Viscum Species Research Articles

Traditional Uses, Phytochemical Constituents and Ethnopharmacological Properties of Mistletoe from Phoradendron and Viscum Species.

Plants from the genus Phoradendron and Viscum, also known as American and European mistletoe, are a group of hemiparasitic plants traditionally used to treat many diseases. Mistletoes have a rich content of natural compounds like terpenes, alkaloids, proteins, and phenolic compounds associated with their potential medicinal properties. In this sense, mistletoes have shown antiproliferative, antioxidant, anti-inflammatory, and antimicrobial activity, which has been attributed to their phytochemical constituents. The mechanisms in which mistletoe plants act vary and depend on their phytochemical content and distribution, which in part will depend on the mistletoe species. In this sense, recent literature research is needed to visualize state of the art in the ethnopharmacological potential of mistletoe. Thus, this literature review aims to systematically report recent studies (2010-2023) on the phytochemical characterization and bioactive studies of mistletoe plants, mainly the Viscum and Phoradendron genera. We gather recent information of 140 references selected in our research. Here we report that although there are several bioactivity studies of mistletoe species, bioavailability studies are still scarce, and the precise mechanisms of action are not fully known. We encourage that further studies include a systematic strategy to cover these areas of opportunity.

Application of the UHPLC-q-TOF-MS and molecular networking in revealing chemo-taxonomical markers of Viscum combreticola Engl. and Viscum album L.

A metabolic profiling approach employing the UHPLC-q-TOF-MS and classical molecular networking was used to investigate the polyphenol profile differences between Viscum combreticola Engl. (African mistletoe) and Viscum album L. (European mistletoe). The findings of this study revealed that V. combreticola was predominantly characterized by a diverse hydroxycinnamic acid derivatives profile, mainly comprising of structural isomers of monoacylated, homodiacylated, heterodiacylated and heterotriacylated chlorogenic acids. Remarkably, a succinoyl and two new hydroxybenzoyl containing chlorogenic acids were identified for the first time in Viscum species in this study. In contrast, V. album contained flavonoids (flavonols, flavanones and flavones) showing various glycosylation patterns, where the majority of these compounds were acylated to a 3-hydroxy-3-methylglutaroyl moiety. Moreover, V. combreticola also displayed a different flavonoid profile that exhibited different glycosylation patterns from that observed in V. album. As such, the distinct polyphenol profiles of these two Viscum species can serve as a chemo-taxonomical markers of these plants. Additionally, this study demonstrated that molecular networking is a powerful tool in visualizing differences between the chemical composition of different samples. The diverse polyphenol profile of these two Viscum species might be attributed to their unique metabolism which could be influenced by their genetic make-up, thereby, allowing them to survive various biotic and abiotic stresses.

A Scoping Review of Genus Viscum: Biological and Chemical Aspects of Alcoholic Extracts.

The genus Viscum comprises a large number of semi-parasitic shrubs popularly known as Mistletoe. The Viscum species grow in many countries of Europe, Africa and Asia with different popular uses in ornamentation, foods and medicine. Many studies about Viscum have been done over the last years focusing on biological activities and chemical composition of the aqueous extracts, mainly related to anthroposophical medicines. However, it is known that non-aqueous preparations, as alcoholic extracts, have demonstrated different biological activities that are species-and host tree-dependent. Considering the potential of these alcoholic extracts, a scoping review was conducted using data from three online databases: PubMed, Scopus and Embase. Inclusion criteria consisted of the in vitro, in vivo, ex vivo, clinical and chemical studies of alcoholic extracts from Viscum species. The present review summarized 124 original publications about fourteen Viscum species. Viscum album, Viscum articulatum and Viscum coloratum were the main studied species. Alcoholic extracts demonstrated hypotensive, anticancer, antimicrobial, analgesic and anti-inflammatory capabilities, among other biological activities. Flavonoids, phenolic acids and terpenoids represented 48%, 24% and 11% of the total identified compounds, respectively. This review contributes to the knowledge of alcoholic preparations of the Viscum species and points out the lack of clinical studies concerning these different extracts.

Utilization of the Viscum Species for Diet and Medicinal Purposes in Ruminants: A Review.

