Helleborus sp. are small, perennial herbs with a wide distribution across central and southern Europe and Asia. Historically, extracts of these plants have been used in remedies exhibiting cathartic and anthelmintic effects; however, their adverse and toxic potential have also been reported. As such, Helleborus extracts have been trialled as alternative approaches to cancer treatment in rare cases. In this study, a detailed phytochemical characterisation of root extracts from Helleborus odorus subsp. cyclophyllus was performed in parallel with an in vitro assessment of their cytotoxicity and effect on cell phenotype. GC/EI/MS metabolite profiling revealed the complexity of the extract, which exhibited a high relative content of fatty acids (17.98%), with the most abundant group being the unsaturated fatty acids, followed by saturated and hydroxy fatty acids. Bioassays indicated the extract had antioxidant capabilities, while in vitro analysis demonstrated the extract induced a pro-oxidant phenotype that reduced cell viability, inhibited growth in bacterial ( E. coli ) and mammalian (human aortic endothelial cells) cell types, and exacerbated pro-inflammatory indices. Helleborus odorus subsp. cyclophyllus contains bioactive molecules that elicit a number of cellular responses, and the therapeutic potential of these molecules warrants further investigation.

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We investigated taxonomic and endemic richness, patterns of spatial distribution, cenotic and spatial diversification, and chorological and life form spectra of montane coniferous forests in the central part of the Balkan Peninsula. We collected information on 1435 taxa (1351 at the level of species and 84 subspecies) with 65,289 species-occurrence data, published in 1930 original plots with a total area of about 215 ha in the analysis. All statistical analyses (univariate and multivariate) were performed on binary matrices prepared for different levels of analysis. Our main results showed that the montane coniferous forests of the central Balkan Peninsula represent very species-rich vegetation. At the same time, the high proportion of endemics indicated that the montane coniferous forests of the central Balkan Peninsula differ significantly from Central European and boreal forests of a similar type. Furthermore, we found that there were regional differences in the species composition of the coniferous forests of the Balkan Peninsula, and that the primary centers of floristic richness are located in the area of the central and continental Dinarides. This latter finding suggested that the true centers of the richness of European coniferous forests are located south of the Limestone Alps-Western Dinarides-Carpathian Foothills line in Romania, which used to be considered the center of the richness of the coniferous forests in Europe.

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Despite their known toxic properties, various Helleborus species are used as medicaments in folk medicine to treat some diseases and health conditions. As the main mechanism of many cytostatic drugs is based on their cytotoxic activity, there is potential for the toxicity of hellebore to be used in anticancer therapy. This study tested the geno- and cytotoxic effects of extracts of three hellebore taxa (Helleborus odorus, Helleborus multifidus and Helleborus hercegovinus) on meristemic onion (Alliumcepa L.) cells and human lymphocytes. Treatments with Helleborus extracts induced cytotoxic and cytostatic effects in meristemic onion cells as well as in cultivated cytokinesis-blocked human lymphocytes. Cytokinesis-block micronucleus cytome assay indicated that treatments with hellebore extracts induce genotoxic effects in human lymphocytes, and that the significant mechanism of their antiproliferative activity is apoptosis induction.

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Background The nuclear DNA amount in an unreplicated haploid chromosome complement (1C-value) is a key diversity character with many uses. Angiosperm C-values have been listed for reference purposes since 1976, and pooled in an electronic database since 1997 (http://www.kew.org/cval/homepage). Such lists are cited frequently and provide data for many comparative studies. The last compilation was published in 2000, so a further supplementary list is timely to monitor progress against targets set at the first plant genome size workshop in 1997 and to facilitate new goal setting. Scope The present work lists DNA C-values for 804 species including first values for 628 species from 88 original sources, not included in any previous compilation, plus additional values for 176 species included in a previous compilation. Conclusions 1998-2002 saw striking progress in our knowledge of angiosperm C-values. At least 1700 first values for species were measured (the most in any five-year period) and familial representation rose from 30 % to 50 %. The loss of many densitometers used to measure DNA C-values proved less serious than feared, owing to the development of relatively inexpensive flow cytometers and computer-based image analysis systems. New uses of the term genome (e.g. in 'complete' genome sequencing) can cause confusion. The Arabidopsis Genome Initiative C-value for Arabidopsis thaliana (125 Mb) was a gross underestimate, and an exact C-value based on genome sequencing alone is unlikely to be obtained soon for any angiosperm. Lack of this expected benchmark poses a quandary as to what to use as the basal calibration standard for angiosperms. The next decade offers exciting prospects for angiosperm genome size research. The database (http://www.kew.org/cval/homepage) should become sufficiently representative of the global flora to answer most questions without needing new estimations. DNA amount variation will remain a key interest as an integrated strand of holistic genomics.

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The structure of 1beta,3beta,11alpha-trihydroxyspirosta-5,25(27)-diene (C(27)H(40)O(5); a steroidal sapogenin) isolated from Helleborus serbicus Adam 1906 (Ranunculaceae) and crystallized from absolute ethanol as a monohydrate (melting point 519-522 K) had been characterized by two symmetry-independent binary (steroid-water) layers, cross-linked by hydrogen bonds [Kálmán et al. (1985). Acta Cryst. C41, 1645-1647]. Recently, a novel monohydrate was crystallized again from absolute ethanol (source: Helleborus multifidus subspecies serbicus) with a somewhat higher melting point of 525-526 K. X-ray analysis of these crystals [Argay et al. (1998). Acta Chim. Hung. 135, 449-456] revealed a novel polymorph (hereinafter denoted polymorph B), which is also built up by two binary layers of C(27)H(40)O(5) and H(2)O, but in which the relative position of these layers differs from that found in the first modification (polymorph A). Comparing the two polymorphs, layers of one type are found to be similar, displaying identical hydrogen bonding, whereas layers of the second type differ with respect to the orientations adopted by the water molecules; these orientations also differ from those in the layers of the first type. Consequently, by these water rotations, hydrogen bonds, at least partly, are reversed. This leads to two different close packings: in form A four consecutive layers are cross-linked by two homomolecular (hydroxyl.hydroxyl and water.water) hydrogen-bond pairs, while in B there are only heteromolecular hydroxyl.water bonds. These hydrogen-bond dissimilarities together with the differences in the weak CH.X etc. interactions explain the greater stability of the higher melting-point form B.

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