Banca de DEFESA: AMANDA VIEIRA DE BARROS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : AMANDA VIEIRA DE BARROS
DATE: 01/10/2021
TIME: 16:00
LOCAL: Plataforma Google Meet
TITLE:

Evaluation of in vitro antibacterial and antibiofilm activity of essential oils from spice plants on potentially pathogenic bacteria

KEY WORDS:

Phytochemicals; Food Preservation; Biofilms; Ginger; Garlic.

PAGES: 85
BIG AREA: Ciências Biológicas
AREA: Microbiologia
SUBÁREA: Microbiologia Aplicada
SPECIALTY: Microbiologia Médica
SUMMARY:

1.   In the search for new alternatives for bacterial control, research using spice plants is gaining more and more prominence. Because of their nutritional value and antibacterial potential, spice plants are being used in alternative methodologies. With this, antimicrobials of natural origin could be an effective and economically viable alternative for food preservation, replacing the use of synthetic substances. Based on these researches, the main objective of this study was to evaluate the antibacterial and antibiofilm potential of essential oils of spicy plants against the strains of food interest Escherichia coli (ATCC 25922) Staphylococcus aureus (ATCC 25923), Klebsiella pneumoniae (ATCC 10031), Pseudomonas aeruginosa (CCBH 5698) and Salmonella Typhimurium. The plants Rosmarinus officinalis (Rosemary), Zingiber officinale (Ginger) and Allium sativum (Garlic) were commercially obtained, and their oils extracted by hydrodistillation coupled with Clevenger. Their chemical profiles were evaluated by the Gas Chromatography technique coupled to Mass Spectrometer. To evaluate the antimicrobial activity, the broth microdilution method was used to determine the Minimum Inhibitory Concentration, and subsequently, the Minimum Bactericidal Concentration. The subinhibitory concentrations of MIC, 2xMIC, and 4xMIC were used to analyse the effect of the oils on biofilm inhibition, and were evaluated by crystal violet uptake tests and optical density reading at 595 nm. In the evaluation of the chemical profile of the essential oils, it was observed a higher concentration of monoterpenes and sesquiterpenes in R. officinalis, Z. officinale, while the oil from A. sativum was composed mostly of organosulfur substances. The essential oils showed activity against the tested strains, especially against P. aeruginosa (MIC 1.33-5.33 µg/mL and BOD 0.83-1 µg/mL). The best results from R. officinalis oil was observed against S. aureus strain (MIC 8 µg/mL and WBC 3.33 µg/mL), while Z. officinale had the best effect against E. coli (MIC 4 µg/mL and WBC 5.33 µg/mL) and the oil of A. sativum showed the best performance in the treatment against K. pneumoniae (MIC 4 µg/mL and WBC 5.33 µg/mL). Evaluating the effect of oils on biofilm inhibition, R. officinalis was able to inhibit only S. aureus formation (≥ 57.33%), showing no free effect to the other biofilms tested. The best antibiofilm effects were observed for Z. officinale and A. sativum, in which, managed to inhibit the formation of almost all biofilms tested with inhibition rate greater than 70%, obtaining better performance than the antibiotic, in most treatments. It is concluded that, due to the concentration of terpenes and organosulfur compounds, the essential oils of Z. officinale and A. sativum showed better antibacterial activity, inhibiting the formation of biofilms and being configured as promising alternatives for the conservation of food and combat of pathogenic microorganisms.

BANKING MEMBERS:
Externa à Instituição - TATIANA PASCHOALETTE RODRIGUES BACHUR - UECE
Externa à Instituição - MANOELA TORRES DO RÊGO - UFRN
Presidente - 1714290 - RENATO MOTTA NETO