Suppression of tumor cell invasiveness by hydrolyzable tannins (plant polyphenols) via the inhibition of matrix metalloproteinase-2/-9 activity.

Elevated expression of matrix metalloproteinases (MMPs), especially that of MMP-2 and MMP-9, is associated with increased metastatic potential in many tumor cells. Recently, green tea polyphenol epigallocatechin-3-O-gallate (EGCG) has been shown to inhibit the MMP-2/-9 activity as well as the invasiveness of tumor cells. In this study, we have examined the inhibitory effect of hydrolyzable tannins (plant polyphenols) on the tumor cell invasion.

Synthesis and structure-activity relationships of thioflavone derivatives as specific inhibitors of the ERK-MAP kinase signaling pathway.

Condensation of nitrobenzaldehydes 3 and alpha-[o-(p-methoxybenzylthio)benzoyl] sulfoxide 4 gave alpha-sulfinyl enones 5. Treatment of 5 with formic acid caused cyclization followed by debenzylation to afford 3-(methylsulfinyl)thioflavanones 6. Double-bond formation with elimination of methanesulfenic acid was performed by refluxing 6 in benzene, and, finally, the nitro group of 2-phenyl-4H-1-benzothiopyran-4-one (thioflavones) 7 was reduced with tin in tetrafluoroboric acid.