UPLC-QTOF-MS/MS characterization of a fraction enriched in saponins from Sarcomphalus joazeiro species and evaluation of the antibacterial activity against multidrug-resistant bacteria

The increase in bacterial resistance is characterized as a serious health problem, the main cause of which is the indiscriminate use of antibiotics, which has adverse effects on the human microbiota. For this reason, more and more natural products are being investigated as accessible and beneficial alternatives for controlling microbial resistance. In view of the above, the aim of this study was to verify the intrinsic antibacterial activity of the saponin-enriched fraction obtained from the Sarcomphalus joazeiro species, as well as its combined effect with antibiotics against multi-resistant bacteria. The fraction obtained from the bark of the S. joazeiro stem was analyzed by UPLC-QTOF-MS/MS, in which 20 compounds were identified: five acids, one nitrogen compound, two triterpenoids, three flavonoids, three saponin derivatives and six saponins. The test to verify the antibacterial activity of the fraction was carried out using the broth microdilution method, obtaining the minimum inhibitory concentration (MIC), and from the value of the sub-inhibitory concentration the activity modifying the antibiotic action was evaluated. The tests were read using a colorimetric indicator and the geometric mean was used for statistical analysis. Thus, the saponin-enriched fraction showed significant results when combined with gentamicin and nofloxacin against Pseudomonas aeruginosa and Staphylococcus aureus bacteria. Therefore, the fraction showed a potentiating effect when associated with antibiotics, thus inducing an increase in antibacterial activity against Gram-positive and Gram-negative bacteria. These results are promising for a possible alternative against bacterial resistance, through the action of natural products associated with antibiotics of clinical importance. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.