Distribution, frequency and host patterns of European mistletoe (Viscum album subsp. album) in the major city of Lodz, Poland

The frequency of parasitism of the European mistletoe, Viscum album L. subsp. album, in the city of Lodz, a typical major city in Poland, was investigated. The infection prevalence and intensity of the mistletoe Viscum album subsp. album on its main host, Acer saccharinum as a function of host size was also investigated. The parasite showed a strong preference for alien, planted tree species (i.e. A. saccharinum, Populus×canadensis and Robinia pseudoacacia). In 2009–2011, V. album subsp. album was observed on 28 host taxa of trees and shrubs, which represents the highest diversity of host trees in a single locality in the Poland. Within the studied area 2147 trees were infested by mistletoe. The distribution of mistletoes (V. album subsp. album) among A. saccharinum hosts is significantly aggregated. The intensity of mistletoe infection in the silver maple trees was affected by the individual tree characteristics, such as the height of the tree. The overall level of aggregation as indicated by the variance to mean ratio of mistletoe numbers per host fell within the midrange of values found in other published studies of host-mistletoe interactions. The higher mistletoe infection prevalence in taller trees results from differential dispersal of mistletoe seeds to tall trees as well as differential survival of established mistletoes on tall trees. The incidence of mistletoe was higher in city centre (zone of high density development) than it was on the outskirts of a city (outer marginal zone). It was found that the abundant occurrence of mistletoe was recorded in the stands of increased nitrogen input, while other stands have little or no mistletoe infection present. Thus, this mistletoe species uses both passive and active uptake, which may be a selective advantage in a nutrient-poor environment or on a nutrient-deficient host species.     

Sequestration of pyridine alkaloids anabasine and nicotine from Nicotiana (Solanaceae) by Orobanche ramosa (Orobanchaceae)

Plants of the root holoparasite Orobanche ramosa L. and four of its potential host species, Nicotiana glauca Graham, Nicotiana rustica L., Nicotiana sylvestris Speg. & S.Comes, and Nicotiana tabacum L., grown in the greenhouse in Kiel/Germany, were analyzed for their contents of pyridine alkaloids anabasine (1) and nicotine (2). All investigated samples contained both alkaloids in different amounts. The distribution of the alkaloids in the various plant organs of Nicotiana differed significantly between the species. The alkaloid contents of the Orobanche samples relative to the alkaloid contents of the roots of the respective host plants varied between 3.47 ± 1.08 and 28.8 ± 37.5%. Orobanche plants drain water and crucial nutrients from their hosts; also, some examples for the sequestration of specialized natural products have been reported. O. ramosa is not able to synthesize pyridine alkaloids anabasine (1) and nicotine (2) itself; therefore, the present study proves the sequestration of pyridine alkaloids by O. ramosa from the four investigated Nicotiana host species.     

Benzophenones from the roots of the Popoluca Amerindian medicinal plant Securidaca diversifolia (L.) S.F. Blake

Three novel benzophenones (1–3) were obtained from the roots of Securidaca diversifolia (L.) S.F. Blake along with two known benzylbenzoates and isovanilline. Compound 2 (2,4-dihydroxy-3,3′-dimethoxy-benzophenone) showed moderate inhibitory activity on Herpes simplex virus type 1 proliferation in vitro. The structures of compounds 1–3 were established by the interpretation of their spectroscopic and spectrometric data.     

Three new neolignan glucosides from the stems of Dendrobium aurantiacum var. denneanum

Three new neolignan glucosides (1–3), together with four known analogs (4–7), have been isolated from the stems of Dendrobium aurantiacum var. denneanum. Structures of the new compounds including the absolute configurations were determined by spectroscopic and chemical methods as (−)-(8R,7′E)-4-hydroxy-3,3′,5,5′-tetramethoxy-8,4′-oxyneolign-7′-ene-9,9′-diol 4,9-bis-O-β-d-glucopyranoside (1), (−)-(8S,7′E)-4-hydroxy-3,3′,5,5′-tetramethoxy-8,4′-oxyneolign-7′-ene-9,9′-diol 4,9-bis-O-β-d-glucopyranoside (2), and (−)-(8R,7′E)-4-hydroxy-3,3′,5,5′,9′-pentamethoxy-8,4′-oxyneolign-7′-ene-9-ol 4,9-bis-O-β-d-glucopyranoside (3), respectively.     

