Banca de DEFESA: ANTONIO CARLOS VITAL JÚNIOR

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANTONIO CARLOS VITAL JÚNIOR
DATE: 17/06/2026
TIME: 09:00
LOCAL: Videoconferência
TITLE:

Effect of the extraction solvent on the phytochemical profile and biological activities of Turnera subulata extracts: with an emphasis on redox modulation and antioxidant, immunomodulatory, cytotoxic, and antimicrobial activities in contexts associated with oxidative stress and neuroinflammation

KEY WORDS:

Guarujá's flower; Oxidative damage; Immune regulation; Cell viability; Bioactive compounds; Microbial inhibition; Anti-inflammatory cytokines.

PAGES: 157
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The rising incidence of chronic inflammatory and neurological diseases, coupled with the rise of antimicrobial resistance, underscores the need for safe and effective therapeutic alternatives. Neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, are associated with oxidative stress and dysregulation of the immune response, which contribute to the progression of neuronal damage. In this context, plant-derived phenolic compounds have been extensively investigated for their ability to modulate redox balance and the inflammatory response. Turnera subulata, a species used in traditional medicine, has a phytochemical profile rich in flavonoids and other bioactive metabolites, whose biological effects may vary depending on the extraction solvent. This study aimed to evaluate the effect of the extraction solvent on the phytochemical profile and the antioxidant, cytotoxic, immunomodulatory, and antimicrobial activities of extracts from the aerial parts of Turnera subulata, with an emphasis on their relationship to processes associated with oxidative stress and the modulation of the immune response. Aqueous (AETS) and hydroethanolic (HETS) extracts were obtained and characterized by LC–MS/MS. Antioxidant activity was assessed using the DPPH, ABTS, TRAP, and deoxyribose/Fenton assays. Cytotoxicity was analyzed in SH-SY5Y cells (MTT and SRB) and in murine splenocytes by flow cytometry (Annexin V/PI). Immune modulation was assessed by quantifying cytokines (IL-4, IL-10, IL-12, and IL-17). Antimicrobial activity was investigated against Staphylococcus aureus, including analysis of interaction with vancomycin. LC–MS/MS analysis revealed a predominance of phenolic compounds, especially flavonoids, with a focus on glycosylated apigenin derivatives. In antioxidant assays, HETS exhibited greater activity in the DPPH and ABTS tests, while AETS demonstrated better performance in the TRAP assay. Both extracts exhibited pro-oxidant behavior in the deoxyribose/Fenton system. In cellular assays, HETS exhibited dose-dependent cytotoxicity in SH-SY5Y cells, while maintaining high viability in murine splenocytes (3.12–50 µg/mL). Analysis of apoptosis and necrosis revealed values similar to those of the control group, with apoptosis ranging from 2.15 ± 0.12% to 3.11 ± 0.20% and necrosis less than 0.15 ± 0.03%. In the immunological assessment, HETS promoted a significant increase in IL-10 (15.48 ± 0.20 to 22.09 ± 0.10 pg/mL; p < 0.05), with no changes in IL-4, IL-12, and IL-17. Additionally, HETS exhibited selective antimicrobial activity against Staphylococcus aureus, with no evidence of synergy with vancomycin. The results demonstrate that the bioactivity of Turnera subulata is strongly influenced by the extraction solvent, with the hydroethanolic extract being the most promising due to its higher relative concentration of phenolic compounds and consistent set of antioxidant, immunomodulatory, and antimicrobial activities. These findings reinforce the species’ potential as a source of bioactive compounds and its relevance for studies aimed at modulating oxidative stress and the immune response.

COMMITTEE MEMBERS:
Presidente - ***.960.650-** - MATHEUS AUGUSTO DE BITTENCOURT PASQUALI - UFCG
Interno - 1880243 - DANIEL CARLOS FERREIRA LANZA
Externo ao Programa - 1507794 - RODRIGO JULIANI SIQUEIRA DALMOLIN - UFRNExterno à Instituição - JOSÉ CLAUDIO FONSECA MOREIRA - UFRGS
Externo à Instituição - JUCIANO GASPAROTTO - UNIFAL-MG