Epigallocatechin gallate inhibits intracellular survival of Listeria monocytogenes in macrophages.

Epigallocatechin gallate (EGCg), the major tea catechin, is known as a potent anti-microbial and anti-tumor compound. The effects of EGCg on host defense mechanisms against Listeria monocytogenes infection were examined in vitro using mouse peritoneal exudate cells. The study showed that EGCg inhibited the intracellular growth of L. monocytogenes in macrophages. The enhancement of in vitro anti-L. monocytogenes activity by EGCg is not due to the modulation of reactive oxygen intermediates or the production of reactive nitrogen intermediates but due to the inhibition of its escaping from the phagosome into cytosolic space. Anti-L. monocytogenes of EGCg is through the inhibition of hemolytic and cholesterol-binding activity of listeriolysin O, which usually disrupts the phagosomal membrane in the escaping phase of L. monocytogenes.