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The flavonoid pattern of an acetonic extract of Grindelia robusta Nutt. was investigated in detail. The flavonoids were enriched by CC. In addition to twelve known methylated exudate flavonols four compounds were identified for the first time in G. robusta. Several substances of the flavonoid complex, among them the main compounds quercetin-3-methylether and 6-OH-kaempferol-3,6-dimethylether, were tested for their activity to inhibit neutrophil elastase. Quercetin-3-methylether was shown to be most active with an IC(50) of 19 microM, thus obviously contributing to the anti-inflammatory activity of the drug.

In a bioassay-guided approach the chemical composition of rhizomes of Metaxya rostrata (Kunth C. Presl) was studied for the first time. Investigations of the cytotoxicity of extracts and fractions on SW480 colorectal carcinoma cells resulted in the isolation of two polyphenols D cinnamtannin B-1 and aesculitannin B. The structures of the compounds were elucidated by different NMR experiments. Additionally, sugars, common sterols, such as sitosterol, stigmasterol and campesterol, as well as chlorogenic acid and caffeic acid were identified in Metaxya rostrata.

The multidrug resistance (MDR) proteins which belong to the ATP-binding cassette superfamily are present in a majority of human tumors and are an important final cause of therapeutic failure. Therefore, some compounds which inhibit the function of the MDR-efflux proteins may improve the cytotoxic action in cancer chemotherapy. The mechanism of action was believed to be a competition between their resistance modifiers and the cytotoxic agents for the same binding site of MDR P-glycoprotein (P-gp) due to a complementarity with a hypothetic receptor site with unknown structure. In the absence of the crystal structures of the P-gp, a receptor fitting was not available. Therefore, we tried to indirectly define the receptor structure or mapping of human MDR1-encoded P-gp in the presence of the structurally unrelated carotenoids, flavonoids, isoflavones and terpenoids.

Red clover, known for its estrogenic activity due to its isoflavones content (biochanin A, genistein, daidzein and formononetin), was inoculated with the arbuscular mycorrhizal fungus Glomus mosseae. Once the symbiotic fungus was well established, plants were harvested and we determined the root and shoot dry weight as well as the P-content. In roots and leaves the levels of biochanin A, genistein, daidzein and formononetin were quantified by reversed-phase HPLC and the estrogenic activity of the leaves was measured by a transactivation assay using a yeast two-plasmid system. Mycorrhization increased the levels of biochanin A in the root and the shoot and reduced the levels of genistein in the shoot of red clover. The levels of the other isoflavones were not affected. The shoot biomass of mycorrhizal plants more than doubled compared with non-mycorrhizal control plants, and this growth-stimulating effect of arbuscular mycorrhiza did not affect the estrogenic activity of red clover. In a control P treatment, the biomass of red clover was greatly enhanced. However, the estrogenic activity was reduced. These results suggest that, in contrast to an enhanced shoot biomass production after P application with a reduced estrogenic activity, with arbuscular mycorrhiza the shoot biomass of red clover can be enhanced without a negative effect on estrogenic activity.

In a study of the anthraderivatives in roots of Rheum emodi, three new anthrone C-glucosides, named 10-hydroxycascaroside C (1), 10-hydroxycascaroside D (2) and 10R-chrysaloin 1-O-beta-D-glucopyranoside (3) were isolated besides the rare compounds cascaroside C (4), cascaroside D (5) and cassialoin (6). Additionally the investigation resulted in the isolation of an acetylated chrysophanol glucoside, 8-O-beta-D-(6'-O-acetyl)glucopyranosyl-chrysophanol (7). The structures were established by comprehensive spectroscopic investigations.

The separation and quantification of the flavonoids occurring in Achillea nobilis L. by a CE-method is described. Using 20 mM sodium borate at pH 9.5 with 20 % of methanol as buffer, the flavonoids were sufficiently separated within 11 minutes. Kaempferol-7-O-neohesperidoside was used as internal standard for the quantification. Analysis of six different samples showed the flavon-C-glycosides isoorientin, orientin and vitexin as the characteristic main compounds. The contents of flavon-C-glycosides determined by this CE-method correlated with the results achieved by a spectrophotometric determination.

