Isolation of Picrotoxanes from Austrobuxus carunculatus Using Taxonomy-Based Molecular Networking

A unique collection of 292 extracts from 107 New Caledonian Euphorbiaceae species sensu lato was profiled by LC-MS² and the metabolite content organized by molecular networking. Based on the assumption that taxon-specific molecules are more likely to be structurally novel, taxonomic data were mapped on spectral networks to detect genus-specific clusters. Using this approach, a group of compounds unique to the genus Austrobuxus was highlighted. The subsequent MS-guided purification of the fruit EtOAc extract of Austrobuxus carunculatus led to the isolation of 13 new monolactone and "norditerpene" picrotoxanes (2-14), along with the known tutin (1). The structures of the new compounds were elucidated by HRESIMS and NMR spectroscopic data analysis, and the absolute configurations of compounds 1, 3, 7, 11, 12, and 14 were determined by single-crystal X-ray diffraction analysis. The relative and absolute configurations of compounds 4 and 5 were ascertained by chemical transformation of compound 3. The absolute configurations of other members of the series have been proposed on the basis of biogenetic considerations and specific rotation values of similar sign and magnitude. Compounds 1-14 were evaluated for their antiproliferative activities against HCT116 colon, U87-MG glioblastoma, and A549 lung human cancer cell lines. Compounds bearing an acyl chain at C-2 (i.e., 2, 4, and 13) showed IC₅₀ values in the micromolar range for the three cell lines used.

Phytochemical and pharmacological aspects of Cnidoscolus Pohl species: A systematic review

BACKGROUND

Cnidoscolus is a genus belonging to the Euphorbiaceae family, distributed in South American countries, such as Mexico and Brazil, which includes several species widely used in folk medicine. However, the genus is not sufficiently exploited from a chemical and pharmacological point of view.

HYPOTHESIS/PURPOSE

This paper aims to present a systematic review of known pharmacological and chemical aspects from Cnidoscolus, an important genus for South America research groups on medicinal plants. In this article, we highlight the importance of Cnidoscolus species in the search for new bioactive molecules.

STUDY DESIGN

A systematic review was conducted in order to collect chemical and pharmacological information on species of this genus in the last 25 years.

METHODS

Literature search was performed through specialized databases (PUBMED, LILACS, SCIELO, Science Direct and Web of Science) using different combinations of the following keywords: Cnidoscolus, phytochemistry, pharmacological activity. For the selection of the manuscripts, two independent investigators (RGOJ and CAAF) first selected the articles according to the title, then to the abstract and finally through an analysis of the full-text publication. All selected manuscripts were analyzed for year of publication, country where the research was performed, reported plant species, isolated chemical compounds and evaluated biological activities.

RESULTS

Most of the studies involving Cnidoscolus were conducted by research groups located in Brazil, Nigeria and Mexico. Regarding the annual evolution of the publications, a larger number of articles published in 2014 were observed. Flavonoids, triterpenes and diterpenes represent the main classes of secondary metabolites that have been isolated from Cnidoscolus. In terms of the pharmacological investigations, C. aconitifolius, C. chayamansa and C. quercifolius are considered the most studied species, with different pharmacological activities.

CONCLUSION

All findings indicate that Cnidoscolus is an important genus of the Euphorbiaceae family. However, considering its chemical and pharmacological importance, the studies developed with Cnidoscolus species are still limited, representing an opportunity to investigate new bioactive molecules.

Biologically Active Orbitides from the Euphorbiaceae Family

A comprehensive overview of natural orbitides isolated from Euphorbiaceae species and their most relevant biological activities are presented. Euphorbiaceae is a large and diverse family, which comprises about 300 genera, and is known as an important source of medicines and toxins. Several classes of secondary metabolites have been described for this taxon, however, orbitides have been broadly reported in Jatropha and Croton genera. Additionally, the latex is documented as the main source of orbitides in this family. Based on their structural and functional diversity, orbitides present a large variety of biological activities described as cytotoxicity, antimalarial, antibacterial, antifungal, enzymatic inhibition, and immunosuppressive, although the mechanism of action still needs to be further investigated. In recent years, the discovery of bioactive cyclic peptides from different sources has grown exponentially, making them promising molecules in the search for new drug leads. This review also highlights the attempts made by many researchers to organize the orbitides nomenclature and amino acid numbering, as well the important progress recently achieved in the biosynthetic study area.