Simple SummaryTrue mistletoe (of the Viscum species) is a semi-parasitic, perennial browse species that is found attached to its host—a shrub or a tree. It has important pharmaceutical and chemical properties that allow it to be used for a variety of purposes, including livestock production. Mistletoes are cheap and are a readily available source of minerals and protein for livestock, especially during the dry season. They grow primarily on the outer branches of the tree crown; however, they also frequently grow directly on the tree trunk in order to consume its nutrients and water, thereby affecting their host’s quality and development. Many countries are expected to discover and explore the potential of Viscum spp. and their management tools, which we investigate through this review.A cost-effective, alternative protein and mineral source such as the Viscum species can be key to livestock production. Viscum spp. are used as feed in many semi-arid and arid regions globally, particularly during feed shortages. The species’ feeding value, and their pharmaceutical attributes, have been recognized worldwide, albeit with variation in nutritive value from one host to another. The antinutritional factors found in Viscum spp. may benefit livestock when consumed in moderation due to their immunomodulatory, proapoptotic, and antimicrobial properties. The Vachellia species are known to be the common hosts for Viscum spp. Further, even though Viscum spp. inhibit host tree development by reducing carbon absorption and the host tree’s carbohydrates, the efforts to regulate their infestation should not result in the plant’s total eradication due to the benefits to livestock (as well as in fodder and medicine). This review will help to improve understanding of Viscum species control measures, while also increasing the productivity of ruminants.

Genes from oxidative phosphorylation complexes II-V and two dual-function subunits of complex I are transcribed in Viscum album despite absence of the entire mitochondrial holo-complex I

Mistletoes (Viscum) and close relatives are unique among flowering plants in having a drastically altered electron transport chain. Lack of complex I genes has previously been reported for the mitochondrial genome, and here we report an almost complete absence of nuclear-encoded complex I genes in the transcriptome of Viscum album. Compared to Arabidopsis with approximately 40 nuclear complex I genes, we recover only transcripts of two dual-function genes: gamma carbonic anhydrase and L-galactono-1,4-lactone dehydrogenase. The complement of genes belonging to complexes II–V of the oxidative phosphorylation pathway appears to be in accordance with other vascular plants. Additionally, transcripts encoding alternative NAD(P)H dehydrogenases and alternative oxidase were found. Despite sequence divergence, structural modeling suggests that the encoded proteins are structurally conserved. Complex I loss is a special feature in Viscum species and relatives, as all other parasitic flowering plants investigated to date seem to have a complete OXPHOS system. Hence, Viscum offers a unique system for specifically investigating molecular consequences of complex I absence, such as the role of complex I subunits involved in secondary functions.

Lectins in Viscum:a progress review

Viscum plants,the evergreen perennial parasitic shrubs or subshrubs,are mainly distributed in tropical and subtropical regions. There are about 70 Viscum species around the world,including 11 species and one variety in China. Mistletoe lectins are typeⅡ ribosome-inactivating proteins( RIPs) extracted from Viscum plants with anticancer and immunoregulatory activities. Many studies have focused on the mistletoe lectins isolated from V. album in Europe and V. album var. coloratum distributed in South Korea,respectively,and several preparations,such as Iscucin Ⓡ,were developed and clinically applied for cancer treatment. Although Viscum plants are widely distributed in China,only a few studies of mistletoe lectins have been reported. The recent progress of mistletoe lectins was reviewed from extraction,purification,quantitative/qualitative detection,molecular structure,pharmacological activities,toxicities,and clinical application,aiming at providing a reference for in-depth research and utilization of mistletoe lectins produced in China.

