Regioselectively Acetylated Silybin Derivatives and their Cytotoxic Activity in Liver Cancer Cells

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=48 SRC="FIGDIR/small/638106v1_ufig1.gif" ALT="Figure 1"> View larger version (11K): org.highwire.dtl.DTLVardef@13744c8org.highwire.dtl.DTLVardef@184bb9borg.highwire.dtl.DTLVardef@138f442org.highwire.dtl.DTLVardef@2c45ca_HPS_FORMAT_FIGEXP M_FIG C_FIG Natural products continue to serve as a valuable source of starting points for therapeutic agents. Six silybin derivatives have been synthesized and tested in vitro for their cytotoxic effect on the human hepatocellular carcinoma line HepG2 using the MTT assay. Results indicate that the 3,5,7,20,23-penta-O-acetyl-2,3-dehydrosilybin possesses a stronger cytotoxic effect than that of the parent silybin by a factor of 12. This compound was further evaluated for its cytotoxic activity on Hep3B, Huh7, and Huh7R hepatocellular carcinoma cell lines, giving similar potencies, arresting the cell cycle at S phase and causing apoptosis. These results illustrate the potential of silybin derivatives as therapeutics against liver cancer.