Embryology of Pera (Peraceae, Malpighiales): systematics and evolutionary implications

Pera is a neotropical genus that currently belongs to the family Peraceae. This circumscription resulted from an inclusion of the Rafflesiaceae between the old tribe Pereae and all other Euphorbiaceae, and wherein Pereae was elevated to family rank making Euphorbiaceae monophyletic again. These changes are necessary although Rafflesiaceae are holoparasitic with extremely reduced vegetative bodies and large flowers while Peraceae and Euphorbiaceae have well developed vegetative parts and reduced flowers. As the embryology of Peraceae was poorly known, and embryological processes are conservative, we studied the embryology of Pera glabrata, searching for similarities between Peraceae, Rafflesiaceae, and Euphorbiaceae that could support this grouping. Usual methods of light microscopy and scanning electron microscopy were utilised. The results show endothecium with reversed-T-shaped cells, prismatic crystals in the tapetum, and disintegrated aerenchymatous septum in the mature fruit as unique features for Peraceae and possibly apomorphies for the family. In addition to the unisexual flowers, porogamous fertilization is present and one ovule per carpel which may support the Peraceae-Rafflesiaceae-Euphorbiaceae clade. The comparative approach also suggests possible (syn-)apomorphies for linoids and phyllanthoids, only linoids, Rafflesiaceae, Euphorbiaceae, and Ixonanthaceae. The presence of a placental obturator found previously unknown in Peraceae emerged as a possible synapomorphy for the euphorbioids (including Ixonanthaceae, Linaceae, Phyllanthaceae, Picrodendraceae, Peraceae, Rafflesiaceae, and Euphorbiaceae), which appeared in a common ancestor of the group and has been lost in Rafflesiaceae.

Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton

Croton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon.

Dated phylogenies of the sister genera Macaranga and Mallotus (Euphorbiaceae): congruence in historical biogeographic patterns?

Molecular phylogenies and estimates of divergence times within the sister genera Macaranga and Mallotus were estimated using Bayesian relaxed clock analyses of two generic data sets, one per genus. Both data sets were based on different molecular markers and largely different samples. Per genus three calibration points were utilised. The basal calibration point (crown node of all taxa used) was taken from literature and used for both taxa. The other three calibrations were based on fossils of which two were used per genus. We compared patterns of dispersal and diversification in Macaranga and Mallotus using ancestral area reconstruction in RASP (S-DIVA option) and contrasted our results with biogeographical and geological records to assess accuracy of inferred age estimates. A check of the fossil calibration point showed that the Japanese fossil, used for dating the divergence of Mallotus, probably had to be attached to a lower node, the stem node of all pioneer species, but even then the divergence time was still younger than the estimated age of the fossil. The African (only used in the Macaranga data set) and New Zealand fossils (used for both genera) seemed reliably placed. Our results are in line with existing geological data and the presence of stepping stones that provided dispersal pathways from Borneo to New Guinea-Australia, from Borneo to mainland Asia and additionally at least once to Africa and Madagascar via land and back to India via Indian Ocean island chains. The two genera show congruence in dispersal patterns, which corroborate divergence time estimates, although the overall mode and tempo of dispersal and diversification differ significantly as shown by distribution patterns of extant species.

Evaluation of hemostatic activity of latex from three Euphorbiaceae species

ETHNOPHARMACOLOGICAL RELEVANCE

Latices from several plant species of Euphorbiaceae family have been traditionally applied over fresh cuts to stop bleeding and subsequently applied over wounds to enhance healing process. The latex arrested bleeding from fresh wounds by reducing bleeding and whole blood coagulation time which are important indices of hemostatic activity. It has been accepted that hemostatic activity is due to the proteolytic fraction of plant latices. Thus, the present study aimed to assess the clot inducing properties of three Euphorbiaceae plants viz., Euphorbia nivulia Buch.-Ham., Pedilanthus tithymaloides (L.) Poit and Synadenium grantii Hook F.

MATERIALS AND METHODS

In the present study, various proteolytic activities namely protease, gelatinase, milk clotting and whole blood clotting assay of the enzyme fraction of latices of Euphorbia nivulia, Pedilanthus tithymaloides and Synadenium grantii have been investigated. The inhibition profile of protease specific inhibitors was assessed. Also, the effects of protein fractions were studied using bleeding/clotting time test of fresh experimentally-induced wounds in mice.

