ABSTRACT
Semiparasitic plants, mistletoes, distributed in Europe and East-Asia mainly, China, Korea and Japan have long been recognised as therapeutic herbs. Since the 1920s, extracts from European mistletoe (Viscum album L) have been popular in Europe as an unconventional cancer treatment. These extracts have been used in adjuvant cancer therapy because their immunostimulatory, cytostatic/cytotoxic and DNA stabilising activities. The main biological activities are addressed to sugar binding proteins, the Mistletoe Lectins, and to micro proteins named viscotoxins. The mistletoe lectins are members of the family of toxic lectins and recognize sugars and glycoconjugates containing galactose and/or N-acetyl-galactosamine groups. In vitro and in vivo assays confLrm that the mistletoe lectins, isolated from the plant and compared with recombinant forms, play an important role as biologically active principles in mistletoe extracts. Limited experimental evidence indicates that other components like glycosides, polysaccharides, amines etc, may also have anticancer activity. Under discussion in Europe is the principal question of using holo plant extracts or single component lectin preparations: wild type iectins or recombinant ones in cancer therapy. Finally problems of preparation, characterization and standardization of commercial mistletoe preparations and evaluation of biological activities are discussed.