Assessment of the toxicological and teratogenic potential of the aqueous extract of the cashew tree (Anacardium occidenale) using zebrafish (Danio rerio) as an experimental model.
Pharmacognosy. Phenolic compounds. Embryotoxicity. Toxicity.
The cashew tree (Anacardium occidentale) is a vegetable native to the Northeast region of Brazil commonly used in folk medicine due to its anti-inflammatory, astringent and healing properties. However, it is also used for abortion, with no scientific evidence regarding the effects related to its use during pregnancy, with little information regarding its chemical composition in aqueous extracts. Considering that the use of plant extracts during pregnancy can cause both maternal and fetal toxicity, the aim of this study was to characterize phytochemically the chemical composition of the aqueous extract (Eaq) of A. occidentale bark tree, as well its possible toxic and teratogenic effects, using zebrafish (Danio rerio) as an experimental model. Acute toxicity tests on embryos and females of D. rerio followed the recommendations of the OECD. The plant extract was prepared and phytochemical characterization by Liquid Chromatography Coupled to Mass Spectrometry (HPLC-MS / MS), followed by tests to determine the median lethal dose (LD50) in embryos and females, behavior tests, evaluation of developmental deformations, testing for abnormalities in DNA, estimation of the fertility rate in the parents, and microscopic analysis of embryos and larvae exposed to Eaq. The results of the phytochemical characterization confirm the presence of phenolic acids, a variety of tannins, gallohexoside, catechin, epicatechin and gallic acid. The results obtained in the toxicity tests suggests a toxic effect in adult females with changes in their behavioral profile, a tendency to decrease changes in the level of DNA, with no effect of the extract on fertility. In embryos exposed at 6, 12, 24- and 48-hours post fertilization (hpf) to sublethal doses of Eaq, there were little teratogenic effects. However, it were observed deformation in the chorionic membrane and delay in hatching, indicating toxic effects of the extract. Although the specialized metabolites found in this species are related to antioxidant activity, it is known that these metabolites in excess can be toxic. However, it could be concluded that the Eaq of A. occidentale shells, in addition to showing signs of teratogenicity to zebra fish in sublethal doses, presented evidence of toxicity in higher doses, both for embryos and adult females.