Impact of Mistletoe Triterpene Acids on the Uptake of Mistletoe Lectin by Cultured Tumor Cells.

Complementary treatment possibilities for the therapy of cancer are increasing in demand due to the severe side effects of the standard cytostatics used in the first-line therapy. A common approach as a complementary treatment is the use of aqueous extracts of Viscum album L. (Santalaceace). The therapeutic activity of these extracts is attributed to Mistletoe lectins which are Ribosome-inactivating proteins type II. Besides these main constituents the extract of Viscum album L. comprises also a mixture of lipophilic ingredients like triterpene acids of the oleanane, lupane and ursane type. However, these constituents are not contained in commercially available aqueous extracts due to their high lipophilicity and insolubility in aqueous extraction media. To understand the impact of the extract ingredients in cancer therapy, the intracellular uptake of the mistletoe lectin I (ML) by cultured tumor cells was investigated in relation to the mistletoe triterpene acids, mainly oleanolic acid. Firstly, these hydrophobic triterpene acids were solubilized using cyclodextrins ("TT" extract). Afterwards, the uptake of either single compounds (isolated ML and the aqueous "viscum" extract) or in combination with the TT extract (ML+TT, viscumTT), was analyzed. The uptake of ML was studied inTHP-1-, HL-60-, 143B- and Ewing TC-71-cells and determined after 30, 60 and 120 minutes by an enzyme linked immunosorbent assay which quantifies the A-chain of the hololectin. It could be shown that the intracellular uptake after 120 minutes amounted to 20% in all cell lines after incubation with viscumTT. The studies further revealed that the uptake in THP-1-, HL-60- and Ewing TC-71-cells was independent of the addition of TT extract. Interestingly, the uptake of ML by 143B-cells could only be measured after addition of triterpenes pointing to resistance to mistletoe lectin.

FT-IR Method for the Quantification of Isoflavonol Glycosides in Nutritional Supplements of Soy (Glycine max (L.) MERR.).

Due to increasing health consciousness, a lot of food supplements are sold and used. Dietary supplements of Glycine max (L.) MERR. are used as an alternative treatment for menopausal complaints such as hot flashes. Thereby, the effective soy compounds are the isoflavones daidzin, genistin, and glycitin. However, only the total soy extract content of the nutritional supplements is indicated. The aim of this study is to introduce a fast, efficient, and economic Fourier transformation infrared (FT-IR) spectroscopy method to quantify the active ingredients in the complex matrix of soy-based supplements. Five different nutritional supplements of Glycine max (L.) MERR. were purchased from a German pharmacy and were extracted with 80% aqueous methanol. A high-performance liquid chromatography (HPLC) method was used for the separation. The samples were concentrated and measured with infrared spectroscopy. An FT-IR method was established to quantify the active ingredients in the complex matrix of soy-based nutritional supplements. The partial least-squares algorithm was used to develop the method, which enabled the estimation of the content of particular isoflavones (daidzin R(2) = 0.86, glycitin R(2) = 0.94, genistin R(2) = 0.96) and the quantification of the total isoflavone content (R(2) = 0.92) despite peak overlap in the infrared (IR) spectra. The method for the quantification of the isoflavonol glycosides is precise with the standard error of prediction being 13.54%.

A Natural Combination Extract of Viscum album L. Containing Both Triterpene Acids and Lectins Is Highly Effective against AML In Vivo.

Aqueous Viscum album L. extracts are widely used in complementary cancer medicine. Hydrophobic triterpene acids also possess anti-cancer properties, but due to their low solubility they do not occur in significant amounts in aqueous extracts. Using cyclodextrins we solubilised mistletoe triterpenes (mainly oleanolic acid) and investigated the effect of a mistletoe whole plant extract on human acute myeloid leukaemia cells in vitro, ex vivo and in vivo. Single Viscum album L. extracts containing only solubilised triterpene acids (TT) or lectins (viscum) inhibited cell proliferation and induced apoptosis in a dose-dependent manner in vitro and ex vivo. The combination of viscum and TT extracts (viscumTT) enhanced the induction of apoptosis synergistically. The experiments demonstrated that all three extracts are able to induce apoptosis via caspase-8 and -9 dependent pathways with down-regulation of members of the inhibitor of apoptosis and Bcl-2 families of proteins. Finally, the acute myeloid leukaemia mouse model experiment confirmed the therapeutic effectiveness of viscumTT-treatment resulting in significant tumour weight reduction, comparable to the effect in cytarabine-treated mice. These results suggest that the combination viscumTT may have a potential therapeutic value for the treatment AML.