Banca de QUALIFICAÇÃO: FÁBIO DO NASCIMENTO SALES
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.STUDENT : FÁBIO DO NASCIMENTO SALES
DATE: 06/02/2023
TIME: 14:30
LOCAL: Sala de aulas da Pós Graduação
TITLE:
Antifungal potential of Lippia grata Schauer (Verbenaceae) essential oil against
Candida and dermatophyte species”
KEY WORDS:
Candida spp.; Dermatophytes; Antifungal activity; Lippia grata; Plant
products.
PAGES: 130
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUMMARY:
According to the World Health Organization (WHO) 300 million of the world's population
is affected by fungal infections. This infections accounting for more than 1.6 million deaths
annually, representing a serious global problem to the world health scenario in the current
context of emerging drug-resistant fungal pathogens. Species of the genus Candida are
responsible for 80% of severe mycosis infections, being Candida albicans the most
commonly isolated species and frequently associated to cutaneous and mucocutaneous
fungal infections. Among filamentous fungi responsible for cutaneous mycoses in humans,
the dermatophytes of the genus Trichophyton, Microsporum and Epidermophyton, have a
prevalence of 25% in cases of dermatophytosis worldwide and between 18 to 23% in
Brazil. In this scenario, incessant search of the scientific community for natural compounds
that have antifungal potential has been noticed in the last decades. Altogether, plant
products have been a great promise due to their antimicrobial properties described in the
literature. Therefore, the present proposal aims to evaluate the antifungal activity of the
essential oil from the plant Lippia grata Schauer (Verbenaceae) against yeasts of the
Candida genus and different species of dermatophyte fungi.The bioactivity of the essential
oil obtained from Lippia grata was investigated in 30 fungal strains by the method of
Minimum Inhibitory Concentration (MIC) by the microdilution broth technique and by
Minimum Fungicidal Concentration (MFC) by the “spot” sowing method. The synergism
test was performed by the "checkerboard" method and for the quantification of the biofilm
formation and antibiofilm activity of the essential oil was performed with the violet crystal
and the obtained optical densities were measured. Furthermore, in order to investigate the
changes in the biofilm structure after exposure to the essential oil, a Scanning Electron
Microscopy (SEM) was performed. Antifungal activity of Lippia grata essential oil was
found for 100% of the strains tested, with MIC ranging from < 0.00075 mg/mL to 3.12
mg/mL, and MFC values ranging from < 0.00075 mg/mL to 25 mg/mL for Candida spp.
and MIC/MFC ranging from < 0.00075 mg/mL to 0.39 mg/mL for dermatophytes.
Regarding the evaluation of the synergistic effect between the essential oil and the
antifungal on the strains that showed high MICs, it was observed that this combination was
indifferent to 50% of the tested strains.The results of biofilm formation revealed that 100%
of the strains were biofilm producers. For Candida strains, 4 (21.05%) were weak
producing strains, 8 (42.11%) moderate producing strains, and 7 (36.84%) strong producing
strains. For dermatophyte strains, 8 (73%) were strong producing strains, 2 (18%) moderate
producing strains and 1 (9%) weak producing strains. For the antibiofilm activity of the
essential oil, it was verified inhibition of cell viability (IC 50% ) ranging from 57.5% to 72.4%
for Candida strains and 42.4% to 96.4% for dermatophytes when these strains were post-
treated, respectively, with the concentrations of 0.78 mg/mL, 1.56 mg/mL and 3.12 mg/mL
of the essential oil of Lippia grata. It was concluded that the essential oil of Lippia grata
showed antifungal activity in the assays, motivating new studies with the intention of future
development of phytodrugs directed to the treatment of fungal infections.
COMMITTEE MEMBERS:
Presidente - 2121234 - VANIA SOUSA ANDRADE
Interna - 1049952 - DEYSIANE OLIVEIRA BRANDAO
Externa ao Programa - 1997012 - RAQUEL CORDEIRO THEODORO - UFRN