Banca de QUALIFICAÇÃO: ANTONIO CARLOS VITAL JÚNIOR

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANTONIO CARLOS VITAL JÚNIOR
DATE: 27/06/2025
TIME: 14:00
LOCAL: Videoconferência - Link para acesso: meet.google.com/sjs-xauc-iak
TITLE:

Biological potential of aqueous and ethanolic extracts of Turnera subulata in antioxidant, anti-inflammatory, cytotoxic and antimicrobial activities as therapeutic avenues for infectious and neurodegenerative diseases

KEY WORDS:

Guarujá's flower, phytotherapy, immunomodulatory activity, synergism, microbial resistance.

PAGES: 110
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The prevalence of chronic inflammatory and neurological diseases, as well as the global increase in antibiotic resistance, highlight the need for innovative, safe and effective treatment approaches. In this sense, phytotherapy based on ethnopharmacological knowledge has attracted increasing scientific interest. The native Brazilian plant Turnera subulata has shown potential as a source of bioactive chemical substances and has long been used to treat gastrointestinal, inflammatory and gynecological disorders. At a molecular and biochemical level, its pharmacological characteristics are still largely unknown. The aim of this study was to evaluate the biological potential of the aqueous (AETS) and 40% ethanolic (HETS) extracts of T. subulata in terms of their cytotoxic, antioxidant, antibacterial and anti-inflammatory activities. The methodology combined phytochemical analysis, biochemical assays and in vitro biological evaluations. Lipid peroxidation, DPPH, ABTS and TRAP tests were used to assess antioxidant capacity. The synergistic impact with therapeutic antibiotics and the minimum inhibitory concentration (MIC) were evaluated using standard bacterial strains (Escherichia coli, Staphylococcus aureus and MRSA). The XTT and SRB assays were used to evaluate the cytotoxicity of human neuroblastoma cells (SH-SY5Y) and murine splenocytes. Using cytokine quantification, the anti-inflammatory capacity of HETS was evaluated (IL-4, IL-6, IL-10, IL-12, IL-17 and TNF-α). HETS outperformed AETS in DPPH tests, with 83.05% radical inhibition at 1000 µg/mL (SD = 0.05) compared to 67.75%. With an inhibition of 85.1% (SD = 1.5) in the ABTS assay, HETS showed potent free radical scavenging. With a substantially higher area under the curve (AUC) than AETS (p < 0.05), the TRAP assay demonstrated that HETS prolonged the antioxidant response over time. MDA levels for HETS (at 250 µg/mL) were reduced by inhibiting lipid peroxidation by 46.7%, while MDA levels for AETS were reduced by only 27.1%. Further proof of HETS' ability to mitigate oxidative stress was provided by its 71.8% suppression of hydroxyl radical scavenging. The antimicrobial tests showed that HETS had MIC values of between 250 and 500 µg/mL against S. aureus and that it worked in conjunction with vancomycin. The MIC of vancomycin against MRSA strains was reduced fourfold as a result of the combination. The low toxicity of both extracts was validated by cytotoxicity tests. SH-SY5Y cells showed greater than 85% viability at concentrations up to 1000 µg/mL, while murine splenocytes showed no discernible necrosis or apoptosis (Annexin V/PI staining). HETS therapy had immunomodulatory effects, resulting in a 49% increase in IL-10, a 43% decrease in IL-6 and a 56% decrease in TNF-α (p < 0.01). These results confirm the anti-inflammatory and neuroprotective properties of the ethanolic extract of T. subulata.

COMMITTEE MEMBERS:
Externo à Instituição - JOSÉ CLAUDIO FONSECA MOREIRA - UFRGS
Externo à Instituição - JUCIANO GASPAROTTO - UFRGS
Presidente - 1507794 - RODRIGO JULIANI SIQUEIRA DALMOLIN