MDL 800 is an allosteric activator of sirtuin 6 (SIRT6). It selectively activates SIRT6 deacetylase activity over SIRT1-5 and -7 and histone deacetylase 1 (HDAC1) and HDAC2-11 deacetylase activity in cell-free assays at 100 µM. It induces histone deacetylation, and reduces proliferation of BEL-7405 hepatocellular carcinoma (HCC) cells with EC50 of 90.4 µM.