CASP8 and cancer: The bioactivity test showed that serratiochelin B (3) displayed weak but selective cytotoxicity against HepG2 cancer cells with an IC50 of 50.6 μmol/L and could trigger apoptosis through both Bcl-2/Bax/caspase-3 and Fas/FasL/caspase-8 signaling pathways.