Untargeted metabolomics approach to discriminate mistletoe commercial products

Mistletoe (Viscum album L.) is used in German-speaking European countries in the field of integrative oncology linking conventional and complementary medicine therapies to improve quality of life. Various companies sell extracts, fermented or not, for injection by subcutaneous or intra-tumoral route with a regulatory status of anthroposophic medicinal products (European Medicinal Agency (EMA) assessment status). These companies as well as anthroposophical physicians argue that complex matrices composed of many molecules in mixture are necessary for activity and that the host tree of the mistletoe parasitic plant is the main determining factor for this matrix composition. The critical point is that parenteral devices of European mistletoe extracts do not have a standard chemical composition regulated by EMA quality guidelines, because they are not drugs, regulatory speaking. However, the mechanism of mistletoe’s anticancer activity and its effectiveness in treating and supporting cancer patients are not fully understood. Because of this lack of transparency and knowledge regarding the matrix chemical composition, we undertook an untargeted metabolomics study of several mistletoe extracts to explore and compare their fingerprints by LC-(HR)MS(/MS) and 1H-NMR. Unexpectedly, we showed that the composition was primarily driven by the manufacturer/preparation method rather than the different host trees. This differential composition may cause differences in immunostimulating and anti-cancer activities of the different commercially available mistletoe extracts as illustrated by structure–activity relationships based on LC–MS/MS and 1H-NMR identifications completed by docking experiments. In conclusion, in order to move towards an evidence-based medicine use of mistletoe, it is a priority to bring rigor and quality, chemically speaking.

Impact of Harvest Conditions and Host Tree Species on Chemical Composition and Antioxidant Activity of Extracts from Viscum album L.

The content of plant secondary metabolites is not stable, and factors such as the region/location effect and seasonal variations have an impact on their chemical composition, especially in parasitic plants. Research in this area is an important step in the development of quality parameter standards of medicinal plants and their finished products. The effects of the time and place of harvest and the host tree species on the chemical composition and antioxidant activity of mistletoe extracts were investigated. Statistical tools were used to evaluate the results of the spectrophotometric and LC-ESI-MS/MS studies of the phenolic composition and antioxidant activity. The investigations indicate that the qualitative and quantitative composition, influencing the biological activity of mistletoe extracts, largely depends on the origin of the plant. The mistletoe extracts exhibited a rich phenol profile and high antioxidant activity. The chemometric analysis indicated that mistletoe collected from conifers (Viscum abietis and Viscum austriacum) had the most advantageous chemical composition and antioxidant activity. Moreover, the chemical profile and biological activity of the plant material were closely related to the climatic conditions and location of the harvested plant. Higher levels of phenolic compounds and high antioxidant activity were found in extracts obtained from plant material collected in cold weather with the presence of snow and less sunshine (autumn–winter period).

Mistletoe Extract Viscum Fraxini-2 for Treatment of Advanced Hepatocellular Carcinoma: A Case Series

Background: Hepatocellular carcinoma (HCC) is the fourth leading cause of death from cancer worldwide, and for advanced HCC the prognosis is poor. Preliminary studies indicate mistletoe extracts may have anticancer activity for HCC. Methods: A prospective observational case series of advanced HCC patients that chose to take a mistletoe extract called viscum fraxini-2 (VF-2) alone for treatment. Time on treatment, imaging, and laboratory values were collected for descriptive analyses. Results: A total of 12 patients with advanced HCC enrolled onto the protocol, and 10 patients had data available for evaluation. The majority were male (10/12) with a median age of 64 (SD 11). Most patients had received sorafenib therapy (9/12) and had varying Child-Pugh classes (A-4, B-6, C-2). Treatment with VF-2 ranged from 1 to 36 weeks with a mean of 12.3 weeks (SD 12). Six patients received 8 weeks of treatment, and 3 patients received 12 or more weeks of treatment. For patients that received at least 4 weeks of treatment, the average AFP value stabilized during the first 4 weeks of treatment. Two patients experienced an AFP decrease of >30%, approximately 37 and 40% decreases at the nadir. One patient had stable disease of 9 months. Major side effects were fever, fatigue, rash, and local injection site reaction of swelling, redness, and tenderness. Conclusion: This case series of advanced HCC indicates that mistletoe extract VF-2 may have potential biological activity against HCC for selected patients. Research is needed to identify the active compound and predictive markers of response.

