Avaliação do potencial leishmanicida in vitro de lectinas de algas marinhas contra leishmania braziliensis

Abstract

Tegumentary leishmaniasis is present in almost every country in America and has different clinical and epidemiological forms. It is an infectious and non-contagious disease caused by several species of the genus Leishmania, with L. braziliensis being the main cause of this zoonosis in Brazil. This disease affects the skin and mucous membranes and its etiological agent is an obligatory cellular parasite that presents the promastigote and amastigote forms. It mainly affects low-income populations and, because of that, the knowledge produced by researches does not revert to therapeutic advances, since the reduced profit potential reflects in a low interest of the pharmaceutical industry. The current treatment for leishmaniasis is restricted to drugs with serious side effects and, increasingly, presenting cases of parasite resistance. Thus, new effective compounds of natural origin, with fewer adverse effects, have been the subject of research. Among these compounds, lectins stand out, which are proteins capable of reversibly binding to carbohydrates and which have shown several pharmacological activities, such as antioxidants, anti-inflammatory, antiparasitic and immunomodulatory. Given the above, the in vitro cytotoxicity and leishmanicidal effect of the lectins from the algae Solieria filiformis (SfL) and Caulerpa cupressoides (CcL) against L. braziliensis promastigotes were evaluated. The lectins cytotoxicity at concentrations of 5, 10, 25, 50 and 100 μg/mL was evaluated by MTT test in macrophages of the J774 lineage for 24 and 48 h. The leishmanicidal effect was evaluated after incubation of these lectins (5, 10, 25, 50 and 100 μg/mL) with L. braziliensis (107 promastigotes/mL) for 24 and 48 h. Test results were expressed as mean + standard error of the mean (S.E.M.) and p < 0.05 was considered significant (ANOVA; Tukey's test). None of the tested concentrations of the lectins showed relevant cytotoxicity after 24 and 48 h. Furthermore, leishmanicidal activity of both lectins was demonstrated at all concentrations tested, mainly after 48 h. Therefore, both SfL and CcL showed to be non-cytotoxic molecules and with great potential against L. braziliensis parasites. These results point to the promising effect of these lectins for the development of new drugs that can be used in the treatment of tegumentary leishmaniasis.