Antibacterial and antibiotic modifying activity evaluation of ruminants' body fat used as zootherapeutics in ethnoveterinary practices in Northeast Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: Northeast Brazilian ethnoveterinary studies associated with the medicinal use of zootherapies have shown that ruminants' body fat such as sheep (Ovis aries), goats (Capra hircus) and cows (Bos taurus) are used in diseases affecting domestic animals. AIM OF THE STUDY: The objective of this study was to evaluate the antibacterial activity of the fixed oils from these ruminants in isolation and in association with antibiotics. RESULTS: Ovis aries (OFOA), Capra hircus (OFCH) and Bos taurus (OFBT) fixed oils were extracted using a Soxhlet apparatus with hexane as the solvent. Through the use of gas chromatography coupled to mass spectrometry (GC-MS) the methyl esters from the ruminants' fixed oils were obtained and the fatty acids present in these oils were indirectly determined. The OFOA, OFCH and OFBT antibacterial and antibiotic modifying activities against standard and multi-resistant bacterial strains were carried out using the broth microdilution test. The fixed oils from these species did not present antibacterial activity when tested in isolation, obtaining Minimal Inhibitory Concentration (MICs) values ≥ 1024 µg/mL. However, when associated with antibiotics, OFBT and OFCH showed a synergistic activity for the Amicacin, Amoxicillin, Norfloxacin and Oxytetracycline antibiotics. CONCLUSION: The OFOA promoted a synergistic action for the same antibiotics with the exception of Norfloxacin.