Compound 2, or 15α-Hydroxy-20-oxo-6,7-seco-ent-kaur-16-en-1,7α(6,11α)-diolide, is an ent-kaurene diterpenoid extracted from Rubescens rubescens. This compound exhibits cytotoxic activity against various cell lines, including EC-1, U87, A549, MCF-7, and HeLa, with IC50 values of 37.69 μM, 79.362 μM, 80.07 μM, 197.35 μM, and 462.13 μM, respectively, as well as 180.09 μM against another unspecified line [1].