Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Lignans”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed1992

[Studies on the TLC scanning determination of lignans in Diphylleia sinensis Li].

A simple, sensitive and accurate method for the separation and determination of the lignans: podophylltoxone (I), isopicropodophyllone (II), picropodophyllone (III), dehydropodophyllotoxin (IV), picropodophyllin (V), podophyllotoxin (VI), 4'-demethylpodophyllotoxin (VII) and diphyllin (VIII) is described. The sample solution was applied at a point 1 cm from the bottom edge of the HPTLC silica gel plate (10 cm x 10 cm), dichloromethane-diethyl ether (4:1) was used as the developing solvent. The plate was saturated for 30 min and then developed twice for 9.5 cm using ascending technique. The plate was sprayed with 2.5% ammonium ceric sulphate--20% nitric acid and toasted for 15 min at 120 degrees C, then fumigated with ammonia solution for 20 min at room temperature to intensify the spot color. The spots were scanned with a Shimadzu CS-930 TLC scanner. The contents of eight lignans in Diphylleia sinensis was calculated by comparison with standards spotted on the same plate. The standard curves were linear in the range of 0.48-2.52 micrograms for the eight lignans. The method has been applied to the analysis of various samples and can be used for the quality control of Diphylleia sinensis, podophyllum and dysosma preparations used in clinic.

Chromatography, Thin Layer↗
PubMed2005

Cytotoxic activity of a podophyllotoxin-like lignan from Linum tauricum Willd.

The present study describes the preliminary evaluation of the cytotoxic activity of a podophyllotoxin-like compound 4'-demethyl-6-methoxypodophyllotoxin (4'-DM-6-Mptox), isolated as one of the main lignans of Linum tauricum Willd. ssp. tauricum. The cytotoxic effects 4'-DM-6-Mptox were assessed by the MTT-dye reduction assay against the human leukemic cell lines HL-60, BV-173 and LAMA-84. DNA-fragmentation analysis and NF-kB inhibition assay were performed in order to elucidate some of the mechanistic aspects of the cytotoxic action of the investigated compound. 4'-DM-6-Mptox was found to exert prominent cytotoxicity, with IC50 values being several-fold lower than those of the referent antineoplastic agent etoposide. The DNA-fragmentation analysis revealed that 4'-DM-6-Mptox treatment triggered apoptosis in BV-173 and HL-60 cells. In our hands 4'-DM-6-Mptox was found to induce concentration-dependent NF-kB inhibition in HeLa cells as assessed by the IL-6 luciferase gene reporter assay, which though not quite prominent, at least partly contributes to the cytotoxic potential of the tested lignan. On the basis of the results obtained it could be concluded that 4'-DM-6-Mptox necessitates further pharmacological and toxicological evaluation as a possible chemotherapeutic agent. Furthermore due to its relatively high concentrations in the described plant source the possibility for its use as a precursor for the semisynthetic production of lignan-based drugs, could be considered.

Antineoplastic Agents, Phytogenic↗
PubMed2005

The inhibitory effect of flaxseed on the growth and metastasis of estrogen receptor negative human breast cancer xenograftsis attributed to both its lignan and oil components.

Our previous studies have shown that dietary flaxseed (FS) can reduce the growth and metastasis of human estrogen receptor negative (ER-) breast cancer in nude mice. The aims of our study were to determine (i) whether the tumor inhibitory effect of FS was due to its oil (FO), lignan secoisolariciresinol diglycoside (SDG), or both components, and (ii) whether the effect on tumor growth was related to increased lipid peroxidation. Athymic nude mice were orthotopically injected with ER- breast cancer cells (MDA-MB-435) and 8 weeks later were fed either the basal diet (BD) or BD supplemented with 10% FS, SDG, FO, or combined SDG and FO (SDG + FO) for 6 weeks. The SDG and FO levels were equivalent to the amounts in the 10% FS. Compared to the BD group, the tumor growth rate was significantly lower (p < 0.05) in the FS, FO, and SDG + FO groups, in concordance with decreased cell proliferation and increased apoptosis; however, these did not significantly relate to the lipid peroxidation, indexed as malonaldehyde (MDA), in the primary tumors. Lung metastasis incidence was reduced (16-70%) by all treatments, significantly in the FS and SDG + FO groups. The distant lymph node metastasis was significantly decreased (52%) only in the FO group. Although the total metastasis incidence was lowered (42%) significantly only in the SDG + FO group, all treatment groups did not differ significantly. In conclusion, FS reduced the growth and metastasis of established ER- human breast cancer in part due to its lignan and FO components, and not to lipid peroxidation.

Animals↗
PubMed2005

Complete assignments of 1H and 13C NMR spectral data for benzylidenebenzyl butyrolactone lignans.

