Banca de QUALIFICAÇÃO: CYNTHIA HAYNARA FERREIRA DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CYNTHIA HAYNARA FERREIRA DA SILVA
DATE: 30/08/2024
TIME: 08:30
LOCAL: Videoconferência - Link para acesso: https://meet.google.com/swa-vntp-xbh
TITLE:

Development of Blends Containing FucA and Evaluation of Antioxidant Activity In Vitro and In Vivo in Caenorhabditis elegans and zebrafish (Danio rerio) Models

KEY WORDS:

Fucoidan, sulfated polysaccharides, brown seaweed, oxidative damage.

PAGES: 93
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Oxidative stress is a crucial physiological process involved in regulating and maintaining several fundamental processes in organisms, as well as in diseases such as cardiovascular diseases, neurodegenerative diseases, and cancer. There is growing interest in identifying new molecules, particularly from natural sources, that possess antioxidant properties. Marine macroalgae have emerged as functional foods and sources of active molecules with various properties, including sulfated polysaccharides (PS). One example is PS fucoidan A (FucA), extracted from the algae Spatoglossum schröederi, which has been studied for its antithrombotic, anti-inflammatory, and non-genotoxic potential. However, FucA does not exhibit significant antioxidant activity. The presence of antioxidant properties could enhance the effects of the biological activities already identified. One strategy to enhance the effects of a molecule is through chemical modification by adding functional groups and developing blends that combine the properties of two components. To improve the antioxidant activity of FucA, factorial design and response surface plots were employed to develop blends containing FucA and dextran modified with gallic acid (Dex-Gal). Chemical and structural analyses confirmed that Dex-Gal was modified with the addition of 3% GA and exhibited a total antioxidant capacity (TAC) 3.2 times higher than that of unmodified Dex. Dex-Gal and FucA were subjected to factorial design to create different proportions and develop five blends (BLD1, BLD2, BLD3, BLD4, and BLD5). Two blends, BLD1 and BLD5, demonstrated low activity in the antioxidant tests performed. In the TAC test, three blends stood out: BLD4 (22 Eq. AA), BLD3 (17 Eq. AA), and BLD2 (13 Eq. AA). In the reducing power test, BLD4 showed a reduction of 28%, compared to 17% for BLD2 and 15% for BLD3. Notably, BLD4 also excelled in the hydroxyl radical scavenging test, demonstrating approximately 100% activity. Analysis of the surface graphs confirmed that the ideal proportion of the FucA and Dex-Gal blend is that formulated in BLD4, with a 1:1 ratio of each component. BLD4 was selected for antioxidant tests in the 3T3 cell line, as well as in biological models of Caenorhabditis elegans and zebrafish (Danio rerio). BLD4 did not exhibit cytotoxicity in 3T3 cells and provided protective effects against oxidative stress induced by H2O2; it enhanced the survival of C. elegans larvae under oxidative stress with T-BOOH and reduced intracellular ROS by 30%; it also protected zebrafish embryos from oxidative stress caused by H2O2. In both cellular and C. elegans models, BLD4 performed better compared to its isolated components.

COMMITTEE MEMBERS:
Externo à Instituição - LEONARDO THIAGO DUARTE BARRETO NOBRE - UFRN
Externo à Instituição - MOACIR FERNANDES DE QUEIROZ NETO - UFPB
Presidente - 2962496 - RAFAEL BARROS GOMES DA CAMARA