Natural compounds with important medical potential found in Helleborus sp

Comparative Evaluation of the Potential Antitumor of Helleborus purpurascens in Skin and Breast Cancer

In the field of oncology, the plant kingdom has an inexhaustible supply of bioactive compounds. Phytochemical compounds isolated from Helleborus species have been found to be useful in various chronic diseases. This has brought Helleborus to the attention of medical researchers. H. purpurascens is a plant characteristic of the Carpathian area, known since ancient times for its beneficial effects. The aim of the study was to evaluate the flavonoids composition of a hydroalcoholic extract of H. purpurascens, as well as to assess its antioxidant activity and antitumor potential at the level of two healthy cell lines and four tumor cell lines. In addition, the expression of the genes involved in the apoptotic process (Bcl-2, Bad, and Bax) were evaluated. The results indicated that the extract has a high concentration of flavonoids, such as epicatechin, quercetin, and kaempferol. The extract has an increased antioxidant activity, very similar to that of the standard, ascorbic acid and cytotoxic effects predominantly in the breast cancer cell line, being free of cytotoxic effects in healthy cell lines. Underlying the cytotoxic effect is the induction of the process of apoptosis, which in the present study was highlighted by decreasing the expression of anti-apoptotic genes (Bcl-2) and increasing the expression of pro-apoptotic genes (Bad and Bax). In conclusion, the hydroalcoholic extract of H. purpurascens can be considered an important source for future medical applications in cancer therapy.

Investigation of Chemical Constituents of Eranthis longistipitata (Ranunculaceae): Coumarins and Furochromones

Aqueous-ethanol extracts (70%) from the leaves of Eranthis longistipitata Regel. (Ranunculaceae Juss.)-collected from natural populations of Kyrgyzstan-were studied by liquid chromatography with high-resolution mass spectrometry (LC-HRMS). There was no variation of the metabolic profiles among plants that were collected from different populations. More than 160 compounds were found in the leaves, of which 72 were identified to the class level and 58 to the individual-compound level. The class of flavonoids proved to be the most widely represented (19 compounds), including six aglycones [quercetin, kaempferol, aromadendrin, 6-methoxytaxifolin, phloretin, and (+)-catechin] and mono- and diglycosides (the other 13 compounds). In the analyzed samples of E. longistipitata, 14 fatty acid-related compounds were identified, but coumarins and furochromones that were found in E. longistipitata were the most interesting result; furochromones khelloside, khellin, visnagin, and cimifugin were found in E. longistipitata for the first time. Coumarins 5,7-dihydroxy-4-methylcoumarin, scoparone, fraxetin, and luvangetin and furochromones methoxsalen, 5-O-methylvisammioside, and visamminol-3'-O-glucoside were detected for the first time in the genus Eranthis Salisb. For all the above compounds, the structural formulas are given. Furthermore, detailed information (with structural formulas) is provided on the diversity of chromones and furochromones in other representatives of Eranthis. The presence of chromones in plants of the genus Eranthis confirms its closeness to the genus Actaea L. because chromones are synthesized by normal physiological processes only in these members of the Ranunculaceae family.

Immunomodulatory Effect of Helleborus purpurascens Waldst. & Kit

(1) Background: Helleborus purpurascens Waldst. & Kit. (hellebore) is a plant species found mainly in Balkans and the Carpathians, and it is traditionally used for a variety of ailments since the time of Hippocrates. The aim of this study was to investigate the immunomodulatory effect of hellebore extracts correlated with relevant chemical compounds and the extraction method. (2) Methods: A methanolic (H1) and a hydroalcoholic extract (H2) were prepared by standard methods. Qualitative (HPTLC) and quantitative (HPLC) chemical analysis were conducted to reveal the ecdysones and polyphenolic compounds. In vitro studies were performed using rat macrophages, murine fibroblasts and immortalized human T-lymphocytes, and their viability was determined by MTS assay. In vivo studies involved a rat immunodepression model. (3) Results: In vitro assays revealed the stronger effect of H2 on cellular proliferation, compared to H1. In the in vivo assay, H2 revealed an immunostimulatory effect in the context of experimentally induced immunosuppression with dexamethasone, a superior effect to levamisole treatment according to the same regimen, in two doses every 24 h. There was no correlation between pharmacological effect and the reference compounds evaluated. (4) Conclusions: The immunomodulatory effect of methanolic and hydroalcoholic hellebore extracts is not due to ecdysones and polyphenolic compounds, but other polar substances, possible steroid glycosides.