Mitochondrial genome evolution in parasitic plants

BackgroundParasitic plants rely on their host to cover their nutritional requirements either for their entire life or a smaller part of it. Depending on the level of parasitism, a proportional reduction on the plastid genome has been found. However, knowledge on gene loss and evolution of the mitogenome of parasitic plants is only available for four hemiparasitic Viscum species (Viscaceae), which lack many of the mitochondrial genes, while the remaining genes exhibit very fast molecular evolution rates. In this study, we include another genus, Phoradendron, from the Viscaceae, as well as 10 other hemiparasitic or holoparasitic taxa from across the phylogeny of the angiosperms to investigate how fast molecular evolution works on their mitogenomes, and the extent of gene loss.ResultsOur observations from Viscum were replicated in Phoradendron liga, whereas the remaining parasitic plants in the study have a complete set of the core mitochondrial genes and exhibit moderate or only slightly raised substitution rates compared to most autotrophic taxa, without any statistically significant difference between the different groups (autotrophs, hemiparasites and holoparasites). Additionally, further evidence is provided for the placement of Balanophoraceae within the order Santalales, while the exact placement of Cynomoriaceae still remains elusive.ConclusionsWe examine the mitochondrial gene content of 11 hemiparasitic and holoparasitic plants and confirm previous observations in Viscaceae. We show that the remaining parasitic plants do not have significantly higher substitution rates than autotrophic plants in their mitochondrial genes. We provide further evidence for the placement of Balanophoraceae in the Santalales.

Morphology, geographic distribution, and host preferences are poor predictors of phylogenetic relatedness in the mistletoe genus Viscum L.

Besides their alleged therapeutic effects, mistletoes of the genus Viscum L. (Viscaceae) are keystone species in many ecosystems across Europe, Africa, Asia and Australia because of their complex faunal interactions. We here reconstructed the evolutionary history of Viscum based on plastid and nuclear DNA sequence data. We obtained a highly resolved phylogenetic tree with ten well-supported clades, which we used to understand the spatio-temporal evolution of these aerial parasites and evaluate the contribution of reproductive switches and shifts in host ranges to their distribution and diversification. The genus Viscum originated in the early Eocene in Africa and appeared to have diversified mainly through geographic isolation, in several cases apparently coinciding with shifts in host preferences. During its evolution, switches in the reproductive mode from ancestral dioecy to monoecy imply an important role in the long-distance dispersal of the parasites from Africa to continental Asia and Australia. We also observed multiple cases of photosynthetic surface reduction (evolution of scale leaves) within the genus, probably indicative of increasing specialization associated with the parasitic lifestyle. Even compared with other parasitic angiosperms, where more host generalists than specialists exist, Viscum species are characterized by extraordinarily broad host ranges. Specialization on only a few hosts from a single family or order occurs rarely and is restricted mostly to very recently evolved lineages. The latter mostly derive from or are closely related to generalist parasites, implying that niche shifting to a new host represents an at least temporary evolutionary advantage in Viscum.

Viscum songimveloensis, a new species of mistletoe from South Africa

A species of Viscum (Santalaceae) was collected in eastern Mpumalanga that did not match V. combreticola, V. anceps or V. shirense. We consider the differences to be sufficient to recognise a new species, Viscum songimveloensis D. Oosthuizen & K. Balkwill. This species has so far only been found on one host, Trichocladus grandiflorus, and in a very restricted geographical range. Consequently a provisional threat status of Vulnerable D2 is proposed. This new discovery brings the total number of Viscum species in the Flora of southern Africa region to twenty and in Mpumalanga to ten. An updated key to the species of Viscum in Mpumalanga is provided.

POTENTIAL ANTI-TUMOR AND ANTI-INFLAMMATORY ACTIVITY OF SIX MISTLETOE PLANTS IN THE FAMILY VISCACEAE PRESENT IN WESTERN GHATS, INDIA

