Motta Neto, RenatoBarros, Amanda Vieira de2022-03-112021-09-21BARROS, Amanda Vieira de. Avaliação da atividade antibacteriana e antibiofilme in vitro de óleos essenciais de plantas condimentares sobre bactérias potencialmente patogênicas. 2021. 130f. Dissertação (Mestrado em Ciências Biológicas) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2021.https://repositorio.ufrn.br/handle/123456789/46529In the search for new alternatives for bacterial control, research using spice plants is gaining more and more prominence. Given their nutritional value and antibacterial potential, spice plants are being used in alternative methodologies. Thus, 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 the study was to evaluate the antibacterial and antibiofilm potential of essential oils from spice plants against 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 (Rosecrim), Zingiber officinale (Ginger), and Allium sativum (Garlic) were commercially obtained, and their oils were extracted by hydrodistillation coupled with Clevenger. Their chemical profiles were evaluated by the Gas Chromatography technique coupled with Mass Spectrometry. To evaluate the antimicrobial activity, the Minimum Inhibitory Concentration and, subsequently, the Minimum Bactericidal Concentration of essential oils were determined. The subinhibitory concentrations of MIC, 2xMIC, and 4xMIC were used to analyze the effect of oils in inhibiting biofilms, being evaluated by crystal violet uptake tests and optical density reading at 595 nm, and the results compared with the effect of the antibiotic Amoxicillin at the same concentrations. In evaluating the chemical profile of essential oils, a higher concentration of monoterpenes and sesquiterpenes was observed in R. officinalis and Z. officinale, while the oil of A. sativum was mainly composed of organosulfur substances. The essential oils showed activity against the strains tested, especially against P. aeruginosa (MIC 1.33-5.33 µg/mL and CBM 0.83-1 µg/mL). The best result of the oil of R. officinalis was observed against the S. aureus strain (MIC 8 µg/mL and MBC 3.33 µg/mL), whereas Z. officinale achieved a better effect against E. coli (MIC 4 µg/mL and MBC 5.33 µg/mL), while A. sativum oil had the best performance against K. pneumoniae (MIC 4 µg/mL and MBC 5.33 µg/mL). Assessing the effect of oils on biofilm inhibition, R. officinalis was able to inhibit only the S. aureus formation (≥ 57.33%) at the concentrations of 2xMIC and 4xMIC, with no effect on other biofilms. The best antibiofilm effects were observed for Z. officinale and A. sativum, in which they managed to inhibit the formation of almost all tested biofilms with an inhibition rate greater than 70%, achieving better performance than the antibiotic Amoxicillin at the same concentrations. It is concluded that, due to the concentration of terpenes and organosulfur, the essential oils of Z. officinale and A. sativum, respectively, showed better antibacterial activity, inhibiting the formation of biofilms and becoming promising alternatives for the preservation of food and combating pathogenic microorganisms.Acesso EmbargadoCompostos fitoquímicosConservação de alimentosBiofilmesZ. officinaleA. sativummasterThesis