Biologically active compounds from European mistletoe (Viscum album L.)1

Abstract

European mistletoe (Viscum album L.) is a commonly occurring semiparasite of trees. The extracts from European mistletoe have been shown to possess immunostimulatory and cytotoxic activity on tumor cells, and are used in Europe in adjuvant cancer therapy. Recently, a number of studies performed have been leading to the identification and characterization of bioactive compounds. Apoptosis-inducing and ribosome-inactivating lectins as well as cytotoxic thionins (viscotoxins) are the main groups of compounds participating in biological activity of V. album. These compounds were isolated and studied in vitro and in vivo for their biological activity and mechanism of action. A comparison of the results to those using whole extracts indicated that lectins and viscotoxins are not the only bioactive compounds present in the mistletoe and among them, high heterogeneity is observed in both structure and activity. In this paper, we review the current state of the art in mistletoe studies, emphasizing its potential application as a drug, its standardization, and taxonomic problems. The nontherapeutic applications and suspected physiological functions of the compounds in question are also discussed briefly.