Phytochemical Profile and Antioxidant Capacity of Viscum album L. Subsp. album and Effects on Its Host Trees

The cardioprotective potential of selected species of mistletoe

Mistletoe is an evergreen woody shrub with stems measuring 30-100 cm. It has leathery, yellowish-green strap-shaped leaves, yellowish-green flowers, and bears typical berries. The most common species is Viscum album L., mainly present in Europe and Asia. It is commonly known as European mistletoe or simply, mistletoe. Scientific interest in mistletoe was awakened in the XX century. Mistletoe, especially V. album L., has historically been used in the treatment and prophylaxis of CVD, with its properties being confirmed in recent studies. This mini-review describes new aspects of the cardioprotective properties of various species of mistletoe, especially V. album L. The effect of oral and subcutaneous application of fresh V. album L. extracts on blood pressure has been studied in various models; while the data suggests that mistletoe may be a promising herbal extract with cardioprotective properties, the species has only been tested in vitro and in vivo, on animals. In addition, it is unclear whether the cardioprotective activity of mistletoe may be due to particular chemical components, as the chemical composition of mistletoe extracts can vary depending on inter alia the time of harvest, extraction method and plant part. Hence, this activity may instead result from synergistic interactions between various secondary metabolites. Therefore, further studies are needed to identify the mechanisms of action of mistletoe compounds on CVDs, and determine their interactions with other cardioprotective drugs, their metabolic mechanisms, pharamacokinetics and adverse effects. More research is also needed to determine the therapeutic doses of active ingredients for use in clinical trials; this would require an accurate understanding of the chemical composition of extracts from different species of mistletoe (not only V. album L.) and from various host trees.

Performance, HSP70 expression, antioxidant enzymes, oxidative DNA damage biomarkers, metabolic hormones, and intestinal microbiota of broiler chickens fed mistletoe leaf powder supplemented diets under tropical high ambient temperatures

The study investigated the impact of Mistletoe Leaf Powder (MLP) supplementation on some parameters in heat-stressed broiler chickens. The standard baseline diets, comprising four different formulations, were provided during the starter and finisher stages. Chickens were randomly assigned to the 4 dietary groups: a negative control (CON) with no supplementation, a positive control (VTC) with 200 mg/kg vitamin C, and 2 experimental treatment groups with 2500 mg/kg (MLP2) and 5000 mg/kg (MLP5) MLP supplementation. The Body Weight Gain (BWG) in MLP2 and MLP5 treatment groups was comparable (P > 0.05) to those in VTC, while the CON group exhibited significantly (P < 0.05) lower BWG. Feed consumption was significantly (P < 0.05) lower broiler chickens in the CON group compared to those VTC, MLP2, and MLP5. Heat shock protein 70 (HSP70) levels were lower in broiler chickens belonging to VTC, MLP2, and MLP5 groups compared to those in CON, and MLP2 showed no difference (P > 0.05) from MLP5 and VTC. Serum glutathione peroxidase and catalase concentrations were higher (P < 0.05) in birds belonging to MLP5, MLP2, and VTC groups compared to CON. The 8-hydroxy-2'-deoxyguanosine concentration was lower (P < 0.05) in birds of VTC, MLP2, and MLP5 compared to the CON, with VTC showing the least concentration. Serum insulin levels were higher (P < 0.05) in MLP5 compared to those in CON, while serum triiodothyronine and leptin concentrations were lower (P < 0.05) in CON compared to birds in VTC, MLP2, and MLP5. Microbiota analysis revealed that the Coliform bacteria population was higher (P < 0.05) in birds belonging to CON compared to those in VTC, MLP2, and MLP5 groups, whereas lactic acid-producing bacteria were significantly (P < 0.05) lower in birds of CON and highest in MLP2 and MLP5 groups. In conclusion, dietary supplementation of MLP at 5000 mg/kg enhanced performance, oxidative status, influenced metabolic hormones, and gut microbiota in broiler chickens raised under high ambient temperature.

The Antioxidant Activity of Mistletoes (Viscum album and Other Species)

In addition to the European mistletoe, Viscum album, which is the most known and utilized one, there are several species commonly known as mistletoe. They are spread in various regions of the planet and are all characterized by hemiparasitism and epiphytic behaviour. The published studies evidence other similarities, including the sharing of important biological properties, with the common presence of antioxidant effects. However, whereas the European mistletoe is largely utilized in medical treatments, although with controversial aspects, the scientific knowledge and medical uses of other mistletoes are still insufficient. This review focuses on the controversial medical story of European mistletoe regarding its antioxidant activity and the potentiality of the other species named mistletoe pertaining to botanical families and genera different from Viscum.

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.

Protein Profiling of Psittacanthus calyculatus during Mesquite Infection

Psittacanthus calyculatus is a hemiparasite mistletoe that represents an ecological problem due to the impacts caused to various tree species of ecological and commercial interest. Although the life cycle for the Psittacanthus genus is well established in the literature, the development stages and molecular mechanism implicated in P. calyculatus host infection are poorly understood. In this study, we used a manageable infestation of P. laevigata with P. calyculatus to clearly trace the infection, which allowed us to describe five phenological infective stages of mistletoe on host tree branches: mature seed (T1), holdfast formation (T2), haustorium activation (T3), haustorium penetration (T4), and haustorium connection (T5) with the host tree. Proteomic analyses revealed proteins with a different accumulation and cellular processes in infective stages. Activities of the cell wall-degrading enzymes cellulase and β-1,4-glucosidase were primarily active in haustorium development (T3), while xylanase, endo-glucanase, and peptidase were highly active in the haustorium penetration (T4) and xylem connection (T5). Patterns of auxins and cytokinin showed spatial concentrations in infective stages and moreover were involved in haustorium development. These results are the first evidence of proteins, cell wall-degrading enzymes, and phytohormones that are involved in early infection for the Psittacanthus genus, and thus represent a general infection mechanism for other mistletoe species. These results could help to understand the molecular dialogue in the establishment of P. calyculatus parasitism.