Banca de DEFESA: FÁBIO DO NASCIMENTO SALES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FÁBIO DO NASCIMENTO SALES
DATE: 24/03/2023
TIME: 14:30
LOCAL: Local: POP-RN (transmissão simultânea) ou apresentação remota (Google Meet)
TITLE:

Antifungal potential of Lippia grata Schauer (Verbenaceae) essential oil against Candida and dermatophyte species”

KEY WORDS:

Candidiasis; dermatophytosis; phytoconstituents; plant products; antimicrobial resistance.

PAGES: 140
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:

Species of the genus Candida are responsible for about 80% of serious fungal infections, being Candida albicans the most commonly isolated specie in these cases, besides tobefrequently associated with cutaneous and mucocutaneous fungal infections. Amongthefilamentous fungi, the dermatophytes that cause cutaneous mycoses in humans affect 25%of the world population and 18% to 23% of the Brazilian population. In the last decades, Candida and dermatophyte species, as well as several other fungal species, have showedresistance development to conventional antifungal drugs used in clinical therapy. Thus, inface of the scenario of emerging drug-resistant fungal pathogens, it is perceivedanincessant search of the scientific community for natural compounds that present antifungal potential, such as those of plant origin, due to their many antimicrobial properties describedin the literature. Therefore, the present proposal aims to evaluate the antifungal activityof the essential oil from the plant Lippia grata Schauer (Verbenaceae) against yeasts of theCandida genus and different species of dermatophyte fungi. The essential oil was obtainedfrom the hydrodistillation process, while its phytochemistry was performed bygaschromatography associated with mass spectrometry. The bioactivity of the essential oil obtained from the Lippia grata plant was investigated on 30 fungal samples by the methodof Minimum Inhibitory Concentration (MIC) by the microdilution broth technique andMinimum Fungicidal Concentration (MFC) by the “spot” sowing method. To evaluatesynergistic activity, the “checkerboard” method was used. The quantification tests of biofilm production and antibiofilm activity of Lippia grata essential oil were performedusing crystal violet to measure the optical densities obtained. Four main phytoconstituentswere identified in the chemical characterization of Lippia grata essential oil: carvacrol (51.4%) as the majority constituent, thymol (15.6%), ρ-cymene (12.2%) and γ-terpinene(7.4%). Antifungal activity of Lippia grata essential oil was found for 100%of the testedstrains with MIC ranging from ≤ 0.00075 mg/mL to 3.12 mg/mL and MFC ranging from≤0.00075 mg/mL to 25 mg/mL against Candida strains while the MIC/MFC ranged from≤0.00075 mg/mL to 0.39 mg/mL for dermatophytes. Regarding the evaluation of thesynergistic effect between the essential oil of Lippia grata and the antifungal on the strainsthat presented high MICs of essential oil, it was observed that this combinationwasindifferent to 50% of the strains tested. The results of biofilm formation revealed that 100%of the strains were biofilm producers. For Candida strains, 4 (21.05%) were weakproducing strains, 8 (42.11%) moderate producing strains and 7 (36.84%) strong producingstrains. For dermatophyte strains, 1 (9%) weak producing strains, 2 (18%) moderateproducing strains and 8 (73%) were strong producing strains. For the antibiofilmactivityof the essential oil, it was verified inhibition of cell viability (IC50%) ranging from57.5%to72.4% for Candida strains and 42.4% to 96.4% for dermatophytes, when these strains werepost-treated, respectively, with concentrations of 0.78 mg/mL, 1.56 mg/mLand3.12mg/mL of Lippia grata essential oil. It was concluded that the essential oil of Lippia gratashowed antifungal activity in the assays, motivating new studies with the intention of futuredevelopment of phytodrugs directed to the treatment of fungal infections.

COMMITTEE MEMBERS:
Presidente - 2121234 - VANIA SOUSA ANDRADE
Interno - 1143204 - RAFAEL WESLEY BASTOS
Externa à Instituição - EULÁLIA CAMELO PESSOA DE AZEVEDO XIMENES