Antimethicillin-resistant Staphylococcus aureus (MRSA) activity of 'pacific propolis' and isolated prenylflavanones

Area of Science:

• Natural Product Chemistry
• Microbiology
• Pharmacology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) infections pose a significant global health threat, necessitating novel therapeutic strategies.
• Propolis, a natural resinous mixture produced by honey bees, possesses traditional antimicrobial properties.
• The exploration of natural products for alternative antimicrobial agents is crucial.

Purpose of the Study:

• To isolate and identify bioactive compounds from Solomon Islands propolis ('Pacific propolis') with activity against MRSA.
• To evaluate the anti-MRSA potential of identified compounds.
• To establish the presence of prenylflavanones in this specific propolis source.

Main Methods:

• Screening of a crude Pacific propolis extract against 15 MRSA clinical isolates using an agar dilution assay.
• Purification of the crude extract into 23 fractions.
• Isolation and structural elucidation of active compounds using spectroscopic techniques (1D- and 2D-NMR, MS) and literature comparison.

Main Results:

• The crude Pacific propolis extract demonstrated significant in vitro activity against MRSA.
• Four prenylflavanones, propolin H (1), propolin G (2), propolin D (3), and propolin C (4), were isolated and identified.
• Propolin D (3) exhibited minimum inhibitory concentrations (MIC) of 8-16 mg/L, and propolin C (4) showed MICs of 8-32 mg/L against MRSA.

Conclusions:

• This study is the first to report the anti-MRSA activity of Pacific propolis.
• The prenylflavanones propolin D and propolin C demonstrate promising anti-MRSA activity, suggesting their potential as novel therapeutic agents.
• Further research into these compounds could lead to the development of new treatments for MRSA infections.