Studies on the standardization of mistletoe preparations.

The newly isolated phenylpropanoids syringin, syringenin-apiosylglucoside, eleutheroside E and the high molecular lectins and viscotoxins were selected for a standardization of mistletoe extracts and drug preparation. The phenylpropanoids found in all alcoholic and aqueous extracts were suitable for an HPLC fingerprint analysis, and for quantitative determination. The lectin content of the drug preparations was determined by single radial immunodiffusion. As shown by the isoelectric focussing method, Iscador and fermented mistletoe extracts contain only the mistletoe lectins ML II/III, whereas the proteins of the ML I complex are missing. For identification and quantitative determination of viscotoxins, an HPLC method was designed.