PHYTOCHEMICAL PROFILE AND ANTIMICROBIAL ACTIVITY OF PLANT EXTRACTS AGAINST PATHOGENIC MICROORGANISMS OF IMPORTANCE TO THE LIVESTOCK INDUSTRY

Abstract

Infections caused by pathogenic bacteria are a recurrent problem in the livestock sector, generating important economic losses in the livestock industry. One of the main strategies includes antibiotic therapy; however, its use is limited since pathogenic bacteria present resistance to these drugs, which makes treatment against microbial infections difficult. Therefore, the hypothesis proposed was that ethanolic extracts of native plants from the state of Sonora, Mexico, can inhibit the growth of Gram (+) and Gram (-) pathogenic bacteria related to common infections in the livestock industry. The objective was to evaluate the phytochemical and antimicrobial profile of native plants from the state of Sonora, Mexico. In this study, 17 ethanolic extracts were obtained from native plants of Sonora, and the antimicrobial activity was evaluated by the agar diffusion method and by the microdilution technique using reference bacteria from the ATCC collection. The phytochemical profile was evaluated by spectrophotometry and the experimental design used was completely randomized with three replicates per treatment at 95 % confidence. The results showed that extracts of Prosopis velutina, Ibervillea sonorae, Populus alba, Ambrosia ambrosioides, Krameria sonorae, and Leucaena leucocephala were effective in eliminating Listeria monocytogenes ATCC 19115, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella enterica serovar Typhimurium ATCC 14028 (p≤ 0.05). In addition, these extracts presented the highest concentration of total polysaccharides, flavones and flavonols, flavanones and dihydroflavonols, tannins and total chlorogenic acid (p ≤ 0.05). Therefore, plant extracts from Sonora, Mexico, represent a natural alternative for the control of Gram (+) and Gram (-) pathogens of importance to the livestock industry.