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Antimicrobial properties of medicinal teas and their interactions with antibiotics

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Abstract (summary)

The rise of antibiotic-resistant bacteria has greatly increased the need for new drugs to be developed. These drugs may be new antibiotics, or synergists of existing antibiotics. Plants have been identified as a valuable source of new drugs, as plants produce secondary metabolites that have antimicrobial and synergistic activity. In addition, plants are the basis of many natural health products and dietary supplements, and public interest in these products continues to increase. The increasing popularity of natural health products also increases the possibility for antagonistic interactions to occur when these products are used in conjunction with antibiotics. The present study investigated the antimicrobial properties of aqueous extracts of three medicinal teas and their interactions with common antibiotics. The antimicrobial properties of the aqueous extracts of Bronchitis tea, Eyebright tea, and Hyssop tea were assessed via disk diffusion. It was found that both Eyebright tea and Hyssop tea extracts have antimicrobial properties, likely due to the phenolic acids and flavonoids found in extracts of these plants. Interactions between the tea extracts and antibiotics were assessed using a double disk diffusion method, where it was found that all three tea extracts interact antagonistically with sulfadiazine. Additionally, Eyebright tea extract was found to interact antagonistically with chloramphenicol. While further research is required to determine the mechanism of this interaction and the specific compounds involved, this research has identified that these teas should potentially be used with caution in combination with antibiotics. In addition, the antimicrobial properties of both Hyssop and Eyebright tea extracts warrant further research as these extracts may be the basis for new antimicrobial drugs in the future.

Publication Information



Presented in absentia on April 27, 2020 at "Student Research Day" at MacEwan University in Edmonton, Alberta. (Conference cancelled). Also presented at the Undergraduate Research in Science Conference of Alberta (URSCA).

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Student Presentation




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