Contribution of flavonoids and catechol to the reduction of ICAM-1 expression in endothelial cells by a standardised Willow bark extract.

INTRODUCTION: A quantified aqueous Willow bark extract (STW 33-I) was tested concerning its inhibitory activity on TNF-α induced ICAM-1 expression in human microvascular endothelial cells (HMEC-1) and further fractionated to isolate the active compounds. RESULTS: At 50 µg/ml the extract, which had been prepared from Salix purpurea L., decreased ICAM-1 expression to 40% compared to control cells without showing cytotoxic effects. Further liquid-liquid partition revealed an ethyl acetate phase with potent reduction of ICAM-1 expression to 40% at 8 µg/ml. This fraction was comprehensively characterised by the isolation of flavanone aglyca and their corresponding glycosides, chalcone glycosides, salicin derivatives, cyclohexane-1,2-diol glycosides, catechol and trans-p-coumaric acid. All compounds were investigated for their activity on TNF-α induced ICAM-1 expression. The flavonoid and chalcone glycosides were not active up to 50 µM, whereas catechol and eriodictyol at the same concentration showed a significant reduction of ICAM-1 expression to 50% of control. Interestingly, other isolated flavanone aglyca like taxifolin, dihydrokaempferol and naringenin showed only weak or moderate inhibitory activity. Eriodictyol was a minor compound in the extract, whereas the catechol content in the extract (without excipients) reached 2.3%, determined by HPLC. One of the isolated cyclohexan-1,2-diol glucosides, 6'-O-4-hydroxybenzoyl-grandidentin, is a new natural compound. CONCLUSION: As catechol is quantitatively important in Willow bark extracts it can be concluded from the in vitro data that not only flavonoids and salicin derivatives, but also catechol can probably contribute to the anti-inflammatory activity of Willow bark extracts.

Mechanisms involved in the gastro-protective effect of STW 5 (Iberogast) and its components against ulcers and rebound acidity.

The protective effect of a commercial preparation (STW 5, Iberogast), containing the extracts of bitter candy tuft, lemon balm leaf, chamomile flower, caraway fruit, peppermint leaf, liquorice root, Angelica root, milk thistle fruit and greater celandine herb, against the development of gastric ulcers was previously reported in an earlier publication (Khayyal et al., 2001). All extracts produced a dose dependent anti-ulcerogenic effect associated with a reduced acid output, an increased mucin secretion, an increase in prostaglandin E(2) release and a decrease in leukotrienes. The effect on pepsin content was not uniform and did not seem to bear a relationship with the anti-ulcerogenic activity. The best effects were observed with the combined formulation, STW 5. Furthermore, the effect of the latter in protecting against the development of rebound gastric acidity was examined experimentally in rats and compared with the effect of some commercial antacid preparations (Rennie, Talcid and Maaloxan). A model of testing rebound acidity was developed by inducing a marginal increase in gastric acidity through the administration of indomethacin, in such a way that it could be easily neutralized, allowing any eventual secondary increase in acidity to be measured within a few hours of administration. In addition, the serum gastrin level was measured after drug treatment to establish any correlation between it and any rebound acidity. The results obtained demonstrated that STW 5 did not only lower the gastric acidity as effectively as the commercial antacid, but it was more effective in inhibiting the secondary hyperacidity. Moreover, STW 5 was capable of inhibiting the serum gastrin level in rats, an effect which ran parallel to its lowering effect on gastric acid production.

Spasmolytic and tonic effect of Iberogast (STW 5) in intestinal smooth muscle.

STW 5 (Iberogast) is a fixed combination of nine medicinal plant extracts effective in the treatment of functional dyspepsia and irritable bowel syndrome. The effects of STW 5, a combination of Iberis amara fresh plant extract, and other eight plant extracts as well as single extract components including extracts from Menthae piperitae folium, Matricariae flos and Liquiritiae radix, were assayed in guinea pig ileum with or without stimulation with acetylcholine or histamine, in order to find a possible effect on the contractility of intestinal smooth muscle. STW 5 decreased acetylcholine- and histamine-induced contraction of guinea pig ileum. This was also true for extracts of Menthae piperitae folium, Matricariae flos and L. radix. Extract from I. amara, however, showed no spasmolytic action; in contrary, it increased the basal resting tone and contraction of atonic ileal segments. This was also true when STW 5 was employed. A spasmolytic action of STW 5 could also be observed in duodenum, jejunum and colon. These data are the first to show not only the spasmolytic effects of STW 5 and its component extracts in intestinal muscle but also the tonicising effects of STW 5 through its component Iberis amara extract in relaxed intestinal muscle. Thus, pharmacological evidence suggests a dual-action principle and may explain, at least in part, the clinically observed therapeutic efficacy of STW 5 (Iberogast) in both hypotonic and spastic dysmotility symptoms of functional dyspepsia and irritable bowel syndrome.