RESULTS

Euphorbia nivulia latex protease has noticeable blood clotting activity followed by Pedilanthus tithymaloides and Synadenium grantii. Stem latex protease of Pedilanthus tithymaloides exhibits superior procoagulant activity in different mammal's blood samples viz., Capra hircus, Bubalus bubalis, Ovibos moschatus and Bos indicus. Blood sample of ox was the most sensitive to latex protease than other mammal's blood. Concomitantly, the plant latex protease could significantly reduce whole blood clotting time of human and mice blood samples.

CONCLUSION

The protease fraction of latices of Euphorbia nivulia, Pedilanthus tithymaloides and Synadenium grantii possesses phytoconstituents capable of arresting wound bleeding, and accelerating whole blood coagulation process. It suggests good potentiality for use of latex proteases in wound management. Also, the finding of this study showed that the protease enzyme of Pedilanthus tithymaloides has the most potent hemostatic agent.

Using DNA barcoding to identify species within Euphorbiaceae

In this study, we tested the applicability of four DNA regions (rbcL, matK, ITS, and ITS2) as barcodes for identifying species within Euphorbiaceae. Based on assessments of the specific genetic divergence, the DNA barcoding gap, and the ability for species discrimination, the present results affirmed that ITS/ITS2 is a potential barcode for the Euphorbiaceae species. This study also provided a large-scale test to evaluate the effectiveness of ITS/ITS2 for differentiating species within Euphorbiaceae. Of the 1183 plant samples collected from 871 species in 66 diverse genera, ITS/ITS2 successfully identified > 90% and 100% of them at the species and genus levels, respectively. Therefore, our research indicates that use of the ITS/ITS2 region is a powerful technique for Euphorbiaceae identification.

Independence of stem and leaf hydraulic traits in six Euphorbiaceae tree species with contrasting leaf phenology

Hydraulic traits and hydraulic-related structural properties were examined in three deciduous (Hevea brasiliensis, Macaranga denticulate, and Bischofia javanica) and three evergreen (Drypetes indica, Aleurites moluccana, and Codiaeum variegatum) Euphorbiaceae tree species from a seasonally tropical forest in south-western China. Xylem water potential at 50% loss of stem hydraulic conductivity (P50(stem)) was more negative in the evergreen tree, but leaf water potential at 50% loss of leaf hydraulic conductivity (P50(leaf)) did not function as P50(stem) did. Furthermore, P50(stem) was more negative than P50(leaf) in the evergreen tree; contrarily, this pattern was not observed in the deciduous tree. Leaf hydraulic conductivity overlapped considerably, but stem hydraulic conductivity diverged between the evergreen and deciduous tree. Correspondingly, structural properties of leaves overlapped substantially; however, structural properties of stem diverged markedly. Consequently, leaf and stem hydraulic traits were closely correlated with leaf and stem structural properties, respectively. Additionally, stem hydraulic efficiency was significantly correlated with stem hydraulic resistance to embolism; nevertheless, such a hydraulic pattern was not found in leaf hydraulics. Thus, these results suggest: (1) that the evergreen and deciduous tree mainly diverge in stem hydraulics, but not in leaf hydraulics, (2) that regardless of leaf or stem, their hydraulic traits result primarily from structural properties, and not from leaf phenology, (3) that leaves are more vulnerable to drought-induced embolism than stem in the evergreen tree, but not always in the deciduous tree and (4) that there exists a trade-off between hydraulic efficiency and safety for stem hydraulics, but not for leaf hydraulics.

