Ambuic Acid (CAS: 340774-69-8)

Ambuic acid is a fungal polyketide identified as an inhibitor of quorum sensing signal biosynthesis in Gram-positive pathogens. It suppresses autoinducing peptide (AIP) production in methicillin-resistant Staphylococcus aureus (MRSA) with micromolar potency and selectively downregulates the quorum-sensing regulon without impairing bacterial viability. In vivo studies demonstrate reduced abscess formation in murine MRSA infection models following ambuic acid treatment. Mechanistic studies reveal inhibition of cyclic peptide quorum-sensing signal biosynthesis in multiple Gram-positive bacteria, including Staphylococcus aureus, Enterococcus faecalis, and Listeria species. The epoxide moiety is implicated in quorum-sensing inhibition of agr and fsr systems. These findings establish ambuic acid as a broad-spectrum anti-virulence agent targeting signal biosynthesis rather than bacterial growth, supporting its development as a lead structure against antibiotic-resistant infections.