Banca de QUALIFICAÇÃO: PEDRO LUCAS VIEIRA ALVES

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : PEDRO LUCAS VIEIRA ALVES
DATE: 18/12/2025
TIME: 14:00
LOCAL: Sala das Algas (CB) e videochamada https://meet.google.com/xmc-atqa-nrn
TITLE:

Prospection of essential oils from Lippia grata Schauer and Croton blanchetianus Baill
Against Sporothrix brasiliensis.

 

KEY WORDS:

Sporotrichosis; subcutaneous mycoses; natural products; bioactivity.

PAGES: 90
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

Sporotrichosis is a disease caused by species of the genus Sporothrix, affecting domestic animals and humans, has become an emerging mycosis in Latin America due to challenges associated with zoonotic transmission and infection management. The emergence of fungal infections and antimicrobial resistance surveillance have intensified the search for new therapeutic agents. In this scenario, the bioprospecting of natural products, particularly essential oils, which are recognized for their antimicrobial potential. Hence, this study evaluated the in vitro and in vivo bioactivity of essential oils of Lippia grata (LgEO) and Croton blanchetianus (CbEO) against Sporothrix brasiliensis samples, including their antibiofilm activity and interactions with a clinical antifungal. For this purpose, after extraction by hydrodistillation and chemical characterization using gas chromatography–mass spectrometry), 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 biofilm formation capacity of Sporothrix brasiliensis samples, as well as the antibiofilm activity of the oils, were determined by quantifying the biomass through optical density measurement following crystal violet staining. To compare the action of the essential oils with itraconazole in vivo, assays were performed using Galleria mellonella larvae, assessing survival and fungal burden.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%), thymol (7.7%), ρ-cymene (15%), and γ-terpinene (13.7%) predominated, while in CbEO, the sesquiterpenes γ-elemene (18.4%), spathulenol (11.6%), β-caryophyllene (10.8%), β-gurjunene (10%), and trans-calamenene (9.4%) were the predominant components. The different oils showed anti-Sporothrix activity. MIC values of LgEO ranged from 48 µg/mL to 12,500 µg/mL for the filamentous form and from 31.25 µg/mL to 250 µg/mL for the yeast form. MIC values remained within these same ranges, confirming potent activity. Fungicidal action was observed against 85.71% and 100%, respectively, for the filamentous and yeast-like forms. For CbEO, the MICs occurred between 97 µg/mL and 6,250 µg/mL in the filamentous form, and 62.5 µg/mL and 250 µg/mL for the yeast-like form, having fungicidal action on 66% and 82.35%, respectively. In the evaluation of the combination of LgEO with itraconazole, synergism (28.5%), additivity (42.8%), and indifference (28.5%) were found in the filamentous form, while for the yeast-like form, 100% additivity was observed. In the analysis of the combination of CbEO with itraconazole, synergism (33%), additivity (50%), and indifference (16.6%) were observed for the filamentous form, while for the yeast-like form, additivity (40%) and synergism (60%) were detected. All samples tested produced biofilms, classified as moderate (17.6%) or strong producers (5.8%).The in vivo tests with Galleria mellonella larvae are currently being repeated and further analyzed. 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 in the development of phytopharmaceuticals or prototype compounds for the treatment of mycoses, including sporotrichosis.

COMMITTEE MEMBERS:
Externo à Instituição - LEANDRO BEZERRA DE LIMA - UERN
Externo ao Programa - 2154712 - THALES DOMINGOS ARANTES - UFRNPresidente - 2121234 - VANIA SOUSA ANDRADE