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Isolation of anti-HIV-1 lignans from Larrea tridentata by counter-current chromatography.

Several lignans, mostly new, were isolated from Larrea tridentata by assay-guided counter-current chromatography (CCC). Using the secreted alkaline phosphatase bioassay of HIV Tat transactivation and the two-phase hexane-ethyl acetate-methanol-water solvent system, two major components (Gr and Lo) were identified as anti-HIV active principles. The chemical structures of the constituents of Gr (G1-G4) and Lo (L1-L4) were determined by GC-MS and NMR. After optimization of isolation conditions, a large-scale isolation with the chloroform-methanol-water system yielded five constituents (FB1-FB5). The most predominant anti-HIV compound FB2 (denoted Malachi 4:5-6 or mal.4), which occurs in 0.23% yield, was separated from its FB1 isomer (0.13% yield). Compound FB4 and two tricyclic lignans (FB3 and FB5) were also isolated in a substantial amount for further testing of their anti-HIV activities. These compounds may represent a new class of anti-HIV agents with important clinical relevance.

Antiviral Agents↗

Inhibition of the erythrocyte Na+, K+-pump by mammalian lignans.

Several mammalian lignans, particularly enterolactone, 3-oxy-methyl enterolactone and prestegane B are able to inhibit Na+, K+-pump activity in human red cells with IC50 of about 1 mM. The inhibition of Na+, K+-pump activity by mammalian lignans have the following properties: the IC50 for ouabain remains unchanged suggesting a noncompetitive inhibition. The apparent affinity for internal Na+ and maximal rate of cation translocation are both diminished. The above inhibition of the Na+, K+-pump was obtained at doses 2-3 orders of magnitude higher than those required for ouabain. However we cannot exclude that a glycosyl- (and/or butenolide)-derivative of enterolactone could be one endogenous ouabain-like factor.

Cross Reactions↗

Phenylethanoid and lignan glycosides from Verbascum thapsus.

Verbascum thapsus afforded, in addition to three known phenylethanoid glycosides and four lignan ones, five new phenylethanoid glycosides and one new lignan glycoside. Structures of the compounds were elucidated by spectroscopic methods and chemical evidence.

Carbohydrate Sequence↗

A lignan and four terpenoids from Brucea javanica that induce differentiation with cultured HL-60 promyelocytic leukemia cells.

A novel lignan, guaiacylglycerol-beta-O-6'-(2-methoxy)cinnamyl alcohol either, three known simaroubolides, brusatol, dehydrobrusatol, yadanziolide C, and the known terpenoid, blumenol A, were obtained as active compounds from an ethyl acetate-soluble extract of Brucea javanica, using a bioassay based on the induction of cell differentiation with human promyelocytic leukemia (HL-60) cells. Also obtained were the known coumarinolignan, cleomiscosin A, and the known quassinoid glycoside, bruceoside B, which were inactive in the HL-60 cell test system. The structure of the new lignan was determined by a combination of 1D and 2D NMR techniques.

Cell Differentiation↗

Lignan models as inhibitors of Phanerochaete chrysosporium lignin peroxidase.

The lignan 8,8'-bis-(methylenedioxy)cinnamic acid (BMDCA) is a powerful competitive inhibitor (K1 = 2.0 microM) of the lignin peroxidase (LiP) from Phanerochaete chrysosporium and of the extracellular peroxidase of Phlebia radiata (I0.5 = 10 microM). BMDCA derivatives with the same double bond system also inhibited these enzymes to some extent. If the double bonds were hydrogenated, the inhibitory effect was lost. HRP-VIII and HRP-XI were slightly inhibited by BMDCA (I0.5 > 50 microM) and two plant peroxidases described as efficient lignan synthesizers were unaffected. Liquid cultures of P chrysosporium did not discolour the dve Poly R478 when 250 microM of BMDCA was present.

Anthraquinones↗

Occurrence and activity of human intestinal bacteria involved in the conversion of dietary lignans.

