STW 5 is effective in dextran sulfate sodium-induced colitis in rats.

PURPOSE: An herbal preparation, STW 5, used clinically in functional dyspepsia and irritable bowel syndrome, has been shown to possess properties that may render it useful in inflammatory bowel disease (IBD). The present work was conducted to study its effectiveness in a rat model of IBD. METHODS: An experimental model reflecting ulcerative colitis in man was adopted, whereby colitis was induced in Wistar rats by feeding them 5 % dextran sulfate sodium (DSS) in drinking water for one week. STW 5 and sulfasalazine (as a reference standard) were administered orally daily for 1 week before colitis induction and continued during DSS feeding. The animals were then sacrificed, and the severity of colitis was evaluated macroscopically and microscopically. Colon samples were homogenized for determination of reduced glutathione, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-3 as well as myeloperoxidase, glutathione peroxidase, and superoxide dismutase. In addition, colon segments were suspended in an organ bath to test their reactivity towards carbachol, KCl, and trypsin. RESULTS: STW 5 and sulfasalazine were both effective in preventing the shortening of colon length and the increase in both colon mass index and total histology score as well as the changes in biochemical parameters measured except changes in dismutase activity. DSS-induced colitis led to marked depression in colonic responsiveness to the agents tested ex vivo, an effect which was normalized by both drugs. CONCLUSIONS: The findings point to a potential usefulness of STW 5 in the clinical setting of ulcerative colitis.

Effect of an herbal preparation, STW 5, in an acute model of reflux oesophagitis in rats.

A multitarget herbal preparation, STW 5, has been used clinically in different gastro-intestinal disorders including functional dyspepsia and irritable bowel syndrome. Previous studies have shown that it possesses properties that may render it useful in gastro-oesophageal reflux disease (GERD). We performed this study to test this compound in an acute model of reflux oesophagitis in rats. Oesophagitis was induced surgically by ligating the pyloric end and fore-stomach. Lower oesophageal pH was measured 3 h later in conscious animals. Five hours after surgery, animals were sacrificed and the oesophagi were examined macroscopically and histologically. Selected markers of inflammation were measured in oesophageal homogenates. STW 5 was given orally for 5 days before induction of oesophagitis. Pantoprazole was used as a reference standard. Ligated animals showed a high incidence of ulcerative lesions associated with a marked increase in myeloperoxidase, thiobarbituric acid-reactive substances, tumor necrosis factor-alpha, and interleukin-1beta. STW 5 did not affect oesophageal pH, but dose-dependently reduced the severity of the oesophageal lesions and normalized the deranged level of the inflammation markers. The beneficial effects were confirmed histopathologically. STW 5 proved to be effective in protecting against inflammatory lesions in this model of oesophagitis, thus warranting further investigation of its potential therapeutic usefulness in GERD.

Anti-inflammatory effects of Phytodolor® (STW 1) and components (poplar, ash and goldenrod) on human monocytes/macrophages.

