Banca de QUALIFICAÇÃO: DIMAS BATISTA DE LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : DIMAS BATISTA DE LIMA
DATA : 12/03/2021
HORA: 14:00
LOCAL: Faculdade de Medicina - FAMED - Barbalha - Googlemeet
TÍTULO:

EVALUATION OF THE IN VITRO LEISHMANICIDAL ACTIVITY  OF Vatairea macrocarpa (Benth.) Ducke

PALAVRAS-CHAVES:

Leishmania. Visceral Leishmaniasis. Lectin. Vatairea macrocarpa.

PÁGINAS: 72
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Leishmaniasis represents a spectrum of neglected diseases that afflicts millions of
individuals 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 side effects. In the current scenario, with the
limitation of alternative treatments, the investigation for other therapeutic 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
(364 - 11.3 µg/mL); 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'-dichlorofluorescein diacetate (H 2 DCFH-DA) and
Propidium Iodide (PI) were carried out 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 264.7 macrophages. VML was able to inhibit the growth
of promastigote forms in a concentration and time dependent manner, with IC50 values:
(IC 50/24h = 300 ± 0.03 μg/mL; IC 50/48h = 160 ± 0.03μg/mL; CI 50/72h = 116 ± 0.02 μg/mL).
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 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 biological systems.

MEMBROS DA BANCA:
Presidente - 1364396 - HEBERTY DI TARSO FERNANDES FACUNDO
Externo ao Programa - 1528282 - MARCOS ANTONIO PEREIRA DE LIMA
Externo ao Programa - 1550021 - MARIA DO SOCORRO VIEIRA GADELHA