Safety Evaluation of the Hexane Leaf Extract of <i>Vismia guianensis</i> (Hypericaceae), a Brazilian Medicinal Plant, Using the <i>Caenorhabditis elegans</i> Model

Vismia guianensis, a plant from the Amazon rainforest, is traditionally used either orally to treat ailments as fever and rheumatism and applied topically for wound management. Despite the local importance, its toxicological properties remain unexplored. This study evaluates the toxicity of a hexane leaf extract rich in anthraquinones, using Caenorhabditis elegans as a model. The extract, analyzed by thin-layer chromatography and ¹H NMR, confirmed vismiaquinone A and physcion as major components. Biological assays determined an LC₅₀ of 6.38 mg/mL and revealed a dose-dependent reduction in worm survival, particularly at the L4 stage. Developmental effects were noted at high concentrations (1.5 mg/mL), while reproduction remained unaffected. Some neurotoxic indications were observed, but only at high concentrations. The extract showed low toxicity in dauer-stage mutants, even at prolonged exposures. Overall, findings suggest the extract is generally well-tolerated, though further studies are needed to establish safe therapeutic applications and effective treatment dosages.