Natural products modulate Shigella-host-cell interaction.

Dan Xu, Amir Saeed, Yili Wang, Véronique Seidel, Gunnar Sandström, Jun Yu

Index: J. Med. Microbiol. 60(Pt 11) , 1626-32, (2011)

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Abstract

This study focused on identifying possible new options derived from natural sources for the treatment of bacterial infections. Several natural products were investigated for their potential in modulating Shigella-host-cell interactions. The proliferation of Shigella sonnei was effectively inhibited inside HEp-2 cells in the presence of 4-methoxycinnamic acid and propolin D. Propolin D also significantly reduced the apoptosis of infected macrophage-like U937 cells and moderately reduced the secretion of interleukin (IL)-1β and IL-18, which probably resulted from the inhibition of invasion plasmid antigen B secretion by this compound. Further characterization showed that propolin D did not prevent escape of Shigella from phagocytic vacuoles, as evidenced by actin-based motility and by the fact that addition of chloroquine did not further reduce the number of intracellular c.f.u. The role of propolin D in modulating autophagy could not be established under the experimental conditions used. As these compounds had no direct anti-Shigella activity in vitro, it was concluded that these compounds modulated Shigella-host-cell interactions by targeting yet-to-be defined mechanisms that provide benefits to host cells.