Reinhard Saller

The Use of Silymarin in the Treatment of Liver Diseases

The high prevalence of liver diseases such as chronic hepatitis and cirrhosis underscores the need for efficient and cost-effective treatments. The potential benefit of silymarin (extracted from the seeds of Silybum marianum or milk thistle) in the treatment of liver diseases remains a controversial issue. Therefore, the objective of this review is to assess the clinical efficacy and safety of silymarin by application of systematic approach. 525 references were found in the databases, of which 84 papers were retained for closer examination and 36 were deemed suitable for detailed analysis.Silymarin has metabolic and cell-regulating effects at concentrations found in clinical conditions, namely carrier-mediated regulation of cell membrane permeability, inhibition of the 5-lipoxygenase pathway, scavenging of reactive oxygen species (ROS) of the R-OH type and action on DNA-expression, for example, via suppression of nuclear factor (NF)-κB.Pooled data from case record studies involving 452 patients with Amanita phalloides poisoning show a highly significant difference in mortality in favour of silibinin [the main isomer contained in silymarin] (mortality 9.8% vs 18.3% with standard treatment; p < 0.01). The available trials in patients with toxic (e.g. solvents) or iatrogenic (e.g. antispychotic or tacrine) liver diseases, which are mostly outdated and underpowered, do not enable any valid conclusions to be drawn on the value of silymarin. The exception is an improved clinical tolerance of tacrine. In spite of some positive results in patients with acute viral hepatitis, no formally valid conclusion can be drawn regarding the value of silymarin in the treatment of these infections.Although there were no clinical end-points in the four trials considered in patients with alcoholic liver disease, histological findings were reported as improved in two out of two trials, improvement of prothrombin time was significant (two trials pooled) and liver transaminase levels were consistently lower in the silymarin-treated groups. Therefore, silymarin may be of use as an adjuvant in the therapy of alcoholic liver disease. Analysis was performed on five trials with a total of 602 patients with liver cirrhosis. The evidence shows that, compared with placebo, silymarin produces a nonsignificant reduction of total mortality by −4.2% [odds ratio (OR) 0.75 (0.5–1.1)]; but that, on the other hand, the use of silymarin leads to a significant reduction in liver-related mortality of −7% [OR: 0.54 (0.3–0.9); p < 0.01]. An individual trial reported a reduction in the numberof patients with encephalopathy of −8.7% (p = 0.06). In one study of patients with cirrhosis-related diabetes mellitus, the insulin requirement was reduced by −25% (p < 0.01). We conclude that available evidence suggests that silymarin may play a role in the therapy of (alcoholic) liver cirrhosis.Silymarin is has a good safety record and only rare case reports of gastrointestinal disturbances and allergic skin rashes have been published. This review does not aim to replace future prospective trials aiming to provide the ‘final’ evidence of the efficacy of silymarin.

Essential Oils of Aromatic Plants with Antibacterial, Antifungal, Antiviral, and Cytotoxic Properties – an Overview

The abundant use of anti-infective agents resulted in the emergence of drug-resistant bacteria, fungi, and viruses. To overcome the increasing resistance of pathogenic microbes, a variety of medicinal plants have been screened worldwide for their antimicrobial properties. The aim is to find new, effective antimicrobial agents with novel modes of actions. Essential oils derived from aromatic medicinal plants have been reported to exhibit exceptionally good antimicrobial effects against bacteria, yeasts, filamentous fungi, and viruses. The progress of this expanding scientific field will be documented by the most important results published in the last decade.

