EFEITO DO EXTRATO HIDROALCOÓLICO DAS FOLHAS DE Syzygium cumini (L.) SKEELS E DOS SEUS COMPOSTOS MAJORITÁRIOS SOBRE BACTÉRIAS PRESENTES NA MICROBIOTA INTESTINAL E SOBRE CAMUNDONGOS INFECTADOS POR Escherichia coli 042

Abstract

The intestinal microbiota (IM) is seen as a key regulator in the physiology and pathophysiology of its hosts, demonstrating a relationship with the regulation of fat storage, obtaining energy, as well as an intimate connection with the intestinal lymphoid tissue and its existing immune network. The agents that have been extensively studied in recent years as potential therapies in the IM scenario are the polyphenols found in plants, such as Syzygium cumini (L.) Skeels, also known as purple olives, jambolão or jamelão. Thus, this study aimed to investigate the effect of the hydroalcoholic extract of the leaves of Syzygium cumini (L.) Skeels and the main compounds present in it on bacteria that make up the intestinal microbiota. For this purpose, the 96-well plate microdilution technique was used to determine the Minimum Inhibitory Concentration (MIC) of the hydroalcoholic extract of S. cumini leaves (EHSC) on Escherichia coli, Staphylococcus aureus, Lactobacillus paracasei and Enterococcus faecalis strains, bacteria belonging or with potential to compose IM. From the result obtained in the MIC, the plating of 10 μl aliquots of the wells was performed on plates containing Mueller Hinton agar to determine the Minimum Bactericidal Concentration (CBM), from the visualization of growth or not of bacterial colonies. In addition, the cytotoxicity test was performed from the cell viability test with MTT using HT29 cells and the in vivo colonization of Swiss mice with the E. coli 042 bacterium, and subsequent treatment with the EHSC for analysis and comparison of results. The MIC result was 3.12 mg / mL showing bacteriostatic effect on E. coli 042, E. coli HB101 and S. aureus ATCC 25923 and E. faecalis 29212, and 1.5 mg / mL on L. paracasei. The result of CBM showing a bactericidal effect was 6.25mg / mL on these same bacteria mentioned, with the exception of L. paracasei, which presented a value of 3.1 mg / mL. As for the isolated compounds of the EHSC: myricetin, quercetin and gallic acid, the MIC was 5mg / mL, 0.25mg / mL and 1.25mg / mL, respectively, over S. aureus and L. paracasei. For E. coli 042 and E. faecalis it was 5 mg / mL, 0.25 mg / mL and 0.31 mg / mL, for the same compounds, and 2.5 mg / mL, 0.12 mg / mL and 0.62 mg / ml on E. coli HB101. In addition, gallic acid potentiated the effect of myricetin and quercetin, reducing the value of their MICs on E. coli 042 and L. paracasei when the three isolates were combined. However, all of these values were bacteriostatic, since when the CBM test was performed, none of the concentrations used showed a bactericidal effect. It was possible to observe that there was no toxicity of any of the substances used here on the HT29 cells or on the organs of the evaluated animals. In the animal colonization test, the S. cumini EH decreased the efficiency of E. coli 042 colonization from the 6th day on in the animals. Therefore, it was possible to demonstrate the potential modulatory effect of EHSC, since it presents different values on different bacteria, as well as the synergy of its main compounds, in addition to the possibility of avoiding negative consequences in a possible pathogenic bacterial colonization by decreasing the capacity of this colonization.