The poly(ADP-ribose) polymerases (PARPs) form a family of enzymes with roles in DNA repair and apoptosis. [1] 1,5-Isoquinolinediol is an inhibitor of poly(ADP-ribose) synthetase (PARP1; IC50 = 0.39 μM). [2] It has been used to study the role of PARP1 in both DNA repair and oxidant stress-induced cell death. [3][4][5] This compound can be used with cells in culture and in animals.[4][6][7]

Reference:
[1]. Davar, D., Beumer, J.H., Hamieh, L., et al. Role of PARP inhibitors in cancer biology and therapy. Current Medicinal Chemistry 19(23), 3907-3921 (2012).
[2]. Banasik, M., Komura, H., Shimoyama, M., et al. Specific inhibitors of poly(ADP-ribose) synthetase and mono(ADP-ribosyl)transferase. The Journal of Biological Chemisty 267(3), 1569-1575 (1992).
[3]. Ruscetti, T., Lehnert, B.E., Halbrook, J., et al. Stimulation of the DNA-dependent protein kinase by poly(ADP-ribose) polymerase. The Journal of Biological Chemisty 273(23), 14461-14467 (1998).
[4]. Chatterjee, P.K., Zacharowski, K., Cuzzocrea, S., et al. Inhibitors of poly (ADP-ribose) synthetase reduce renal ischemia-reperfusion injury in the anesthetized rat in vivo. The FASEB Journal 14(5), 641-651 (2000).
[5]. Bowes, J., McDonald, M.C., Piper, J., et al. Inhibitors of poly (ADP-ribose) synthetase protect rat cardiomyocytes against oxidant stress. Cardiovascular Research 41(1), 126-134 (1999).
[6]. Byun, J.Y., Kim, M.J., Eum, D.Y., et al. Reactive oxygen species-dependent activation of Bax and poly(ADP-ribose) polymerase-1 is required for mitochondrial cell death induced by triterpenoid pristimerin in human cervical cancer cells. Molecular Pharmacology 76(4), 734-744 (2009).
[7]. Kang, Y.H., Yi, M.J., Kim, M.J., et al. Caspase-independent cell death by arsenic trioxide in human cervical cancer cells: Reactive oxygen species-mediated poly(ADP-ribose) polymerase-1 activation signals apoptosis-inducing factor release from mitochondria. Cancer Research 64(24), 8960-8967 (2004).