Two new pyrrolizidine alkaloids, O7-3-hydroxy-3-methylbutanoyl-O9-(—)-hydroxyviridifloryl retronecine and its acetyl derivative were

An RP-HPLC method for the determination of daidzein, genistein, formononetin and biochanin A in red clover (Trifolium pratense L.) was developed and validated. The compounds are quantified after hydrolytic extraction using an internal standard. On a base-deactivated C(18) column good separation of the analytes, also from accompanying substances, and excellent peak shape are achieved by gradient elution with aqueous sulfuric acid and acetonitrile. The method was applied to the analysis of different red clover cultivars.

Extracts and fluid extracts from the aerial parts from Passiflora incarnata L. are widely used as components of herbal sedatives. Many pharmacological investigations confirm the sedative effects of Passiflorae herba. From some of the studies also anxiolytic effects can be deduced. As Passionflower is mainly used in combinations, clinical studies of the single drug are not available. Based on pharmacological data, the experiences of traditional use and the use in combinations Passiflora extracts are an important factor in the phytotherapy of tenseness, restlessness and irritability with difficulty in falling asleep.

Isoflavones are the most potent estrogenic compounds in red clover extracts. Standardized extracts have been discussed as an alternative for hormone replacement therapy. Variation due to extraction procedure and natural seasonal variation and variations originating from agricultural conditions have prevented the large scale use of such phytochemicals. An improved extraction procedure and careful analysis of the raw material yielded in a highly standardized preparation (Menoflavon) with an average isoflavone content of approximately 9% (dry weight) determined by HPLC. The estrogenic activity has been further evaluated by a yeast two plasmid system using estrogen receptor alpha (ER alpha) and estrogen receptor beta (ER beta). An estrogenic activity corresponding to a transactivational capacity of ca. 18 microg 17 beta-estradiol per g red clover extract for ER alpha and ca. 78 microg 17 beta-estradiol per g red clover for ER beta was obtained. The difference is explained by the higher affinity of ER beta to isoflavones than that observed for ER alpha. Calculation of potency from isoflavone content measured by HPLC yielded a comparable potency to that experimentally determined by the bioassay. The high content of isoflavones as well as the higher transactivational potency for ER beta than ER alpha make these extracts interesting candidates for HRT.

In a detailed study on the flavonoid pattern of Achillea collina BECKER ten flavonoids were isolated from a methanolic extract of aerial parts of the plant. Their structures were determined by UV, ESI-MS, GC-MS and NMR spectroscopic methods including 2D-NMR. Apigenin-7-O-rutinoside was proven for the first time in the genus Achillea.

Two new bufadienolides, 11α-acetylgamabufotalin 3- O -(4- O -β- d -glucosyl)-α- l -rhamnoside ( 1 ) and 11α-hydroxyscilliglaucoside ( 2 ), were isolated from bulbs of hexaploid Urginea maritima and identified by means of FAB-MS, 1 H-NMR and 13 C-NMR studies.

Four cardenolides were isolated for the first time from the aerial parts of Adonis aestivalis. The compounds were identified by spectrometry and for 3-epi-periplogenin, helveticoside also by comparison with authentic substances. Two new cardenolides were structurally elucidated: strophanthidin-3-O-β- d -digitoxosido-α- l -cymarosido-β- d -glucoside and strophanthidin-3-O-β- d -digitoxosido-β- d -digitoxosido-β- d -diginosido-β- d -glucoside.

Metaxya rostrata, a tree fern belonging to the family of Metaxyaceae, is found in lowland rain forests of Central and South America. The chemical composition of M. rostrata has not been fully investigated. Until now only two polyphenols (cinnamtannin B-1 and aesculitannin), sugars and common sterols have been isolated [1].[...]

In an investigation of herbal material of Passiflora incarnate the flavone C -glycoside, isoscoparin-2″- O -glucoside, was detected and isolated together with eleven known flavonoids. This glycoside was found for the first time in Passifloraceae. © 1997 Elsevier Science Ltd. All rights reserved

From bulbs of Urginea maritima (L.) s.l. was isolated 9-hydroxyscilliphaeoside (1) and its structure established by use of 2D NMR techniques (HH-COSY, TOCSY, ROESY, TOCSY−ROESY, HMQC, HMBC).