A Natural Combination Extract of Viscum album L. Containing Both Triterpene Acids and Lectins Is Highly Effective against AML In Vivo

Aqueous Viscum album L. extracts are widely used in complementary cancer medicine. Hydrophobic triterpene acids also possess anti-cancer properties, but due to their low solubility they do not occur in significant amounts in aqueous extracts. Using cyclodextrins we solubilised mistletoe triterpenes (mainly oleanolic acid) and investigated the effect of a mistletoe whole plant extract on human acute myeloid leukaemia cells in vitro, ex vivo and in vivo. Single Viscum album L. extracts containing only solubilised triterpene acids (TT) or lectins (viscum) inhibited cell proliferation and induced apoptosis in a dose-dependent manner in vitro and ex vivo. The combination of viscum and TT extracts (viscumTT) enhanced the induction of apoptosis synergistically. The experiments demonstrated that all three extracts are able to induce apoptosis via caspase-8 and -9 dependent pathways with down-regulation of members of the inhibitor of apoptosis and Bcl-2 families of proteins. Finally, the acute myeloid leukaemia mouse model experiment confirmed the therapeutic effectiveness of viscumTT-treatment resulting in significant tumour weight reduction, comparable to the effect in cytarabine-treated mice. These results suggest that the combination viscumTT may have a potential therapeutic value for the treatment AML.     

Two new glycosides from the whole plant of Anemone rivularis var. flore-minore

Phytochemical investigation on the whole plant of Anemone rivularis var. flore-minore led to the isolation of a new labdane-type diterpene glycoside (1) and a new trihydroxyfuranoid lignanoid glycoside (2), together with three known triterpene and triterpenoid glycosides (3–5). The structures of the two new compounds were elucidated as β-d-glucopyranosyl (13S)-13-hydroxy-7-oxo-labda-8,14-diene-18-oate (1) and (7S,7′R,8R,8′S)-7′-butoxy-7,9′-epoxy-4,4′,9-trihydroxy-3,3′-dimethoxylignane 9-O-β-d-glucopyranoside (2), on the basis of extensive spectral analysis and chemical evidence. Compound 1 is characterized by a glucose (Glc) esterified C-18 carboxyl group, which is a rarely encountered labdane-type diterpene glycoside in nature. The two new compounds (1 and 2) reported here are the first examples of diterpene glycoside and lignanoid glycoside found in the genus Anemone, and the known triterpene and triterpenoid glycosides (3–5) are identified for the first time from the title plant.     

Synthesis and antimicrobial activities of halogenated bis(hydroxyphenyl)methanes

A series of halophenols was prepared by the reaction of bis(hydroxyphenyl)methanes with effective halogenating agents such as bromine and sulfuryl chloride. One of these compounds, a biologically active halophenol—2,2′,3,3′-tetrabromo-4,4′,5,5′-tetrahydroxydiphenylmethane (1)—frequently isolated from red algae, was synthesized for the first time. Other halophenols included several novel compounds, together with known derivatives that were synthesized from the phenolic intermediates, bis(3,4-dihydroxyphenyl)methane (5) and bis(2-hydroxyphenyl)methane (14). All of the synthesized compounds were tested for antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. The preliminary structure–activity relationship was investigated in order to determine the essential structural requirements for their antimicrobial activity. Of all these halophenols, 2,2′,3,3′,6-pentabromo-4,4′,5,5′-tetrahydroxydiphenylmethane (8) was found to be the most active against Candida albicans, Aspergillus fumigatus, Trichophyton rubrum, and Trichophyton mentagrophytes while 3,3′,5,5′-tetrachloro-2,2′-dihydroxydiphenylmethane (18) exerted a powerful antibacterial effect against Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Proteus vulgaris, and Salmonella typhimurium.     

