Banca de DEFESA: DINALVA RIBEIRO DE OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DINALVA RIBEIRO DE OLIVEIRA
DATE: 15/09/2021
TIME: 09:00
LOCAL: https://meet.google.com/
TITLE:

Evaluation of the antiophidic potential of the aqueous extract of corama Kalanchoe brasiliensis Cambess (Crassulaceae)

KEY WORDS:

traditional use. medicinal plant. antiophidic extract.

PAGES: 76
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

Kalanchoe brasiliensis, popularly known as corama, is widely used as a tea or poultice in the western region of Pará, to block the local effects caused by poisoning with Bothrops atrox. The aqueous extract of its leaf was tested against local effects of Bothrops jararaca (Southeastern jararaca) venom, with no studies proving its effectiveness against the North Jararaca (Bothrops atrox) venom, which is the main cause of accidents snakes in the region. Therefore, the objective of this work was to evaluate the local antivenom potential of the aqueous extract of K. brasiliensis, prepared according to traditional use, in addition to determining the main classes present in the extract and its cytotoxicity. For this purpose, thin leaves and stems of K. brasiliensis were collected at Escola da Floresta, located in Santarém / Pará - Brazil. The preparation of the aqueous extract of K. brasiliensis (EAKb) simulated one of the traditional methods of use (leaf juice). The B. atrox (VBa) venom was acquired from adult snakes from the Tapajós National Forest. The phytochemical profile of EAKb was evaluated by thin layer chromatography (TLC), and the determination of phenolic compounds by colorimetric assays. The cytotoxicity of the extract was verified by the Alamar blue method and the antioxidant activity by the MRC-5 cell culture method. The antivenom potential of EAKb was evaluated against the coagulant and phospholipase activities induced by VBa, using pre-incubation protocols (poison: extract) and without pre-incubation. The extract was tested for blocking the main causes, a result of the snake's oral cavity. To verify an interaction between EAKb and VBa, SDS PAGE electrophoresis was performed. No EAKb prepared according to traditional use was detected the presence of flavonoids, terpenes, tannins and coumarins. However, when evaluating the content of phenolic compounds by assay, it was not possible to quantify flavonoids and tannins. The extract was not considered toxic and antioxidant presentations of 46% at the highest concentration evaluated (20 µg mL^-1). EAKb completely inhibited coagulant activity when pre-incubated with the venom. However, in the protocol without previous incubation, the maximum block was 14.1%. Regarding phospholipase activity, in the protocol without pre-incubation, EAKb inhibited 58.4% (1:30, poison:extract), and in the pre-incubation the maximum block was 31.6% (1:10, poison: extract). EAKb was effective in inhibiting the growth of 09 of the 12 microorganisms evaluated. In the interaction of VBa with EAKb, a modification in the profile of protein bands in the gel with pre-incubation was observed. EAKb totally blocked the coagulant activity of the venom by pre-incubation method but was ineffective when tested protocol without previous incubation. The blockage observed when the extract was pre-incubated with poison may be due to the presence of tannins in the extract, which would act as chelators, removing the Ca²⁺ íons, thus preventing the action of serine proteases present in VBa. The EAKb showed very promising results in terms of antioxidant, anti-hemolytic and antimicrobial potential, and after further studies, it can be used as a complementary treatment in local actions and secondary infections, frequent in accidents with snakes of the genus Bothrops sp.

BANKING MEMBERS:
Externo ao Programa - 1782412 - ALFREDO PEDROSO DOS SANTOS JUNIOR
Externa à Instituição - LEOMARA ANDRADE DA SILVA
Interno - 1739961 - MANOEL ROBERVAL PIMENTEL SANTOS
Externa à Instituição - SANDRA LAYSE FERREIRA SARRAZIN - UFOPA
Presidente - 011.678.013-42 - VALÉRIA MOURÃO DE MOURA - UEA