Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Mistletoe”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1997

Differences in the apoptosis-inducing properties of Viscum album L. extracts.

Viscum album L. (mistletoe) extracts are widely used in adjuvant cancer therapy. In contrast to purified components, such as mistletoe lectins and viscotoxins, whole plant extracts of mistletoe resulted in DNA stabilizations in cyclophosphamide-treated lymphocytes but also provided cytotoxicity in tumour cells and lymphocytes. The killing capacities of mistletoe extracts were host tree-specific and not correlated with mistletoe lectin or viscotoxin content. In human lymphocytes, only mistletoe lectins induced a pathway of apoptotic killing. Within 72 h, the lectin B chains also increased the number of lymphocytes undergoing apoptosis. This finding suggests that inhibition of protein synthesis by the A chain of the hololectin may accelerate a receptor-mediated killing pathway induced by the B chains. An unexpected finding was related to the mistletoe-mediated killing, which was more effective against CD8+T cells with an activated phenotype than CD19+ B cells and CD4+ T cells. In vitro treatment of human neutrophils with mistletoe resulted in a slight decrease of phagocytosis and burst activity. The observed dose-dependent occurrence of two neutrophil subsets with different burst activities indicates differences in their susceptibility to mistletoe and suggests the implication of an induction of the apoptotic killing pathway.

Animals↗
PubMed2004

Differences in the influx of glutamine and nitrate into Viscum album from the xylem sap of its hosts.

The flux of inorganic and organic nitrogen into the mistletoe Viscum album L. from the xylem sap of a deciduous (Populus x euamericana) and a coniferous host (Abies alba Mill.) was analyzed. For this purpose, a perfusion system was developed in which the xylem sap of the host was replaced by an artificial perfusion solution. With this system flux rates into the mistletoe were determined in feeding experiments either with the organic nitrogen source [1,2-13C2]glutamine at high and the inorganic nitrogen source 15NO3- at low concentration or vice versa. Glutamine influx was already saturated at the low concentration in the xylem sap and was--different from nitrate--not enhanced, when a 250-fold higher concentration was applied. Nitrate influx matched glutamine influx only at high inorganic/organic nitrogen ratios in the perfusion solution. This result indicates a preferential influx of glutamine over nitrate from the host xylem into the mistletoe at the concentrations found in the xylem sap of trees. Surprisingly, a high percentage of both N sources were accumulated in the mistletoe stem, indicating excessive N nutrition of the mistletoe leaves. Since 13C isotope signature was significantly reduced in the outflowing perfusion solution, either an upload of organic compounds from the phloem into the xylem, or an efflux of organic compounds from haustorium of mistletoe into the xylem has to be assumed. 15N isotope signatures enriched in the outflowing perfusion solution support the idea of a nitrate uptake system at the host xylem-haustorium interface, which favors the light N isotope of nitrate.

Germany↗
PubMed1997

The Viscum album preparation Isorel inhibits the growth of melanoma B16F10 by influencing the tumour-host relationship.

The aim of this study was to analyse whether Viscum album (mistletoe; Isorel) modulates the tumour-host relationship and whether this might be a basic mechanism of the antitumorous activity of the drug. The effects of a single intraperitoneal injection of the drug (100 mg/kg single 'planta tota' dose) were analysed for mice-bearing melanoma B16F10 growing in the hind limb. Injection of Isorel reduced the size of the tumour and caused abundant tumour necrosis with inflammatory response, oedema and destruction of the malignant tissue. Furthermore, the lymphocytes of saline-treated tumorous mice were not able to respond to the mitogenic lectin concanavalin A in vitro, while those of mistletoe extract-treated mice showed high reactivity too the mitogen, but only if cultured in the medium supplemented with the plasma of the mistletoe extract-treated mice. Moreover, melanoma cells exposed to the mistletoe extract were more sensitive to the cytotoxic activity of the lymphocytes than the control tumour cells, particularly in the presence of the plasma of mistletoe extract-treated mice. The plasma itself, however, did not show any cytotoxic activity. These results indicate that the antitumour activity of the mistletoe drug is due to a modulation of the tumour-host relationship, mediated by direct cytotoxicity of the drug to tumour cells and/or through a potentiation of immune response by certain, as yet unidentified, growth modifying humoral factors of the host.

