There is provided a novel compound of the general formula I in which each of R8 to R10 is hydrogen, aryl, C1-6 alkyl, trialkylsilyl or acyl; R1 to R5 are individually selected from hydrogen, hydroxy, C1-6 alkoxy and acyloxy; R6 and R7 are H, C1-4 alkyl, trialkylsilyl or acyl; X is O or NR, and R is H or Me; in which any of the alkyl groups including alkyl groups in alkoxy, acyl and acyloxy groups may be substituted by aryl, C1-4 alkyl, C1-4 alkoxy, hydroxyl, trialkylsiloxy or acyloxy groups; with the proviso that R2 and R3 are not both OH when R4 is H or OH, R1 and R5 are both H, and X is O. The amide compounds (X is NR) are analogues of epigallocatechin gallate or epicatechin galate, with an amide bond in place of the natural ester bond, with resistance to hydrolysis by esterase enzymes. The ester compounds (X is O) have a different hydroxylation pattern on the B ring as compared to the natural products. The compounds may be used to modulate the resistance to β-lactam antibiotics of various infections, especially methicillin resistant Staphylococcus aureus (MRSA). Pharmaceutical compositions containing the novel compounds and combinations of the novel compounds and β-lactam antibiotics are described.