The human intestinal microbiota is necessary for the production of enterolignans from the dietary lignan secoisolariciresinol diglucoside (SDG). However, little is known about the bacteria that contribute to SDG conversion. Therefore, we aimed at describing the occurrence and activity of SDG metabolising bacteria. The data showed differences in conversion efficiency between SDG deglycosylating species, but SDG was completely deglycosylated within 20 h by five of six strains. The strain Clostridium sp. SDG-Mt85-3Db showed the highest initial rate of SDG deglycosylation. Furthermore, we found that Bacteroides distasonis and B. fragilis made up 0.5% and 3.3% of total faecal bacteria, respectively. However, Clostridium sp. SDG-Mt85-3Db was detected within the dominant microbiota of only two out of 20 faecal samples. Bacteria involved in the demethylation step of SDG conversion also demethylated a variety of compounds other than SDG. In particular, Peptostreptococcus productus demethylated the lignans pinoresinol, lariciresinol and matairesinol. Finally, Eggerthella lenta catalysed the reduction of pinoresinol and lariciresinol to secoisolariciresinol.

Bacteroides↗

Absolute configuration and anticancer activity of taxiresinol and related lignans of Taxus wallichiana.

Absolute configuration of taxiresinol 1, a lignan from the heartwood of Taxus wallichiana has been determined as 8R, 8'R, and 7'R with the help of chemical correlation method and X-ray crystallography. The anticancer activity of taxiresinol 1 and other two lignans 2, 3 were also studied. Taxiresinol 1 showed notable anticancer activity in the in vitro bioassays against colon, liver, ovarian and breast cancer cell lines.

Antineoplastic Agents, Phytogenic↗

Differential effects of isoflavones and lignans on invasiveness of MDA-MB-231 breast cancer cells in vitro.

Metastasis is a major cause of morbidity and mortality in breast cancer with tumour cell invasion playing a crucial role in the metastatic process. The effects of a panel of phytoestrogens, including isoflavones and lignans on the invasion of a breast cancer cell-line (MDA-MB-231) through Matrigel were assessed. Genistein, glycitein, daidzein, equol, O-Desmethylangolensin (O-Dma) and coumestrol exerted a potent inhibitory effect on cell invasion (e.g. inhibition of 41.7+/-15% (P = 0.007) coumestrol (10 microM)). In contrast the lignans exerted minimal effects on invasion. Inhibition of invasion induced by the phytoestrogens occurred without affecting cell viability, highlighting the possible chemoprotective effects of these compounds.

Breast Neoplasms↗

Separation and determination of lignans from seeds of Schisandra species by micellar electrokinetic capillary chromatography using ionic liquid as modifier.

In this paper, a micellar electrokinetic chromatographic (MEKC) method using ionic liquid as modifier for the quantification of the active components of lignans found in the medicinal herbs Schisandra species was developed for the first time. Preliminary investigations employing sodium dodecyl sulfate (SDS) as surfactant did not lead to the necessary resolution of the studied compounds, the addition of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4) to the SDS micellar system resulted in the complete separation of all the compounds. The effects on the separation by several parameters such as BMIM-BF4 and SDS concentration, applied voltage, background electrolyte pH and concentration, were evaluated. Under the optimal conditions (5 mM borate-5 mM phosphate buffer in the presence of 20 mM SDS and 10 mM BMIM-BF4, pH 9.2, applied voltage 25 kV and detection at 254 nm), the method successfully applied to the determination of lignans in extracts of Schisandra chinensis (Turcz.) Baill. and Schisandra henryi C.B. Clarke in less than 13 min. The separation mechanism was also discussed.

Borates↗

Antiinflammatory and antiallodynic actions of the lignan niranthin isolated from Phyllanthus amarus. Evidence for interaction with platelet activating factor receptor.

