Cytotoxic effect of Vernonanthura polyanthes leaves aqueous extracts/Efeito citotoxico do extrato aquoso de folhas de Vernonanthura polyanthes

Vernonanthura polyanthes, popularly known as assa-peixe, is a medicinal plant that has been widely used by Brazilian Cerrado population for treatment of diseases without a detailed evaluation of their effectiveness, toxicity, and proper dosage. Thus, more studies investigating the safety of V. polyanthes aqueous extract before the use are needed. The purpose of this study was to evaluate the toxicity, cytotoxicity and genotoxicity of V. polyanthes leaves aqueous extract using the Artemia salina and Allium cepa assays. For the A. salina assay, three groups of 10 larvae were exposed to V. polyanthes leaves aqueous extract at the concentrations of 5, 10, 20, 40, and 80 mg/ml. For the A. cepa assay, 5 onion bulbs were exposed to V. polyanthes leaves aqueous extract at 10, 20, and 40 mg/ml, and then submitted to macroscopic and microscopic analysis. As result it was identified a toxicity and cytotoxicity of V. polyanthes dependent on the extract concentration. The A. salina assay suggests that the concentration of 24 mg/ml of the V. polyanthes extract is able to kill 50% of naupllis; while the A. cepa assay suggests that V. polyanthes leaves aqueous extract is toxic at concentrations higher than 20 mg/ml; however the cytotoxic effect in A. cepa root cells was observed at 40 mg/ml of the extract. It is important to say that the V. polyanthes leaves aqueous extract concentration commonly used in popular medicine is 20 mg/ml. Thus, the popular concentration used is very close to toxicity limit in A. salina model (24 mg/ml) and is the concentration which showed toxic effect in A. cepa root cells (20 mg/ml). No genotoxic activity of V. polyantes leaves aqueous extract was observed in the conditions used in this study. Because of the antiproliferative action and no genotoxic activity, V. polyanthes leaves aqueous extract may present compounds with potential use for human medicine. However more detailed studies need to be performed to confirm this potential.