Animals↗
PubMed2005

Host physiological condition regulates parasitic plant performance: Arceuthobium vaginatum subsp. cryptopodum on Pinus ponderosa.

Much research has focused on effects of plant parasites on host-plant physiology and growth, but little is known about effects of host physiological condition on parasite growth. Using the parasitic dwarf mistletoe Arceuthobium vaginatum subsp. cryptopodum (Viscaceae) and its host Pinus ponderosa, we investigated whether changes in host physiological condition influenced mistletoe shoot development in northern Arizona forests. We conducted two studies in two consecutive years and used forest thinning (i.e., competitive release) to manipulate host physiological condition. We removed dwarf mistletoe shoots in April, before the onset of the growing season, and measured the amount of regrowth in the first season after forest thinning (Study I: n=38 trees; Study II: n=35 trees). Thinning increased tree uptake of water and carbon in both studies, but had no effect on leaf N concentration or delta13C. Mistletoe shoot growth was greater on trees with high uptake of water and carbon in thinned stands than trees with low uptake in unthinned stands. These findings show that increased resource uptake by host trees increases resources to these heterotrophic dwarf mistletoes, and links mistletoe performance to changes in host physiological condition.

Arizona↗
PubMed2006

Molecular characterization of the recombinant A-chain of a type II ribosome-inactivating protein (RIP) from Viscum album coloratum and structural basis on its ribosome-inactivating activity and the sugar-binding properties of the B-chain.

Mistletoe (Viscum album) lectins, which are classified as a type II ribosome-inactivating protein (RIP) due to their unique biological function and the potential medical and therapeutic application in cancer cells, receive a rising attention. The heterodimeric glycoproteins contain the Achain with catalytic activity and the B-chain with sugar binding properties. In recent years, studies involving the lectins from the white berry European mistletoe (Viscum album) and the yellow berry Korean mistletoe (Viscum album coloratum) have been described. However, the detailed mechanism in exerting unique cytotoxic effect on cancer cells still remains unclear. Here, we aim to understand and define the molecular basis and biological effects of the type II RIPs, through the studies of the recombinant Korean mistletoe lectin. To this end, we expressed, purified the recombinant Korean mistletoe lectin (rKML), and investigated its molecular characteristics in vitro, its cytotoxicity and ability to induce apoptotic cell death in cancer cells. To gain structural basis for its catalytic activity and sugar binding properties, we performed homology modeling studies based on the high degree of sequence identity and conserved secondary structure prediction between Korean and European, Himalayan mistletoe lectins, and Ricin.

Amino Acid Sequence↗
PubMed1994

Non-lectin component in a fermented extract from Viscum album L. grown on pines induces proliferation of lymphocytes from healthy and allergic individuals in vitro.

Mistletoe preparations have been shown to express immunomodulatory properties. In order to evaluate the stimulatory potency of different mistletoe extracts, peripheral blood mononuclear cells (PBMC) from healthy and allergic/atopic individuals were exposed to aqueous or fermented extracts derived from Viscum album L. grown on apple trees (Mali-extracts) or on pines (Pini-extracts). None of them had received any mistletoe treatment. Iscador Pini was the only extract which strongly induced proliferation of PBMC in contrast to the other five preparations. On testing these extracts by Western blotting with anti-mistletoe lectin-1 (ML-1) antibody positive sera from mistletoe-treated patients, it became evident that Iscador Pini was almost devoid of lectins. The stimulatory potency of Iscador Pini for PBMC from three different groups was examined: PBMC from 35 normal controls (Group I), 23 patients with drug-induced adverse effects (Group II) and 16 individuals with allergic manifestations (Group III). Cells were exposed in 7-day cultures to the extract at concentrations between 1 and 10,000 micrograms/ml. PBMC from 63% of Group III individuals showed strong stimulation (SI varying from 6 to 97) in contrast to only 9% from Group I and 22% from Group II individuals. Anti-ML-1 antibodies were detected in 5% and anti-IP antibodies in 11% of subjects in the three groups. They were either of the IgA or IgM type but not of the IgG type. Our findings strongly imply that a non-lectin associated antigen from Iscador Pini is able to activate PBMC from healthy and allergic/atopic individuals, thereby demonstrating sensitization to probably highly conserved plant antigens.