Previous studies have shown that the extracts obtained from Phyllanthus amarus, and some of the lignans isolated from it, exhibit pronounced antiinflammatory properties. In the present study, we have assessed whether the antiinflammatory actions of these lignans can be mediated by interaction with platelet activating factor (PAF) receptor or interference with the action of this lipid. The local administration of nirtetralin, phyltetralin or niranthin (30 nmol/paw), similar to WEB2170 (a PAF receptor antagonist, 30 nmol/paw), significantly inhibited PAF-induced paw oedema formation in mice. The extracts of P. amarus (100 microg/ml) and niranthin (30 microM), but not nirtetralin or phyltetralin (30 microM), decreased the specific binding of [(3)H]-PAF in mouse cerebral cortex membranes. Furthermore, both niranthin and WEB2170 displaced, in a concentration-dependent manner, the [(3)H]-PAF binding sites. The mean IC(50) values from these effects were 6.5 microM and 0.3 microM, respectively. Additionally, both niranthin and WEB2170 (30 nmol/paw) inhibited the increase of myeloperoxidase activity induced by PAF injection in the mouse paw. When assessed the mouse model of pleurisy induced by PAF, pretreatment with niranthin (100 micromol/kg, p.o.) or WEB2170 (1.7 micromol/kg, i.p.) significantly inhibited PAF-induced protein extravasations. Moreover, in the rat model of PAF-induced allodynia, both niranthin (30 nmol/paw) and WEB2170 (30 nmol/paw) treatment significantly inhibited PAF-induced allodynia. In addition, niranthin had a rapid onset and long-lasting antiallodynic action when compared with WEB2170. Collectively, the present findings suggest that niranthin exhibits antiinflammatory and antiallodynic actions which are probably mediated through its direct antagonistic action on the PAF receptor binding sites.

Analgesics↗

Antioxidant lignan glucosides from Strychnos vanprukii.

From the stem of Strychnos vanprukii, two new lignan glucosides, vanprukoside (1) and strychnoside (2), were isolated together with the known lignan glucoside, (+)-lyoniresinol-3 alpha-O-beta-glucopyranoside (3). The structures of these compounds were elucidated on the basis of their spectroscopic data. All three compounds exhibited antioxidant activity.

Antioxidants↗

Anti-inflammatory and antinociceptive activity of taxoids and lignans from the heartwood of Taxus baccata L.

Four taxoids (taxusin, baccatin VI, baccatin III and 1beta-hydroxybaccatin I) and five lignans (lariciresinol, taxiresinol, 3'-demethylisolariciresinol-9'-hydroxyisopropylether, isolariciresinol and 3-demethylisolariciresinol) were isolated from the heartwood of Taxus baccata L. (Taxaceae) growing in Turkey through chromatographic techniques. In vivo anti-inflammatory and antinociceptive activity of these compounds were investigated. All the compounds were shown to possess significant antinociceptive activity against p-benzoquinone-induced abdominal contractions, while only lignan derivatives significantly inhibited carrageenan-induced hind paw edema in mice.

Analgesics↗

Quantification of isoflavones and lignans in urine using gas chromatography/mass spectrometry.

Phytoestrogens (isoflavones and lignans) are of increasing interest due to their potential to prevent certain types of complex diseases. However, epidemiological evidence is needed on the levels of phytoestrogens and their metabolites in foods and biological fluids in relation to risk of these diseases. We report an assay for phytoestrogens which is sensitive, accurate, and uses low volumes of sample. Suitable for epidemiological studies, the assay consists of a simple sample preparation procedure and has been developed for the analysis of five isoflavones (daidzein, O-desmethylangolensin, equol, genistein, and glycitein) and two lignans (enterodiol and enterolactone), which requires only 200 microl of urine and utilizes one solid-phase extraction stage for sample preparation prior to derivatization for GC/MS analysis. Limits of detection were in the region 1.2 ng/ml (enterodiol) to 5.3ng/ml (enterolactone) and the method performed well in the UK Government's Food Standards Agency-sponsored quality assurance scheme for phytoestrogens. For the first time, average levels of all the above phytoestrogens were measured in samples of urine collected from a free living population sample of women. Results show a large range in both the amount and the type of phytoestrogens excreted.

4-Butyrolactone↗

Separation of diastereoisomers of podophyllum lignans by micellar electrokinetic chromatography.

Seven pairs of diastereoisomers of podophyllum lignans at 2-position, including two pairs of spin-labeled compounds, were separated by micellar electrokinetic chromatography with 5 mM sodium tetraborate-20 mM NaH2PO4-120 mM sodium dodecylsulfate-30% (v/v) 2-propanol (pH 6.5-7) within 35 min. The migration behaviors of the compounds with different types and concentrations of organic modifiers were studied. The method can be used to identify the purification of the lignans, monitor the 2-H configuration transformation, and determine the 2-H configuration of the spin-labeled derivatives.

