The food-grade antimicrobial xanthorrhizol targets the enoyl-ACP reductase (FabI) in Escherichia coli

Abstract Xanthorrhizol, isolated from the Indonesian Java turmeric Curcuma xanthorrhiza, displays broad-spectrum antibacterial activity. We report herein the evidence that mechanism of action of xanthorrhizol may involve FabI, an enoyl-(ACP) reductase, inhibition. The predicted Y156V substitution in the FabI enzyme promoted xanthorrhizol resistance, while the G93V mutation originally known for triclosan resistance was not effective against xanthorrhizol. Two other mutations, F203L and F203V, conferred FabI enzyme resistance to both xanthorrhizol and triclosan. These results showed that xanthorrhizol is a food-grade antimicrobial compound targeting FabI but with a different mode of binding from triclosan.