Adult↗
PubMed2004

Oxygen and carbon isotope composition of parasitic plants and their hosts in southwestern Australia.

We measured leaf dry matter delta(18)O and delta(13)C in parasitic plants and their hosts growing in southwestern Australia. Parasite/host pairs included two mistletoe species, three species of holoparasites, and five species of root hemiparasites. Among these parasite functional types, significant variation was observed in parasite/host isotopic differences for both delta(18)O ( P<0.0001, n=65) and delta(13)C ( P<0.0001, n=64). Mistletoes were depleted in both (18)O and (13)C compared to their hosts; parasite/host differences were -4.0 per thousand for delta(18)O ( P<0.0001) and -1.9 per thousand for delta(13)C ( P<0.0001). The lower delta(18)O in mistletoe leaf dry matter compared to their hosts is consistent with the frequently observed high transpiration rates of these parasites. Root hemiparasites were also depleted in (18)O and (13)C compared to their hosts, but not to the same extent as mistletoes; parasite/host differences were -1.0 per thousand for delta(18)O ( P=0.04) and -1.2 per thousand for delta(13)C ( P=0.0006). In contrast to mistletoes and root hemiparasites, holoparasites were enriched in both (18)O and (13)C compared to their hosts; parasite/host differences were +3.0 per thousand for delta(18)O ( P<0.0001) and +1.5 per thousand for delta(13)C ( P=0.02). The enrichment in (18)O for holoparasite dry matter did not result from more enriched tissue water; holoparasite tissue water delta(18)O was less than host leaf water delta(18)O by a difference of -3.8 per thousand when sampled at midday ( P=0.0003). Enrichment of holoparasites in (13)C compared to their hosts is consistent with a generally observed pattern of enrichment in heterotrophic plant tissues. Results provide insights into the ecology of parasitic plants in southwestern Australia; additionally, they provide a context for the formulation of specific hypotheses aimed at elucidating mechanisms underlying isotopic variations among plants.

Australia↗
PubMed2004

Retrolective, comparative, epidemiological cohort study with parallel groups design for evaluation of efficacy and safety of drugs with "well-established use".

UNLABELLED: The randomized controlled clinical trial (RCT) is accepted as the "golden standard" for the evaluation of efficacy and safety of new drugs. In contrast, to demonstrate efficacy and safety of drugs with "well-established use" that have been on the European Community market for long time, observational comparative epidemiological studies can be used according to the European drug regulation directive. However, because comparative epidemiological cohort studies can share some risk of bias with other nonrandomized observational study designs, there is a need for an approach that could effectively reduce the bias risk in this type of studies. STUDY OBJECTIVES: The purpose of the study was to evaluate the therapeutic efficacy and safety of a long-term complementary therapy of primary, non-metastatic breast carcinoma patients treated with standardized European mistletoe extract Iscador("mistletoe") in addition to the conventional adjuvant oncologic therapy, and compared to the control group treated with the conventional therapy alone. METHODS: The multicenter, comparative, retrolective, pharmaco-epidemiological cohort study with parallel groups design and randomly selected centers that routinely used both treatments was carried out according to Good Epidemiological Practice rules under a standard operating procedure control. The test group patients received the mistletoe extract treatment subcutaneously for at least 3 months, while the control group patients of the same cohort was exclusively treated with the conventional therapy. The patients were followed up for at least 3 years or until death. The primary endpoint of efficacy was the incidence of adverse reactions to the conventional oncologic therapy. Secondary endpoints were change from baseline of the symptoms associated with the disease and treatment as well as overall survival. All endpoints were adjusted to baseline imbalance and confounders. Safety was assessed descriptively by the number of patients with adverse drug reactions (ADRs) attributed to the test treatment. RESULTS: 1442 patients (710 tests and 732 controls) were eligible for the "per protocol" analysis of efficacy and safety. At baseline, the test group had a more advanced disease and worse prognostic factors profile. After a median follow-up of 66 vs. 60 months, and a median mistletoe therapy duration of 52 months, significantly fewer test group patients (16.2%) than control patients (54.0%) developed ADRs attributed to the conventional therapy [adjusted odds ratio, OR (95% confidence interval, CI), OR = 0.47 (0.32-0.67), p < 0.001]. In the test group, the majority of the symptoms disappeared more frequently, and overall mortality hazard was significantly lower [adjusted hazard ratio, HR (95% CI), HR = 0.46 (0.22-0.96), p = 0.038] than in the control group. Systemic ADRs attributed to the test treatment developed in 0.8%, and local ADRs in 17.3% of the patients. ADR severity was mild to intermediate. Tumor enhancement was not observed. CONCLUSIONS: Complementary therapy of patients with primary, non-metastatic breast carcinoma with the mistletoe extract Iscador was safe and in comparison to the control group within the same study cohort showed considerably fewer ADRs attributed to concurrent conventional therapy, reduced disease symptoms, and suggested a significant improvement of survival. Despite some methodical limitations that require careful study planning and conduction as well as critical interpretation, the applied study design seems suitable to evaluate the efficacy and safety of drugs with "well-established use", particularly in oncology.