Hyperforin a constituent of St John's wort (Hypericum perforatum L.) extract induces apoptosis by triggering activation of caspases and with hypericin synergistically exerts cytotoxicity towards human malignant cell lines

Hyperforin (HP) is an abundant component of St Johns wort with antibiotic and antidepressive activity. We report here the ability of HP and that of polyphenolic procyanidin B2 (PB-2) to inhibit the growth of leukemia K562 and U937 cells, brain glioblastoma cells LN229 and normal human astrocytes. HP inhibited the growth of cells in vitro with GI(50) values between 14.9 and 19.9 microM. The growth inhibitory effect of PB-2 was more pronounced in leukemia cell lines K562 and U937, the GI(50) concentrations being about 12.5 microM established after 48 h incubation differed significantly (P<0.05) from those of LN229 and normal human astrocytes (103.1 and 96.7 microM), respectively. Further, HP and hypericin (HY) (a naphthodianthrone from St Johns wort) acted synergistically in their inhibitory effect on leukemic (K562, U937) cell growth. Cell death occurred after 24 h treatment with HP and PB-2 by apoptosis. A dose-dependent loss of membrane phospholipid asymmetry associated with apoptosis was induced in all cell lines as evidenced by the externalization of phosphatidylserine (PS) and morphological changes in cell size and granulosity by scatter characteristics. In leukemia U937 cells, HP increased the activity of caspase-9 and caspase-3 and in K562 cells caspase-8 and caspase-3. In addition, the broad spectrum caspase inhibitor z-VAD-fmk inhibited both the appearance of PS exposure and the activation of caspases, illustrating the functional relevance of caspase activation during HP-induced apoptosis. Cytocidal effects of HP and its cooperation with HY on tumor growth inhibition in a synergistic manner make the St Johns wort an interesting option in cancer warranting further in vitro and in vivo investigation.

An Updated Systematic Review with Meta-Analysis for the Clinical Evidence of Silymarin

Background: The potential benefit of silymarin (special extract from the fruits of Silybum marianum) in the treatment of liver diseases remains a controversial issue. Methods: For this systematic review electronic databases identified 65 papers for the search terms silymarin, silibinin, silicristin or milk thistle and clinical trial. Only 19 complied with the criteria ‘double-’ or ‘single-blind’. These publications were analysed from a clinical point of view and meta-analytic calculations were performed. Results: The clinical evidence of a therapeutic effect of silymarin in toxic liver diseases is scarce. There is no evidence of a favourable influence on the evolution of viral hepatitis, particularly hepatitis C. In alcoholic liver disease, comparing with placebo, aspartate aminotransferase was reduced in the silymarin-treated groups (p = 0.01) while alkaline phosphatase was not. In liver cirrhosis, mostly alcoholic, total mortality was 16.1% with silymarin vs. 20.5% with placebo (n.s.); liver-related mortality was 10.0% with silymarin vs. 17.3% with placebo (p = 0.01). Conclusions: Based on the available clinical evidence it can be concluded - concerning possible risks / probable benefits - that it is reasonable to employ silymarin as a supportive element in the therapy of Amanita phalloides poisoning but also (alcoholic and grade Child ‘A’) liver cirrhosis. A consistent research programme, consolidating existing evidence and exploring new potential uses, would be very welcome.

Meta-analysis: phytotherapy of functional dyspepsia with the herbal drug preparation STW 5 (Iberogast)

Background : Despite a long‐standing use of herbal drugs with dyspeptic symptoms, little attention has been paid to their clinical evaluation.

An updated systematic review of the pharmacology of silymarin.