Role of Plant-Derived Natural Compounds in Experimental Autoimmune Encephalomyelitis: A Review of the Treatment Potential and Development Strategy

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that is mainly mediated by pathological T-cells. Experimental autoimmune encephalomyelitis (EAE) is a well-known animal model of MS that is used to study the underlying mechanism and offers a theoretical basis for developing a novel therapy for MS. Good therapeutic effects have been observed after the administration of natural compounds and their derivatives as treatments for EAE. However, there has been a severe lag in the research and development of drug mechanisms related to MS. This review examines natural products that have the potential to effectively treat MS. The relevant data were consulted in order to elucidate the regulated mechanisms acting upon EAE by the flavonoids, glycosides, and triterpenoids derived from natural products. In addition, novel technologies such as network pharmacology, molecular docking, and high-throughput screening have been gradually applied in natural product development. The information provided herein can help improve targeting and timeliness for determining the specific mechanisms involved in natural medicine treatment and lay a foundation for further study.

Study of potent cytotoxic activity of Helleborus cyclophyllus Boiss against a human adenocarcinoma cell line

Helleborus cyclophyllus Boiss is a rhizomatous plant species, with strong allelochemical properties, that has been used since ancient times for its therapeutic properties. In the present study we investigated the ability of an aqueous-soluble fraction of the methanol extract of H. cyclophyllus Boiss leaves, to induce apoptotic cell death on A549 human bronchial epithelial adenocarcinoma cells. A primary human lung fibroblasts' cell line was used as a model of normal-healthy cells for comparison. Cell morphology was examined after appropriate staining, cytotoxic activity of the extract was determined by the MTT assay, the type of cell death was analyzed by flow cytometry, confirmation of apoptosis was evaluated with the analysis of caspase-3, PARP1 by western blotting, while the chemical composition was assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). H. cyclophyllus Boiss extract was selectively active on A549 cells inducing significant morphological changes, even at low concentrations. Characteristic morphological alterations included the release of vesicular formations from A549 cell membranes (ectosomes), detachment of cells from their substrate, generation of a large vesicle into the cytoplasm (thanatosome) and the formation of apoptotic bodies. The selective apoptotic action on treated cells was also confirmed by biochemical criteria. Low concentrations, however, did not affect normal cells. The phytochemical analysis of the extract revealed the presence of cardiac glucosides, bufadienolides and phytoecdysteroids. To the best of our knowledge, the above-mentioned sequences of events leading selectively cancer cells to apoptosis, has not been reported before.

Antiseizure potential of the ancient Greek medicinal plant Helleborus odorus subsp. cyclophyllus and identification of its main active principles

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological data and ancient texts support the use of black hellebore (Helleborus odorus subsp. cyclophyllus, Ranunculaceae) for the management and treatment of epilepsy in ancient Greece.

AIM OF THE STUDY

A pharmacological investigation of the root methanolic extract (RME) was conducted using the zebrafish epilepsy model to isolate and identify the compounds responsible for a potential antiseizure activity and to provide evidence of its historical use. In addition, a comprehensive metabolite profiling of this studied species was proposed.

MATERIALS AND METHODS

The roots were extracted by solvents of increasing polarity and root decoction (RDE) was also prepared. The extracts were evaluated for antiseizure activity using a larval zebrafish epilepsy model with pentylenetetrazole (PTZ)-induced seizures. The RME exhibited the highest antiseizure activity and was therefore selected for bioactivity-guided fractionation. Isolated compounds were fully characterized by NMR and high-resolution tandem mass spectrometry (HRMS/MS). The UHPLC-HRMS/MS analyses of the RME and RDE were used for dereplication and metabolite profiling.

RESULTS

The RME showed 80% inhibition of PTZ-induced locomotor activity (300 μg/ml). This extract was fractionated and resulted in the isolation of a new glucopyranosyl-deoxyribonolactone (1) and a new furostanol saponin derivative (2), as well as of 20-hydroxyecdysone (3), hellebrin (4), a spirostanol glycoside derivative (5) and deglucohellebrin (6). The antiseizure activity of RME was found to be mainly due to the new furostanol saponin (2) and hellebrin (4), which reduced 45% and 60% of PTZ-induced seizures (135 μM, respectively). Besides, the aglycone of hellebrin, hellebrigenin (S34), was also active (45% at 7 μM). To further characterize the chemical composition of both RME and RDE, 30 compounds (A7-33, A35-37) were annotated based on UHPLC-HRMS/MS metabolite profiling. This revealed the presence of additional bufadienolides, furostanols, and evidenced alkaloids.