Antineoplastic Agents, Phytogenic↗
PubMed1987

Proton magnetic resonance characterization of phoratoxins and homologous proteins related to crambin.

The mistletoe protein toxins ligatoxin, phoratoxins A and B, and viscotoxins A3 and B have been investigated by 1H NMR spectroscopy at 300 and 600 MHz. The five polypeptides define a set of closely related homologues, containing 46 amino acid residues each, in a structure constrained by three cystine bridges. Their methyl and aromatic spectra were analyzed and a number of signals identified and assigned via comparative criteria, two-dimensional chemical-shift correlated spectroscopy, acid-base titration, and proton Overhauser experiments in 1H2O. The spectra indicate a compact globular conformation and a common folding pattern for the toxins. In particular, use was made of well-resolved aliphatic and aromatic resonances in order to compare the mistletoe proteins with the thionins, a set of homologous toxins from gramineae, and with crambin, a closely related polypeptide from a crucifer, which we have previously studied by NMR. We observe that while all the investigated proteins have very similar secondary and tertiary structures, they differ widely in their dynamic characteristics as probed by the amide NH 1H-2H exchange kinetics in deuteriated solvents; thus, while crambin and the thionins exhibit very fast isotope exchange, the kinetics for the mistletoe toxins are slow, with some NH groups showing exchange half-lives that extend up to several days at pH* 5.8 or that are too long to be measurable at ambient temperature. The temperature dependence of the 1H NMR spectrum also indicates that the toxins are endowed with a thermally very stable native (ground-state) structure, with little evidence of large amplitude structural breathings up to approximately 370 K, although irreversible chemical degradation (denaturation) becomes evident at temperatures greater than or equal to 350 K. It is concluded that the mistletoe toxins afford valuable rigid structures for NMR conformational studies.

Amino Acid Sequence↗
PubMedDate not supplied

Cytokine release of a keratinocyte model after incubation with two different Viscum album L extracts.

