Effect of European mistletoe (Viscum album L.) grown on plums under antioxidant status of Ehrlich tumor cells in vivo

Abstract

Extracts from European mistletoe (Viscum album L.) have been known as secondary medicaments, widely used in therapy of hypertension. Also, they have been reported to exert cytotoxic and immunomodulatory effects in vitro and in vivo. The mechanism of anti-tumoral activity is, however, largely unknown. In this study, we tested the hypothesis that aqueous extract from the European mistletoe grown on plums (Viscum extract), exhibits in vivo cytotoxic activity against Ehrlich tumor cells, due to induction of oxidative stress in tumor cells. Aqueous Viscum album L. extract was given to experimental animals (NMRI mice) in three different ways - as pre-treatment, treatment and post-treatment. We have observed significant reduction of cancer incidence in all groups that received mistletoe extract, in comparison to Ehrlich control. Number of tumor cells was decreased up to almost 95% in male animals that received mistletoe extract before implantation, and up to 53% in female animals. A significantly reduced number of EAC cells was also obtained in animals with developed carcinoma. Activities of antioxidative enzymes in EAC cells confirmed the absence of oxidative stress, and also the process of peroxidation of membrane lipids (indicator of the oxidative damage of cell membranes) was almost absent. In contrast, significant changes in antioxidative enzyme activities were observed after administration of Viscum extract, and that might be the result of oxidative stress in EAC cells. This was in accordance with the increase of damaged cells percentage. Furthermore, treatment with the Viscum extract alone did not change the antioxidative status in healthy animals, possibly indicating that oxidative stress might be involved in plum's V. album-mediated EAC cell death. © by PSP 2007.