Banca de QUALIFICAÇÃO: JOAO PEDRO BAUMAN QUIEREGATI

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JOAO PEDRO BAUMAN QUIEREGATI
DATE: 09/06/2023
TIME: 09:00
LOCAL: DEFESA REMOTA - https://meet.google.com/ner-moqv-cmf
TITLE:

SOME METHODOLOGICAL PROBLEMS IN THE DETERMINATION OF POLYSACCHARIDE ANTIOXIDANT ACTIVITY USING DPPH ASSAY.

KEY WORDS:

Keywords: antioxidant methods; stress oxidative; sugar; carbohydrate; hydrocolloids 

PAGES: 27
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUMMARY:

The DPPH-assay is one of the most widely used antioxidant tests. Several protocols for performing this test have been published. The DPPH reagent is solubilized in organic solvents. However, these solvents are also used to precipitate polymers, such as polysaccharides. Therefore, we determined whether polysaccharide precipitation occurred during the DPPH-test. The antioxidant activity of fucoidans from Undaria pinatiffida and Fucus vesiculosus were evaluated. Regardless of the protocol used, the presence of a precipitate was observed. The use of “sample blank” (fucoidan-solution + solvent used to dilute DPPH) and centrifugation increased the antioxidant activity of fucoidan. However, it was not possible to determine whether these values corresponded exclusively to the antioxidant action of the polysaccharide. A precipitate was observed when the antioxidant activity of other polysaccharides or polysaccharide-rich fractions was evaluated using the DPPH assay. Overall, the data suggest that the DPPH assay would not be the most adequate assay for evaluating the antioxidant activity of polysaccharides or polysaccharide-rich fractions. Studies on other polysaccharides and fractions must be conducted to support the conclusions obtained in this study.

COMMITTEE MEMBERS:
Presidente - 2195251 - HUGO ALEXANDRE DE OLIVEIRA ROCHA
Externa ao Programa - 3309409 - KAROLINE RACHEL TEODOSIO DE MELO - nullExterna ao Programa - 1997012 - RAQUEL CORDEIRO THEODORO - null