Dialkylresorcinols (DARs) are naturally occurring compounds produced in several species of the Photorhabdus and Pseudomonas bacterial genera, which are involved in modulating quorum-sensing in the producing organisms, as well as possessing significant antimicrobial properties. A range of dialkylresorcinols were synthesized, systematically varying the chain-lengths of the C-2 and C-5 alkyl chains, and the antimicrobial properties of the products assessed. Against two Staphylococcus test strains, medium-length alkyl chains (5–7 carbons) in both positions proved optimum for high antibiotic activity, with several derivatives displaying low micromolar activity. Activity against other test organisms was very different, with 2-hexylresorcinol (11) displaying the highest potency against Escherichia coli, Pseudomonas syringae, and Xanthomonas campestris test strains; its structure likely enables efficient membrane interaction while maintaining bioavailability.
Yang et al. (2026) studied this question.