[Mites (Acari) from rubber trees (Hevea brasiliensis Muell. Arg., Euphorbiaceae) and spontaneous euphorbiaceous in rubber trees cultivation]

Quarterly samples were done in 2001 on three rubber tree plantation in the northwest of the state of São Paulo. Three rubber trees of each locality were sampled. Between the rows of rubber tree four species of spontaneous euphorbiaceous were collected: Chamaesyce hirta, C. hyssopifolia, Euphorbia heterophylla and Phyllanthus tenellus. A total of 8.954 mites of 38 species, belonging to 31 genera of 11 families were collected. Tydeidae and Phytoseiidae had the highest diversity of species, 9 and 7, respectively. The most abundant families were Eriophyidae (3.594), Tydeidae (2.825) and Tenuipalpidae (1.027). The most abundant species on the rubber trees were: phytophagous - Calacarus heveae Feres, Tenuipalpus heveae Baker, Lorryia sp.2, Lorryia formosa Cooreman and Lorryia sp.1; predators - Zetzellia quasagistemas Hernandes & Feres, Pronematus sp., Iphiseiodes zuluagai Denmark & Muma and Euseius citrifolius Denmark & Muma. Among the spontaneous euphorbiaceous, predatory mites were abundantly found on C. hirta and E. heterophylla, mainly Pronematus sp. and E. citrifolius, suggesting that these plants could be important in the maintenance of these predators in the rubber tree cultivation areas. However, plants that can shelter predators and at the same time exert strong competition (nutrients, water etc) to rubber trees, can not be recommended for pest management programs. Studies about competition between rubber trees and spontaneous plants need to be conducted for feasible efficient programs of environmental management, aiming at the control of pest mites of rubber tree.

Molecular phylogenetic analysis of Euphorbiaceae sensu stricto based on plastid and nuclear DNA sequences and ovule and seed character evolution

A phylogenetic analysis of Euphorbiaceae sensu stricto is presented using sequences from rbcL, atpB, matK and 18S rDNA from 85 species and 83 genera. The combined analysis of four molecular markers resulted in only one most parsimonious tree and also generated new supported clades, which include Euphorbioideae + Acalyphoideae s.s., subclades A2 + A3, subclades A5 + A6 and a clade uniting subclades A2-A8 within Acalyphoideae s.s. A palisadal exotegmen is a possible synapomorphy for all the Euphorbiaceae, except for the subfamily Peroideae. The presence of vascular bundles in the inner integument and a thick inner integument were shown to be synapomorphies for the clade of inaperturate and articulated crotonoids and for the large clade of Euphorbioideae, Acalyphoideae s.s., inaperturate and articulated crotonoids, respectively. Characters of the aril and vascular bundles in the outer integument are discussed. The selected embryological characters were seen to be highly correlated with the molecular phylogeny. When the results of molecular phylogenetic analysis of a previous study and this study were adjusted along with the selected embryological characters, all clades within Euphorbiaceae were supported except for a clade comprising Euphorbioideae + Acalyphoideae s.s. + inaperturate crotonoids + articulated crotonoids + Adenoclineae s.l. and a clade uniting subclades A4-A8 within Acalyphoideae s.s.

Floral gigantism in Rafflesiaceae

Species of Rafflesiaceae possess the world's largest flowers (up to 1 meter in diameter), yet their precise evolutionary relationships have been elusive, hindering our understanding of the evolution of their extraordinary reproductive morphology. We present results of phylogenetic analyses of mitochondrial, nuclear, and plastid data showing that Rafflesiaceae are derived from within Euphorbiaceae, the spurge family. Most euphorbs produce minute flowers, suggesting that the enormous flowers of Rafflesiaceae evolved from ancestors with tiny flowers. Given the inferred phylogeny, we estimate that there was a circa 79-fold increase in flower diameter on the stem lineage of Rafflesiaceae, making this one of the most dramatic cases of size evolution reported for eukaryotes.

Phylogenetic analyses of Malpighiales using plastid and nuclear DNA sequences, with particular reference to the embryology of Euphorbiaceae sens. str

We present phylogenetic analyses of Malpighiales, which are poorly understood with respect to relationships within the order, using sequences from rbcL, atpB, matK and 18SrDNA from 103 genera in 23 families. From several independent and variously combined analyses, a four-gene analysis using all sequence data provided the best resolution, resulting in the single most parsimonious tree. In the Malpighiales [bootstrap support (BS) 100%], more than eight major clades comprising a family or group of families successively diverged, but no clade containing more than six families received over 50% BS. Instead, ten terminal clades that supported close relationships between and among families (>50% BS) were obtained, between, for example, Balanopaceae and Chrysobalanaceae; Lacistemataceae and Salicaceae; and Phyllanthaceae and Picrodendraceae. The monophyly of Euphorbiaceae sens. str. were strongly supported (BS 100%), but its sister group was unclear. Euphorbiaceae sens. str. comprised two basally diverging clades (BS 100%): one leading to the Clutia group (Chaetocarpus, Clutia, Pera and Trigonopleura), and the other leading to the rest of the family. The latter shared a palisadal, instead of a tracheoidal exotegmen as a morphological synapomorphy. While both Acalyphoideae (excluding Dicoelia and the Clutia group) and Euphorbioideae are monophyletic, Crotonoideae were paraphyletic, requiring more comprehensive analyses.

