In addition, the extract of S. barbata D. Don by methylene chloride also exhibited significant cytotoxicity against human leukemia U937 cells at the concentrations of 5–15 μg/ml via inducing apoptosis by activating caspases and altering the ratio of Bax/Bcl-2 (Cha et al., 2004). This evidence concerns the gene BAX and leukemia.