The Marine Microbial Alkaloid (R)-Salsolinol is Effective Against Trypanosoma cruzi

Chagas disease is a parasitic disease with approximately 8 million people infected worldwide, presenting a limited and toxic treatment. Comprising a vast chemodiversity, microbial metabolites are among the most important sources of FDA-approved anti-infectives. In this work, the bioactivity-guided fractionation from an extract obtained from the bacterium Bacillus altitudinis, isolated from a red seaweed, afforded an antitrypanosomal alkaloid which was characterized as (R)-salsolinol by ¹H NMR and HR-ESIMS analysis. (R)-Salsolinol showed a trypanocidal effect against the trypomastigotes (EC₅₀ = 14 µg/mL) and a selective activity against the intracellular amastigotes (EC₅₀ = 19 µg/mL), with no mammalian cytotoxicity in human monocytic cells THP-1 (CC₅₀ > 36 µg/mL). In silico studies predicted a high permeability into cell membranes, as well as a high gastrointestinal absorption, with acceptable parameters in pharmaceutical filters, as well as cruzipain as a possible target protein, suggesting that (R)-salsolinol can be used as a prototype for drug design studies in Chagas disease.