CONCLUSIONS

This study is the first to identify the molecular basis of the ethnopharmacological use of black hellebore for the treatment of epilepsy. This was achieved using a microscale zebrafish epilepsy model to rapidly quantify in vivo antiseizure activity. The UHPLC-HRMS/MS profiling revealed the chemical diversity of the extracts and the presence of numerous bufadienolides, furostanols and ecdysteroids, also present in the decoction.

Differential cytotoxic properties of Helleborus niger L. on tumour and immunocompetent cells

ETHNOPHARMACOLOGICAL RELEVANCE

In Romanian folk medicine, Helleborus niger L. is used for the treatment of rheumatoid arthritis or viral infections and in complementary therapy, especially in anthroposophic medicine (AM), where the plant is administered as an adjuvant to treat malignant diseases. In the present study, we investigated the differential cytotoxic effects of H. niger on human tumour and healthy cells of the human immune system in vitro.

MATERIAL AND METHODS

Protoanemonin and saponins, as significant constituents of H. niger extracts, were quantified in five individual batches using validated HPLC methods. Further, the impact of H. niger on proliferation capacity (MTT assay) as well as on apoptosis and necrosis induction in a panel of tumour cell lines and human lymphocytes (combined annexin V and propidium iodide staining) was monitored. In addition, NK cell function (degranulation-CD107a assay and IFN-gamma secretion) was also investigated since these immunocompetent cells are important for the control of malignancies within the human body.

RESULTS

Extracts of H. niger induced proliferation inhibition not only of lymphoblastic leukaemia cells (MOLT4; IC50: 171 µg/mL) but also of myosarcoma (SK-UT-1b; IC50: 304 µg/mL) and melanoma cells (HT-144; IC50: 569 µg/mL) due to the induction of apoptosis. Purified T cells or NK cells were significantly affected through the presence of high H. niger concentrations while bulk lymphocytes were not affected. NK cells' anti-tumour functions expressed by degranulation capacity as well as IFN-y production were unaffected by the presence of the H. niger extract. Since protoanemonin and saponins have been reported in the literature to exert cytotoxic effects, their content was also determined.

CONCLUSIONS

H. niger extracts exhibit differential cytotoxicity towards tumour cell lines and healthy human T- and NK-cells.

LC-MS(n) characterization of steroidal saponins in Helleborus niger L. roots and their conversion products during fermentation

Steroidal saponins comprise a substantial part of the secondary metabolite spectrum in the medicinal plant Helleborus niger L. (black hellebore). The saponin fraction from the roots was investigated by LC-MS(n) resulting in 38 saponins and β-ecdysone. Nine diosgenyl-type glycosides, mainly furostanols consisting of the aglycones diosgenin, macranthogenin, sceptrumgenin, and sarsasapogenin were accompanied by 5 diosgenyl-type saponins exhibiting an aglycone with an additional OH group. However, the most relevant compounds were 24 acetylated polyhydroxy saponins including hellebosaponins A and D. The enzymes glucuronidase, β-glucosidase, and pectinase were used to obtain an idea on potential fermentative transformation reactions by incubation of the isolated model saponins macranthosid I and hellebosaponin A. In a second step, aqueous H. niger extracts containing a much greater range of saponins were monitored during fermentation and 12months of storage. The metabolites were examined and assigned by LC-MS(n) and targeted extracted ion current (EIC) scan analyses. Good agreement was found among the results from the model compounds and the whole aqueous fermented extracts. The native diosgenyl-type furostanol saponins were converted to spirostanols under scission of hexoses. Alteration of the acetylated polyhydroxy saponins, exclusively spirostanols, took place following cleavage of acetyl groups and terminal deoxyhexoses. Most interestingly, the pentoses of the sugar chain at C(1) were not affected. Conversion of acetylated polyhydroxy saponins resulted in a final structure type which was stable and detectable, even after 12months of fermentation and storage.

Copy number variation and mosaicism

Mosaicism is the presence of cells within an organism that have a different genetic composition despite deriving from a single zygote. The consequence of this depends on the number and type of cells that are affected as well as the specific DNA involved. There are several diseases where mosaicism is known to occur, but the currently observed frequency is presumably an underestimation due to the difficulty of detecting changes in only a percentage of cells. Recent advances in technology have provided a greater insight into the frequency and mechanisms of mosaicism in all forms. This review will cover the different techniques that can be used for detecting copy number variation (CNV) in mosaic form, and describe some of the insights that different diseases have given on the true frequencies and mechanisms responsible for somatic rearrangements. It will conclude with a discussion of the implications of the recent description of CNV in identical twins, and what remains to be elucidated in the world of mosaic CNV.