Mistletoe Extract Targets the STAT3-FOXM1 Pathway to Induce Apoptosis and Inhibits Metastasis in Breast Cancer Cells

Mistletoe extracts (Viscum album L.) have been widely used as complementary and alternative medicines for the treatment of cancer, and their cytotoxic effects have been reported on various types of cancer. However, the molecular targets of mistletoe extracts have not been well studied. Herein, we investigated molecules associated with the in vitro and in vivo anticancer effects of mistletoe extract using 4T1 murine breast cancer cells. Mistletoe extract induced apoptosis and inhibited the signal transducer and activator of transcription3 (STAT3) phosphorylation. This inhibition was accompanied by the downregulations of forkhead box M1 (FOXM1) and the DNA repair proteins, RAD51 and survivin. Mistletoe extract simultaneously increased the expression of the DNA damage marker proteins, phosphorylated H2A histone family member X (H2A.X), and phosphorylated p38. Furthermore, mistletoe extract effectively suppressed tumor growth in 4T1 tumor-bearing BALB/c mice. In addition to tumor growth inhibition, mistletoe extract inhibited lung metastasis in the tumor-bearing mice and cell invasiveness by downregulating the expressions of matrix metalloproteinases (MMPs), urokinase-type plasminogen activator (uPA), uPA receptor, and markers of epithelial-mesenchymal transition (snail and fibronectin). Taken together, our results suggest that mistletoe extract targets the STAT3-FOXM1 pathway for its cytotoxic effects, and that mistletoe extracts might be useful for the treatment of patients with cancers highly expressing the STAT3-FOXM1 pathway.

Quality of life in cancer patients treated with mistletoe: a systematic review and meta-analysis

BackgroundMistletoe extracts are used as an adjunct therapy for cancer patients, but there is dissent as to whether this therapy has a positive impact on quality of life (QoL).MethodsWe conducted a systematic review searching in several databases (Medline, Embase, CENTRAL, CINAHL, PsycInfo, Science Citation Index, clinicaltrials.gov, opengrey.org) by combining terms that cover the fields of “neoplasm”, “quality of life” and “mistletoe”. We included prospective controlled trials that compared mistletoe extracts with a control in cancer patients and reported QoL or related dimensions. The quality of the studies was assessed with the Cochrane Risk of Bias tool version 2.We conducted a quantitative meta-analysis.ResultsWe included 26 publications with 30 data sets. The studies were heterogeneous. The pooled standardized mean difference (random effects model) for global QoL after treatment with mistletoe extracts vs. control was d = 0.61 (95% CI 0.41-0.81; p<0,00001). The effect was stronger for younger patients, with longer treatment, in studies with lower risk of bias, in randomized and blinded studies. Sensitivity analyses support the validity of the finding. 50% of the QoL subdomains (e.g. pain, nausea) show a significant improvement after mistletoe treatment. Most studies have a high risk of bias or at least raise some concern.ConclusionMistletoe extracts produce a significant, medium-sized effect on QoL in cancer. Risk of bias in the analyzed studies is likely due to the specific type of treatment, which is difficult to blind; yet this risk is unlikely to affect the outcome.PROSPERO registration numberCRD42019137704

Use and Safety of Viscum album L Applications in Cancer Patients With Preexisting Autoimmune Diseases: Findings From the Network Oncology Study

Background: Viscum album L (VA, mistletoe) extracts are commonly used in integrative oncology. Here the clinical safety profile of additional VA-treatments to standard care in cancer patients with preexisting autoimmune diseases was analyzed. Methods: In this observational cohort study medical data and recorded adverse events (AEs) of treated patients were retrieved from the Network Oncology registry and a safety analysis was performed. Results: A total of 106 patients (median age 63 years) treated with add-on VA-extracts were analyzed. Most frequent autoimmune diseases were Hashimoto’s thyroiditis (27%), psoriasis (19%), and ulcerative colitis (15%). Seventeen patients (16%) experienced VA-related AEs, but neither long-term side effects nor VA-therapy discontinuations were recorded. In a subgroup of 30 patients receiving long-term VA-therapy no exacerbations or flares of underlying autoimmune diseases were recorded. Additionally, a significant halving of overall AE-rates was observed during VA-treatment periods (p= 0.019). Conclusions: Our findings suggest that add-on VA-therapy in cancer patients with preexisting autoimmune diseases as Hashimoto’s thyroiditis, psoriasis, ulcerative colitis, Grave’s disease, and some rheumatic diseases is safe. No higher rates of VA-associated AEs were observed and the overall AE-rates were significantly lowered in VA-therapy periods. However, results should be interpreted with caution in light of the study’s observational character.