Banca de DEFESA: PEDRO LUCAS VIEIRA ALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : PEDRO LUCAS VIEIRA ALVES
DATE: 25/03/2026
TIME: 14:00
LOCAL: meet.google.com/oja-kggu-pkf
TITLE:

Prospection of the essential oils from Lippia grata Schauer e Croton blanchetianus Baill against Sporothrix brasiliensis.

KEY WORDS:

Sporotrichosis; natural products; antifungals.

PAGES: 133
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

Sporotrichosis is a disease caused by species of the genus Sporothrix, affecting domestic animals and humans, resulting in an emerging mycosis in Latin America due to the challenges involved in controlling the infection. The emergence of fungal infections and the surveillance of antimicrobial resistance have driven the search for new drugs. In this scenario, the bioprospecting of natural products, particularly essential oils, already recognized for their promising antimicrobial activity, stands out. Hence, this study evaluated the in vitro and in vivo bioactivity of the essential oils of Lippia grata (LgEO) and Croton blanchetianus (CbEO) against S. brasiliensis samples. For this purpose, after obtaining and describing the chemical composition of LgEO and CbEO, the antifungal activity of the oils was evaluated by determining the minimum inhibitory concentration (MIC) by broth microdilution and the minimum fungicidal concentration (MFC) by plating on solid culture medium. The combination of the oils with itraconazole was performed using the checkerboard method. The antibiofilm activity of the oils was evaluated by quantifying the biomass after staining with crystal violet. The in vivo effect of the essential oils was analyzed through toxicity and treatment assays using a Galleria mellonella larvae model, evaluating morbidity and mortality curves, as well as fungal load. As a result, yields of 1.05% and 0.3% were obtained, respectively, for LgEO and CbEO. In the composition of LgEO, the monoterpenes carvacrol (48.5%) and ρ-cymene (15%) predominated, while in CbEO, the sesquiterpenes γ-elemene (18.4%) and spathulenol (11.6%) were the predominant components. Both oils showed anti-Sporothrix activity. The MIC90 values found for LgEO were 781.25 µg/mL and 125 µg/mL for the filamentous and yeast-like forms, respectively. For CbEO, the observed MIC90 was 6,250 µg/mL in the filamentous form and 250 µg/mL for the yeast-like form. The fungicidal action of the oils was found for most strains, reaching 100% for LgEO and 82.35% for CbEO against the yeast-like form. In the evaluation of the combination of LgEO with itraconazole, positive synergistic and additivity interactions were found in the filamentous form (57.14% - 71.42%), as well as for the yeast-like form (100%). Similarly, these interactions were observed in the analysis of the combination of CbEO with itraconazole for the filamentous form (83%) and for the yeast-like form (100%). All tested samples produced biofilms, being classified as moderate (17.6%) and strong producers (11.7%). Activity against pre-formed and forming biofilms was detected in at least 60% of the strains at a concentration of 125 µg/mL for LgEO and 2,500 µg/mL for CbEO . Only the concentration of 125 µg/mL of LgEO reached the CIMB50 in two strains, showing an inhibition rate of around 60%. In toxicity tests, both oils proved safe for the larvae. In the treatment assay, the 20 mg/kg dose of LgEO was the only one that aided in the survival of larvae infected by S. brasiliensis (40%). In conclusion, the results found in this study allow us to affirm that LgEO and CbEO demonstrate significant anti-Sporothrix activity, supporting future investigation of isolated constituents and acquisition of prototypes that can be used in the treatment of mycoses, including sporotrichosis.

COMMITTEE MEMBERS:
Externa ao Programa - 1549705 - ADRIANA FERREIRA UCHOA - nullExterno à Instituição - FELIPE QUEIROGA SARMENTO GUERRA - UFPB
Presidente - 2121234 - VANIA SOUSA ANDRADE