The structures of three benzylidenebenzyl butyrolactone lignans (gossypifan, carthamogenin, and savinin) have been established on basis of 1H NMR and 13C NMR spectroscopic data. The 1H NMR and 13C NMR spectra of these lignans have been fully assigned by the use of techniques such as gCOSY, non-edited gHSQC, and gHMBC. Complete assignment and most homonuclear hydrogen coupling constant measurements were performed, also providing enough data for the determination of the relative stereochemistry.

Carbon Isotopes↗
PubMedDate not supplied

Lignans and secoiridoids from the root bark of Chionanthus virginicus L.: isolation, identification and HPLC analysis.

Five lignans, phillyrin (1), pinoresinol-beta-D-glucoside (2), pinoresinol di-beta-D-glucoside (3), phillyrin-2-O-beta-D-glucoside (6), phillyrin-6-O-beta-D-glucoside (7), and three secoiridoids, oleuropein (4), ligustroside (5) and angustifolioside B (8), have been isolated from the root bark of Chionanthus virginicus L. (Oleaceae), a raw material used in the commercial preparation of homeopathy tinctures. Compound 6 is a new lignan, and compounds 2, 3, 4, 5, 7 and 8 are described for the first time in the title plant. The structures of these compounds were elucidated by spectroscopic methods (NMR and HPLC-MS). An isocratic HPLC method for the rapid characterisation and quantification of the major constituents, 1 and 4, of the root bark is described and validated.

Chromatography, High Pressure Liquid↗
PubMed2005

Lignans from Acanthopanax chiisanensis having an inhibitory activity on prostaglandin E2 production.

The chloroform and the ethyl acetate fractions from the roots of Acanthopanax chiisanensis exhibited the significant inhibition of TPA-induced prostaglandin E(2) (PGE(2)) production in rat peritoneal macrophages. Five lignans were isolated from the chloroform fraction and their structures were elucidated as l-sesamin, helioxanthin, savinin, taiwanin C, and 3-(3,4-dimethoxybenzyl)-2-(3,4-methylenedioxybenzyl)butyrolactone. Among the lignans tested, taiwanin C showed the most potent inhibitory activity (IC(50) = 0.12 microM) on PGE(2) production with the relative order of potency, taiwanin C >> 3-(3,4-dimethoxybenzyl)-2-(3,4-methylenedioxybenzyl)butyrolactone > savinin = helioxanthin. l-Sesamin showed no inhibitory activity at 30 microM.

Animals↗
PubMed2003

Quantification of isoflavones and lignans in serum using isotope dilution liquid chromatography/tandem mass spectrometry.

Phytoestrogens (isoflavones and lignans) are receiving increasing attention due to a potential protective effect against a number of complex diseases. However, in order to investigate these associations, it is necessary to accurately quantify the levels of phytoestrogens in foods and biological fluids. We report an assay for three isoflavones (daidzein, genistein, and glycitein), two metabolites of daidzein (O-desmethylangolensin and equol), and two lignans (enterodiol and enterolactone) in human serum using electrospray ionisation liquid chromatography/mass spectrometry (LC/MS) with selective reaction monitoring. A simple, highly automated sample preparation procedure requires only 200 microL of sample and utilises one solid-phase extraction stage. Limits of detection are in the region of 10 pg/mL for all analytes except equol, which had a limit of detection of approximately 100 pg/mL. The method developed is suitable for measuring the concentrations of phytoestrogens in blood samples collected from large epidemiological studies. The results of the analysis of serum samples from 300 men and women living in the UK are reported.

Calibration↗
PubMed1994

Investigation of mammalian lignan precursors in flax seed: first evidence of secoisolariciresinol diglucoside in two isomeric forms by liquid chromatograph/mass spectrometry.

A strong research effort has been devoted in recent years to the mammalian lignans enterolactone and enterodiol because of their claimed protective effects against breast and colon cancer. Some plant lignans appear to be precursors of these molecules. This paper reports a novel identification procedure for one of these precursors, the secoisolariciresinol diglucoside, in the extracts of defatted flax-seed meal. The procedure is based on high-performance liquid chromatography coupled with either ionspray or continuous-flow fast-atom bombardment mass spectrometry. The application of these techniques allowed the identification in flax seed of two isomeric forms of this precursor for the first time. The isomers are reasonable the two diastereoisomers, due to the two equivalent stereogenic centers present in the molecule.

Butylene Glycols↗
PubMed1996

Isotope dilution gas chromatographic-mass spectrometric method for the determination of isoflavonoids, coumestrol, and lignans in food samples.

