Banca de DEFESA: MARCIO MICHAEL PONTES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARCIO MICHAEL PONTES
DATE: 30/06/2026
TIME: 14:00
LOCAL: Auditório do departamento de química-UFRPE
TITLE:

EVALUATION OF THE CHEMICAL PROFILE, ANTIOXIDANT POTENTIAL, ANTIMICROBIAL ACTIVITY AND ANTIVIRULENCE MODULATING EFFECT OF Schinopsis brasiliensis Engl. (ANACARDIACEAE)

KEY WORDS:

Antimicrobial resistance; Staphylococcus aureus; staphylococcal mastitis; barauna.

PAGES: 81
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Inspeção de Produtos de Origem Animal
SUMMARY:

Antimicrobial resistance represents a growing challenge in animal health, particularly in dairy cattle farming, where staphylococcal mastitis is one of the leading causes of production losses and animal culling. Staphylococcus aureus, frequently associated with persistent intramammary infections and resistant strains, complicates conventional treatment and reinforces the need for effective and safe therapeutic alternatives. In this context, medicinal plants from the Brazilian Caatinga biome have attracted scientific interest due to their chemical diversity and biological potential. Schinopsis brasiliensis Engl. (Anacardiaceae), popularly known as “baraúna,” is a species widely used in traditional medicine, yet it remains poorly explored from pharmacological and microbiological perspectives. Therefore, the present study aimed to evaluate the chemical profile, antioxidant potential, antimicrobial activity, cytotoxicity, and virulence-modulating effects of the ethanolic extract and fractions obtained from the leaves of S. brasiliensis, with emphasis on the control of resistant S. aureus strains associated with bovine mastitis. The plant material was subjected to ethanol extraction followed by fractionation using solvents of different polarities. Chemical characterization was performed by gas chromatography (GC–MS) and liquid chromatography (HPLC-DAD-qTOF-MS/MS, negative ion mode). Antioxidant activity was assessed using DPPH and ABTS assays, while antimicrobial activity was investigated against standard MRSA strains and clinical isolates. Additionally, modulation of staphyloxanthin production, as an antivirulence marker, and cytotoxicity in the MAC-T cell line were evaluated. GC–MS analysis of the hexane fraction allowed the identification of 13 nonpolar compounds, predominantly steroids (campesterol, stigmasterol, stigmastanol, and β-sitosterol) and triterpenes (lupeol, α-amyrin, and β-amyrin). In the ethyl acetate fraction, 33 phenolic compounds were identified, including quercetin derivatives (isoquercitrin and rutin), hydrolyzable tannins (pentagalloylglucose and hexagalloylglucose), and the chemotaxonomic marker ethyl 2,4-dihydroxy-3-(3,4,5-trihydroxybenzoyloxy)benzoate. The results demonstrated that the ethanolic extract and, particularly, the ethyl acetate fraction exhibited high radical-scavenging activity (EC₅₀ of 0.93 ± 0.02 μg/mL in the ABTS assay and 2.24 ± 0.02 μg/mL in the DPPH assay), which was associated with their high phenolic content. Significant antimicrobial effects were observed against resistant S. aureus strains, along with a reduction in staphyloxanthin production (at 312 μg/mL, the ethyl acetate fraction promoted a 38% reduction), suggesting interference with bacterial virulence mechanisms. Cytotoxicity assays indicated low toxicity at bioactive concentrations (IC₅₀ of 446.8 μg/mL), reinforcing the safety potential of the samples. Overall, these findings highlight S. brasiliensis as a promising source of natural compounds for the development of alternative therapeutic strategies to control resistant bacterial infections.

COMMITTEE MEMBERS:
Presidente - TANIA MARIA SARMENTO DA SILVA
Interna - ANA LUCIA FIGUEIREDO PORTO
Externo à Instituição - ERYVELTON DE SOUZA FRANCO