ABSTRACTObjectivesTo find out the cytotoxicity, anti-tumor and anti-inflammatory activities of six species of plants belongs to Viscaeceae family available in Western Ghats (India).MethodsIn vitro cytotoxicity of Viscum extracts was studied by trypan blue exclusion method and MTT assay using various cell lines. Anti-tumor activity was determined using Ehrlich ascites carcinoma (EAC) and Dalton’s lymphoma ascites (DLA) cells in mice. Anti-inflammatory activities of Viscum extracts were studied using carrageenan and dextran induced mouse paw edema models in mice.ResultsAll six Viscaeceae plant extracts studied were cytotoxic towards transformed cell lines like DLA and EAC as well as to MCF-7, MDA-MB-231 and SKBR3 cell lines. V.orientale, V.nepalense and V.ramosissimum, V.trilobatum were cytotoxic towards normal cells while V.angulatum and V.capitellatum were found to be nontoxic. Excepting V.angulatum all the other species selected here showed toxicity to animals. Administration of nontoxic concentration of extracts of Viscaeceae plants significantly (P<0.001) increased the lifespan of ascites tumor bearing animals and reduced DLA cells induced solid tumor development. All these plants except V.capitallatum and V.trilobatum showed significant (P<0.001) anti-inflammatory activity against carrageenan and dextran models and reduced pro-inflammatory cytokine levels.ConclusionOut of six species studied four species of Viscum species studied were cytotoxic to tumour cells and inhibited tumour development. Of the six species studied V. angulatum was non-toxic to animals and showed maximum efficiency as an antitumour agent. These plants showed significant anti-inflammatory activity and reduced inflammatory markers.

Massive gene loss in mistletoe (Viscum, Viscaceae) mitochondria.

Parasitism is a successful survival strategy across all kingdoms and has evolved repeatedly in angiosperms. Parasitic plants obtain nutrients from other plants and some are agricultural pests. Obligate parasites, which cannot complete their lifecycle without a host, may lack functional photosystems (holoparasites), or have retained photosynthesis (hemiparasites). Plastid genomes are often reduced in parasites, but complete mitochondrial genomes have not been sequenced and their mitochondrial respiratory capacities are largely unknown. The hemiparasitic European mistletoe (Viscum album), known from folklore and postulated therapeutic properties, is a pest in plantations and forestry. We compare the mitochondrial genomes of three Viscum species based on the complete mitochondrial genome of V. album, the first from a parasitic plant. We show that mitochondrial genes encoding proteins of all respiratory complexes are lacking or pseudogenized raising several questions relevant to all parasitic plants: Are any mitochondrial gene functions essential? Do any genes need to be located in the mitochondrial genome or can they all be transferred to the nucleus? Can parasitic plants survive without oxidative phosphorylation by using alternative respiratory pathways? More generally, our study is a step towards understanding how host- and self-perception, host integration and nucleic acid transfer has modified ancestral mitochondrial genomes.

Plastome Evolution in Hemiparasitic Mistletoes.

Santalales is an order of plants consisting almost entirely of parasites. Some, such as Osyris, are facultative root parasites whereas others, such as Viscum, are obligate stem parasitic mistletoes. Here, we report the complete plastome sequences of one species of Osyris and three species of Viscum, and we investigate the evolutionary aspects of structural changes and changes in gene content in relation to parasitism. Compared with typical angiosperms plastomes, the four Santalales plastomes are all reduced in size (10–22% compared with Vitis), and they have experienced rearrangements, mostly but not exclusively in the border areas of the inverted repeats. Additionally, a number of protein-coding genes (matK, infA, ccsA, rpl33, and all 11 ndh genes) as well as two transfer RNA genes (trnG-UCC and trnV-UAC) have been pseudogenized or completely lost. Most of the remaining plastid genes have a significantly changed selection pattern compared with other dicots, and the relaxed selection of photosynthesis genes is noteworthy. Although gene loss obviously reduces plastome size, intergenic regions were also shortened. As plastome modifications are generally most prominent in Viscum, they are most likely correlated with the increased nutritional dependence on the host compared with Osyris.

Wo new species of Viscum (Viscaceae) from China

Two new species of Viscum from the southern and southwestern China are described and illustrated. Both Viscum macrofalcatum and V. hainanense are monoecious plants with inflorescences axillary, usually 3–5 flowers in one cyme, the middle one male, outer ones females. Viscum macrofalcatum differs from V. hainanense by having 1–6 sessile cymes in the axil, whereas V. hainanense has only 1 cyme in the axil, and peduncle 0.5–1 mm long. The most closely related species to these entities is V yunnnanense. Based on the habit and habitat, external morphology, and palynological characters, we concluded that the three entities are specifically distinct.

Dry matter and crude protein degradability of four parasitic plants (mistletoes) associated with browse trees in Botswana.