The gene space of European mistletoe (Viscum album)

European mistletoe (Viscum album) is a hemiparasitic flowering plant that is known for its very special life cycle and extraordinary biochemical properties. Particularly, V. album has an unusual mode of cellular respiration that takes place in the absence of mitochondrial complex I. However, insights into the molecular biology of V. album so far are very limited. Since the genome of V. album is extremely large (estimated 600 times larger than the genome of the model plant Arabidopsis thaliana) it has not been sequenced up to now. We here report sequencing of the V. album gene space (defined as the space including and surrounding genic regions, encompassing coding as well as 5′ and 3′ non-coding regions). mRNA fractions were isolated from different V. album organs harvested in summer or winter and were analyzed via single-molecule real-time sequencing. We determined sequences of 39 092 distinct open reading frames encoding 32 064 V. album proteins (designated V. album protein space). Our data give new insights into the metabolism and molecular biology of V. album, including the biosynthesis of lectins and viscotoxins. The benefits of the V. album gene space information are demonstrated by re-evaluating mass spectrometry-based data of the V. album mitochondrial proteome, which previously had been evaluated using the A. thaliana genome sequence. Our re-examination allowed the additional identification of nearly 200 mitochondrial proteins, including four proteins related to complex I, which all have a secondary function not related to respiratory electron transport. The V. album gene space sequences are available at the NCBI.     

Sesquiterpenoids and lignans from the fruits of Illicium simonsii Maxim

Twenty-two known compounds were isolated from the 95% alcohol extract of the fruits of Illicium simonsii Maxim, including seven sesquiterpenoids (16–22) and fifteen lignans (1–15). In the present research, compounds 3 ((7S,8R,8′S)-3,3′-dimethoxy-4,4′,9-trihydroxy-7,9′-epoxylignan-7′-one), 4 ((−)-(7′S,8S,8′R)-4,4′-dihydroxy-3,3′,5,5′-tetramethoxy-7′,9-epoxylignan-9′-ol-7-one), 5 ((+)-8-hydroxypinoresinol), 6 ((+)-8-hydroxymedioresinol), 8 ((2R,3R)-2β-(4″-hydroxy-3″-methoxybenzyl)-3α-(4′-hydroxy-3′-methoxybenzyl)-γ-butyrolactone 2-O-(β-D-glucopyranoside), 12 ((+)-8-methoxyisolariciresinol), 13 (α-conidendrin), 14 (boehmenan) and 15 (7R,8R,7′E-7′,8′-didehydro-4,7,9,9′- tetrahydroxy-3-methoxy-8-O-4′-neolignan) were reported from the Illicium genus for the first time, and compounds 1 (simulanol), 7 ((+)-secoisolariciresinol monoglucoside), 10 ((+)-9-O-β-D-glucopyranosyl lyoniresinol), 11 ((+)-isolariciresinol), 18 (neoanisatin), 19 (veranisatin A), 20 (4,5-d₂-8′-oxo-dihydrophaseic acid) and 22 (Oligandrumin A) were firstly isolated from the plant. Their structures were elucidated on the basis of NMR spectroscopic and mass spectrometric data. Moreover, the chemotaxonomic significance of the isolated compounds is discussed.     

Direct cryopreservation of winter-acclimated buds of Dracocephalum austriacum (Lamiaceae) from field material