Binding of STW 5 (Iberogast) and its components to intestinal 5-HT, muscarinic M3, and opioid receptors.

Clinical studies with the fixed herbal combination product STW 5 (Iberogast) have indicated an efficacy comparable to metoclopramide (5-HT(3) antagonist) and cisapride (5-HT(4) agonist) in functional gastro-intestinal diseases like functional dyspepsia (FD) and irritable bowel syndrome (IBS). Since serotonin (5-HT(3) and 5-HT(4)) and muscarinic M(3) receptors are known to play a central role in the etiology of FD and IBS, the extracts contained in STW 5 and several of their phytochemical components were studied in vitro for binding affinities to these receptors of the intestine. STW 5 inhibited the binding of (3)H-GR113808 and (3)H-4-DAMP to 5-HT(4) and M(3) receptors, respectively, about 10 times more potently than the binding of (3)H-GR65630 to 5-HT(3) receptors. IC(50) values for STW 5 did correspond to extract dilutions of 1:1000 (M(3) binding) and 1:2000 (5-HT(4) binding). In addition, STW 5 also potently inhibited the binding to opioid receptors with an IC(50) value of 1:2000. Of the nine herbal extracts contained in STW 5, the fresh plant extract of bitter candy tuft (Iberis amara) selectively inhibited binding to M(3) receptors, while ethanolic extracts of celandine herb and chamomile flower were selective to 5-HT(4), and liquorice root to 5-HT(3) receptors. Binding affinities to human recombinant 5-HT(3), 5-HT(4) and M(3) receptors were qualitatively similar to those of the corresponding intestinal receptors. The benzylisoquinoline alkaloid berberine had significant inhibitory action on 5-HT(4) and M(3) binding, showing IC(50) values of 40 ng/ml (100 nM) and 200 ng/ml (500 nM), respectively, but is present in the extract of celandine herb only in traces, so that also for the celandine extract a cooperative effect of several phytochemical constituents can be assumed. These in vitro data indicate that 5-HT(4) (to a lesser degree 5-HT(3)), muscarinic M(3), and opioid receptors represent target sites for the treatment of FD and IBS with STW 5 (Iberogast).

Ex vivo/in vitro absorption of STW 5 (Iberogast) and its extract components.

To correlate the pharmacological effects of the fixed herbal combination STW 5 (Iberogast) containing nine extract components with its confirmed clinical efficacy, ex vivo/in vitro absorption tests were performed. For the investigation, the everted gut sac technique and, in a pilot study, the Caco-2-cell model were used. The absorption rate of the extracts was determined by measuring characteristic marker substances of each of the individual extracts using HPLC or GC techniques. The results allow us to conclude that the investigated substances from STW 5 possess a good bioavailability, which is in accordance with the rapid onset of the therapeutic efficacy and explains its known pharmacological effects and clinical efficacy in terms of multiple drug action and multi-target therapy, respectively.

Antiulcerogenic effect of some gastrointestinally acting plant extracts and their combination.

Extracts from the plants Iberis amara, Melissa officinalis, Matricaria recutita, Carum carvi, Mentha x piperita, Glycyrrhiza glabra, Angelica archangelica, Silybum marianum and Chelidonium majus, singly and combined in the form of a commercial preparation, STW 5 (Iberogast) and a modified formulation, STW 5-II, lacking the last 3 constituents, were tested for their potential anti-ulcerogenic activity against indometacin induced gastric ulcers of the rat as well as for their antisecretory and cytoprotective activities. All extracts produced a dose dependent anti-ulcerogenic activity associated with a reduced acid output and an increased mucin secretion, an increase in prostaglandin E2 release and a decrease in leukotrienes. The effect on pepsin content was rather variable and did not seem to bear a relationship with the anti-ulcerogenic activity. The most beneficial effects were observed with the combined formulations STW 5 and STW 5-II in a dose of 10 ml/kg b.w., comparable with cimetidine in a dose of 100 mg/kg b.w. The anti-ulcerogenic activity of the extracts was also confirmed histologically. The cytoprotective effect of the extracts could be partly due to their flavonoid content and to their free radical scavenging properties.

