Evaluación de la actividad antibacteriana de extractos etanólicos sobre bacterias que causan enfermedades transmitidas por alimentos


Facultad de Ciencias Químicas

Q. Perla Yaneth Villa Silva

Abstract: Tagetes lucida, Yucca filifera and Prosopis glandulosa are used for food consumption and used in traditional medicine for their antimicrobial properties. Consequently, in this study, the antibacterial effect of ethanolic extracts of these plants on Escherichia coli (ATCC11229), Salmonella choleraesuis (ATCC1070), Staphylococcus aureus (ATCC6538) and Pseudomonas aeruginosa (ATCC15442) was evaluated. Additionally, extraction performance, toxicity on A. salina, was determined. Furthermore, a qualitative phytochemical analysis was done to identify the main groups of compounds and the antioxidant effect determined by the techniques of total polyphenols, FRAP, ABTS and DPPH. The antibacterial effect by the disk diffusion method, microdilution in plate and bioautography was evaluated. The site of action of the most active extract was identified on the most sensitive strain. The decrease in viability of the Vero and Hek-293 cell lines of the extract with the most antibacterial effect was evaluated. On the other hand, the extract by Rp-HPLC was characterized. The Y. filifera extract showed greater toxicity in A. salina, while the extracts of T. lucida and P. glandulosa had moderate toxicity. All the extracts presented flavonoids, coumarins and lactones, which may have phenolic unsaturations and hydroxides in their chemical structures. The extract of T. lucida revealed a greater antioxidant and antibacterial effect as well as a MIC100 of 4 mg / mL on S. aureus. The technique of bioautography showed a synergism between the compounds of the extracts. In addition, was detected that T. lucida extract permeabilizes the plasma membrane of S. aureus so that it penetrates inside and causes DNA damage. On the other hand, the extract of T. lucida decreased viability on cell lines and 9 compounds were detected, among which 3,4-DHPEA-EA, medioresinol and tangeretin are responsible for the antibacterial effect.

Thesis Perla Villa Silva