Selective inhibitor of SIRT1 that does not inhibit histone deacetylase (HDAC) or other sirtuin deacetylase family members (IC50 values are 98, 19600, 48700, > 100000 and > 100000 nM for SIRT1, SIRT2, SIRT3, HDAC and NADase respectively). Enhances p53 acetylation in response to DNA damaging agents.