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In this study, we investigated the chemical composition, and antioxidant and antibacterial properties of ethanolic extracts of propolis (EEP) from  Melipona quadrifasciata quadrifasciata  and  Tetragonisca angustula . Chemical composition of EEP was determined by colorimetry and chromatographic (HPLC-DAD and UPLC-Q/TOF-MS/MS) analysis. Antimicrobial activity of EEP was evaluated against gram-positive ( S. aureus , methicillin-resistant  S. aureus ,  E. faecalis ) and gram-negative ( E. coli  and  K. pneumoniae ) bacteria by the minimal inhibitory concentration (MIC) test using the microdilution method. Furthermore, the growth curve and integrity of cell membrane of  S. aureus  and  E. coli  were investigated using standard microbiological methods. HPLC-DAD analysis showed that the EEP of  M. quadrifasciata quadrifasciata  has a more complex chemical composition than the EEP of  T. angustula . Moreover, UPLC-MS analyses of  M. quadrifasciata quadrifascita  indicated flavonoids and terpenes as major constituents. The bactericidal activity of both EEPs was higher against gram-positive bacteria than for gram-negative bacteria. The EEP from  M. quadrifasciata quadrifasciata  presented MIC values lower than the EEP from  T. angustula  for all tested bacteria. The EEP from  M. quadrifasciata quadrifasciata  caused lysis of the bacterial wall and release of intracellular components from both  E. coli  and  S. aureus . Our findings indicate that the chemical composition of propolis from stingless bees is complex and depends on the species. The extract from  M. quadrifasciata quadrifascita  was more effective against gram-positive than gram-negative strains, especially against  S. aureus  and methicillin-resistant  S. aureus  compared to  T. angustula  extract, by a mechanism that involves disturbance of the bacterial cell membrane integrity.

brazilian journal of medical and biological research

Chemical characterization, antioxidant and antimicrobial activity of propolis obtained from Melipona quadrifasciata quadrifasciata and Tetragonisca angustula stingless bees