BACKGROUND: Populus tremula L. (Poplar), Fraxinus excelsior L. (ash) and Solidago virgaurea L. (goldenrod) have been used for medicinal purposes through centuries, to treat pain, fever and inflammation, but their mechanisms of action are still not fully understood. The present study was performed to investigate, whether the herbal medicinal product Phytodolor® (STW 1) and its components have anti-inflammatory effects on activated human monocytes and differentiated human macrophages to elucidate their modes of action in comparison with well-known analgesic, non-steroidal anti-inflammatory drug (NSAIDs) as diclofenac. METHODS: Adherent human monocytes obtained from peripheral blood mononuclear cells (PBMCs) were cultured in serum-free medium and pre-treated with 50-100 µg/ml of diclofenac, STW 1, their components, poplar, ash or goldenrod or its combination (0.05% to 2%). Thereafter, monocytes were activated with 0.1 or 1 µg/ml LPS for 24 h. The intracellular expressions of TNF-α or PTGS2 were determined by cell-based ELISA. Apoptotic cells were identified by YO-PRO-1 staining. Protein or total RNA were isolated to perform SDS-PAGE/Western blot and qRT-PCR analyses. PMA-differentiated human THP-1 macrophages were pre-treated with diclofenac (50 µg/ml) or STW1 (0.1%) and afterwards with LPS (1 µg/ml) and the translocation of the intracellular p62 NF-κB subunit was detected by immunofluorescence. RESULTS: STW 1 inhibited the intracellular content of TNF-α and PTGS2 protein, as well as of TNF-α and PTGS2 gene expression and induced apoptosis in LPS-activated human monocytes under serum free conditions. Furthermore, STW 1 inhibited the translocation of the p65 subunit of the redox-regulated NF-κB into the nucleus in LPS-activated human macrophages. CONCLUSION: The present in vitro investigations suggest a significant anti-inflammatory activity of STW 1 and its components by inhibiting pro-inflammatory cytokine as TNF-α and the key enzyme PTGS2 in LPS-activated human monocytes, which is, at least partly mediated through the suppression of NF-κB activation. Our results provide evidence for distinctive anti-inflammatory effects of STW 1 and its components on LPS-activated human monocytes/macrophages and, thus, for the therapeutic use of STW 1 in inflammation and pain related disorders.

Downregulation of ß1 -adrenergic receptors in rat C6 glioblastoma cells by hyperforin and hyperoside from St John's wort.

OBJECTIVES: While the use of St John's wort extracts as treatment for mild to moderate depression is well established the mode of action is still under investigation. Individual constituents of St John's wort extract were tested for possible effects on the ß1 AR density and a subsequent change in downstream signalling in rat C6 glioblastoma cells. METHODS: The effect of compounds from St John's wort extract on the downregulation of ß1 -adrenergic receptor-GFP fusion proteins (ß1 AR-green fluorescent protein (GFP)) of transfected rat C6 gliobastoma cells (C6-ß1 AR-GFP) was investigated by means of confocal laser scanning microscopy (LSM). The influence on the lateral mobility of ß1 AR-GFP in C6-ß1 AR-GFP was investigated by fluorescence correlation spectroscopy. The formation of second messenger was determined by c-AMP-assay. KEY FINDINGS: Confocal LSM revealed that pretreatment of cells with 1 µm of hyperforin and hyperoside for 6 days, respectively, led to an internalization of ß1 AR-GFP under non-stimulating conditions. Observation by fluorescence correlation spectroscopy showed two diffusion time constants for control cells, with τdiff1 = 0.78 ± 0.18 ms and τdiff2 = 122.53 ± 69.41 ms, similarly distributed. Pretreatment with 1 µm hyperforin or 1 µm hyperoside for 3 days did not alter the τdiff values but decreased the fraction of τdiff1 whereas the fraction of τdiff2 increased significantly. An elevated level of ß1 AR-GFP with hindered lateral mobility was in line with ß1 AR-GFP internalization induced by hyperforin and hyperoside, respectively. A reduced ß1 -adrenergic responsiveness was assumed for C6 gliobastoma cells after pretreatment for 6 days with 1 µm of both hyperforin and hyperoside, which was confirmed by decreased cAMP formation of about 10% and 5% under non-stimulating conditions. Decrease in cAMP formation by 23% for hyperforin and 15% for hyperoside was more pronounced after stimulation with 10 µm dobutamine for 30 min. CONCLUSIONS: The treatment of C6 gliobastoma cells with hyperforin and hyperoside results in a reduced ß1 AR density in the plasma membrane and a subsequent reduced downstream signalling.

Adenosine A2A receptor contributes to the anti-inflammatory effect of the fixed herbal combination STW 5 (Iberogast®) in rat small intestinal preparations.