Purification and characterization of a 34-kDa, heat stable glycoprotein from Synadenium grantii latex: action on human fibrinogen and fibrin clot

Latex glycoprotein (LGP) from Synadenium grantii latex was purified by the combination of heat precipitation and gel permeation chromatography. LGP is a heat stable protein even at 80 degrees C showed a sharp single band both in SDS-PAGE as well as in native (acidic) PAGE. LGP is a monomeric protein appears as single band under reducing condition. It is a less hydrophobic protein showed sharp single peak in RP-HPLC with retention time of 13.3 m. The relative molecular mass of LGP is 34.4 kDa. CD spectrum of LGP explains less content of alpha-helix (7%), and high content of beta-pleated sheets (48%) and random coils (46%). The N-terminal sequence of LGP is D-F-P-S-D-W-Y-A-Y-E-G-Y-V-I-D-R-P-F-S. Purified LGP is a fibrinogen degrading protease hydrolyses all the three subunits in the order of Aalpha, Bbeta and gamma. The hydrolytic pattern is totally different from plasmin as well as thrombin. LGP reduces recalcification time from 165 to 30 s with citrated human plasma but did not show thrombin like as well as factor Xa-like activity. Although LGP induces procoagulant activity, it hydrolyses partially cross-linked fibrin clot. It hydrolyses all the subunits of partially cross-linked fibrin clot (alpha- chains, beta-chain and gamma-gamma dimer). LGP is a serine protease, inhibited by PMSF. Other serine protease inhibitors, aprotinin and leupeptin did not inhibit the caseinolytic activity as well as fibrinogenolytic activity. We report purification and characterization of a glycoprotein from Synadenium grantii latex with human fibrino(geno)lytic activity.

A New Cytotoxic Daphnane Diterpenoid, Rediocide G, from Trigonostemon reidioides

Rediocide G (7), a new daphnane diterpenoid, was isolated from the roots of Trigonostemon reidioides (Euphorbiaceae), together with two congeners, rediocide A and rediocide B, (+)-syringaresinol, scopoletin, tomentin and stigmasterol. The structure of the new natural product was elucidated by comparison of its NMR and mass spectral data with those of previously known rediocides and confirmed by extensive 2D NMR spectral analysis. Rediocide G (7) was found to be cytotoxic to various cancer cell lines.

An EST resource for cassava and other species of Euphorbiaceae

Cassava (Manihot esculenta) is a major food staple for nearly 600 million people in Africa, Asia, and Latin America. Major losses in yield result from biotic and abiotic stresses that include diseases such as Cassava Mosaic Disease (CMD) and Cassava Bacterial Blight (CBB), drought, and acid soils. Additional losses also occur from deterioration during the post-harvest storage of roots. To help cassava breeders overcome these obstacles, the scientific community has turned to modern genomics approaches to identify key genetic characteristics associated with resistance to these yield-limiting factors. One approach for developing a genomics program requires the development of ESTs (expressed sequence tags). To date, nearly 23,000 ESTs have been developed from various cassava tissues, and genotypes. Preliminary analysis indicates existing EST resources contain at least 6000-7000 unigenes. Data presented in this report indicate that the cassava ESTs will be a valuable resource for the study of genetic diversity, stress resistance, and growth and development, not only in cassava, but also other members of the Euphorbiaceae family.

[Euphorbiaceae diterpenes: plant toxins or promising molecules for the therapy?]

