Relationship between the antibacterial activity towards Escherichia coli NCTC 5933 and the physico-chemical properties of some esters of 3,4,5-trihydroxybenzoic acid (Gallic acid).

Aqueous solubilities, oleyl alcohol: water and octanol: water partition coefficients, RM values, reduction in surface tension of water, relative antioxidant activities and pKa values, were determined for gallic acid and a series of its alkyl esters. Correlations were sought between these physico-chemical measurements and MIC, MBC and killing-rate determinations against Escherichia coli. Variations in antibacterial activity generally correlated well with partition parameters, but these correlations did not accurately predict the cut-off point in antibacterial activity.