Sirtinol is a cell permeable specific inhibitor of sirtuin NAD-dependant deacetylases. Sirtinol has been shown to inhibit yeast Sir2 at IC50 = 70 uM, human SIRT2 at IC50 = 40 uM human SIRT1 at IC50 = 131 uM, yet has shown no effect on human HDAC1. In the Arabidopsis plant Sirtinol strongly affected root and vascular tissue development by activating the auxin signaling pathway. Sirtinol has also been shown to induce senescence-like growth arrest in human breast cancer MCF-7 and lung cancer H1299 cells by imapaired activation of MAPK.