Banca de DEFESA: LUCIANA FENTANES MOURA DE MELO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCIANA FENTANES MOURA DE MELO
DATE: 29/03/2023
TIME: 13:00
LOCAL: Videoconferencia - Link para acesso: https://meet.google.com/qxf-ewvt-ogz
TITLE:

EXTRACTS AND FRACTIONS OF Coccoloba alnifolia: ANTIOXIDANT, IMMUNOMODULATION AND HEALING POTENTIAL in vitro

KEY WORDS:

Cauaçu; Leaves, ROS, NO reduction, phagocytosis, wound healing, qRT-PCR

PAGES: 78
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUBÁREA: Biologia Molecular
SUMMARY:

Oxidative stress is an imbalance between the production of reactive species and antioxidants. The accumulation of reactive species can result in damage to tissues and organs, and it can induce various physiological changes that compromise cellular homeostasis. This imbalance can be associated with diseases such as cardiac, neurological, and cancer. It has been observed that plants' phenolic compounds can scavenge and neutralize the excess of free radicals. C. alnifolia, the plant that is the focus of our research, is a tree from the Atlantic Forest and is known to have few ethnobotanical studies. Previous studies by our group have shown that extracts obtained from the leaves of this plant have antioxidant potential. Thus, in this work, the aim was to evaluate the antioxidant and immunomodulatory potential of the ethanolic extract (EE), aqueous extract (AE), and two fractions obtained from the aqueous extract – the ethyl acetate (AF) and butanolic (BF). These two fractions were chosen based on the profile obtained after analysis in high-performance liquid chromatography coupled to a diode detector (HPLC-DAD). In addition, these fractions were characterized here for their antioxidant potential by using in vitro assays. It was observed that both have antioxidant potential. The FB, however, displayed higher antioxidant potential compared to the FA. Within the antioxidant activity, the results obtained pointed out the chelation of copper, which had not been observed previously in the crude extract (EA). From these results, the immunomodulatory potential was evaluated through assays with the RAW 267.4 cell. First, it was verified that both the extracts and the two fractions were not cytotoxic. Then, considering the complexity of the inflammatory process, the effect of EE and EA on the production of ROS after treatment with lipopolysaccharide (LPS) was analyzed. For this, three concentrations of extracts were used (100, 250, and 500 µg/mL). Both extracts were found to be able to reduce ROS production when compared to the positive control (treated with LPS). Furthermore, the ROS reduction achieved with EE was similar to the negative control (without LPS treatment). Next, the ability of the extracts and fractions to inhibit nitric oxide production was verified. Both the extracts and the fractions were able to inhibit the production and release of NO at the three concentrations tested, in a dose-dependent manner, with a reduction of more than 50%. Moreover, the phagocytic activity was evaluated only for EE and AE. This analysis was done only at a concentration of 500 μg/mL, and a reduction in phagocytosis of 30% for EE and 50% for EA was observed. Considering that cytokines are important mediators for the immune and inflammatory response, they were evaluated using two methods such as the measurement of cytokines by flow cytometry, where there was observed an increase in IL-17, and by qRT-PCR, where there was a reduction in iNOS and IL -10 mRNA in the treatment with EE. Based on these results, the potential of extracts and fractions in cell migration was also evaluated using the NHI/3T3 cell line (fibroblasts) in cultures submitted to the wound assay. The results obtained showed that both extracts and fractions in 24 h promoted cell migration, with 60% wound closure for the extracts, and 75% for the FB fraction, while the control (no extract) migration percentage was around 40%. Therefore, the data presented here show that the EE and EA and the FA and FB fractions of C. alnifolia have antioxidant and immunomodulatory potential, as well as the ability to induce cell migration involved in the in vitro wound healing process. Besides, it was evidenced in this study important properties of extracts and fractions that have the potential to act on the dynamics of the inflammatory process and tissue damage. Consequently, both extracts and fractions have potential applications for health biotechnology.

COMMITTEE MEMBERS:
Presidente - 1453487 - KATIA CASTANHO SCORTECCI
Interno - 2962496 - RAFAEL BARROS GOMES DA CAMARA
Externa ao Programa - 1251018 - RIVA DE PAULA OLIVEIRA - UFRNExterno à Instituição - CARLOS HENRIQUE SALVINO GADELHA MENESES - UEPB
Externa à Instituição - DEBORAH YARA ALVES CURSINO DOS SANTOS - USP