When injected subcutaneously, extracts from the white berry mistletoe (Viscum album L) lead to a dose-dependent local inflammatory reaction at the injection site. From in vitro investigations with V album extracts, the release of proinflammatory cytokines from peripheral blood mononuclear cells and from a human skin model (Skin(2) model; Advanced Tissue Sciences, La Jolla, CA) is known. This shows dose dependence for mistletoe lectin-I in the range of 0.02 ng/mL to 10.0 ng/mL. In this study, an investigation was conducted of which cytokines are released in the skin by the mistletoe lectin-standardized mistletoe extracts Viscum album QuFrF (VaQuFrF) and Iscador Qu Spzial (IQuS) (Institute Hiscia, Arlesheim, Switzerland) and whether dose dependency exists. The model used for this study is the multilayered skin model EpiDerm (MatTek Corporation, Ashland, MA), which consists of multilayered keratinocytes. The viability of the cell culture was measured after incubation with 0.01, 0.1, 0.2, 0.3, 0.5, and 15.0 ng/mL VaQuFrF or 0.01, 0.1, 0.2, 0.3, 0.5, 5.0, and 15.0 ng/mL IQuS. The release of interleukin (IL)-1alpha, IL-2, IL-6, IL-8, IL-10, IL-12p(40+70), IL-12p(70), tumor necrosis factor-alpha (TNFalpha), interferon (IFN)-alpha, IFNgamma, granulocyte macrophage-colony stimulating factor, and RANTES was determined after incubation with 0.5 ng/mL of IQuS ng/mL and VaQuFrF. The dose dependency of the release of IL-1alpha and IL-6 after incubation with 0.5 and 15.0 ng/mL VaQuFrF or 0.5 ng/mL, 5.0 ng/mL, and 15.0 ng/mL IQuS and that of the release of IL-1alpha, IL-2, IL-6, IL-10, and TNFalpha after incubation with 0.01 ng/mL, 0.1 ng/mL, 0.2 ng/mL, 0.3 ng/mL, and 0.5 ng/mL VaQuFrF or IQuS were determined. A dose-dependent decrease of cellular viability and an increase of IL-1alpha, IL-6, and TNFalpha as well as the release of IL-8 could be demonstrated. These results are compatible with the hypothesis that the subcutaneous injection of VaQuFrF and IQuS leads to a release of proinflammatory cytokines at the injection site.

Cell Survival↗
PubMed2006

Evolution of larval host plant associations and adaptive radiation in pierid butterflies.

Butterflies in the family Pieridae (Lepidoptera: Papilionoidea) feed as larvae on plants belonging primarily to three distantly related angiosperm orders: Fabales (legumes and allied plants), Brassicales (crucifers and related plants containing mustard oil glucosides), and Santalales ('mistletoes'). However, some utilize plants from 13 other families in a further eight orders. We investigated the evolutionary history of host plant use of the Pieridae in the context of a recent phylogenetic hypothesis of the family, using simple character optimization. Although there is a close association between host plant and butterfly higher classification, we find no evidence for cospeciation but a pattern of repeated colonization and specialization. The ancestral host of the family appears to be Fabaceae or Fabales, with multiple independent shifts to other orders, including three to Santalales. The shift to Brassicales, which contain secondary compounds (glucosinolates), promoted diversification and adaptive radiation within the subfamily Pierinae. Subsequent shifts from crucifers to mistletoes (aerial-stem hemiparasites) facilitated further diversification, and more recent shifts from mistletoes to mistletoe host trees led to exploitation of novel host plants outside the conventional three orders. Possible mechanisms underlying these host shifts are briefly discussed. In the Pierinae, a striking association between host plant, larval and adult behaviour, adult phenotype, and mimicry calls for further research into possible relationships between host specialization, plant chemistry and butterfly palatability.

Adaptation, Physiological↗
PubMed1979

Combination of immunological and lectin reactions in affinity histochemistry: proposition of the term affinitin.

Using the series system cell receptor leads to mistletoe lectin leads to antiferritin-antibody leads to ferritin, the possibilities for combination of lectin and immunological reactions for histochemistry are discussed. The system cell antigen leads to antibody leads to labelled mistletoe (or other) lectin is recommended for visualization of cell antigens (mistletoe lectin as common immunoglobulin reagent). It is pointed out that lectin reactions do not belong to immunhistochemistry but to affinity histochemistry. For all receptor specific proteins (antibodies, lectins, enzymes, haptoglobin and other) the term affinitin is proposed. In consideration of this new definition a common scheme is formulated: Affinitin reacts with affinitin receptor forming affinity product.

Animals↗
PubMed1997

Stimulation of antitumour immunity by intrapleural instillation of a Viscum album L. extract.