Effect of magnesium pyridoxal 5-phosphate glutamate on vascular reactivity in experimental hypercholesterolemia.

Hypercholesterolemia is known to affect the responsiveness of various blood vessels to endogenous and to exogenous vasoactive agents. Of particular interest is the increased responsiveness to vasoconstrictors, e.g., 5-hydroxy tryptamine and noradrenaline, and the decreased reactivity towards vasodilators, e.g., acetylcholine. This, together with the development of arteriosclerosis, could play an important role in the progression of many vascular complications, such as hypertension and coronary heart disease. Magnesium pyridoxal 5-phosphate glutamate (MPPG) has been shown to effectively reduce serum lipids in animals and in man, and to retard the progression of atherosclerotic lesions in experimental animals. It was therefore considered of interest to investigate the reactivity of both the aorta and the renal artery to different vasoactive substances in hypercholesterolemic rabbits under the influence of MPPG as well as the effect of such substances on the blood pressure of the anesthetized animals. The rabbits were fed a high cholesterol diet for 2 months, followed by MPPG for 1 month, while keeping the rabbits on the same diet. One batch of animals was used for blood pressure recording and testing drug effects, and another was used for testing the responsiveness of their aortae and renal arteries to the different mediators. In hypercholesterolemic rabbits, treatment with MPPG tended to normalize the increased responsiveness of the blood pressure to the vasoconstrictors: noradrenaline and angiotensin and the diminished sensitivity to histamine and acetylcholine. For the isolated arteries, however, MPPG did not significantly affect the responses to noradrenaline nor potassium chloride, but tended to normalize responses to clonidine and acetylcholine. It could be concluded from the present findings that the high cholesterol diet induces changes in vascular reactivity which are possibly related to endothelial and/or receptor sensitivity changes. Treatment with MPPG helps to reverse these changes and to restore normal vascular reactivity, a fact that could have important clinical implications in the management of cardiovascular diseases.

Study of the anti-inflammatory activity of Populus tremula, Solidago virgaurea and Fraxinus excelsior.

Aqueous/alcoholic extracts of Populus tremula, Solidago virgaurea and Fraxinus excelsior (components of Phytodolor N) were tested individually and in 3 different combinations for anti-inflammatory activity using carrageenan induced edema and/or adjuvant induced arthritis of the rat paw. The tested combinations as well as the individual extracts significantly reduced the paw edema to varying degrees and also dose dependently inhibited the arthritic paw volume. The anti-inflammatory activity of the combinations was respectively comparable to the tested doses of diclofenac.

[Genotoxicity of a standardized Hypericum extract]. / Genotoxizität eines standardisierten Hypericum-Extraktes.

St. John's wort (Hypercum perforatum) contains hypericin and hypericin-like substances as well as flavonoids, of which particularly Quercetin has generated a wide-spread controversial discussion with respect to mutagenic action. The genotoxicity of a standardized aqueous ethanolic Hypericum extract (Hypericum extract Steigerwald, Psychotonin M) was verified in different in-vivo and in-vitro testsystems with mammalian cells. The in-vitro investigations were performed with the HGPRT (hypoxanthine guanidine phosphoribosyl transferase)-test, UDS (unscheduled DNA synthesis)-test and with the cell transformation test using Syrian hamster embryo cells. Both the in-vitro tests as well as the in-vivo tests--fur spot test of the mouse and the chromosome aberration test with the bone marrow cells of the chinese hamster--were negative, giving completely no indication of a mutagenic potential of Hypericum extract. These investigations lend support to the view that results from bacterial short-term tests are of very limited transferability to human.

[Modification of avian humoral immunoreactions by Influex and Echinacea angustifolia extract]. / Beeinflussung der aviären humoralen Immunreaktionen durch Influex und Echinacea Angustifolia Extrakt.

