Banca de DEFESA: WESLLEY DE SOUZA PAIVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : WESLLEY DE SOUZA PAIVA
DATE: 23/07/2022
TIME: 08:30
LOCAL: https://meet.google.com/wnt-rpqw-hms
TITLE:

A DEFINIR

KEY WORDS:

Oxidative stress, fungal chitosan, zebrafish.

PAGES: 71
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Oxidative stress is a cause of numerous diseases in humans, this causes a constant search for  new molecules that may have antioxidant capacity and prevent the emergence of diseases.  The objective of this work was to extract chitosan from fungi (Chit-F) and synthesize a new  molecule, conjugating it with gallic acid, which was called Chit-FGal, in order to potentiate  its antioxidant action. After collection, isolation and identification of the fungus as being of  the species Rhizopus arrhizus, it was possible to extract chitosan and after physical-chemical  tests such as high performance liquid chromatography (HPLC), Fourier transform infrared  (FTIR) and nuclear magnetic resonance (NMR) ), it was confirmed that the sample was  chitosan, with a degree of deacetylation of 86% and low molecular weight, in addition,  without the presence of proteins and phenolic compounds. After that, the synthesis of fungal  chitosan + AG (Chit-FGal) was successfully performed, confirmed by the 4x increase in the  amount of phenolic compounds in relation to Chit-F, as well as the appearance of a peak in  the region of the aromatic rings in the NMR analysis. When the 2 samples were  extracted/synthesized and characterized, the in vitro antioxidant tests were performed (Copper  Chelation, Iron Chelation, Total Antioxidant Capacity (CAT), reducing power and superoxide  radical scavenging), where the samples had activities in all the tests, however Chit-FGal  obtained results at least 50% (p <0.05) higher, demonstrating the potentiation of activities  when modifying the native molecule. When testing Chit-F and Chit-FGal in fibroblast cells  (3T3), there was no decrease in cell viability measured by MTT ((3-(4,5-Dimethylthiazolyl 2)-2,5-diphenyltetrazolium bromide) in any sample. , in addition, a protection test against  damage caused by hydrogen peroxide was performed, where Chit-FGal at a concentration of  0.05 mg/mL showed better protection. A protective effect of embryos against damage caused  by 0.06 mM hydrogen peroxide (100% live embryos) and 0.5% alcohol (93% live embryos)  was obtained. acridine orange, where both Chit-F and Chit-FGal demonstrated protective  action against cell death caused by hydrogen peroxide and alcohol. These results demonstrate  the good antioxidant potential of chitosan extracted from soil fungi of the Caatinga biome  (Chit-F), as well as the enhancement of this action by conjugating this polymer with gallic  acid (Chit-FGal), which makes this new synthesized molecule promising for use as  antioxidants with the potential to avoid a series of problems caused by oxidative stress. 

COMMITTEE MEMBERS:
Externa à Instituição - FERNANDA FOGAGNOLI SIMAS TOSIN - UFPR
Externo à Instituição - DIEGO DE ARAUJO SABRY - UFPI
Presidente - 2195251 - HUGO ALEXANDRE DE OLIVEIRA ROCHA
Interna - 1453487 - KATIA CASTANHO SCORTECCI
Externa ao Programa - 1997012 - RAQUEL CORDEIRO THEODORO - null