Avaliação do potencial Leishmanicida in vitro contra Leishmania braziliensis dos Polissacarídeos Sulfatados das Algas Marinhas Hypnea musciformis e Sphaerococcus coronopifolius

Abstract

Sulfated polysaccharides are complex molecules formed by monosaccharides linked by glycosidic bonds and possessing sulfate as a substituent. Marine algae are known as a rich source of sulfated polysaccharides with beneficial health effects. The species Hypnea musciformis and Sphaerococcus coronopifolius are red macroalgae that are sources of various metabolites with great potential for new biologically active substances, such as sulfated polysaccharides, which are still poorly explored. Leishmaniasis is a pathology caused by the protozoan Leishmania sp. and affects a significant portion of the world's population, being a disease that is difficult to treat and prevent. Therefore, the search for new molecules that can eliminate these parasites, leading to the control of this parasitosis, is necessary. Given the above, this study evaluated the in vitro cytotoxic and leishmanicidal potential against Leishmania braziliensis of sulfated polysaccharides from the marine algae H. musciformis and S. coronopifolius. To this end, an extraction was performed using papain. The total sulfated polysaccharides were added to a promastigote suspension for up to 48 hours, and the antipromastigote effect was measured by microscopic analysis with Trypan Blue. To evaluate the effect against amastigote forms, J774 macrophages infected with L. braziliensis and treated or not with PHM (5, 10, and 25 μg/mL) and PSC (5, 10, 25, and 50 μg/mL) were used. The cytotoxicity of PSTs was evaluated by MTT assay, parasite load, cytokine and NO levels after 24 and 48 hours of infection. Thus, the concentrations with the lowest cytotoxicity were selected to continue the experiments. The PSTs evaluated showed anti-promastigote effect, PHM and PSC demonstrated better inhibition of the parasites (25 μg/mL; 74.03% ± 8.40%; 60.06% ± 7.66%; 48h). Against amastigote forms, PHM and PSC (5 μg/mL) reduced the intracellular parasite load in 24 and 48 hours of incubation (maximum reduction: 52.17% ± 1.49%; 45.29% ± 0.74% respectively), accompanied by an increase in NO production (5

μg/mL/48h: 5.34 μmol/mL; 5.64 μmol/mL). Significant levels of IL-12, TNFα, IL-10, and IL- 4 were observed in the experiments. Based on the results obtained, PHM and PSC showed a

promising in vitro leishmanicidal effect against L. braziliensis; however, the mechanisms of immunological function that indicate the action of sulfated polysaccharides are a complex process that can be regulated by one or more pathways.