Banca de QUALIFICAÇÃO: RICARDO BASÍLIO DE OLIVEIRA CALAND

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RICARDO BASÍLIO DE OLIVEIRA CALAND
DATA : 04/12/2018
HORA: 14:00
LOCAL: A DEFINIR
TÍTULO:

A DEFINIR

PALAVRAS-CHAVES:

Orange juice, antioxidant, neuroprotective and Caenorhabditis elegans.

PÁGINAS: 100
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Introduction: Citrus sinensis L. Osbeck orange juice is considered an excellent dietary source of several bioactive compounds with beneficial properties for human health due to its high content of flavonoids, carotenoids, sugars, minerals, and fiber. In this study, we worked with Citrus sinensis L. Osbeck cv. ‘Bahia’ and ‘Cara Cara’ pasteurized orange juices. Both have a high content of vitamin C and flavonoids, however, ‘Cara Cara’ orange differs and stands out for being also rich in carotenoids (phytoene, phytofluence, lycopene and β-carotene). Given that, oxidative damage and increased neuroinflammation are critically related with the pathogenesis of and neuronal loss in neurodegenerative diseases, the neuroprotective effect of carotenoids has been of specific interest in the search for effective treatments for these diseases. Some epidemiological and intervention studies have provided substantial evidence to support an inverse correlation between orange juice intake and the occurrence of cardiovascular disease, cancer, and aging related disorders. Despite this, there is still a substantial lack of animal models to show the therapeutic effect of orange juice in its integral and complete form, since in isolated form its compounds have already demonstrated positive antioxidant and neuroprotective effects. In this context, we used the nematode worm Caenorhabditis elegans, which is an established model organism to study oxidative stress resistance, longevity and neuroprotective mechanisms. Objective: This work aimed to evaluate and compare the antioxidant and neuroprotective activity of Citrus sinensis L. Osbeck (Bahia and Cara Cara) orange juices in the Caenorhabditis elegans model. Methodology: In all experiments, the animals were synchronized and treated for 48h at 20ºC with Bahia or Cara Cara orange juice. Results: Treatment with orange juice provided positive antioxidant effects: reduction in endogenous levels of reactive oxygen species (ROS), increased survival under standard and oxidative stress conditions, and increased expression of the reporter genes g-glutamyl cysteine synthetase (gcs-1), glutathione-S-transferase (gst-4) and superoxide dismutase (sod-3) and hsp-16.2 chaperonin. The results showed that the oranges have bactericidal effect, since they were able to diminish the growth of the bacterium E. Coli OP50. Now, regarding the neuroprotective effects, it was observed that the orange treatment delays the profile of paralysis induced by the superexpression of the Aβ1-42 peptide in the muscle of the C. elegans model for Alzheimer's disease and decreases the polyglutamine aggregation in the C. elegans model for Huntington's disease. In addition, the treatment was still able to improve physiological parameters related to quality of life: increased progeny, pharyngeal beats and body movements per minute. In order to confirm the stress response signaling pathways role in the antioxidant effect of juices, we evaluate: ROS levels, oxidative stress resistance, gst-4::GFP expression, and paralysis assays  in animals submitted to RNAi for the SKN-1, DAF-16 and HSF-1 transcription factors. The results showed that the increase in oxidative stress resistance depends mainly on SKN-1, the reduction of ROS levels is dependent on SKN-1 and DAF-16 with an emphasis on SKN-1 and on the activation of gst-4::GFP and β-amyloid-induced paralysis protection, the effects were dependent on the three SKN-1, DAF-16 and HSF-1 transcription factors, with emphasis on SKN-1. Conclusion: We concluded that the treatment with orange juice produced excellent antioxidant and neuroprotective effects in C. elegans, with emphasis on cara cara orange juice that induced significantly better responses than Bahia juice in all experiments, possibly due to its higher carotenoid content

MEMBROS DA BANCA:
Externo ao Programa - 1228866 - EDUARDO LUIZ VOIGT
Presidente - 1453487 - KATIA CASTANHO SCORTECCI
Externo ao Programa - 1871916 - RAQUEL BRANDT GIORDANI