Banca de DEFESA: RODRIGO DIAS ALVES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RODRIGO DIAS ALVES
DATE: 08/06/2026
TIME: 14:00
LOCAL: Videoconferência
TITLE:

Seasonal Variation in the Chemical Composition and Bioactivity of Essential Oils from Lippia alba (Lemon Balm) Obtained in a Semi-Arid Northeastern Environment

KEY WORDS:

Seasonal variation; Citral chemotype; Oxidative stress; Reactive oxygen species; Antiproliferative activity

PAGES: 109
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Seasonal environmental conditions influence the secondary metabolism of medicinal plants, affecting the composition of volatile constituents and their biological activities. This study investigated the chemical profile, antioxidant activity, cytotoxicity, and cytoprotective effects of essential oils obtained from Lippia alba (Mill.) N.E. Br. (lemon balm), collected during dry and rainy seasons in a semi-arid region. Chemical characterization by gas chromatography–mass spectrometry (GC–MS) showed the preservation of the citral chemotype across all samples. Principal Component Analysis (PCA) identified citral as the main discriminant metabolite, while seasonal variation was associated with quantitative differences in minor oxygenated monoterpenes, including geraniol, carvone, and nerolidol. Two representative samples, one from each season, were selected for comparative analysis. The essential oil obtained during the rainy season exhibited higher in vitro antioxidant activity than that from the dry season, as determined by DPPH radical scavenging, reducing power, total antioxidant capacity, and hydrogen peroxide scavenging assays. Intracellular reactive oxygen species (ROS) levels, assessed using the DCFH-DA assay, were reduced by both samples in murine fibroblasts (L929). The rainy season oil showed a greater cytoprotective effect. Cytotoxicity assays performed on non-tumor (NIH/3T3, L929, and CHO-K1) and tumor cell lines (HeLa and HepG2) revealed selective antiproliferative activity, with higher sensitivity observed in tumor cells. The oil obtained during the rainy season demonstrated a stronger inhibitory effect on cell growth. These findings indicate that seasonal variation affects minor chemical constituents and is associated with differences in biological activity, without altering the predominant chemotype.

COMMITTEE MEMBERS:
Externo à Instituição - CARLOS EDUARDO BEZERRA DE MOURA - UFERSA
Presidente - 2195251 - HUGO ALEXANDRE DE OLIVEIRA ROCHA
Externo à Instituição - MOACIR FERNANDES DE QUEIROZ NETO - UFPB
Externo à Instituição - RANIERE FAGUNDES DE MELO SILVEIRA - UNINASSAU
Externo à Instituição - ÉDER GALINARI FERREIRA - UFOP