Banca de DEFESA: MAYLLA MARIA CORREIA LEITE SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MAYLLA MARIA CORREIA LEITE SILVA
DATE: 08/10/2021
TIME: 14:00
LOCAL: Videoconferência
TITLE:

COMPARISON OF ANTIOXIDANT POTENTIAL IN VITRO, IN CELL CULTIVATION AND IN VIVO OF COMMERCIALLY OBTAINED FUCOIDANS

KEY WORDS:

Sulphated polysaccharides; seaweed; oxidative stress; zebrafish

PAGES: 91
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Fucoidans are sulfated L-fucose-rich polysaccharides that are extracted from brown seaweed. These polymers are already commercially available and have been evaluated for various purposes. One of the most evaluated activities is the antioxidant, among the fucoidans that have already been analyzed for antioxidant capacity are the fucoidans from brown seaweed: Undaria pinnatifida; Macrocystis pyrifera and Fucus vesiculosus. However, the antioxidant activity of fucoidans from the respective seaweeds have not yet been compared. Thus, the objective of this work was to identify which of these fucoidans, which are commercially obtained (Sigma-Aldrich), has the best antioxidant activity. Therefore, the fucoidans were analyzed for their physicochemical composition, the results obtained showed that they are rich in fucose and sulfate. And regarding the apparent molecular mass, it was found that it ranged from 70.4 to 168.5 kDa. The fucoidan from U. pinnatifida being the largest polymer. In vitro antioxidant tests all showed fucoidans with moderate activity, except for the H₂O₂ scavenging assay, where all fucoidans exhibited high activity. When fucoidans were evaluated under macrophage cell culture conditions (RAW 264.7) by MTT (3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide) and live/dead reduction assays, after induction of oxidative stress with H₂O₂, it was observed that fucoidans reduced the effect of H₂O₂ on the metabolism of these cells, especially the fucoidan from F. vesiculosus (5 mM). The data obtained in vitro and with cells provided support for the performance in vivo tests with the Danio rerio (zebrafish) embryo model. Two analyzes were carried out: determination of the survival rate of the embryos and quantification of the fluorescence intensity of the hatched larvae. It was observed that in the presence of fucoidans and H₂O₂, the survival rate of the embryos was little affected, compared to the treatment that received only H₂O₂ (0.4 mM), where there was a 50% reduction in the survival rate. The evaluation of larvae treated with fucoidan and with H₂O₂ (0.4 mM) showed that the lowest percentage of fluorescence intensity was observed with those treated with F. vesiculosus and M. pyrifera fucoidan. Considering the results of the tests carried out, fucoidan from M. pyrifera is pointed out as the fucoidan with the best antioxidant potential, especially in vivo tests. Thus, fucoidan from M. pyrifera is the most promising in terms of antioxidant activities.

BANKING MEMBERS:
Externo ao Programa - 3050287 - EUDES EULER DE SOUZA LUCENA
Externo à Instituição - MARIA APARECIDA DA SILVA PINHAL - UNIFESP
Presidente - 2962496 - RAFAEL BARROS GOMES DA CAMARA