IN-VITRO EVALUATION OF EXTRACT OF MEDICINAL PLANTS FROM CERRADO AGAINST THE STAPHYLOCOCCUS AUREUS ISOLATED FROM DIFFERENT ORIGINS ON DAIRY FARMS

ABSTRACT The objective of this study is to evaluate the potencial microbial activity in-vitro from the extract of some endemic plants from Cerrado such as Baccharis dracunculifolia. Cochlospermum regium. Croton antisyphiliticus. Eugenia dysenterica and Lippia sidoides, against the agent Staphylococcus aureus isolated from bovine mastitic milk, osteo from cow’s teat, milker equipament, nasal cavitites and milker’s gullet. The extracts were prepared from aerial parts as well as the reticular systems of plants using the solvents methanol, hexane and chloroform at a concentration of 10%. To evaluate the antimicrobial activity, the technique of microdilution in broth was used for determining the Minimal Inibitory Concentration (MIC) followed by the determination of Minimal Bactericidal Concentration (MBC). The extracts from Baccharis dracunculifolia and Croton antisyphiliticus, followed by extracts from Lippia sidoides, reported respectively, presented better inhibitory activity against the multiplication of the bacteria Staphylococcus aureus. Furthermore, the results demonstrate that the isolated strains from the milk and nasal cavities of the milker showed strong resistance against gentamicin, active agent commonly applied to combat mastitis bovine. However, there was sensitivity against extracts from the reported plants, reinforcing the importance of the medicinal plants as a therapeutic resource and its aplicability.摘要 本研究旨在体外（in vitro）评估塞拉多（Cerrado）地区几种特有植物提取物的潜在微生物活性，涉及的植物包括Baccharis dracunculifolia、Cochlospermum regium、Croton antisyphiliticus、Eugenia dysenterica及Lippia sidoides。试验针对从奶牛乳腺炎乳样、奶牛乳头骨组织、挤奶设备、鼻腔及挤奶者食道中分离得到的病原菌金黄色葡萄球菌（Staphylococcus aureus）展开。本研究以甲醇、正己烷、氯仿为溶剂，以10%的浓度，从植物的地上部分及网状组织中制备提取物。为评估提取物的抗菌活性，本研究采用肉汤微量稀释法测定最低抑菌浓度（Minimal Inhibitory Concentration, MIC），随后进一步测定最低杀菌浓度（Minimal Bactericidal Concentration, MBC）。结果显示，Baccharis dracunculifolia与Croton antisyphiliticus的提取物对金黄色葡萄球菌的增殖具有最优的抑制活性，其次为Lippia sidoides的提取物。此外，研究结果表明，从乳样及挤奶者鼻腔中分离得到的菌株对庆大霉素表现出较强耐药性，而庆大霉素是常用于防治奶牛乳腺炎的活性药物。然而，上述分离菌株对本次研究所用的植物提取物均表现出敏感性，这进一步凸显了药用植物作为治疗资源的重要价值及其应用潜力。