Four parasitic plants (Tapinanthus lugardii, Erianthenum ngamicum, Viscum rotundifolium and Viscum verrucosum) associated with browse trees in Botswana were evaluated for the degradability of their dry matter (DM) and crude protein (CP). All these plants have high levels of crude protein, ranging from 144.5 to 163.4 g/kg DM, with a significant (p < 0.001) difference in crude protein content between the plants. The rate of degradation of DM was highest for V. rotundifolium (0.197 h(-1)) and lowest for E. ngamicum (0.031 h(-1)). The two Viscum species had the highest effective DM degradability at an outflow rate of 0.05%. The rate of degradation of crude protein was highest for V. rotundifolium (0.144 h(-1)) and lowest for T. lugardii (0.0346 h(-1)). The effective degradability (ED) of crude protein was highest for V. rotundifolium at 0.03 and 0.05 h(-1) outflow rates. T. lugardii and E. ngamicum had an apparently low effective degradability, but this may result from an association of their protein with tannins, which would be able to supply amino acids in the small intestine after dissociation due to the abomasal pH.

Sex-determining and floating translocation complexes in Viscum cruciatum Sieber ex Boiss. (Viscaceae) in southern Spain. Some evolutionary and ecological comments

Abstract As in other dioecious species of Viscum, males of V. cruciatum always produce large rings of chromosomes during meiosis due to the existence of permanent translocation heterozygosity. Only rings often (and very rarely 12) chromosomes have been found in this species, probably a relative of V. album in the Mediterranean area. Females form bivalents. Another two floating translocations—not sex-associated and affecting different chromosomes—have been observed in both male and female plants in some populations. These produce meiotic configurations previously unrecorded in Viscum . This floating heterozygosity seems to be correlated with the aptitude of V. cruciatum to develop on different hosts, especially Prunus . All studied populations showed an excess of female plants, perhaps partly due to facultative agamospermy.

Sex-determining and floating translocation complexes in Viscum cruciatum Sieber ex Boiss. (Viscaceae) in southern Spain. Some evolutionary and ecological comments

As in other dioecious species of Viscum, males of V. cruciatum always produce large rings of chromosomes during meiosis due to the existence of permanent translocation heterozygosity. Only rings often (and very rarely 12) chromosomes have been found in this species, probably a relative of V. album in the Mediterranean area. Females form bivalents. Another two floating translocations—not sex-associated and affecting different chromosomes—have been observed in both male and female plants in some populations. These produce meiotic configurations previously unrecorded in Viscum . This floating heterozygosity seems to be correlated with the aptitude of V. cruciatum to develop on different hosts, especially Prunus . All studied populations showed an excess of female plants, perhaps partly due to facultative agamospermy.

Fine Structure of Mistletoe Pollen. IV. Eurasian and Australian viscum L. (Viscaceae)

Fifteen Eurasian and Australian species of Viscum L. were examined by light, scanning, and transmission electron microscopy. Pollen characters divide the species into two groups, each correlated with differences in habit and inflorescence structure: Group I (12 spp.) characterized by psilate or slightly sculptured exines and a non-uniform ektexine pattern and Group II (3 spp.) possessing highly sculptured (echinate, rodlet) surfaces and uniform ektexine patterns. Within each of the groups, pollen characters divide the species into several subgroups. Among Group I, species V. nepalense, V. heyneanum and V. ovalifolium are particularly close. The Group I species, V. trilobatum, is placed in its own subgroup primarily because of its uniform ektexine pattern—a unique feature among Asian and Australian Viscum. Of the three Group II species, V. album and V. alniformosanae are palynologically almost indistinguishable. Pollen of the Group II V. cruciatum, though exomorphologically similar to V. album, is closest ultrastructurally to the Indian V. trilobatum. Overall, the most common and probably basic pollen characters among the Eurasian and Australian species include: subprolate, rounded convex almost spherical shapes; tricolporate apertures, and non-uniform sculpturing and ektexine patterns. Oblate-spheroidal or prolate-spheroidal shapes, prominent sculpturing, and a uniform ektexine pattern are derived characters largely restricted to the Eurasian and Asian Group II species (V. album, V. alniformosanae, V. cruciatum).