STW 5 (Iberogast®), an established herbal combination, was effective in randomized, double blind clinical studies in functional dyspepsia and irritable bowel syndrome. Since STW 5 was found to influence intestinal motility and has anti-inflammatory properties, this study investigated the expression of adenosine receptors and characterized their role in the control of the anti-inflammatory action of STW 5 and its fresh plant component STW 6 in inflammation-disturbed rat small intestinal preparations. The inflammation was induced by intraluminal instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 0.01 M). The effects of coincubation with selective receptor agonists and antagonists, STW 5, STW 6, or combinations of these compounds on acetylcholine (ACh)-evoked contraction of ileum/jejunum preparations were tested. Adenosine receptor mRNA expression was examined by reverse transcription-polymerase chain reaction (RT-PCR). In untreated preparations, RT-PCR revealed the presence of all adenosine receptor subtypes. Suppressed expression was detected for all subtypes in inflamed tissues, except for A(2B)R mRNA, which was unaffected. STW 5 reversed these effects and enhanced A(2A)R expression above control levels. Radioligand binding assays confirm the affinity of STW 5 to the A(2A)R, and the A(2A)R antagonist was able to prevent the effect of STW 5 on TNBS-induced attenuation of the ACh contraction. Our findings provide evidence that STW 5, but not STW 6 interacts with A(2A)R, which is involved in the anti-inflammatory action of STW 5. STW 6 did not contribute to adenosine A(2A)R-mediated anti-inflammatory effect of STW 5. Other signaling pathways could be involved in the mechanism of action of STW 6.

In vitro anti-proliferative effects of the willow bark extract STW 33-I.

The well-known anti-inflammatory and analgesic effects of the phytopharmacon willow bark extract have been attributed to the content of salicin; however, pharmacological studies have shown that salicin alone, despite being involved in its therapeutic action, cannot fully explain its clinical efficacy. In addition to reducing inflammation and pain, acetylsalicylic acid (ASA, CAS 50-78-2), like other synthetic non-steroidal anti-inflammatory drugs (NSAIDs), has been shown to exert anti-proliferative effects and to induce apoptosis in a variety of cell lines, e.g., colon, stomach, and prostate cancer cells. To investigate the mechanism of action and possible anti-proliferative and proapoptotic effects of willow bark, a water extract (STW 33-I) and a polyphenol rich fraction (fraction E) have been tested by using the colon-carcinoma cell line HT-29. Both, STW 33-I and its fraction E showed significant anti-proliferative and (1) Introduction The most well-known component of willow bark extract is salicin, which is metabolized in vivo to salicylic acid. The standardized aqueous willow bark extract STW 33-I, which is an effective analgesic and anti-inflammatory drug, contains 23-26% total salicin derivatives and additionally flavonoids, condensed tannins and polyphenols. Typical representatives of the flavonoids are glycosides of naringenin, isosalipurpuroside or eriodictyol. In vitro experiments have demonstrated for pro-apoptotic effects on HT-29 cancer cells. Related to the salicin content of the willow bark extract, a higher dosage of ASA was needed. Furthermore, compared to ASA and to diclofenac (Diclo, CAS 15307-79-6), the COX-1 and COX-2 mRNA expressions were influenced differently by STW 33-I and fraction E. ASA and Diclo inhibited both the COX-1 and COX-2 mRNA expressions, whereas STW 33-I and its fraction E increased the COX-1 mRNA expression. In addition to the already well-known anti-inflammatory and analgesic effects, willow bark extract has been found to possess anti-proliferative and pro-apoptotic effects similar to NSAIDs. The different influence of willow bark on the COX-1 and COX-2 mRNA expressions in comparison to NSAIDs might be relevant, e.g., for prevention of undesirable side effects such as gastric erosions.

Cholesterol diet and effect of long-term withdrawal on plaque development and composition in the thoracic aorta of New Zealand White rabbits.