Most of the species of Euphorbiaceae are known to be toxic and poisonous plants because their milky latex has strong skin irritant activity, and chronic exposure can result carcinogenic effect. The toxic constituents of Euphorbiaceae species are specific diterpenes, called in common as phorboids. These compounds (tigliane, ingenane and daphnane derivatives) possess extreme pro-inflammatory and tumour promoting effects due to the activation of protein kinase C enzyme. The present article gives a survey about the present estimation of Euphorbiaceae diterpenes on the basis of own experimental results and literature data. The study tries to answer the question whether these compounds can be regarded as plant toxins or they may have therapeutic relevance? It was concluded that one group of diterpenes, such as most of phorbol and ingenol esters can be considered exclusively as toxins without any possible medicinal use. The other group of diterpenes comprises compounds, which display toxicity, but in adequate dose they have therapeutic perspective (e.g. the resiniferatoxin with capsaicine-like effect). The third group of compounds such as diterpenes of non-phorboid type with macrocyclic or polycyclic structures do not have toxic effect or this property is markedly reduced, however demonstrate interesting biological activities (anti-MDR, antiproliferative and tubulin-interacting effects). Thus, these compounds may be promising lead compounds for natural product based drug developments.

Terpenoids and glycolipids from euphorbiaceae

The family Euphorbiaceae is widely distributed throughout both hemispheres and ranges in morphological form from large desert succulents to trees and even small herbaceous types. Many species contain a milky juice which is more or less toxic, especially for cold-blooded animals, and can produce a dermatitis similar to that from poison ivy. Separation procedures and characterization of the less polar fractions of the plant extracts have been widely described in the literature for their content in diterpene derivatives. In the continuing research on biologically active compounds from Euphorbiaceae, a series of studies on the isolation and structure elucidation of glyceroglycolipids (GGLs) and glycosphingolipids (GSLs) have been carried out in order to develop the novel medicinal resources from natural Euphorbiaceae products. Glyceroglycolipids are major constituents of the chloroplast membrane in the plant kingdom. Recently, glycolipids were found to possess antitumor-promoting activity while glyceroglycolipids isolated from Euphorbiaceae have shown an interesting anti-inflammatory activity in vivo. Glycosphingolipids are present at the outer layer of the lipid-bilayer in biological membranes and are thought to participate in antigen-antibody reactions and transmission of biologically informations. Sphingolipid breakdown products, sphingosine and lysosphingolipids, inhibit protein kinase C, a pivotal enzyme in cell regulation and signal transduction. Sphingolipids and lysosphingolipids affect significantly cellular responses and exhibit antitumor promoter activities in various mammalian cells. These molecules may function as endogenous modulators of cell function and possibly as second messengers.

Molecular phylogeny of Crematogaster subgenus Decacrema ants (Hymenoptera: Formicidae) and the colonization of Macaranga (Euphorbiaceae) trees

To elucidate the evolution of one of the most species-rich ant-plant symbiotic systems, the association between Crematogaster (Myrmicinae) and Macaranga (Euphorbiaceae) in South-East Asia, we conducted a phylogenetic analysis of the ant partners. For the phylogenetic analysis partial mitochondrial cytochrome oxidase I and II were sequenced and Maximum Parsimony analysis was performed. The analyzed Crematogaster of the subgenus Decacrema fell into three distinct clades which are also characterized by specific morphological and ecological traits (queen morphology, host-plants, and colony structure). Our results supported the validity of our currently used morphospecies concept for Peninsula Malaysia. However, on a wider geographic range (including North and North-East Borneo) some morphospecies turned out to be species complexes with genetically quite distinct taxa. Our phylogenetic analysis and host association studies do not indicate strict cocladogenesis between the subgenus Decacrema and their Macaranga host-plants because multiple ant taxa occur on quite distinct host-plants belonging to different clades within in the genus Macaranga. These results support the view that host-shifting or host-expansion is common in the ants colonizing Macaranga. Additionally, the considerable geographic substructuring found in the phylogenetic trees of the ants suggests that allopatric speciation has also played a role in the diversification and the current distribution of the Decacrema ants.

Sesquineolignans and other constituents from the seeds of Joannesia princeps

From the methanolic extract of the seeds of the Brazilian Joannesia princeps 3,3'-bisdemethylpinoresinol and six new sesquineolignans were isolated besides the known neolignans americanol A, isoamericanol A and isoamericanin A which were found to be the major constituents. A method was developed to distinguish americanol- from isoamericanol-type compounds spectroscopically.

