In Vitro Antimicrobial Potential of Portuguese Propolis Extracts from Gerês against Pathogenic Microorganisms.

Area of Science:

• Microbiology
• Natural Products Chemistry
• Pharmacology

Background:

• Antimicrobial resistance (AMR) is a growing global health crisis, with increasing microbial resistance to existing antibiotics.
• Natural products, such as propolis, are being investigated for their potential antimicrobial properties as alternatives to conventional treatments.

Purpose of the Study:

• To evaluate the in vitro antimicrobial potential of Portuguese propolis from the Gerês apiary.
• To assess the efficacy of hydroalcoholic propolis extracts against a panel of bacteria and yeasts, including antibiotic-resistant strains.

Main Methods:

• Preparation of five hydroalcoholic propolis extracts from single samples and one from a mixture.
• Determination of minimum inhibitory concentration (MIC) against Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus (MSSA & MRSA)), Gram-negative bacteria (Escherichia coli), and yeasts (Candida albicans, Saccharomyces cerevisiae).
• Disk diffusion assay comparing propolis extracts with commercial antibiotics (erythromycin, vancomycin, amoxicillin/clavulanic acid).

Main Results:

• Propolis extracts demonstrated concentration-dependent antibacterial effects.
• Hydroalcoholic extracts showed superior antimicrobial capacity compared to vancomycin against B. subtilis and MSSA.
• Methicillin-resistant Staphylococcus aureus (MRSA) was susceptible to propolis extracts but resistant to all tested antibiotics.

Conclusions:

• Propolis from the Gerês apiary exhibits significant in vitro antimicrobial activity.
• These findings highlight propolis as a promising natural agent for combating antimicrobial resistance.
• Further research into Gerês propolis could lead to novel therapeutic strategies against resistant microbial infections.