Intrapleural administration of mistletoe extracts is reported to result in pleurodesis in cancer patients with malignant pleural effusions. In a recent study, 20 consecutive cancer patients with malignant pleural effusions were treated intrapleurally with the mistletoe extract Helixor. The overall response rate for pleurodesis was 72%, with only 1.2% displaying side effects of the World Health Organization classification I. The decline of tumour cells in the effusion liquid correlated negatively with the number of instillations. However, the elimination of tumour cells was associated with a transient increase in macrophages and eosinophils, and a constant increase in CD8+T cells. Compared to the responder group, the non-responders exhibited high proportions of macrophages, CD8+T cells and T cells with human leukocyte antigens with DR specificity (HLA-DR) in the effusion liquid, compatible with a disturbance of macrophage/T cell co-operation and thus failure to eliminate the malignant cells. The preliminary results suggest that mistletoe-mediated pleurodesis is due to a stimulation of antitumour immunity rather than mechanical sclerosis.

Animals↗
PubMed1990

[Vysorel/Isorel--cancer drug from Viscum album. Documentation No.20].

Vysorel/Isorel is an aqueous extract from fresh mistletoe (viscum album). A number of components with different possible effects have been isolated, but exact analyses of the preparation have not been published. One ampoule 'Stärke 60' of 1 ml contains the extract of 60 mg mistletoe. Vysorel/Isorel is recommended in all malignant diseases, in 'precancerous' conditions and for prevention of relapse. Vysorel/Isorel is supposed to be taken subcutaneously according to a rhythmic schedule. Drug costs for one year in precancerous conditions are approximately 900 DM, for prevention of recurrence approximately 1800 DM, in the case of inoperable tumour approximately 3800 DM. Vysorel/Isorel is also a product of the anthroposophical medicine according to R. Steiner. It is marketed by Novipharm GmbH as Isorel in Austria and as Vysorel in the Federal Republic of Germany. The clinical efficacy of Vysorel/Isorel is derived from the demonstration of proteins from mistletoe (so-called 'Vester's Protein') with cancerostatic activity in vitro. No preclinical or clinical investigations are available. None of the 33 case histories suggests that Vysorel/Isorel is effective in the treatment of malignant diseases. Vysorel/Isorel is not registered in Switzerland at the IKS. It has been permitted in Austria since 1983 and in Germany since 1986.

Adult↗
PubMed2007

Living in forest fragments reduces group cohesion in diademed sifakas (Propithecus diadema) in eastern Madagascar by reducing food patch size.

Forest fragmentation is thought to threaten primate populations, yet the mechanisms by which this occurs remain largely unknown. However, fragmentation is known to cause dietary shifts in several primate species, and links between food resource distribution and within-group spatial dynamics are well documented. Thus, fragmentation has the potential to indirectly affect spatial dynamics, and these changes may present additional stresses to fragmented populations. I present the results from a 12-month study of Propithecus diadema at Tsinjoarivo, eastern Madagascar, including two groups in fragments and two in continuous forest. Instantaneous data on activity and spatial position were collected during all-day focal animal follows. Fragment groups had much lower cohesion, being more likely to have no neighbor within 5 and 10 m. For continuous forest groups, cohesion was highest in the rainy season (when food patches are large) and lowest in winter (when the animals rely on small-crowned mistletoes), and the chance of having no neighbor within 5 m was positively correlated with mistletoe consumption. Thus their decreased cohesion in fragment groups is inferred to result from their increased reliance on mistletoes and other small resources, which causes them to spread out among multiple patches. This scenario is consistent with the reduced body mass of subordinate individuals (males and immatures) in fragments, and suggests the occurrence of steeper within-group fitness gradients. Further research is necessary to determine whether these patterns apply to other primates; however, since fragmentation tends to cause the loss of the largest trees, many primates in fragments may lose their largest food resources and undergo similar behavioral shifts.

Analysis of Variance↗
PubMedDate not supplied

Evaluation of traditional plant treatments for diabetes: studies in streptozotocin diabetic mice.

