Anti-tumour activity of Digitalis purpurea L. subsp. heywoodii

Abstract

Recent research has shown the anticancer effects of digitalis compounds suggesting their possible use in medical oncology. Four extracts obtained from the leaves of Digitalis purpurea subsp. heywoodii have been assessed for cytotoxic activity against three human cancer cell lines,using the SRB assay. All of them showed high cytotoxicity,producing IC50 values in the 0.78 - 15 1gfmL range with the methanolic extract being the most active,in non toxic concentrations. Steroid glycosides (gi- toxigenin derivatives) were detected in this methanolic extract. Gitoxigenin and gitoxin were evaluated in the SRB assay using the three human cancer cell lines,showing IC50 values in the 0.13 - 2.8 1M range,with the renal adenocarcinoma cancer cell line (TK-10) being the most sensitive one. Morphological apopto- sis evaluation of the methanolic extract and both compounds on the TK-10 cell line showed that their cytotoxicity was mediated by an apoptotic effect. Finally,possible mechanisms involved in apoptosis induction by digitalis compounds are discussed.