Antimicrobial activity of plants native to Sonora, Mexico, against pathogenic bacteria isolated from milk from cows diagnosed with mastitis

Bovine mastitis is a disease caused by pathogenic bacteria that infect the mammary gland of dairy cattle, which generates significant economic losses, in addition, due to the excessive use of antibiotics to treat this disease, microorganisms have created resistance to these drugs, therefore, new alternatives are sought for this purpose. The objective was to evaluate the antimicrobial effect of extracts of plant native to Sonora against pathogenic bacteria isolated from cows diagnosed with mastitis. Seventeen ethanolic extracts were obtained from plants native to Sonora, and their antimicrobial activity was evaluated by the agar diffusion method against seven pathogens isolated from milk from cows with mastitis, using a concentration of 50 mg/ml of each extract. The content of total phenols and flavonoids was determined by spectrophotometry. The results showed that extracts of Ibervillea sonorae (wereke, tuber), Populus alba (poplar, leaves), Ambrosia ambrosioides (chicura, stems), Krameria sonorae (cosahui, roots) and Prosopis velutina (mesquite, leaves) were effective in eliminating S. aureus, Streptococcus spp., E. coli, Enterobacter spp., Proteus spp., Shigella spp. and Citrobacter spp. (P<0.05). In addition, extracts high in total phenols and flavonoids (wereke, poplar, chicura, cosahui and mesquite) showed an inverse correlation with respect to pH (r= -0.94, r= -0.92, respectively) (P<0.05) and had greater antimicrobial activity against the tested pathogens. Therefore, the extracts of plants from Sonoran could represent an alternative for the control of Gram (+) and Gram (-) pathogens that infect the mammary gland of dairy cattle.