Leishmaniasis is a zoonosis caused by the protozoan of the genus Leishmania, which affects both humans and animals through a phlebotomist. After malaria and lymphatic filariasis, leishmaniasis is the third most common disease on a global scale. Leishmania infantum is the species spread in the European continent and the Mediterranean basin. In Italy, from the hilly coastal areas and major islands, the infection has spread to many pre-Alpine areas and northern Italy. Our research is evaluating the effectivenes of the activity of polysaccharides and biometabolites extracted from marine macroalgae against L. infantum. The polysaccharides were extracted from two brown algae from the Venice Lagoon, Sargassum muticum and Undaria pinnatifida; the biometabolites were extracted from the red alga Asparagopsis taxiformis present in the Strait of Messina. MTT tests did not show cytotoxic activity of algal extracts on DH82, VERO, L929, MDCK and U937 cell lines. The extracts were inoculated at different concentrations in cultures of L. infantum (MHOM / IT / 80 / IPT1) showing that they have a remarkable activity even at low concentrations.
There is currently no vaccine and the treatment of leishmaniasis is not curative. Unlike the active compounds used in drugs on the market (e.g. pentavalent antimonials, pentamidine and amphotericin B), which are of synthetic origin and with high toxicity at effective therapeutic doses, the product here proposed has a natural origin and is not citotoxic. In fact, polysaccharides and algal biometabolites play an important role in pharmaceutical applications due to their intrinsic biocompatibility and potential low cost. Furthermore, data on the anti-leishmanial potential of marine algae are extremely limited to some non-Mediterranean strains (Leishmania donovani, L. mexicana, L. major and L. amazonensis). Our study represents the first investigation of the application of algal polysaccharides and biometabolites on the Mediterranean strain L. infantum. From an environmental point of view, technology wants to propose the ecosustainable use of those algal species which, by producing high biomass in the Venice Lagoon, cause significant inconvenience to human activities, within the framework of a Bio-based Circular Economy process.