Banca de QUALIFICAÇÃO: FLAVIA ROBERTA MONTEIRO DE SOUZA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : FLAVIA ROBERTA MONTEIRO DE SOUZA
DATE: 11/07/2022
TIME: 09:00
LOCAL: Videoconferência
TITLE:

SULFATED POLYSACCHARIES OF Gracilaria birdiae, LEAF EXTRACT OF Baccharis trimera AND BLENDS CONSTITUTED BY THESE COMPOUNDS: EVALUATION OF THEIR ANTIOXIDANT AND ANTIOBESITY ACTIVITIES

KEY WORDS:

Obesity, oxidative stress, natural products, blends, Caenorhabditis elegans.

PAGES: 120
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Obesity is a multifactorial chronic disease, characterized by excess body fat being a risk factor for several diseases. One of the characteristics of obesity is high oxidative stress. Medications used to treat obesity are expensive and associated with dangerous side effects. Within this context, antioxidants of natural origin are pointed out as promising agents that should be incorporated in the treatment of obesity. The red algae Gracilaria birdiae has sulfated polysaccharides with several known biological effects. Baccharis trimera is used in folk medicine for the treatment of various pathologies such as obesity. Thus, the present study sought to evaluate the antioxidant activities and inhibition of the accumulation of lipids of sulfated polysaccharides from the red alga G. birdiae (GB) and extracts from the leaves of B. trimera (BT), as well as to verify if the blends obtained from these products can optimize such biological activities in vitro and in vivo. GB were obtained by the proteolysis process. BT were obtained by decoction. Through the formulation of blends, samples with different concentrations of GB and BT were obtained. GB, BT and the blends were subjected to physicochemical analysis to determine their composition. It was observed that, regarding the content of sulfate and total sugars, the highest values were observed in the samples with the highest content of GB, in relation to the content of proteins and phenolic compounds, the samples that had the highest content of BT had higher percentages. The tests to evaluate the antioxidant activity in vitro showed an increase in the antioxidant potential mainly in the blends with 50% GB and 50% (BTGB50-BT50) and 25% GB and 75% (GB25-BT75) that optimized the activity of GB and BT in most antioxidant tests performed. As for the in vivo analyses, the Caenorhabditis elegans model was used. ROS production in C. elegans was reduced mainly in GB50-BT50 and GB25-BT75 at a concentration of 5 mg/mL. In relation to the survival assay, all tested samples promoted an increase in the survival of the animals in relation to the control. The ability of GB, BT and blends to inhibit the accumulation of lipids in C. elegans in the absence or presence of glucose was also evaluated. The groups that showed the most significant reduction in fat inhibition by the Oil Red O dye were BT100 and GB25-BT75. As for triglycerides, the greatest reduction was observed in the GB25-BT75 blend, in the groups treated with and without glucose. ROS quantification assays were also performed in knockdown animals for transcription factors SKN-1 and DAF-16 through RNA interference (RNAi) and survival assay under oxidative stress conditions in skn-1(zu67) mutant animals. Still using the RNAi technique, the mechanisms involved in the accumulation of lipids for the TUB-1 and NHR-49 transcription factors were evaluated. The results showed that the effects provided by the treatment with the samples in the reduction of oxidative stress were dependent on the transcription factor SKN-1. Regarding the inhibition of lipid accumulation, the main transcription factor involved was NHR-49. In view of the results presented, it was observed the potential antioxidant activity and inhibition of the accumulation of lipids of GB and BT, alone, and the potential of the therapeutic action of these components when combined together in the form of blends.

COMMITTEE MEMBERS:
Interna - 2578619 - ANA HELONEIDA DE ARAUJO MORAIS
Externa à Instituição - JOANNA DE ANGELIS DA COSTA BARROS GOMES - UNI-RN
Presidente - 2832746 - MONIQUE GABRIELA DAS CHAGAS FAUSTINO ALVES