Banca de QUALIFICAÇÃO: MAYLLA MARIA CORREIA LEITE SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MAYLLA MARIA CORREIA LEITE SILVA
DATE: 31/08/2021
TIME: 08:30
LOCAL: Videoconferência
TITLE:

EVALUATION OF ANTIOXIDANT POTENTIAL IN VITRO, IN CELL CULTIVATION AND IN VIVO OF FUCOIDANS OBTAINED FROM THREE BROWN ALGAE

KEY WORDS:

Sulphated polysaccharides; seaweed; oxidative stress; zebrafish

PAGES: 83
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The imbalance of redox reactions leads to oxidative stress, an imbalance condition between the production of pro-oxidants and antioxidants. When antioxidant defenses do not prevent the action of reactive species involved in the process, various cell damage occurs, and the accumulation of damaged cells leads to damage to tissue and organ damage, Parkinson's disease, atherosclerosis, and psychic deficiencies, or potentiating the deleterious effects of preexisting situations, as premature aging. To combat this, the search for molecules with antioxidant potential has been taking place, mainly from natural sources. One such source is brown seaweed, which synthesize molecules called fucoidan (sulfated alpha-L-fucose containing polysaccharide) in their makeup. Several pharmacological activities are attributed to fucoidans from the several seaweeds. However, regarding its antioxidant potential, it was not evaluated whether there is a difference in antioxidant activity between different fucoidans. Thus, the objective of this work was to identify which of the commercial fucoidans, obtained from the three seaweeds: Undaria pinnatifida (FUP), Macrocystis pyrifera (FMP) and Fucus vesiculosos (FFV), has the best antioxidant activity in vitro, in cells and in vivo. Fucoidans were obtained commercially, and the analysis of their composition showed that they are fucose and sulfate rich polysaccharides. HPLC analyzes indicated different apparent molecular masses: from: 168.5 (FUP); 70.4 (FMP) and 97.7 kDa (FFV). In vitro antioxidant activities indicated that FUP is more potent. In summary, FUP was able to chelate ~25% copper ions, scavenge ~50% H₂O₂ and 73% hydroxyl radicals. When fucoidans were evaluated under cell culture conditions in macrophages (RAW264.7), they all inhibited the effect of hydrogen peroxide in decreasing the viability of these cells. The results corroborate the data obtained in the live/dead assay, where cells treated with fucoidans exhibited fewer red markings, indicative of cell damage, compared to the positive control to which only H₂O₂ was added. The data obtained in vitro and with cells provided support for carrying out the in vivo tests. For this purpose, embryos of Danio rerio (zebrafish) were used as a model. Regarding the survival rate of embryos, in the presence of fucoidans and H₂O₂, a higher percentage was observed compared to the positive control. And with the hatching of the larvae, it was noticed that the marking by acridine orange, which marks dead cells or cells in the process of cell death, in animals treated with FFV and FMP was significantly lower than that observed with the negative control group, which highlights the protective effect of fucoidans. Considering the antioxidant activity promoted by FMP, it is concluded that this fucoidan has the best antioxidant potential, both in cells and in vivo environments, although in vitro it did not stand out, the fucoidan from M. pyrifera is the most promising in terms of activities antioxidants.

BANKING MEMBERS:
Interno - 3060683 - LEONARDO THIAGO DUARTE BARRETO NOBRE
Presidente - 1544647 - MATHEUS DE FREITAS FERNANDES PEDROSA
Interna - 2085604 - SUSANA MARGARIDA GOMES MOREIRA