AIMS: Experimental study on plaque progression, regression and composition in atherosclerotic thoracic aorta of hypercholesterolemic rabbits after long-term withdrawal of cholesterol-enriched diet (CED). METHODS: Rabbits were fed 2% cholesterol for 6 weeks followed by withdrawal periods for 15, 23, 34, 68, or 78 weeks. Cholesterol, triglyceride, and phospholipids levels in blood and cholesterol concentrations in aorta were quantified. Plaque size and cellularity, phenotype of macrophages and smooth muscle cells were (immuno)histomorphometrically analyzed in segments of the thoracic aorta. RESULTS: After 6 weeks of CED, blood cholesterol levels were about 80-fold higher, whereas atherosclerosis and cholesterol content in the thoracic aorta were only minimally increased. However, the latter significantly increased within 15 weeks after cholesterol withdrawal, while serum cholesterol level was still 10-fold increased. Thereafter plaque area and cholesterol content remained almost unchanged until the end of the study despite a long-term normalization of serum cholesterol level after withdrawal of CED. Directly after 6 weeks of CED the densities of macrophages and apoptotic cells within plaques were highest, decreasing after cholesterol withdrawal, whereas, vice versa the density of smooth muscle cells (SMCs) significantly increased. CONCLUSION: We suggest that atherosclerotic plaques respond to long-term withdrawal of CED by decrease in number and phenotype of macrophages and increase of SMCs without regression of the lesion size. The cellular changes are suggested to considerably contribute to higher plaque stability.

Glutamate-induced cell death in neuronal HT22 cells is attenuated by extracts from St. John's wort (Hypericum perforatum L.).

Glutamate-induced cell death of hippocampal HT22 cells is a model system for neuronal disorders due to depletion of glutathione levels and increase of intracellular reactive oxygen species. Standardized extracts of Hypericum perforatum (HPE) contain flavonoids known for antioxidative properties. In the above model, cytoprotective effects at a concentration of 0.05% HPE by attenuation of calcium fluxes and cellular energy statuses are reported.

Reduction of high-affinity beta2-adrenergic receptor binding by hyperforin and hyperoside on rat C6 glioblastoma cells measured by fluorescence correlation spectroscopy.

Beta-adrenergic receptors (beta-AR) are potential targets for antidepressants. Desensitization and downregulation of beta-AR are discussed as possible modes of action for antidepressants. We have investigated the effects of hyperforin and hyperoside, compounds with potentially antidepressant activity from St. John's Wort, on the binding behavior and dynamics of beta2-AR in living rat C6 glioblastoma cells, compared to desipramine (desmethylimipramine; DMI) by means of fluorescence correlation spectroscopy (FCS) and fluorescence microscopy. FCS-binding studies with the fluorescently labeled ligand Alexa532-noradrenaline (Alexa532-NA) binding to beta2-AR of C6 cells showed a significant reduction in total beta2-AR binding after preincubation with hyperforin and hyperoside for 3 days, respectively, which was also found for DMI. This was mainly observed in high-affinity receptor-ligand complexes with hindered lateral mobility (D2 = 1.1 (+/-0.4) microm2/s) in the biomembrane. However, internalization of beta2-AR was found neither in z-scans of these C6 cells nor in HEK 293 cells stably transfected with GFP-tagged beta2-adrenergic receptors (beta2AR-GFP) after incubation up to 6 days with either DMI, hyperforin, or hyperoside. Thus, under these conditions reduction of beta2-AR binding was not mediated by receptor internalization. Additionally, preincubation of C6 cells with DMI, hyperforin, and hyperoside led to a loss of second messenger cAMP after beta2-adrenergic stimulating conditions with terbutaline. Our current results indicate that hyperforin and hyperoside from St. John's Wort, as well as DMI, reduce beta2-adrenergic sensitivity in C6 cells, emphasizing the potential usefulness of St. John's Wort dry extracts in clinical treatment of depressive symptoms.

Investigation of the effect on photosensitivity following multiple oral dosing of two different hypericum extracts in healthy men.

