Crovatin, isolated from the stem bark of C. oblongifolius, shows anti-tumor effect[1].
References
[1] Sophon Roengsumran, et al. Croblongifolin, a new anticancer clerodane from Croton oblongifolius. Planta Med. 2002 Mar;68(3):274-7. DOI:10.1055/s-2002-23138