Mistletoes are semiparasite plants containing pharmaceutical proteins with applications in cancer treatment. Previous research has demonstrated that somaclonal variation can lead to the biosynthesis of novel proteins from mistletoe callus cultures. The protein content of Viscum album subsp. abietis tissues and biotechnologically propagated calluses, was analyzed to identify proteins with putative anticancer properties. In addition, evolutionary relations among linked species to Viscum were studied. Calluses were propagated from stem explants. The protein extracts mass spectra were processed with Proteome Discoverer and a search was performed using as reference the Uniprot V. album reviewed database. A phylogenetic tree was reconstructed using the LG amino acid substitution model by homologous sequences for Beta galactoside-specific lectin 2. The homology modeling of the Beta-galactoside-specific lectin 2 was carried out using Modeller software. Considerable differences were observed by comparing the protein content of the calluses and the maternal tissues. Four mistletoe lectins, six viscotoxins and the chitin binding lectin-cbML were identified within the species tissues. An in silico phylogenetic and structural study provides insights to the role of these lectins and the mechanism of semiparasite survival and evolution, towards a novel anticancer and immune system modulation pipeline. Callogenesis exhibited protein biosynthesis alterations and novel protein isoforms expression. Phyllogenetic analysis revealed evolutionary relations primarily within the Viscum genus and other species containing 2-ribosome inactivating proteins. The homology modeling of the mistletoe lectin 2 revealed possible structure related anticancer properties. In conclusion, mistletoe calluses were shown to possess a unique protein biosynthetic profile compared to donor plant tissues.

     

Secondary metabolites from the leaves of the medicinal plant goldenseal (Hydrastis canadensis)

The study presented herein constitutes an extensive investigation of constituents in Hydrastis canadensis L. (Ranunculaceae) leaves. It describes the isolation and identification of two previously unknown compounds, 3,4-dimethoxy-2-(methoxycarbonyl)benzoic acid (1) and 3,5,3′-trihydroxy-7,4′-dimethoxy-6,8-C-dimethyl-flavone (2), along with the known compounds (±)-chilenine (3), (2R)-5,4′-dihydroxy-6-C-methyl-7-methoxy-flavanone (4), 5,4′-dihydroxy-6,8-di-C-methyl-7-methoxy-flavanone (5), noroxyhydrastinine (6), oxyhydrastinine (7) and 4′,5′-dimethoxy-4-methyl-3′-oxo-(1,2,5,6-tetrahydro-4H-1,3-dioxolo-[4′,5′:4,5]-benzo[1,2-e]-1,2-oxazocin)-2-spiro-1′-phtalan (8). Compounds 3–8 have been reported from other sources, but this is the first report of their presence in H. canadensis extracts. A mass spectrometry based assay was employed to demonstrate bacterial efflux pump inhibitory activity against Staphylococcus aureus for 2, with an IC₅₀ value of 180 ± 6 μM. This activity in addition to that of other bioactive compounds such as flavonoids and alkaloids, may explain the purported efficacy of H. canadensis for treatment of bacterial infections. Finally, this report includes high mass accuracy fragmentation spectra for all compounds investigated herein which were uploaded into the Global Natural Products Social molecular networking library and can be used to facilitate their future identification in H. canadensis or other botanicals.     

Chemotaxonomic significance of lignans from Serissa japonica (Thunb.) Thunb

Sixteen known lignans were isolated from the 95% alcohol extract of the whole plant of Serissa japonica (Thunb.) Thunb., including nine furofurans (1–9), three tetrahydrofurans (10–12) and four arylnaphthalenes (13–16). In the present report, compounds (+)-epipinoresinol (1), (+)-1-hydroxy-6-epipinoresinol 4,4″-di-O-methyl ether (3), (−)-pinoresinol (4), (+)-8-hydroxypinoresinol (6), pseuderesinol (7), (+)-1-hydroxysyringaresinol (8), (−)-(7′S,8S,8′R)-4,4′-dihydroxy-3,3′,5,5′-tetramethoxy-7′,9-epoxylignan-9′-ol-7-one (10), wikstrone (11), 7'-(+)-oxomatairesinol (12), (+)-cycloolivil (13), (+)-isolariciresinol (14), 5-methoxy-(+)-isolariciresinol (15) and cyclolignans (16) were reported from the Serissa genus for the first time, and compounds (+)-lirioresinol A (2) and (−)-lirioresinol B (5) were firstly isolated from the plant. Their structures were elucidated on the basis of extensive spectroscopic and chemical analyses. Moreover, the chemotaxonomic significance of the isolated compounds is discussed.     

