Analysis of the Ability of Cumin to Suppress Verocytotoxin by Enterohemorrhagic Escherichia coli O157

Abstract

　We examined the ability of cumin to suppress the production of verocytotoxin (VT) by enterohemorrhagic Escherichia coli (EHEC) O157. An extract of cumin seeds was prepared with 70% ethyl alcohol. When EHEC O157 cells were grown at 37℃ to the stationary phase in Luria-Bertani medium supplemented with 0.02% cumin extract, the production of both VT1 and VT2 was significantly suppressed. Neither growth inhibition nor a delay in the lag phase was observed under these culture conditions. An active component of the cumin extract was purified by high-pressure liquid chromatography and was identified as 4-isopropylbenzaldehyde (IPBA). When we examined the suppressive effect of IPBA on VT production by EHEC O157, the amounts of both intracellular and extracellular VTs were found to decrease with an increase in IPBA concentration. Our results suggest that IPBA may be potentially useful in reducing the virulence of EHEC O157.