Stereochemistry of megastigmane glucosides from Glochidion zeylanicum and Alangium premnifolium

From Glochidion zeylanicum, two megastigmane glucosides, 3- and 9-O-beta-D-glucopyranosides of (3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetrol (1 and 2, respectively), were isolated. Their structures were different from those of kiwiionoside (3) and actinidioionoside (4), isolated from Actinidia chinensis and Actinidia polygama, respectively, in the stereochemistry at the 9-positions. Alangionosides E (5) and O (6), isolated from the leaves of Alangium premnifolium, are also megastigmane glucosides, and the latter is closely related to 1 and actinidioionoside (4). However, the absolute configurations of the 9-position remained to be determined. They were analyzed to be R by means of a modified Mosher's method. Alangionoside E (5) is identical with corchoionoside A in all aspects. The name of corchoionoside A must be retained thereafter.

Chemotaxonomy of the tribe Antidesmeae (Euphorbiaceae): antidesmone and related compounds

Selected species of the tribe Antidesmeae (Euphorbiaceae, subfamily Phyllanthoideae) have been screened for antidesmone occurrence and its content by quantitative HPLC (UV) and qualitative LC-MS/MS analysis. The LC-MS analysis allowing the additional detection of 17,18-bis-nor-antidesmone, 18-nor-antidesmone, 8-dihydroantidesmone and 8-deoxoantidesmone was carried out in the selected reaction monitoring (SRM) mode. Leaf material from herbarium specimens of 13 Antidesma spp., Hyeronima alchorneoides and Thecacoris stenopetala (all subtribe Antidesminae), as well as Maesobotrya barteri, Aporosa octandra (both Scepinae) and Uapaca robynsii (Uapacinae) were analysed. Additionally, freshly collected samples of different plant parts of two Antidesma spp. were investigated to ensure the significance of the results on herbarium specimens and to compare the antidesmone content in bark, root and leaves. Antidesmone could be unambiguously identified in 12 of 13 Antidesma spp., as well as in the two other investigated genera of subtribe Antidesminae, in levels of up to 65 mg/kg plant dry weight. Antidesmone was not found in specimens from other subtribes. Antidesmone-derived compounds occur in much lower concentrations than antidesmone.

[Leaf anatomy of the subtribe Conceveibinae (Euphorbiaceae)]

A comparative study of the leaf anatomy of the subtribe Conceveibinae was carried out. Leaves show a similar structural arrangement in all species, however, there are small variations among the taxa that allow definitions of species or groups. It is not possible to recognize infrageneric divisions or to maintain some genera as different from Conceveiba. The analysis included the study of 11 characters of taxonomic importance of the leaf: the form, the size and the apex of the papillae of the lower side of the blade, the number of layers of the palisade parenchyma, the presence or absence of the midrib pith, the number of vascular bundles of petiole as well as the central cylinder and the medulla, and the presence or absence of the sclerenchyma in the different levels of the petiole. The results are evaluated from a taxonomical point of view. With leaf anatomy characters only, it is possible to separate the genus Conceveiba in the subtribe.

[Comparative studies on the fatty acids contained in four species of medicinal plants from family Euphorbiaceae and their endophytic fungi]

OBJECTIVE

The relation of four species of medicinal plants from family Euphorbiaceae and their endophytic fungi was studied to find the source of active substances for developing new pharmaceutical resources.

METHOD

The main fatty acids contained in Sapium sebiferum, Euphorbia pekinensis, Euphorbia helioscopia, Bischofia polycarpam and their 28 strains of endophytic fungi were compared and analysed by GC.

RESULT

The main fatty acids of the plants are: alpha-linolenic acid, palmitic acid, linolenic acid and oleic acid. Linolenic acid, palmitic acid and oleic acid are the main fatty acids of the endophytic fungi.

CONCLUSION

The fatty acids could be produced by the endophytic fungi, which could be used as a factor for identification. There are great differences at the contents of alpha-linolenic acid between the plants and their endophytic fungi, which were suggested to be related with the nutrition absorption and the relationship between the endophytes and the host plant.

