title: Differential cytotoxic properties of Helleborus niger L. on tumour and immunocompetent cells.
abstract: BACKGROUND
  In Romanian folk medicine, Helleborus niger L. is used for the treatment of rheumatoid arthritis or viral infections and in complementary therapy, especially in anthroposophic medicine (AM), where the plant is administered as an adjuvant to treat malignant diseases. In the present study, we investigated the differential cytotoxic effects of H. niger on human tumour and healthy cells of the human immune system in vitro.
  
  
  METHODS
  Protoanemonin and saponins, as significant constituents of H. niger extracts, were quantified in five individual batches using validated HPLC methods. Further, the impact of H. niger on proliferation capacity (MTT assay) as well as on apoptosis and necrosis induction in a panel of tumour cell lines and human lymphocytes (combined annexin V and propidium iodide staining) was monitored. In addition, NK cell function (degranulation-CD107a assay and IFN-gamma secretion) was also investigated since these immunocompetent cells are important for the control of malignancies within the human body.
  
  
  RESULTS
  Extracts of H. niger induced proliferation inhibition not only of lymphoblastic leukaemia cells (MOLT4; IC50: 171 µg/mL) but also of myosarcoma (SK-UT-1b; IC50: 304 µg/mL) and melanoma cells (HT-144; IC50: 569 µg/mL) due to the induction of apoptosis. Purified T cells or NK cells were significantly affected through the presence of high H. niger concentrations while bulk lymphocytes were not affected. NK cells' anti-tumour functions expressed by degranulation capacity as well as IFN-y production were unaffected by the presence of the H. niger extract. Since protoanemonin and saponins have been reported in the literature to exert cytotoxic effects, their content was also determined.
  
  
  CONCLUSIONS
  H. niger extracts exhibit differential cytotoxicity towards tumour cell lines and healthy human T- and NK-cells.
authors.affiliation: Helixor Heilmittel GmbH & Co. KG, Fischermühle 1, 72348 Rosenfeld, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schink
authors.affiliation: Center for Complementary Medicine, University Medical Center Freiburg, Breisacherstr. 115B, 79106 Freiburg, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Garcia-Käufer
authors.affiliation: WALA Heilmittel GmbH, Department of Analytical Development & Research, Dorfstrasse 1, D-73087 Bad Boll/Eckwälden, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Bertrams
authors.affiliation: WALA Heilmittel GmbH, Department of Analytical Development & Research, Dorfstrasse 1, D-73087 Bad Boll/Eckwälden, Germany.
authors.forename: Sarina M
authors.initials: SM
authors.lastname: Duckstein
authors.affiliation: WALA Heilmittel GmbH, Department of Analytical Development & Research, Dorfstrasse 1, D-73087 Bad Boll/Eckwälden, Germany.
authors.forename: Margit B
authors.initials: MB
authors.lastname: Müller
authors.affiliation: Center for Complementary Medicine, University Medical Center Freiburg, Breisacherstr. 115B, 79106 Freiburg, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Huber
authors.affiliation: WALA Heilmittel GmbH, Department of Analytical Development & Research, Dorfstrasse 1, D-73087 Bad Boll/Eckwälden, Germany.
authors.forename: Florian C
authors.initials: FC
authors.lastname: Stintzing
authors.affiliation: Center for Complementary Medicine, University Medical Center Freiburg, Breisacherstr. 115B, 79106 Freiburg, Germany. Electronic address: carsten.gruendemann@uniklinik-freiburg.de.
authors.forename: Carsten
authors.initials: C
authors.lastname: Gründemann
mesh_terms: D015550:Cell Degranulation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D005663:Furans / Q000032:analysis / Q000494:pharmacology; D039322:Helleborus; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000502:physiology; D009336:Necrosis / Q000139:chemically induced; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D012503:Saponins / Q000032:analysis / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects*
chemical_list: D005663:Furans; D010936:Plant Extracts; D012503:Saponins; C037354:protoanemonin
keywords: Anthroposophical medicine; Complementary medicine; Lymphocytes; Protoanemonin; Ranunculaceae; Saponin; Tumour therapy