Seven plants and a herbal mixture used for traditional treatment of diabetes were studied in streptozotocin diabetic mice. The treatments were supplied as 6.25% by weight of the diet for 9 days. Consumption of diets containing bearberry (Arctostaphylos uva-ursi), golden seal (Hydrastis canadensis), mistletoe (Viscum album) and tarragon (Artemisia dracunculus) significantly reduced the hyperphagia and polydipsia associated with streptozotocin diabetes, but bayberry (Cinnamomum tamala), meadowsweet (Filipendula ulmaria), senna (Cassia occidentalis) and the herbal mixture did not alter these parameters. Bearberry, mistletoe and tarragon retarded the body weight loss but none of the eight treatments significantly altered plasma glucose or insulin concentrations. These studies suggest that bearberry, golden seal, mistletoe and tarragon may counter some of the symptoms of streptozotocin diabetes without, however, affecting glycemic control.

Animals↗
PubMed2004

Study on anti-diabetic activities of crude methanolic extracts of Loranthus micranthus (Linn.) sourced from five different host trees.

The hypoglycaemic and anti-hyperglycemic activities of dried leaves of Loranthus micranthus (Linn.) (Loranthaceae), parasitic on Persea americana, Baphia nitda, Kola acuminata, Pentaclethra macrophylla, Azadirchta indica, were evaluated in normoglycemic and alloxan-induced diabetic albino rats. Normoglycemic and alloxan-induced diabetic rats were treated (intraperitoneally) with 200 mg/kg of the respective methanolic extracts of Loranthus micranthus (Linn.), glibenclamide (positive control), and 20% (v/v) Tween 20 solution (negative control). The sugar levels of the withdrawn blood samples were determined by o-toluidine spectrophotometric method. The studies indicate that the crude methanolic extract of Loranthus micranthus (Linn.) exhibited statistically significant hypoglycaemic (P < 0.001) and anti-hyperglycemic (P < 0.001) activities in normoglycemic and alloxan-induced diabetic albino rats, respectively. The hypoglycaemic effect was found to be dose-dependent. The maximum effect of the mistletoe extract (400 mg/kg) from Persea americana on alloxan-induced diabetic rats was found to be statistically comparable with that of the positive control, glibenclamide, at 24 h after administration, with a percentage reduction of blood sugar levels of 82.59 and 83.34%, respectively. Acute toxicity tests of the methanolic extracts of Persea americana, Baphia nitda, Kola acuminata, Pentaclethra macrophylla, Azadirchta indica host trees in mice gave LD(50) values of 11650, 11650, 5900, 5900 and 5900 mg/kg, respectively, which are all within the practically non-toxic range. The methanolic extract of African mistletoe was found to be a good candidate for alternative and/or complimentary medicine in the management of diabetes mellitus. The leaves of the Eastern Nigerian species of the African mistletoe harvested from Kola acuminata, Azadirchta indica and Baphia nitda host trees exhibited comparatively better anti-hyperglycemic activities among the host trees studied.

Animals↗
PubMed2002

Comparison between the mechanisms of action of plant toxins ricin and viscumin on the stage of intracellular dissociation.

Pharmacological effects of mistletoe extracts are determined by the concentration of three toxic lectins: mistletoe lectin I (MLI, or viscumin), MLII, MLIII. These proteins, as well as ricin, belong to ribosome-inactivating proteins type 2 (RIP2). However, the extracts from the plant Ricinus communis, containing ricin, are highly toxic. Ricin is about 30 times more effective in cell culture than viscumin. The dissociation of subunits and the transmembrane transport of catalytic subunit into the cytoplasm are needed to obtain the cytotoxic effect of RIP2. In this paper, hybridomas producing monoclonal antibodies against catalytic subunits of ricin and viscumin are described. Monoclonal antibodies against different epitopes, including one localized in intra-subunit area of catalytic subunits of ricin and viscumin, do not inhibit the enzymatic activity of these proteins in cell-free system. These hybridomas are resistant to the cytotoxic action of native toxins. Protective effect of antibodies are about the same for both toxins, though the dissociation of the subunits of ricin is more effective. The causes of the differences in activity of plant toxins as pharmacological agents, and the importance of above mentioned epitopes for neutralizing antibodies at the clinical applications of mistletoe extracts are discussed.

Animals↗