The naphthodiantrones hypericin and pseudohypericin, ingredients of hypericum extracts, are known as potent photosensitizers that may cause phototoxic effects in grazing animals after excessive ingestion of hypericum species and in some cases in higher concentrations of hypericum extracts oder pure hypericin in humans as well. Therefore, the objective of the present studies was to investigate the effect of two different hypericum extracts (STW 3, STW 3-VI) on photosensitivity with respect to minimal erythema dose (MED) after 14 days treatment. Both open, multiple-dose, one-phase studies were conducted in 20 healthy men, receiving one tablet per day. MED values were determined prior to hypericum extract administration (baseline) and after 14 days treatment using an erythem tester emitting a light very similar to sun light (main emission spectrum: 285-350 nm). Skin reactions with respect to MED were evaluated 12 h, 24 h (primary endpoint), 48 h and 7 days after irradiation. All volunteers reached steady-state of hypericin/pseudohypericin plasma concentrations before study day 14, when the irradiation under treatment conditions took place. In all subjects MED was measurable under baseline and under hypericum treatment conditions. With respect to the primary endpoint, in both studies, mean MED (24 h) were not significantly different between baseline and after 14 days hypericum treatment. However, individually photosensitivity of the skin could increase under treatment conditions, just as well photosensitivity could decrease or remain unchanged. There were no clinically relevant changes in the laboratory parameters, the vital signs, physical findings and other observations related to safety during the examinations. In one study (STW 3), two adverse events were reported, both described as hypersensitivity to light in mild Intensity. The two studies showed that treatment with the two hypericum extracts under steady state and under prescribed conditions were safe medications without significant increases of photosensitivity.

Investigation of pharmacokinetic data of hypericin, pseudohypericin, hyperforin and the flavonoids quercetin and isorhamnetin revealed from single and multiple oral dose studies with a hypericum extract containing tablet in healthy male volunteers.

Hypericins, hyperforin and flavonoids are discussed as the main components contributing to the antidepressant action of St. John's wort (Hypericum perforatum). Therefore, the objective of the two open phase I clinical trials was to obtain pharmacokinetic data of these constituents from a hypericum extract containing tablet: hypericin, pseudohypericin, hyperforin, the flavonoid aglycone quercetin, and its methylated form isorhamnetin. Each trial included 18 healthy male volunteers who received the test preparation, containing 900 mg dry extract of St John's wort (STW 3-VI, Laif 900), either as a single oral dose or as a multiple once daily dose over a period of 14 days. Concentration/time curves were determined for the five constituents, for 48 h after single dosing and for 24 h on day 14 at the end of 2 weeks of continuous daily dosing. After single dose intake, the key pharmacokinetic parameters were determined as follows: Hypericin: Area under the curve (AUC(0-infinity)) = 78.33 h x ng/ml, maximum plasma concentration (Cmax) = 3.8 ng/ml, time to reach Cmax (tmax) = 7.9 h, and elimination half-life (t1/2) = 18.71 h; pseudohypericin: AUC(0-infinity) = 97.28 h x ng/ml, Cmax = 10.2 ng/ml, tmax = 2.7 h, t1/2 = 17.19 h; hyperforin: AUC(0-infinity) = 1550.4 h x ng/ml, Cmax = 122.0 ng/ml, tmax = 4.5 h, t1/2 = 17.47 h. Quercetin and isorhamnetin showed two peaks of maximum plasma concentration separated by about 3-3.5 h. Quercetin: AUC(0-infinity) = 417.38 h x ng/ml, Cmax (1) = 89.5 ng/ml, tmax (1) = 1.0 h, Cma (2) = 79.1 ng/ml, tmax (2) = 4.4 h, t1/2 = 2.6 h; isorhamnetin: AUC(0-infinity) = 155.72 h x ng/ml, Cmax (1) = 12.5 ng/ml, tmax (1) = 1.4 h, Cmax (2) = 14.6 ng/ml, tmax (2) = 4.5 h, t1/2 = 5.61 h. Under steady state conditions reached during multiple dose administration similar results were obtained. Further pharmacokinetic characteristics calculated from the obtained data were the mean residence time (MRT), the lag-time, the peak-trough fluctuation (PTF), the lowest observed plasma concentration (Cmin), and the average plasma concentration (Cav). The data obtained for the five consitituents generally corresponded well with values previously published. The trial preparation was well tolerated.

Investigation of the bioavailability of hypericin, pseudohypericin, hyperforin and the flavonoids quercetin and isorhamnetin following single and multiple oral dosing of a hypericum extract containing tablet.