Recent years have seen an explosion of scientific papers that deal with drugs from the fruits of milk thistle and its active substances silymarin (standardized mixture of flavonolignanes), thus justifying an updated systematic review. Methods: Electronic databases identified silymarin, silibinin, silicristin or milk thistle as descriptors in >700 papers (34% published in last 5 years; 92% dealt with animal pharmacological). Only papers adequately reporting on experimental conditions, dosing, variables tested and statistics were analysed. Results: Silymarin was found to modify specifically the functions related to various transporters and receptors located in the cell membranes; that is, organic anion uptake transporter peptides (OATP), ABC transporters (P-gp), bile salt export pump, as well as TNF-a-dependent and possibly selectin-dependent phenomena. In the cytoplasm, some antioxidant properties and the inhibition of the lipoxygenase pathway seem quite selective and could concur to the antitoxic effects. Some effects like the inhibition of inducible nitric-oxide synthase, of nuclear factor κ B, and reduction of collagen synthesis are indicative of DNA/RNAmediated effects. Several studies using ‘in vitro’ and ‘in vivo’ cancer models suggest a potential of silymarin in such diseases. Topical and systemic silymarin has skin protective properties against UV-induced damage in epidermis and causes an up-regulation of tumour-suppressor genes p53- and p21CIP1. There were no data on hepatic viral replication, viremia or spontaneous tumours in the data examined. Conclusions: Data presented here do not solve the question about the complex mechanism(s) of action of the medicinal herbal drug silymarin. Silymarin may be a natural multi-functional and multi-target drug.

Cimicifuga racemosa Extract Inhibits Proliferation of Estrogen Receptor-positive and Negative Human Breast Carcinoma Cell Lines by Induction of Apoptosis

Hormone replacement therapy is contraindicated in women with breast cancer. Extracts from the rhizomes of Cimicifuga racemosa, have gained acceptance as a natural alternative for the treatment of menopausal symptoms. In the present study we investigated the antiproliferative activity of C. racemosa extracts (isopropanolic and ethanolic) on the estrogen receptor positive MCF-7 and estrogen receptor negative MDA-MB231 breast cancer cells by WST-1 assay. Down regulation of the proliferative activity and cell killing by isopropanolic and ethanolic extracts occurred in a clear dose-dependent response with a 50% growth inhibitory concentration of 54.1 ± 11.4 and 80.6 ± 17.7 µg/ml in MCF-7 cells and of 29.5 ± 3.0 and 58.6 ± 12.6 µg/ml in MDA-MB231 cells, respectively. Further, the mode of cell death was identified as apoptosis by microscopic inspection and confirmed by light scatter characteristics and by detection of Annexin V adherence to phosphatidylserine by flow cytometry. In addition, the involvement of activated caspases was supported by the cleavage of cytokeratin 18 detected with M30 antibody. Increases in the level of M30-antigen of about 4-fold and 2-fold over untreated controls were observed in C. racemosa-treated MCF-7 and MDA-MB231 cells. These results indicate that C. racemosa extract exerts no proliferative activity, but kills the estrogen receptor positive MCF-7 as well as estrogen receptor negative MDA-MB231 cells by activation of caspases and induction of apoptosis.

Mechanisms Involved in Spontaneous and Viscum album Agglutinin-I-Induced Human Neutrophil Apoptosis: Viscum album Agglutinin-I Accelerates the Loss of Antiapoptotic Mcl-1 Expression and the Degradation of Cytoskeletal Paxillin and Vimentin Proteins Via Caspases

Viscum album agglutinin-I (VAA-I) is a plant lectin that possesses interesting potential therapeutic properties and immunomodulatory activities. We have recently found that VAA-I is a potent inducer of human neutrophil apoptosis, but the mechanism(s) involved require further elucidation. In this study, we found that VAA-I alters mitochondrial transmembrane potential and increases intracellular levels of reactive oxygen species (ROS). Despite these observations, treatment with the mitochondrial stabilizer, bongkrekic acid, or with catalase, known to degrade H2O2, fails to reverse VAA-I-induced apoptosis. Moreover, VAA-I was found to induce apoptosis in PLB-985 cells deficient in gp91phox, indicating that the lectin acts via an ROS-independent mechanism. Pretreatment of neutrophils with brefeldin A, an inhibitor of vesicular transport, was found to reverse VAA-I-induced apoptosis. Protein expression of Mcl-1 was decreased by VAA-I. The role of caspases in the degradation of cytoskeletal proteins during both spontaneous and VAA-I-induced neutrophil apoptosis was also investigated. Paxillin and vimentin were markedly degraded by VAA-I when compared with neutrophils that undergo spontaneous apoptosis, but not vinculin or α- and β-tubulin. Caspases were involved in cytoskeletal protein degradation because preincubation with the pan-caspase inhibitor N-benzyloxycarbonyl-V-A-D-O-methylfluoromethyl ketone was found to reverse protein cleavage. We conclude that VAA-I needs to be internalized to mediate apoptosis and that its activity is not dependent on a cell surface receptor-mediated pathway. Also, we conclude that VAA-I induces apoptosis by ROS-independent and Mcl-1-dependent mechanisms and that caspases are involved in cytoskeletal protein degradation in both spontaneous and VAA-I-induced neutrophil apoptosis.