Medicinal complex drugs as well as single ethanolic or aqueous extracts of several plants are commonly used to increase the natural resistance to various infections, though their efficacy and mechanism of action are not yet well elucidated. In the present study, we investigated two problems: firstly, whether the complex drug (Influex) and Echinacea angustifolia extract do stimulate the immunoglobulin and antibody synthesis in chickens immunized with human serum albumin; and secondly, whether a restoration of IgG-synthesis in immunodefective (dysgammaglobulinemic) UM-B 19 chickens is possible with these plant preparations, i.e. if the BG cells which may possibly be present can be polyclonally or antigen specifically stimulated. The preparations were administered orally in two doses, after which the complete immunoglobulin concentration was determined by rocket immunoelectrophoresis and the antibody production by ELISA. The effect of ethanolic solvent was taken into account. The administration of the complex drug to normal Leghorn chickens induced a rise in the serum immunoglobulin concentration, as well as an increase in the three classes of antibody. By the immunodeficient chickens (IgG concentration was below the level of test sensitivity at the start), the administration of the drug led to a slight production in IgG and antibody.

[Anti-inflammatory, analgesic and antipyretic effect of various plant extracts and their combinations in an animal model]. / Antiphlogistische, analgetische und antipyretische Wirkung unterschiedlicher Pflanzenextrakte und deren Kombination im Tiermodell.

Antiinflammatory, Analgesic and Antipyretic Effects of Various Plant Extracts and a Combination Thereof in Animal Models. The three main components comprising the efficacy of non-steroidal antiinflammatory drugs could be demonstrated for STW 1 in different animal models. The phytotherapeutic preparation, containing three individual plant extracts (Populus tremula, Solidago virgaurea, Fraxinus excelsior) produced dose-dependent antiinflammatory, analgesic and antipyretic effects which were similar to those of the reference substances salicyl alcohol and indometacin. As each of the individual extracts displayed considerable efficacy, it may be assumed that each of them contributes to the overall effects of the combination STW 1.

[Animal experiments on the psychotropic action of a Hypericum extract]. / Tierexperimentelle Untersuchunger zur psychotropen Wirksamkeit eines Hypericum-Extraktes.

Extracts of Hypericum perforatum (Psychotonin M) (St. John's wort) with known concentrations of hypericin were tested in several models generally accepted as screening methods in experimental animal studies for the recognition of psychotropic, and in particular of antidepressant activity. Hypericum extract enhanced the exploratory activity of mice in a foreign environment, significantly prolonged the narcotic sleeping time dose-dependently, and within a narrow dose range exhibited reserpine antagonism. Similar to most other antidepressants, hypericum extract enhanced significantly the activity of mice in the water wheel test and after a prolonged daily administration decreased aggressiveness in socially isolated male mice. The presented data in addition to the already proven clinical efficacy justify the use of standardised Hypericum extract in the treatment of mild to moderate depression.

[Studies on DNA content of tissues and organs. 1st communication: changes in cell content of some mesenchymal and parenchymatous rat organs during development, maturation, and in part aging (determinations of DNA) (author's transl)]. / Untersuchungen zum DNS-Gehalt von Geweben und Organen. 1. Mitt.: Veränderungen des Zellgehaltes einiger bindegewebiger und parenchymatöser Organe der Ratte während Entwicklung und Reifung, zum Teil auch bei Alterung (DNS-Bestimmungen).

In this study the cell content was analyzed by means of the DNA content of certain mesenchymal and parenchymal organs of the rat. The main aspects were the postnatal stages of development and maturation. Their correlation to aging was examined only on examples, so was their correlation to the prenatal development (on 2 examples: liver and skin). One important result of this research is that a gradual reduction in the exponential growth takes place with increasing maturation and development. The "growth by production" prevails over the "growth by division" (of cells). This is the explanation for the "relative" (= apparent) decrease in the cell content of the tissues and organs analyzed during the decisive postnatal development and maturation phases. In this period the complete differentiation of the cytoplasmic structures and of the differentiation products of the tissues and organs here analyzed occurs. This leads to a shift in their relative amounts to the disadvantage of the cell nuclei, which prevailed in the total weight of tissues and organs during the early phases of development. This concerns determinations of the DNA content related to wet weight even more than such of the DNA content related to dry weight. As already shown clearly, the different tissues and organs of the mammalian organism (here on the example of the rat) grow, mature and age differently. During growth different phases can be distinguished, too, by analysis of the DNA content which partly correlate with phases of growth which were differentiated morphologically. Determinations of DNA contents are necessary as parameters for determinations of the production metabolism (e.g. activities of enzymes, products of formation and differentiation) of the different tissues and organs during their development, maturation and aging.