Banca de DEFESA: ANTONIO CARLOS VITAL JÚNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ANTONIO CARLOS VITAL JÚNIOR
DATE: 27/02/2020
TIME: 09:00
LOCAL: POP Centro de Convivência
TITLE:

ANTIFUNGAL AND ANTIBIOFILM ACTIVITY OF THE EXTRACT FRACTION Ag2 FROM Agelas dispar AGAINST SPECIES OF Candida

KEY WORDS:

Candidiasis. Yeasts. Natural products. Alkaloids. Scanning Electron Microscopy

PAGES: 114
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
SPECIALTY: Microbiologia Médica
SUMMARY:

Microbial biofilms are especially a structural barrier that hinders antimicrobial therapy, having a relevant role in human diseases. For yeasts of the genus Candida, biofilms are characterized as a complex three-dimensional arrangement, consisting of different cellular forms incorporated into an extracellular polymeric matrix. In the last decades, the search for natural compounds for the treatment of microbial infections has grown in order to find new alternatives to the mechanisms of resistance to antimicrobials, including those induced by biofilms. The marine sponge, Agelas dispar (Family Agelasidae) has been mentioned as a bioactive source, due to its secondary metabolites, the alkaloid derivatives, which have significant pharmacological activity. In this context, the aim of this study was to determine the antifungal and antibiofilm activity of the Ag2 fraction of the A. dispar metanolic extract on biofilm-producing strains of the genus Candida. The biological activity was investigated in 13 species of Candida, evaluating the Minimum Inhibitory Concentration (MIC) by the broth microdilution technique and by the Minimum Fungicide Concentration (MFC) method. The quantification of biofilm formation and antibiofilm activity of the Ag2 fraction of the extract was performed with the violet crystal and the obtained optical densities were measured. The Ag2 fraction of the extract showed antifungal activity for 13 strains, demonstrating MIC’s ranging between 2.5 mg/mL and 0.1562 mg/mL. The compound analyzed showed MFC's ranging from 5.0 mg/mL to 0.3125 mg/mL against Candida spp. The results of biofilm formation indicated that all strains were biofilm producers. 10 (77%) weak producing strains and 3 (23%) moderate producing strains. The species C. krusei, C. glabrata and C. parapsilosis were used to test the antibiofilm activity (in formation and mature), resulting in inhibition of cell viability (IC50%) ranging from 49.6% to 57.6%, 70.5% to 76.3% (biofilm in formation) and 42.8% to 67.2%, 63.3% to 78.8% (mature biofilm) when these strains were post-treated, respectively, with the concentrations of 1.25 mg/mL and 2.5 mg/mL of the Ag2 fraction. The Scanning Electron Microscopy (SEM), allowed the visualization of the antibiofilm activity, quantitative decrease of the microbial community, structural alteration and destruction at the cellular level in both the forming and mature biofilms. It was concluded that the Ag2 fraction of A. dispar methanolic extract showed antifungal activity and fungicide nature, in addition to being efficient in decreasing the microbial load and providing changes in the structural morphology of the yeasts involved in the biofilm, as observed in the SEM. Such findings suggest that the mechanism of action of the fraction is at the level of plasma membrane and/or cell wall, inferring that the Ag2 fraction may be a promising antifungal and antibiofilm therapeutic strategy against the different species of Candida.

BANKING MEMBERS:
Interno - 348473 - JOSE VERISSIMO FERNANDES
Externo à Instituição - MARIA APARECIDA RESENDE STOIANOFF - UFMG
Presidente - 2121234 - VANIA SOUSA ANDRADE