The objective of these two open phase I clinical trials was the investigation of the bioavailability of five constituents from a hypericum extract containing tablet, which are discussed as the components contributing to the antidepressant action. Each trial included 18 healthy male volunteers who received the test preparation, containing 612 mg dry extract of St John's wort (STW-3, Laif 600), either as a single oral dose or as a multiple once daily dose over a period of 14 days. Concentration/time curves were determined for hypericin, pseudohypericin, hyperforin, the flavonoid aglycone quercetin, and its methylated form isorhamnetin for 48 h after single dosing and for 24 h on day 14 at the end of 2 weeks of continuous daily dosing. After single dose intake, the key pharmacokinetic parameters were determined as follows: hypericin: area under the curve (AUC(0-infinity)) = 75.96 h x ng/ml, maximum plasma concentration (Cmax) = 3.14 ng/ml, time to reach Cmax (t(max)) = 8.1 h, and elimination half-life (t1/2) = 23.76 h; pseudohypericin: AUC(0-infinity) = 93.03 h x ng/ml, Cmax = 8.50 ng/ml, t(max) = 3.0 h, t1/2 = 25.39 h; hyperforin: AUC(0-max) = 1009.0 h x ng/ml, Cmax = 83.5 nglml, t(max) = 4.4 h, t1/2 = 19.64 h. Quercetin and isohamnetin showed two peaks of maximum plasma concentration separated by about 4 h. Quercetin: AUC(0-infinity) = 318,7 h x ng/ml, Cmax (1) = 47.7 ng/ml, t(max) (1) = 1.17 h, Cmax (2) = 43.8 ng/ml, t(max) (2) = 5.47 h, t1/2 = 4.16 h; isorhamnetin: AUC(0-infinity) = 98.0 h x ng/ml, Cmax (1) = 7.6 ng/ml, t(max) (1) = 1.53 h, Cmax (2) = 9.0 ng/ml, t(max), (2) = 6.42 h, t1/2 = 4.45 h. Under steady state conditions reached during multiple dose administration similar results were obtained. Further pharmacokinetic characteristics calculated from the obtained data were the mean residence time (MRT), the lag-time, the peak-trough fluctuation (PTF), the lowest observed plasma concentration (Cmin), and the average plasma concentration (Cav). The data obtained for hypericin, pseudohypericin and hyperforin generally corresponded well with values previously published, with some deviations observed for the extent of absorption of hypericin and the time course of absorption and elimination of hyperforin. The kinetic characteristics of the hypericum flavonoids are reported here for the first time. The trial preparation was well tolerated.

Mechanisms involved in the anti-inflammatory effect of a standardized willow bark extract.

A standardized willow bark extract (STW 33-I) has been examined to clarify its possible mechanism of action as an anti-inflammatory agent. Various facets have been investigated in two inflammation models: the 6-day air pouch model in rats, representing the acute state and the adjuvant induced arthritis representing the chronic one. Parameters included leukocytic infiltration, levels of cytokines and prostanoids in blood, and effects on cyclo-oxygenase (COX)-1 and/or COX-2 enzymes as well as effects involving free radical production. The effect of the extract was compared at two dose levels with comparable anti-inflammatory doses of acetylsalicylic acid (CAS 50-78-2, ASA) as a non-selective COX inhibitor, and celecoxib (CAS 169590-42-5) as a selective COX-2 inhibitor. On a mg/kg basis, the extract was at least as effective as ASA in reducing inflammatory exudates and in inhibiting leukocytic infiltration as well as in preventing the rise in cytokines, and was more effective than ASA in suppressing leukotrienes, but equally effective in suppressing prostaglandins. On COX-2, STW 33-I was more effective than ASA. The present findings show that STW 33-I significantly raises GSH (reduced glutathione) levels, an effect which helps to limit lipid peroxidation. The extract was more potent than either ASA or celecoxib. Higher doses of the extract also reduced malondialdehyde levels and raised shows definite superiority to either ASA or celecoxib in protecting the body against oxidative stress. It is therefore evident that STW 33-I is at least as active as ASA on all the parameters of inflammatory mediators measured, when both are given on a similar mg/kg dose. Considering, however, that the extract contains only 24% salicin (molecular weight 286.2), while ASA has a molecular weight of 180.3, it follows that on a molar basis of salicin vs salicylate, the extract contains less than a sixth of the amount of salicin as the amount of salicylate in ASA. Thus it appears that STW 33-I with its lower "salicin" content than an equivalent dose of ASA, is at least as active as ASA on the measured parameters, a fact that leads one to speculate that other constituents of the extract contribute to its overall activity. The presence of polyphenols in STW 33-I probably plays a significant role in enhancing its free radical scavenging properties. The fact that STW 33-I was superior to ASA in this respect would suggest that the extract may have a better anti-inflammatory effect than ASA on a weight to weight basis, with possibly less side effects.