FINE STRUCTURE OF MISTLETOE POLLEN. IV. EURASIAN AND AUSTRALIAN VISCUM L. (VISCACEAE)

Fifteen Eurasian and Australian species of Viscum L. were examined by light, scanning, and transmission electron microscopy. Pollen characters divide the species into two groups, each correlated with differences in habit and inflorescence structure: Group I (12 spp.) characterized by psilate or slightly sculptured exines and a non‐uniform ektexine pattern and Group II (3 spp.) possessing highly sculptured (echinate, rodlet) surfaces and uniform ektexine patterns. Within each of the groups, pollen characters divide the species into several subgroups. Among Group I, species V. nepalense, V. heyneanum and V. ovalifolium are particularly close. The Group I species, V. trilobatum, is placed in its own subgroup primarily because of its uniform ektexine pattern—a unique feature among Asian and Australian Viscum. Of the three Group II species, V. album and V. alniformosanae are palynologically almost indistinguishable. Pollen of the Group II V. cruciatum, though exomorphologically similar to V. album, is closest ultrastructurally to the Indian V. trilobatum. Overall, the most common and probably basic pollen characters among the Eurasian and Australian species include: subprolate, rounded convex almost spherical shapes; tricolporate apertures, and non‐uniform sculpturing and ektexine patterns. Oblate‐spheroidal or prolate‐spheroidal shapes, prominent sculpturing, and a uniform ektexine pattern are derived characters largely restricted to the Eurasian and Asian Group II species (V. album, V. alniformosanae, V. cruciatum).

Translocation heterozygosity in southern African species of &lt;i&gt;Viscum&lt;/i&gt;

Sex-associated and floating translocation complexes are characteristic of dioecious species of Viscum, but are virtually absent in monoecious species. The majority of dioecious species has fixed sex-associated translocation complexes with the male being the heterozygous sex. The sex-associated multivalent is usually O4 (ring-of-four) or O6 , rarely O8 . Dioecious species without sex-associated translocations are much less common. Most of the dioecious species are also polymorphic for floating translocations, producing one or more additional multivalents ranging from O4 to O12. Floating translocations may be more frequent in species that do not have sex-associated translocations. Supernumerary chromosomes are also present in several species. Sex ratios are at unity in most dioecious species, but female-biased ratios may occur in some species. The high correlation between dioecy and translocation heterozygosity suggests that translocations are primarily associated with the origin and establishment of dioecy. Any róle in the maintenance of biased sex ratios through meiotic drive is probably secondary. Sex-associated translocations may serve to stabilize dioecy by bringing the sex factors into close linkage. Subsequent structural rearrangements within a sex-associated translocation complex may bring the sex factors together in one chromosome pair, releasing floating translocations. The high frequencies of floating translocation heterozygosity in some species indicate that such heterozygosity also has adaptive value.

Translocation heterozygosity and the origin of dioecy in Viscum

Sex-associated and floating translocation complexes are characteristic of dioecious species of Viscum, but are virtually absent in monoecious species. In most of the dioecious species, fixed sex-associated translocation complexes are present, with the male being the heterozygous sex. The sex-associated multivalent is usually ⊙4 (ring-of-four) or ⊙6, rarely ⊙8. In only a few of the dioecious species are sex-associated translocations not apparent. Most of the dioecious species are also polymorphic for floating translocations, producing one or more additional multivalents ranging from ⊙4 to ⊙12. Floating translocations may be more frequent in species which do not have sex-associated translocations. Supernumerary chromosomes are also present in several species. Sex ratios are at unity in most dioecious species, but female-biased ratios as low as 0·52 and male-biased ratios as high as 1·40 may occur in some species. The high correlation between dioecy and translocation heterozygosity suggests that translocations are primarily associated with the origin and establishment of dioecy, and any role they play in the maintenance of biased sex ratios through meiotic drive is probably secondary. A model is presented in which male- and female-determining factors are non-allelic, and sex-associated translocations serve to stabilise dioecy by bringing the sex factors into linkage. Subsequent structural rearrangements within a sex-associated translocation complex may bring the sex factors together in one chromosome pair, releasing floating translocations. The high frequencies of floating translocation heterozygosity in some species indicate that such heterozygosity has adaptive value.