Leishmaniases are characterized as a complex group of polymorphic, anthropozoonotic, infectious and non-contagious diseases caused by protozoa of the genus Leishmania. In this eukaryotic cell, lipophosphoglycan (LPG) is the main glycoconjugate present on the outer surface of the plasma membrane. This molecule has important intra- and interspecific polymorphism, being crucial for the development and survival of the parasite in its hosts.

Natural products are relevant sources of new compounds that have biotechnological applications. Within this context, lectins stand out, proteins of non-immune origin capable of binding in a specific and reversible way to carbohydrate residues or glycoconjugates free or attached to cell surfaces. In view of the above, the present study aimed to evaluate the intraspecific polymorphism of LPG against the in vitro anti-promastigote activity of the lectin from Canavalia ensiformis (ConA). Promastigote forms of L. amazonensis strains PH8 and Josefa were incubated with different concentrations of ConA (298 - 4.65 μg/mL) and cell viability was determined by counting in a Neubauer chamber, as well as the participation of the carbohydrate recognition domain (DRC) on lectin activity. Fluorescence assays with 2’,7’-dichlorodihydrofluorescein diacetate (DCFH2-DA) and Propidium Iodide (IP) were carried out in order to verify the production of reactive oxygen species (ROS) and damage to the integrity of the parasite cell membrane, respectively. ConA inhibited the growth of promastigotes in a concentration- and time-dependent manner, with IC50/24h = 56.48 ± 0.02 μg/mL; IC50/48h = 54.34 ± 0.03 μg/mL; IC50/72h = 39.61 ± 0.02 μg/mL, for Josefa strain, and IC50/24h = 21.05 ± 0.02 μg/mL; IC50/48h = 14.08 ± 0.01 μg/mL; IC50/72h = 13.90 ± 0.01 μg/mL, for strain PH8. The data obtained demonstrated that the activity of the lectin is probably related to its ability to recognize and bind to glycans present in the LPG of L. amazonensis, being capable of inducing the production of ROS and damaging the integrity of the parasite`s membrane. The results suggest that the ConA lectin may be promising for in vivo tests related to glycoconjugate polymorphisms in protozoa belonging to the Leishmania genus.