Banca de QUALIFICAÇÃO: CAMILA APARECIDA PEREIRA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : CAMILA APARECIDA PEREIRA DA SILVA
DATE: 28/03/2025
TIME: 14:00
LOCAL: Sala de Videoconferência - Faculdade de Medicina - UFCA
TITLE:

ANTIBACTERIAL POTENTIAL OF BETULINIC ACID: IN SILICO AND IN VITRO STUDY OF THE INHIBITION OF THE EFFLUX PUMPS NorA AND MepA

KEY WORDS:

Betulinic acid, Efflux pumps, Resistance.

PAGES: 92
BIG AREA: Ciências da Saúde
AREA: Medicina
SUMMARY:

Treatment for various infectious diseases is seriously threatened by the rapid development of bacterial resistance mechanisms. The adaptation and evolution of microorganisms moves much faster than the development of new antibiotic substances, which makes the treatment of infectious diseases increasingly ineffective and costly for the public health system.To mitigate this problem, new strategies are urgently needed, including the discovery of substances that subsidize the production of new drugs and/or the search for adjuvant compounds to conventional therapy, such as efflux pump inhibitors.Betulinic acid is a pentacyclic triterpene of the lupane type, which has a range of biological activities such as antitumor, anti-inflammatory, antiviral, antimalarial, antifungal and antibacterial action. In this context, the aim of this study was to evaluate “in vitro” and “in silico” the antibacterial and resistance reversal potential of betulinic acid (BA) by inhibiting efflux pumps. The minimum inhibitory concentrations (MIC) were determined using the broth microdilution method.Subsequently, their effects on antibiotic resistance mediated by the efflux pump were evaluated by reducing the MIC of the antibiotics norfloxacin, ciprofloxacin and ethidium bromide (EtBr), while fluorimetry and permeability potential tests were carried out using the fluorescence method.Molecular docking experiments were carried out to evaluate the interaction with efflux proteins, using AutoDock Vina. AB did not show significant intrinsic antibacterial activity against the SA-1199, SA-1199B and SA-K2068 strains, with an MIC of ≥ 1024 μg/mL.However, against MepA the compound was able to reduce the MIC of ciprofloxacin and BrEt by 4 times. In the tests with NorA, AB reduced the MIC of norfloxacin sixteenfold and the MIC of BrEt fourfold, indicating possible inhibitory effects for Nora and MepA. AB induced a significant increase in the fluorescence emission of the two pumps, with increases of 71% and 88%, respectively.The permeability test showed that AB increased the fluorescence of sytox green, inducing a 61% increase for MepA and 66% for NorA, demonstrating the ability to permeabilize the bacterial membrane of SA-1199B and SA- K2068. In silico modeling showed that AB has a high affinity for the NorA binding site, suggesting that efflux pump inhibition may result from competition for the binding site. The in silico modeling of MepA indicates that the binding of BA to the transporter occurs with high thickness, preventing the binding and translocation of substrates, which keeps these substances inside the cell.This work is the first to evaluate the potential of AB to inhibit MepA and NorA efflux pumps.in conclusion, AB did not show significant intrinsic antibacterial activity, however, the results suggest that the compound may inhibit the MepA and NorA efflux pumps, increase EtBr fluorescence emission and induce an increase in bacterial membrane permeability.

COMMITTEE MEMBERS:
Interno - FRANCISCO NASCIMENTO PEREIRA JUNIOR
Presidente - JACQUELINE COSMO ANDRADE PINHEIRO
Externa à Instituição - MARIA FLAVIANA BEZERRA MORAIS BRAGA - URCA