Natural Product Communications. 6(6):803-806, 2011 Cytotoxic Cardenolide and Sterols from Calotropis gigantea

6-hydroxy-24-ethylcholest-4,22-dien-3-one ( 3b ), and another mixture of (24 R)-24-ethylcholest-4-en-3one ( 4a ) and (24 S)-24-ethylcholest-4,22-dien-3-one ( 4b ). Cardenolide 1 exhibited extreme toxicity to A549, HCT 116 and Hep G2 with IC 50 values of 0.003 g/mL, 0.013 g/mL, and 0.018 g/mL, respectively, while sample 3 exhibited an IC 50 of 1.35 g/mL, 4.46 g/mL, and 3.83 g/mL, respectively.