Synergistic Effect of Peperomia pellucida L. Kunth Aerial Part and Amoxicillin against Methicillin-Resistant Staphylococcus aureus (MRSA)

The combination of natural substances with antibiotics is a novel approach to combating antibiotic resistance. Several studies have shown that plant bioactive compounds can boost antibiotic action against pathogenic bacteria that are resistant to antibiotics. The aim of this study was to determine the synergistic effect of the aerial part of Peperomia pellucida (P. pellucida) with amoxicillin against Methicillin-Resistant Staphylococcus aureus (MRSA). P. pellucida aerial part extract was obtained by maceration in 70% ethanol followed by partitioning with n-hexane to give n-hexane soluble and n-hexane insoluble fractions. The phytochemical constituents of the extract and fractions were determined by thin layer chromatography (TLC) and spray reagents. The antibacterial activity of the extract and fractions as well as its synergistic effect with amoxicillin was assessed using the broth microdilution assay. The extract and fractions at 10 mg/mL demonstrated significant antibacterial activity against MRSA. The bacterial growth inhibition zone diameters were 9.33 ± 1.25 mm, 10.16 ± 0.28 mm, and 9.00 ± 1.00 mm for the ethanol extract, n-hexane soluble fraction, and n-hexane insoluble fraction of P. pellucida, respectively. The hexane soluble fraction of P. pellucida showed synergistic effect with amoxicillin against MRSA, resulting in a Fractional Inhibitory Concentration Index (FICI) of 0.25. The results obtained from this study suggest that P. pellucida n-hexane fraction could enhance the antibacterial effect of amoxicillin against methicillin-resistant Staphylococcus aureus.