Generalist birds govern the seed dispersal of a parasitic plant with strong recruitment constraints

Mistletoes constitute instructive study cases with which to address the role of generalist consumers in the study of plant–animal interactions. Their ranges of safe sites for recruitment are among the most restricted of any plant; therefore, frugivores specializing in mistletoe have been considered almost indispensable for the seed dispersal of these parasitic plants. However, the absence of such specialists in numerous regions inhabited by many mistletoe species raises the question of whether unspecialized vectors may successfully disperse mistletoe seeds to narrowly defined safe sites. Using the European mistletoe Viscum album subsp. austriacum as a study case, we recorded a broad range of 11 bird species that disperse mistletoe seeds. For these species, we studied the mistletoe-visitation rate and feeding behavior to estimate the quantity component of dispersal effectiveness, and the post-foraging microhabitat use, seed handling, and recruitment probabilities of different microhabitats as a measure of the quality component of effectiveness. Both endozoochory and ectozoochory are valid dispersal mechanisms, as the seeds do not need to be ingested to germinate, increasing seed-dispersal versatility. Thrushes were the most effective dispersers, although they were rather inefficient, whereas small birds (both frugivores and non-frugivores) offered low-quantity but high-quality services for depositing seeds directly upon safe sites. As birds behave similarly on parasitized and non-parasitized hosts, and vectors have broad home ranges, reinfection within patches and the colonization of new patches are ensured by an ample assemblage of generalist birds. Thus, a parasitic plant requiring precision in seed dispersal can rely on unspecialized dispersers.     

New coumarins from Coleonema album

Six coumarins have been isolated from the aerial parts of Coleonema album and identified as ulopterol, 7-(3′, 3′-dimethylallyloxy)-coumarin, (R)-(+)-2′,3′-epoxy-suberosin, and the novel coumarins (R)-(+)-7-(2′, 3′-epoxy-3′-methylbutoxy)-coumarin, (R)-(+)-7-(2′,3′-dihydroxy-3′-dihydroxy-3′-methylbutoxy)-coumarin and (R)-(+)-7-methoxy-8-(2′,3′-epoxy-3′-methylbutoxy)-coumarin.     

Phenolic derivatives and an antifungal and cytototoxic labdane diterpenoid from the root bark of Turraeanthus mannii

The structures of two new compounds from the root bark of Turraeanthus mannii (Meliaceae) were determined as (3R,4R,3′R,4′R)-6,6′-dimethoxy-3,4,3′,4′-tetrahydro-2H,2′H-[3,3′]bichromenyl-4,4′-diol (1) and 15-acetoxy-labda-8(17),12E,14Z-trien-16-al (2) by means of spectroscopic analysis. Five further known compounds including one coumarin derivative, one chromenone, two labdane diterpenes and one pregnane steroid have been isolated from the same source. In antifungal and cytotoxic assays, 15-acetoxy-labda-8(17),12E,14Z-trien-16-al (2) was highly active against Mucor miehei and Artemia salina, respectively.     

Parasitic Bacteria and Fungi on Common Mistletoe (Viscum album L.) and Their Potential Application in Biocontrol

This study was carried out to identify pathogenic bacteria and fungi on mistletoe (Viscum album L.) and investigate their potential use in biological control of this parasitic plant. For this purpose, a total of 48 fungal isolate and 193 bacterial strains were isolated from contaminated V. album during the summers 2005–2006. The isolated bacterial strains and fungal isolates were identified by using the Sherlock Microbial Identification System (MIS; Microbial ID, Newark) and microscopic methods, respectively. The bacterial strains that induced hypersensitive reaction (HR) on tobacco (Nicotiana tabacum L.) and fungal isolates were tested for pathogenicity on young shoots of mistletoe by using injection methods. The pathogenic bacterial strains and fungal isolates were also tested for their activity against mistletoe using spray methods. Five bacterial strains (two Burkholderia cepacia, one each of Bacillus megaterium, Bacillus pumilus and Pandoraea pulminicola) were HR and pathogenicity positive when injected but none of them when sprayed on mistletoe. When fungi were injected, 32 isolates were pathogenic but only thirteen when sprayed on mistletoe. Alternaria alternata VA?‐202, VA?‐205, VA?‐217 and Acremonium kiliense VA‐11 fungal isolates were the most effective ones and caused strong disease symptoms on mistletoe. The present study is the first report on the efficiency of potential biocontrol agents against mistletoe in Turkey.     

