European Mistletoe (Viscum album) Extract Is Cytotoxic to Canine High-Grade Astrocytoma Cells In Vitro and Has Additive Effects with Mebendazole

Viscum album (mistletoe) extract for dogs with cancer?

Compared with the options available to human patients with cancer, treatment choices for dogs are often more limited. Chemotherapy is frequently the first-line treatment for many cancers. However, its efficacy can be limited, and its side effects can affect the quality of the remaining life. This paper briefly summarizes the experience with Viscum album L. (mistletoe) extract in human patients as a stipulation to consider treatment with mistletoe extract for canines with cancer. The mistletoe extract contains -among others - lectins and viscotoxins that have documented anti-proliferative effect on cancer cells as well as immune-stimulatory function. Importantly, it also improves the well-being of patients with cancer due to its lectin ML-1 content, which can trigger the release of endorphins. Being cross-reactive with canine cells and having a relatively low side effect profile, it raises the question of whether mistletoe preparations might be considered as part of the treatment approach for dogs with cancer.

The Anti-Inflammatory Activity of Viscum album

The therapeutic story of European mistletoe (Viscum album L.) presents a seesawing profile. In ancient times, this hemiparasitic plant was considered a panacea and even to be endowed with exceptional beneficial properties. In more recent times, despite its multiple uses in traditional medicines, some parts of the plant, in particular the berries, were considered poisonous and dangerous, including concerns of cytotoxicity, which spread serious suspicion on its medicinal utility. However, since the last century, medical interest in mistletoe has come back in force due to its utilization in clinical cancer treatments, based on its selective action on tumor cells. In Central Europe, the hydro-alcoholic extracts of European mistletoe register a relevant and continuous utilization in anthroposophic medicine, which is a holistic system that includes the utilization of phytomedicinal substances. In Switzerland and Germany, most physicians and patients use these products as complementary therapy in oncological treatments. However, despite its increasing use in this field, the results of mistletoe's use are not always convincing, and other aspects have appeared. Nowadays, products that contain mistletoe are utilized in several fields, including diet, phytotherapy, veterinary medicine and homeopathy, but in particular in cancer therapies as coadjuvant factors, in consideration of several positive effects including effects in the improvement of quality-of-life conditions and reinforcement of the immune system. In this review, based on the understanding of the association between cancer and inflammation, we propose a relationship between these recent uses of mistletoe, based on its antioxidant properties, which are supported by phytochemical and pharmacological data. The unicity of mistletoe metabolism, which is a direct consequence of its hemiparasitism, is utilized as a key interpretation element to explain its biological properties and steer its consequent therapeutic uses.