Anti-Tumour Activity of Digitalis purpurea L. subsp. heywoodii
Miguel López-Lázaro1
, Nieves Palma de la Peña2
, Nuria Pastor2
, Carmen Martín-Cordero1
, Eduardo Navarro3
, Felipe Cortés2
, María Jesús Ayuso1
, María Victoria Toro1
1Departamento de Farmacología, Facultad de Farmacia, Universidad de Sevilla, Spain
2Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Spain
3Departamento de Farmacología, Facultad de Medicina, Universidad de la Laguna, Tenerife, Spain
This work has been supported by the Spanish Ministry of Science and Technology (SAF 2000-0167)
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 μg/mL range with the methanolic extract being the most active, in non toxic concentrations. Steroid glycosides (gitoxigenin 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 μM range, with the renal adenocarcinoma cancer cell line (TK-10) being the most sensitive one. Morphological apoptosis 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.
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