Cytotoxic Activity of Medicinal Plant Extracts against Human Tumor Cell Lines

The cytotoxic activities of the methanol extracts of 44 plant species in 31 families against five human solid A549 (lung), SK-OV-2 (ovarian), SK-MEL-2 (melanoma), XF-498 (central nervous system), and HCT-15 (colon) tumor cell lines were examined using the sulforhodamine B (SRB) assay. Responses varied with both cell line and plant species used. Potent cytotoxic activities ($ED_{50}$, <$40{\mu}g/ml$) against all model tumor cell lines were produced from the extracts of Rhus chinensis gall (Galla rhois), Betula platyphylla var. japonica bark, Inula helenium root, Cinnamomum cassia bark, Cinnamomum sieboldii root bark, Lysimachia davurica whole plant, and Evodia rutaecarpa fruit. These plants may be useful for developing new types of naturally occurring anti-tumor agents.