Antioxidative properties of Iberis amara extracts in biochemical model reactions.

Gastro-intestinal disorders such as the non-ulcer dyspepsia and irritable bowel syndrome expatiate on/with inflammatory processes of the gastro-intestinal mucosa. Iberogast is used in treatment of such disorders. Iberis amara L. extract (IAE) is one of nine components of the drug. There is increasing evidence that mediators of inflammation processes in the stomach and intestine include reactive oxygen species (ROS), arising from several enzymic reactions characteristic for inflammatory events. In this study it was shown that Iberis amara extract (STW 6) has the potential for scavenging ROS, dependent on the individual test system. Biochemical model reactions relevant for the formation of ROS in vivo at inflammatory sites were used. Inhibition of the formation of ROS could be shown to be excellent in test systems known to preferentially produce reactive species (myeloperoxidase-generated HOCl, peroxynitrite) with high affinities to sulfur-containing compounds, e.g. mustard oil glycosides such as glucoiberin. Furthermore ROS, generated during xanthine oxidase (XOD)-catalysed oxidation of xanthine into uric acid, were also efficiently decreased by IAE. However, an inhibition of XOD could be excluded, but chelation of metal ions (Fe, Cu) decreasing their redox-cycling activities seems to play a role. A major activity of IAE proved to represent inhibition of lipid peroxidation processes, shown as delay of the lag phase of the Cu(II)-induced LDL oxidation as well as protection of alpha-linolenic acid from peroxidation by singlet oxygen.

Comparison of the inhibition of myeloperoxidase-catalyzed hypochlorite formation in vitro and in whole blood by different plant extracts contained in a phytopharmacon treating functional dyspepsia.

Ethanolic extracts from nine medicinal plants are combined in Iberogast (IG). This phytomedicine is successfully used in the treatment of gastrointestinal disorders. Functional gastrointestinal diseases such as non-ulcerous dyspepsia (NUD) are in many cases initiated by, or correlated to, inflammatory processes, where reactive oxygen species (ROS) play a crucial role. In this respect one prominent source of ROS are myeloperoxidase (MPO)-driven oxidation and chlorination reactions, assumed to be mainly responsible for tissue damage. In this study the contribution of the nine extracts to the overall performance of IG was compared with emphasis on MPO produced ROS. Concerning the influence on MPO-dependent chlorination reactions, it turned out that of the nine IG-components Iberis amara extract (IAE) exerted the highest activity. Furthermore, this can impressively be reproduced in an ex vivo experiment with whole blood, where neutrophilic leukocytes are activated by zymosan. Moreover, along with the extract of chamomile flowers, IAE counteracts the pro-oxidative properties of caraway, peppermint and celandine. As a consequence. IG was also efficiently inhibiting MPO-catalysed chlorinations. As shown by the addition of catalase, the pro-oxidative effects of caraway, peppermint and celandine are due to their content of hydrogen peroxide. The latter is probably an autoxidation product of certain monoterpenes in the essential oil part of these extracts. If one of the component extracts of IG is omitted, the antioxidant acitivity is reduced. Thus we conclude that all the single extracts combined in IG are of importance for the therapeutical effect, working in concert.