Gram negative bacteria utilize N-acylated homoserine lactones to coordinate expression of virulence in response to the density of the surrounding bacterial population in a process termed quorum sensing. By interfering with this communication and thereby disrupting virulence expression, quorum sensing inhibitors are emerging as an alternative to the conventional ways of fighting bacterial infections. Penicillic acid is a mycotoxin produced from Penicillium species identified in molds on corn and other grains. At 80 μM, penicillic acid inhibits bacterial quorum sensing communication in P. aeruginosa by selectively repressing various virulence factor and other quorum sensing-regulated genes. It has been shown to inhibit Fas-mediated apoptosis at 100-200 μM by targeting caspase-8 activity in Burkitt’s lymphoma Raji cells.
