Antitumor Activity of Arnoglossum atriplicifolium

Western North Carolina is home to one of the most diverse collections of botanical species in the temperate world. The region is also an extensive repository of herbal natural healing knowledge, developed through the centuries by Native American and European settler practitioners, regional plant species with documented medicinal properties number in the hundreds. These factors combine to present urgent need for Western North Carolina to use cutting edge technology to identify, validate, protect, and use its matchless natural resources in innovative, sustainable, and productive ways including careful bioexploration. We have recently launched a targeted screening program for identifying plants indigenous to Western North Carolina with potential antitumor activity. Initial screening against the MCF-7 breast tumor cell line identified an extract of Arnoglossum atriplicifolium (whole plant) as having cytotoxic activity. Numerous lipophilic fractions exhibit dose-dependent toxicity towards MCF-7 and PC-3 cells, with IC₅₀ values as low as 20 µg/mL. The results of bioassay-guided fractionation by reverse phase C₁₈ open column chromatography followed by reverse phase C₁₈ HPLC will be presented as will data demonstrating that many of the fractions show low to moderate cytotoxicity against fibroblasts in cell culture. Acknowledgements: This work was supported, in part, by the NC Biotechnology Center's Biotechnolgy Research Program grant. We thank the Western Carolina University Quality Enhancement Program for summer support for T.J.W. We thank Wake Forest University Health Sciences Virus and Vector Core Laboratory for assay work.