Banca de DEFESA: DIMAS BATISTA DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : DIMAS BATISTA DE LIMA
DATA : 12/04/2021
HORA: 09:00
LOCAL: Faculdade de Medicina - FAMED - Barbalha - Googlemeet
TÍTULO:

Evaluation of in vitro Leishmanicidal activity of Vatairea macrocarpa (Benth.) Ducke Lectin

PALAVRAS-CHAVES:

Leishmania. Visceral Leishmaniasis. Lectin. Vatairea macrocarpa. VML

PÁGINAS: 73
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Leishmaniasis represents a spectrum of neglected diseases that afflict millions of people
worldwide. The treatment of leishmaniasis has remained the same for decades and consists, in
particular, in the use of pentavalent antimonials. It should be noted that these drugs have
important effects. In the current scenario, with the limitation of alternative treatments,
investigating other options is a real challenge. Natural products are important sources of
compounds with different therapeutic applications, with special emphasis on lectins. VML
(Vatairea macrocarpa Lectin), lectin extracted from the seeds of Vatairea macrocarpa, with
specificity of recognition and binding to the carbohydrates α-D-galactose / N-
acetylgalactosamine, has proved to be a biotechnological tool with promising applications.
The present study aimed to evaluate, in vitro, the leishmanicidal potential of VML using
Leishmania infantum. Promastigote forms were incubated with different concentrations of
VML (13.8 - 0.4 μM); in addition, the IC50 was incubated in association with galactose in
order to assess the participation of the carbohydrate recognition domain (CRD); the cell
density of the parasites was determined by counting in a Neubauer chamber. Fluorescence
assays with 2',7'-dichlorodihydrofluorescein diacetate (DCFH2-DA) and Propidium Iodide
(IP) were performed to evaluate the possibility of the involvement of reactive oxygen species
and damage to membranes as probable mechanisms of action of VML. The cytotoxic effect of
VML on Raw 264.7 macrophages was verified using the MTT assay; additional evaluations
were carried out to identify the likely effect of the association of VML with Amphotericin B
and Glucantime on promastigote forms, as well as its cytotoxicity on Raw macrophages
264.7. VML was able to inhibit the growth of promastigote forms in a concentration and time
dependent manner, with IC50 values: IC50 / 24h = 11.4 ± 0.03 μM; IC50 / 48h = 6.7 ± 0.04
μM; IC50 / 72h = 4.7 ± 0.02 μM. The results showed that the leishmanicidal effect is related
to the ability of VML to recognize glycans from L. infantum and that the treatment of
promastigotes with VML induces oxidative stress and damage to the membrane of the
protozoa. In addition, lectin had no toxic effect on mammalian cells (Raw 264.7). The
association of VML with Amphotericin B and Glucantime improved the activity of these
drugs, in addition to reversing their cytotoxic effect on Raw 264.7 cells. Our findings suggest
that VML is a promising alternative for the treatment of leishmaniasis. However, further
studies are needed to better understand its effect on intracellular amastigote forms, its action
on the repertoire of cytokines in the immune cells involved in the anti-Leishmania response,
as well as their molecular mechanisms in biological systems.

MEMBROS DA BANCA:
Interno - 1250782 - CLAUDENER SOUZA TEIXEIRA
Presidente - 1353800 - CLAUDIO GLEIDISTON LIMA DA SILVA
Externo à Instituição - GABRIELA SANTOS-GOMES - UNL
Externo à Instituição - ISABEL PEREIRA DA FONSECA - ULISBOA