusion, the results demonstrated the toxic potential of this plant for aquatic species. [Display omitted] •Zebrafish livers suffered toxicity at concentrations of 80 and 100 mg/L of G. americana extract.•Flavonoids and iridoids were identified in Genipa americana leaf extract.•The evaluated extract did not show genotoxicity for zebrafish adults.•Despite the lack of genotoxicity, gill lesions such as aneurysms and necrosis occurred.