Abstract

Viscum album L. is a widely used medicinal plant in cancer treatment, known since ancient times. The aim of this study was to investigate the antimetastatic properties of the ethanolic extracts of synergistic plants Viscum album L. (epiphyte) and Abies alba (host) each one alone or both in combination (mixture). Inhibition of platelet aggregation was evaluated in washed rabbit and human platelets. Levels of thromboxane A2 (TXA2) were estimated by radioimmune assay and natural killer cells (NKCs) cytotoxicity by flow cytometry. The antimetastatic properties of Viscum album L. and Abies alba were studied in a tumour-bearing Wistar rat model. All extracts inhibited platelet aggregation in a dose-dependent manner as well as TXA2 production by three pathways of aggregation (ADP, PAF and ARA) while the mixture significantly increased NKCs cytotoxicity against cancer cells. In tumour-bearing Wistar rats the treatment with the mixture of Viscum album L. and Abies alba extract reduced almost by 77% the metastatic locations. These data suggest that Viscum album L. and Abies alba extract reduced metastasis through inhibition of platelet aggregation and amplification of the body defence mechanisms against cancer cells.

Key words: Viscum album L.; Abies alba; platelet aggregation; metastasis; cancer