Effect of a Recombinant Lectin, Viscum album Agglutinin on the Secretion of Interleukin-12 in Cultured Human Peripheral Blood Mononuclear Cells and on NK-Cell-Mediated Cytotoxicity of Rat Splenocytes in vitro and in vivo

A plant lectin, Viscum album agglutinin-I (VAA-I) has been shown to increase the number and cytotoxic activity of natural killer (NK) cells in animal models, but the mechanisms underlying these effects are poorly understood. We investigated the effects of the recombinant form of this lectin (rVAA) on secretion of interleukin (IL)-12 and on NK-mediated cytotoxicity against K562 target cells in cultures of human peripheral blood mononuclear cells (PBMC) as well as against YAC-1 target cells in cultured rat spleen cells. In 24-hour cultures of PBMC, 10 ng/ml plant VAA-I and 50 ng/ml rVAA induced significant increases in the secretion of total IL-12. Its biologically active heterodimeric form, p70, was also significantly induced by rVAA. Preincubation of PBMC or splenocytes for 48 h with rVAA in concentrations ranging between 10 pg/ml and 100 pg/ml resulted in moderate enhancements of NK-mediated cytotoxicity. However, coincubation of a low dose of rVAA (100 pg/ml) together with IL-2 and IL-12 (60 U/ml and 2 U/ml, respectively) led to additive stimulation of NK activity. In in vivo experiments, rVAA showed an enhancing effect on NK activity with a bell-shaped curve of efficacy. Forty-eight hours after a single intravenous injection of its most effective doses, 0.5 and 1 ng/kg, into Wistar rats, the NK cytotoxicity of splenocytes against YAC-1 targets doubled, and the frequency of large granular lymphocytes in peripheral blood showed 2.1- and 3-fold increases as compared to control animals. Twenty-four hours following these low lectin doses, the number of large granular lymphocytes was also significantly elevated. After 48 h, 0.5 ng/kg rVAA induced a significant augmentation in the percentage of peripheral Mac-1+ mononuclear cells, including activated monocytes and NK cells. The present results suggest that rVAA augments the secretion of an active form of IL-12 and potentiates the cytokine-induced NK activation. These effects of rVAA may be related to its stimulatory effects on MHC-unrestricted cytotoxicity in vivo.

Systematic reviews of complementary therapies - an annotated bibliography. Part 2: herbal medicine

BackgroundComplementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with herbal medicine. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of herbal medicines; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pre-tested form and summarized descriptively.ResultsFrom a total of 79 potentially relevant reviews pre-selected in the screening process 58 met the inclusion criteria. Thirty of the reports reviewed ginkgo (for dementia, intermittent claudication, tinnitus, and macular degeneration), hypericum (for depression) or garlic preparations (for cardiovascular risk factors and lower limb atherosclerosis). The quality of primary studies was criticized in the majority of the reviews. Most reviews judged the available evidence as promising but definitive conclusions were rarely possible.ConclusionsSystematic reviews are available on a broad range of herbal preparations prescribed for defined conditions. There is very little evidence on the effectiveness of herbalism as practised by specialist herbalists who combine herbs and use unconventional diagnosis.