Chromatography, Micellar Electrokinetic Capillary↗

Sesamin, a sesame lignan, is a potent inducer of hepatic fatty acid oxidation in the rat.

The effects of sesamin, one of the most abundant lignans in sesame seed, on hepatic fatty acid oxidation were examined in rats that were fed experimental diets containing various amounts (0%, 0.1%, 0.2%, and 0.5%) of sesamin (a 1:1 mixture of sesamin and episesamin) for 15 days. Dietary sesamin dose-dependently increased both mitochondrial and peroxisomal palmitoyl-coenzyme A (CoA) oxidation rates. Mitochondrial activity almost doubled in rats on the 0.5% sesamin diet. Peroxisomal activity increased more than 10-fold in rats fed a 0.5% sesamin diet in relation to rats on the sesamin-free diet. Dietary sesamin greatly increased the hepatic activity of fatty acid oxidation enzymes, including carnitine palmitoyltransferase, acyl-CoA dehydrogenase, acyl-CoA oxidase, 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase. Dietary sesamin also increased the activity of 2,4-dienoyl-CoA reductase and delta3,delta2-enoyl-CoA isomerase, enzymes involved in the auxiliary pathway for beta-oxidation of unsaturated fatty acids dose-dependently. Examination of hepatic mRNA levels using specific cDNA probes showed a sesamin-induced increase in the gene expression of mitochondrial and peroxisomal fatty acid oxidation enzymes. Among these various enzymes, peroxisomal acyl-CoA oxidase and bifunctional enzyme gene expression were affected most by dietary sesamin (15- and 50-fold increase by the 0.5% dietary level). Sesamin-induced alterations in the activity and gene expression of carnitine palmitoyltransferase I and acyl-CoA oxidase were in parallel with changes in the mitochondrial and peroxisomal palmitoyl-CoA oxidation rate, respectively. In contrast, dietary sesamin decreased the hepatic activity and mRNA abundance of fatty acid synthase and pyruvate kinase, the lipogenic enzymes. However, this lignan increased the activity and gene expression of malic enzyme, another lipogenic enzyme. An alteration in hepatic fatty acid metabolism may therefore account for the serum lipid-lowering effect of sesamin in the rat.

Administration, Oral↗

nor-Lignans from the leaves of Styrax ferrugineus (Styracaceae) with antibacterial and antifungal activity.

Chemical examination of the leaves of Styrax ferrugineus yielded 5-[3''-(beta-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-dimethoxyphenyl) benzofuran, along with the known nor-lignans 5-(3''-hydroxypropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl) benzofuran, 5-(3''-hydroxypropyl)-7-methoxy-2-(3',4'-dimethoxyphenyl)benzofuran, 5-[3''-(beta-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-methylenedioxyphenyl)benzofuran and the lignan, dihydrodehydrodiconiferyl alcohol. All arylpropanoids isolated showed antibacterial and antifungal activities. The structures of the isolates were established by spectroscopic analysis.

Anti-Bacterial Agents↗

Dibenzocyclooctadiene-type lignans from Magnolia pyramidata.

Eight dibenzocyclooctadiene-type lignans, pyramidatin A-H, were isolated from the leaves of Magnolia pyramidata. Their structures were established by spectral methods, mainly 2D NMR spectroscopic techniques, which involved combined applications of COSY, DEPT. 1H, 13C correlations, COLOC, INAPT and long-range inverse 1H, 13C NMR correlations. The molecular structures of pyramidatin A and B were determined by single crystal X-ray diffraction. The absolute configurations of all eight lignans were derived from CD spectral correlations with structurally related dibenzocyclooctadienes of known absolute configuration.

Circular Dichroism↗

Phenylpropanoids and tetrahydrofuran lignans from Piper solmsianum.

A tetrahydrofuran lignan as well as the known tetrahydrofuran lignan, (-)-grandisin, and five phenylpropanoid derivatives were isolated from Piper solmsianum. Their structures were determined by means of spectral analyses, including 2D NMR techniques such as NOE-DIFF and HMBC 3J(C-H).

Anthracenes↗