Banca de QUALIFICAÇÃO: SARA THAMIRES DIAS DA FONSECA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : SARA THAMIRES DIAS DA FONSECA
DATE: 15/10/2020
TIME: 13:30
LOCAL: Plataforma Digital Google Meet
TITLE:

ANTIOXIDANT, ANTIMICROBIAL AND ANTIBIOFILM ACTIVITY OF EXTRACTS AND FRACTIONS OF Bauhinia holophylla (FABACEAE: CERCIDEAE)

KEY WORDS:

Pata-de-vaca, Cerrado, phenolic compounds, antimicrobial activity, biofilm.

PAGES: 84
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Medicinal plants have bioactive substances responsible for biological activities such as antifungal, antibiofilm, antibacterial and antioxidant. Yeasts of the genus Candida, mainly Candida albicans, correspond to the main cause of fungal infections in humans and most infections are due to the formation of resistant biofilms. Bacterial resistance has increased rapidly and bacteria are already resistant to all antibiotics. Plants of the genus Bauhinia are rich in phenolic compounds and flavonoids, which have been associated with antimicrobial activity. The objectives of this study are to evaluate the antimicrobial, antibiofilm and antioxidant activities of extracts and fractions of leaves of Bauhinia holophylla and to identify possible compounds or groups of compounds related to this activity. B. holophylla leaves were collected in 2014 and 2018 and extracts were prepared with 70º GL ethanol and 95º GL ethanol, respectively. The extracts were fractionated by partition, with solvents of increasing polarity. The contents of phenols and total flavonoids were determined using usual methodologies and the antioxidant activity of extracts and fractions by the DPPH inhibition method. For the antimicrobial tests, the Minimum Inhibitory Concentration (MIC) of the extracts and fractions against C. albicans, Klebsiella pneumoniae, Staphylococcus epidermidis and Acinetobacter baumannii were determined at concentrations from 0.24 to 125 µg mL-1. The same concentrations were used for the C. albicans antibiofilm assay. The results showed that the tested extracts and fractions did not show antifungal or antibacterial activity. The crude extracts and the dichloromethane and acetoethyl fractions showed higher levels of total phenols and flavonoids, as well as higher antioxidant activities. The dichloromethane and acetoethyl fractions from the fractionation of the hydroethanolic extract showed the greatest antibiofilm activities. The difference in the year of collection and the solvents used in the extraction influenced the phytochemical profile of the extracts.

BANKING MEMBERS:
Presidente - 395916 - ANA HORTENCIA FONSECA CASTRO
Interna - 1540495 - LUCIANA ALVES RODRIGUES DOS SANTOS LIMA
Interna - 1742677 - JAQUELINE MARIA SIQUEIRA FERREIRA
Externa ao Programa - 1581671 - MAGNA CRISTINA DE PAIVA
Externa ao Programa - 1584015 - ANA GABRIELA REIS SOLANO