[Inhibitory effects of garlicin and cinnamaldehyde on SOS response and their mechanisms in Escherichia coli].

Inhibitory effects of garlicin and cinnamaldehyde on SOS response and their mechanisms in Escherichia coli were investigated. Garlicin and cinnamaldehyde suppressed the lambda cI depended SOS response induced by 4-nitroquinoline-N-oxide (4NQO), mytomycin (MMC) and methyl methane-sulfonate (MMS), and the lexA-depended SOS response induced by 4NQO and UV to various extent, respectively. They also diminished the rexA 441-depended SOS response induced by temperature (at 42 degrees C) However, they did not show any effect on the constitution of SOS functions. It suggested that this inhibitory effect could be via RecA protease which regulates the cleavage of lexA repressor, and perhaps, lambda cI repressor.