Ações antibacteriana, moduladora de antibióticos e antiproteásicas de frações proteicas da semente de catingueira (Poincianella pyramidalis Tul.)

Abstract

Bacterial resistance, as well as inflammatory disorders, are significant public health problems that take thousands of people to hospitals every year, often requiring several days of hospitalization for treatment, generating excessive costs and, sometimes, without solving the problem. Considering the importance of discovering new substances that mitigate these problems, this study aimed to evaluate the crude extract and protein fractions of the seed of Poincianella pyramidalis (Tul.) for antibacterial, antibiotic-modulating, and protease-inhibiting activities. The protein extracts were obtained from extraction with 0.05M Tris-HCL buffer pH 7.5 and subsequent fractionation with ammonium sulfate in different saturation ranges 0-30%, 30-60% and 60-90% of sodium sulfate ammonium. The electrophoretic profile revealed several protein bands between 12 KDa and 225 KDa. The inhibitor-enriched fraction (FE) was obtained using only a Trypsin-Sepharose affinity chromatography after extraction. The antimicrobial activity test was performed through the microdilution assay and the modulating action of the antibiotics ampicillin, norfloxacin and gentamicin, using a subinhibitory concentration MIC/8. Although the samples did not show direct antimicrobial action against the ATCC strains Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA), it was observed that, at a concentration of 128 µg/mL, the samples associated with the different antibiotics (aminoglycoside, β-lactam and fluoroquinolone) had a synergistic action against the multiresistant strains of E. coli, S. aureus and Pseudomonas aeruginosa. While the other samples inhibited the action of the serine proteases tested in percentages above 80%, FE reduced 50% of the activities of the enzymes trypsin, human neutrophil elastase (HNE) and chymotrypsin, at concentrations of 0.017, 0.023 and 0.156 µg/µL, respectively, and its antitrypsin activity was maintained at high temperatures (80 ºC) and a wide pH range (2 to 12). No hemolytic activity was observed at concentrations up to 10x higher than the IC50, thus enabling its use in possible pharmacological preparations. In this way, we were able to separate, in a relatively simple way, products derived from P. pyramidalis seeds with relevant activities in the clinical context, considering their potential application in combating infections caused by resistant bacteria, as well as in inflammatory protease disorders, and with reduced treatment costs.