The MTT assay which was employed was performed according
to a previously published method (Vareed et al., 2006). MCF-7
(breast), SF-268 (CNS), NCI-H460 (lung), HCT-116 (colon) and AGS
(gastric) human tumor cells were maintained in a humidified
chamber at 37 8C with 5% CO2 in RPMI-1640 medium containing
penicillin–streptomycin (10 units/mL and 10 mg/mL, respectively)
and 10% fetal bovine serum. The extracts were assayed at 250 mg/
mL. Triplicate analyses were performed for each sample. Extracts
exhibiting no activity or very low activity relative to the associated
error were not included in the data.