Synthesis and reactions of 1′,2:4,6-di-o-isopropylidene-sucrose

The reaction of sucrose with a combination of 2,2-dimethoxypropane, N,N-dimethylformamide, and toluene-p-sulphonic acid (reagent A) gave, after acetylation followed by chromatography, 1′,2:4,6-di-O-isopropylidenesucrose tetra-acetate (1) in 15% yield. The structure of 1 was determined on the basis of p.m.r. and mass spectrometry, and by chemical transformations. Treatment of 1 with aqueous acetic acid afforded sucrose 3,3′,4′,6′-tetra-acetate 2. Reacetalation of 2 using reagent A gave 1 in 80% yield. The p.m.r. spectrum of 2 confirmed the presence of hydroxyl groups at C-2 and C-4. The following sequence of reactions showed that the remaining two hydroxyl groups were located at C-6 and C-1′. Selective tritylation of 2 gave 1′,6-di-O-tritylsucrose 3,3′,4′,6′-tetra-acetate (3) as the minor, and 6-O-tritylsucrose 3,3′,4′,6′-tetra-acetate (4) as the major, product. When tritylation was carried out under forcing conditions, 2 gave 3 as the major product. Acetylation of 4 afforded 6-O-tritylsucrose hepta-acetate. Mesylation of 2 gave the tetramethanesulphonate 5, which afforded the 6-dcoxy-6-iodo derivative 6 on treatment with a refluxing solution of sodium iodide in butanone. Treatment of 3 with methanesulphonyl chloride in pyridine gave the disulphonate 7, which on detritylation followed by acetylation gave 2,4-di-O-methanesulphonylsucrose hexa-acetate (9). Treatment of 9 with sodium benzoate in hexamethylphosphoric triamide displaced the 4-sulphonate, with inversion of configuration, to give the galacto derivative 10.     

Dicorynamine and harmalan-N-oxide,two new β-carboline alkaloids from Dicorynia guianensis Amsh heartwood

The chemical investigations of Dicorynia guianensis heartwood led to the isolation of four new indole alkaloids for the first time in this plant. Compound (1) identified as spiroindolone 2′,3′,4′,9′-tetrahydrospiro [indoline-3,1′pyrido[3,4-b]-indol]-2-one, and compound (3) described as nitrone 1-methyl-4,9-dihydro-3H-pyrido [3,4-b] indole 2-oxide and were isolated for the first time as natural products. ABTS antioxidant activity guided their isolation.     

Australian marine sponge alkaloids as a new class of glycine-gated chloride channel receptor modulator

Chemical analysis of a specimen of the sponge Ianthella cf. flabelliformis returned two new sesquiterpene glycinyl lactams, ianthellalactams A (1) and B (2), the known sponge sesquiterpene dictyodendrillin (3) and its ethanolysis artifact ethyl dictyodendrillin (4), and five known sponge indole alkaloids, aplysinopsin (5), 8E-3′-deimino-3′-oxoaplysinopsin (6), 8Z-3′-deimino-3′-oxoaplysinopsin (7), dihydroaplysinopsin (8) and tubastrindole B (9). The equilibrated mixture 6/7 exhibited glycine-gated chloride channel receptor (GlyR) antagonist activity with a bias towards α3 over α1 GlyR, while tubastrindole B (9) exhibited a bias towards α1 over α3 GlyR. At low- to sub-micromolar concentrations, 9 was also a selective potentiator of α1 GlyR, with no effect on α3 GlyR—a pharmacology that could prove useful in the treatment of movement disorders such as spasticity and hyperekplexia. Our investigations into the GlyR modulatory properties of 1–9 were further supported by the synthesis of a number of structurally related indole alkaloids.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.