[Latex allergy. Diagnosis and therapeutic aspects]

In the last two decades of the 20th century, latex allergy has reached epidemic proportions. Epidemiological studies demonstrate that 3-25 % of health personnel is allergic to latex. The main risk groups are health workers, machine operators in latex factories, and children with spina bifida and urogenital anomalies. From the allergenic point of view, latex contains 240 peptides but approximately 50 are able to react to IgE. Latex elongation factor Hevdl is the relevant allergen in patients with spina bifida. Prohevein (hev B6) behaves as a major allergen, since it reacts to IgE in most of the sera of patients with latex allergy. The nature of latex is complex; it is an allergenic mixture that depends on chemical, immunological and epidemiological variables. Latex proteins show strong cross reactivity with several proteins from fruit and vegetable grains such as avocado, potato, banana, tomato, chestnut, and kiwi. In vivo studies have shown that class I chitinase from avocado and chestnut behave as major allergens in allergic patients with latex-fruit syndrome. The clinical manifestations related to the use of latex products depend on the type of exposure, the amount of the allergen, and individual variability. The most useful diagnostic method is the skin prick test. Several perioperative guidelines are recommended in patients sensitized to latex as well as various alternatives to rubber gloves. An increasing number of studies describe the efficacy of etiological treatment (immunotherapy), using different guidelines and routes of administration. These preliminary data encourage the hope that in the near future immunomodulatory therapy will be available to mitigate against the latex allergy epidemic.

Evolution of myrmecophytism in western Malesian Macaranga (Euphorbiaceae)

Plants inhabited by ants (myrmecophytes) have evolved in a diversity of tropical plant lineages. Macaranga includes approximately 300 paleotropical tree species; in western Malesia there are 26 myrmecophytic species that vary in morphological specializations for ant association. The origin and diversification of myrmecophytism in Macaranga was investigated using phylogenetic analyses of morphological and nuclear ITS DNA characters and studies of character evolution. Despite low ITS variation, the combined analysis resulted in a well-supported hypothesis of relationships. Mapping myrmecophytism on all most parsimonious trees resulting from the combined analysis indicated that the trait evolved independently between two and four times and was lost between one and three times (five changes). This hypothesis was robust when tested against trees constrained to have three or fewer evolutionary transformations, although increased taxon sampling for the ITS analysis is required to confirm this. Mapping morphological traits on the phylogeny indicated that myrmecophytism was not homologous among lineages; each independent origin involved a suite of different specializations for ant-plant association. There was no evidence that myrmecophytic traits underwent sequential change through evolution; self-hollowing domatia evolved independently from ant-excavated domatia, and different food-body production types evolved in different lineages. The multiple origins of myrmecophytism in Macaranga were restricted to one small, exclusively western Malesian lineage of an otherwise large and nonmyrmecophytic genus. Although the evolution of aggregated food-body production and the formation of domatia coincided with the evolution of myrmecophytism in all cases, several morphological, ecological, and biogeographic factors appear to have facilitated and constrained this radiation of ant-plants.

Molecular analysis of phylogenetic relationships among Myrmecophytic macaranga species (Euphorbiaceae)

Many species of the paleotropical pioneer tree genus Macaranga Thou. (Euphorbiaceae) live in association with ants. Various types of mutualistic interactions exist, ranging from the attraction of unspecific ant visitors to obligate myrmecophytism. In the latter, nesting space and food bodies are exchanged for protection by highly specific ant partners (mainly species of the myrmicine genus Crematogaster). As a first step toward elucidating the coevolution of ant-plant interactions in the Macaranga-Crematogaster system, we have initiated a molecular investigation of the plant partners' phylogeny. Nuclear ribosomal DNA internal transcribed spacer (ITS) sequences were analyzed for 73 accessions from 47 Macaranga species, representing 17 sections or informally described species groups. Three accessions from the putative sister taxon Mallotus Lour, were included as outgroups. Cladograms of the ITS data revealed Macaranga to be nested within Mallotus. ITS sequences are highly similar within section Pachystemon s.str., suggesting a relatively recent and rapid radiation of obligate myrmecophytes within this section. Forty-three accessions, mainly of ant-inhabited species, were additionally investigated by random amplified polymorphic DNA (RAPD) and microsatellite-primed PCR (MP-PCR) techniques. Phenetic analysis of RAPD and MP-PCR banding profiles generally confirmed the ITS results. Best resolutions for individual clades were obtained when ITS and RAPD/MP-PCR data were combined into a single matrix and analyzed phenetically. The combined analysis suggests multiple (four) rather than a single evolutionary origin of myrmecophytism, at least one reversal from obligate myrmecophytism to nonmyrmecophytism, and one loss of mutualistic specifity.