Synthesis and antibacterial activity of hydrolytically stable (−)-epicatechin gallate analogues for the modulation of β-lactam resistance in Staphylococcus aureus

Hydrolytically more stable analogues of (−)-epicatechin gallate (ECg) have been synthesised from ECg where an amine or amide function has been substituted for the ester linkage that joins the C-ring with the galloyl D-ring. Sub-inhibitory concentrations (25 mg/L) of the amide analogue 7, possessing the natural C-3 stereochemistry, were able to reduce the resistance to oxacillin of three strains of methicillin resistant Staphylococcus aureus (BB 568, EMRSA-15 and EMRSA-16) comparable to levels achieved with ECg.