From bulbs of Drimia robusta 7 bufadienolides were isolated, 3 of them new natural compounds. Structure elucidation was performed by comparison with authentic substances or by means of 1H-, 13C-NMR-spectroscopy and FAB-MS. The substances were identified as scilliroside (1), 12ß-hydroxyscillirosidin (2), 12ß-hydroxyscilliroside (3), hellebrigenin-3-0-ß-glucoside (4), 16ß-hydroxyhellebrigenin (5), 16ß-hydroxyhellebrigenin-3-O-ß-glucoside (6) and 5ß,16ß-dihydroxybufalin-3-O-ß-glucoside (7).

The naphthoquinones plumbagin and 7-methyljuglone are considered to be responsible for the spasmolytic and antimicrobial properties of sundew herb (Hb. Droserae), used mainly in pediatrics against whooping-cough. For the quality control of the drug a high performance liquid chromatographic method was established, which permits the simultaneous assay of the two substances within 16 minutes. The samples are processed with a base deactivated C18 reverse phase column by isocratic elution with 0.2M acetic acid (pH adjusted to 3): acetonitrile: tetrahydrofuran (62:36,1:1,9 v/v) as mobile phase. The quantification is performed by internal standardization with juglone. Regression equations show linear relationships between the peak area ratios of each naphthoquinone to juglone and concentration. The relative standard deviation for plumbagin was ±1.3% and for 7-methyljuglone ±4.0%. The method was applied successfully in the analysis of commercial samples of Hb. Doserae.

In the first detailed study of the flavonoid pattern of Achillea roseo-alba rutin, apigenin-7-O-ß-glucopyranoside, luteolin-7-O-ß-glucopyranoside, isorhamnetin-3-O-rutinoside, schaftoside, luteolin-4’-O-ß-glucopyranoside and 6-OH-luteolin-7-O-ß-glucopyranosid were proven in the methanolic extract of aerial parts of the plant. Additionally quercetin-3-O-[ß-apiofiranosyl-(1′′′→2′′)-ß-glucopyranoside] was identified for the first time in the genus Achillea.

The detailed investigation of a methanolic extract of aerial parts of Achillea pannonica SCHEELE. within a chemotaxonomic study led to the isolation of 6 flavonoid glycosides. Besides rutin, apigenin-7-O-glucopyranoside, luteolin-7-O-glucopyranoside, apigenin-7-O-rutinoside and acacetin-7-O-rutinoside, an unusual flavondiglucoside was isolated. Its structure was established by UV, 1HNMR and 13C NMR spectroscopic methods including 2D-NMR techniques and ESI-MS as luteolin-7,4′-O-β-diglucoside. This substance is reported for the first time in the genus Achillea. Chemotaxonomic aspects are discussed briefly

Four new natural compounds, namely 2-deprenyl-7-hydroxy-rheediaxanthone B, (2E)-2-(hydroxyl hexyliden)-cyclopropyl-1 ® 3-diglucoside and (6E)-6[2-( β -gluco­pyranosyloxy)-cyclopropyliden] hexanoic acid methylester as well as the first glucocerebroside from a fern, (4E)-1-O-(β-glucopyranosyl)-N-(2’-hydroxy­tetra­cosanoyl)-4,8-sphingadienine (d18:2/h24:0-GlcCer) , were isolated for the first time from the rootlets of the tree fern Metaxya rostrata C. Presl. Two of these compounds contain a very rare cyclopropyliden structure which until now is only known from two other compounds from this plant. In addition, this is the first report of the tannin pro­anthocyanidin A2 and the triterpenes squalene and fern-9(11)-ene in this tree fern, of which the two latter were isolated from the leaves. The structures of all compounds were elucidated on the basis of detailed spectroscopic and mass spectrometric analyses, including 1D-, 2D-NMR and HR Q-TOF-MS.