Antibacterial activity of alkyl gallates and related compounds against Ralstonia solanacearum

Antibacterial activity of alkyl gallates and their analogs against Ralstonia solanacearum was examined. Methyl gallate showed the strongest activity among the alkyl gallates; activity decreased as the carbon number of esters increased. This tendency of alkyl gallates to act against R. solanacearum was dissimilar to its previously reported action against Gram-negative and Gram-positive bacteria and fungi. Among related compounds with a differing position and number of phenolic hydroxyl groups, methyl 2,3-dihydroxybenzoate showed comparable or slightly stronger activity than methyl gallate. Geraniin, one of the characteristic secondary metabolites produced by Geranium spp., showed moderate activity. (C) Pesticide Science Society of Japan