Banca de QUALIFICAÇÃO: JÚLIA MARIA RODRIGUES GUIMARÃES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JÚLIA MARIA RODRIGUES GUIMARÃES
DATE: 02/12/2025
TIME: 15:00
LOCAL: Diretoria do Departamento de Morfologia e Fisiologia Animal
TITLE:

Evaluation of the pharmacological and insecticidal potential of cladode preparations of Cereus jamacaru DC

KEY WORDS:

Mandacaru; bacterial resistance; natural insecticides; bioactive compounds; Aedes aegypti

PAGES: 43
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

The cladode extract of Cereus jamacaru DC. (Cactaceae) (CjCE), an endemic plant from the Brazilian semiarid region with economic and popular medicinal relevance, was investigated as a promising source of bioactive substances. This study addresses the growing global concern regarding antibiotic bacterial resistance and the high environmental toxicity of synthetic insecticides. The aim was to chemically characterize CjCE and evaluate its antimicrobial and larvicidal potential. CjCE was obtained from dried and ground cladodes, homogenized in 0.15 M NaCl solution, followed by filtration and centrifugation. Chemical characterization involved the quantification of phenolic compounds and flavonoids (expressed as gallic acid and quercetin equivalents, respectively), and the investigation of lectins (using rabbit erythrocytes) and protease inhibitors (using trypsin). The detailed profile was obtained by Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier-Transform Infrared Spectroscopy (FTIR). Antioxidant activity was assessed by the DPPH, ABTS, and phosphomolybdenum methods. In biological assays, CjCE's antibacterial potential was tested against sensitive and resistant pathogenic strains, determining the Minimum Inhibitory Concentration (MIC) via microdilution. The extract's ability to reduce human erythrocyte lysis induced by Staphylococcus aureus was evaluated using a hemolysis assay. Finally, the larvicidal effect was investigated against L3 larvae of Aedes aegypti L. (Diptera: Culicidae), exposed to different CjCE concentrations (0.40 - 3.5%, w/v) for 48 h. The extract showed hemagglutinating activity (8 HAU), indicating the presence of lectins, and inhibited trypsin activity. Chemical analysis revealed 40.20 ± 0.97 mgGAE/g of phenolic compounds, of which 8.36% (3.36 ± 0.07 mgGAE/g) were flavonoids. CjCE exhibited relevant antioxidant activity, with radical scavenging capacity for ABTS (IC50 = 3735 µg/mL) and DPPH (IC50 = 2704,5 µg/mL), but did not reduce phosphomolybdenum. Among the tested strains, S. aureus (UFPEDA 02) was sensitive to CjCE, which showed a strong bacteriostatic effect (MIC = 199,09 ± 0,85 µg/mL). The extract reduced the hemolysis caused by the bacterium by over 90%. Regarding the larvicidal effect, a dose-dependent mortality was observed with an LC50 of 0,68% (w/v). Larvae treated with 3.5% CjCE eliminated their gut contents covered by the peritrophic membrane, indicating a defense response to the extract's toxic components. In conclusion, the cladode extract of C. jamacaru possesses bioactive compounds with antimicrobial and insecticidal potential, acting by inhibiting the growth of S. aureus and causing mortality in A. aegypti larvae. These results highlight C. jamacaru as a promising source for the development of alternative natural agents to synthetic products.

COMMITTEE MEMBERS:
Presidente - EMMANUEL VIANA PONTUAL
Interna - JAQUELINE BIANQUE DE OLIVEIRA
Externa à Instituição - AMANDA LINS BISPO MONTEIRO - UFRPE