Introduction: infections caused by protozoa of the genus Leishmania are a global health problem with a high prevalence in underdeveloped countries. There is no vaccine against this disease at present and the treatment used is poor, so the search for more effective and safe medicines is an urgent need.
Objective: to assess the in vitro antileishmanial activity of six aqueous and hydroalcohol extracts from marine organisms.
Methods: the activity of six extracts against Leishmania amazonensis promastigots and amastigots as well as their toxicity against peritoneal macrophages in BALB/c mice.
Results: in the promastigot assay, the extracts from Bryothamnion Iriquetrum, Bunodosoma granulifera, Halimeda opuntia and Physalia physalis showed growth inhibition at concentrations lower than 100 microg/mL whereas in amastigots, these last two extracts were the most active and least toxic with a selectivity index of 6 and 8 respectively.
Conclusions: taking these results into account, it was considered that the H. opuntia and P. physalis extracts showed a promising activity, so it is suggested that further studies on its in vivo activity be conducted.