We present a method for the quantitative determination of the phytoestrogens formononetin, biochanin A, daidzein, genistein, and coumestrol and simultaneously the lignans secoisolariciresinol (SECO) and matairesinol in plant-derived foods. These compounds are measured by isotope dilution gas chromatography-mass spectrometry in the selected ion monitoring mode (ID/GC/MS/SIM) using synthesized deuterated internal standards for the correction of losses during the procedure. A three-step hydrolysis--a rehydration with distilled H2O, followed by enzymatic and acid hydrolysis--has been applied in order to convert the diphenolic glycosides into their respective aglycones. Purification and separation are carried out in two ion-exchange chromatographic steps followed by derivatization and GC-MS. The within-assay imprecision values vary 3.1-9.6% and the between-assay imprecision 7.0-21.2%. The mean recovery of authentic standards processed through the whole procedure varied from 95.5 to 105.5%. Values for some different food samples are presented. The simultaneous determination of the biologically most interesting phytoestrogens and lignans in foods has not been carried out previously and the method will be useful for screening of important foods in populations with different risk of cancer and coronary heart disease, and for metabolic studies.

Anion Exchange Resins↗
PubMed2000

Extraction and quantification of lignan phytoestrogens in food and human samples.

Dietary phytoestrogens have a number of biological effects, including endocrine disruption, antioxidant potential, and protein tyrosine kinase inhibition. Secoisolariciresinol, matairesinol, and shonanin are lignan phytoestrogens found in foodstuffs, especially flaxseed. Normally they are glycosidically linked to carbohydrates and in the large intestine are deconjugated from the carbohydrate portion by bacteria. The aglycone lignans can be further modified to form the mammalian phytoestrogens enterodiol, enterolactone, and enterofuran, which are absorbed into the body and excreted in urine. To assess the health implications of phytoestrogens in general populations, knowledge of the quantity in the foods eaten is necessary. This article describes a simple preparative procedure for the assay of secoisolariciresinol, matairesinol, and shonanin in foodstuffs after hydrolytic removal of any conjugated carbohydrate. The difficulties in the practical application of the assay procedure are illustrated and discussed. Analytical results indicating the concentration of secoisolariciresinol, matairesinol, and shonanin in a number of foodstuffs are presented. Also, the mass spectral data of a putative mammalian phytoestrogen, called enterofuran, identified in urine are presented.

Butylene Glycols↗
PubMed1982

Cutaneous cytodestructive potency of lignans. I. A comparative evaluation of influence on epidermal and dermal DNA synthesis and on dermal microcirculation in the hairless mouse.

The four lignans: podophyllotoxin, 4'-demethyl-podophyllotoxin, alpha-peltatin and beta-peltatin represent the podophyllin ingredients believed to exert lesional necrosis after application to condylomata acuminata. This study comparatively evaluates cutaneous cytodestructive potency of these drugs, as evaluated by measurement of epidermal and dermal 3H-thymidine incorporation and injury of dermal microcirculation at intervals in the range of 9--168 h after application to hairless mouse skin. Influence on DNA-synthesis was measured using a disc technique for isolation of standardized skin areas followed by alkali extraction of DNA from respective tissues after separation through potassium bromide incubation. Any capillary injury was demonstrated by visual assessment of leakage of i.v. injected trypan blue to test areas. An analytical method compensating for variations in DNA synthesis in individual controls is presented. Using 0.5% preparations of the lignans, podophyllotoxin most consistently influenced the variables indicating cytodestructive effect, while 4'-demethyl-podophyllotoxin exerted the weakest degree of damage.

Animals↗
PubMed2004

Inhibition of phospholipase Cgamma1 and cancer cell proliferation by lignans and flavans from Machilus thunbergii.

Thirteen compounds were isolated from the CH2Cl2 fraction of Machilus thunbergii as phospholipase Cgamma1 (PLCgamma1) inhibitors. These compounds were identified as nine lignans, two neolignans, and two flavans by spectroscopic analysis. Of these, 5,7-di-O-methyl-3',4'-methylenated (-)-epicatechin (12) and 5,7,3'-tri-O-methyl (-)-epicatechin (13) have not been reported previously in this plant. In addition, seven compounds, machilin A (1), (-)-sesamin (3), machilin G (5), (+)-galbacin (9), licarin A (10), (-)-acuminatin (11) and compound 12 showed dose-dependent potent inhibitory activities against PLCgamma1 in vitro with IC50 values ranging from 8.8 to 26.0 microM. These lignans, neolignans, and flavans are presented as a new class of PLCgamma1 inhibitors. The brief study of the structure activity relationship of these compounds suggested that the benzene ring with the methylene dioxy group is responsible for the expression of inhibitory activities against PLCgamma1. Moreover, it is suggested that inhibition of PLCgamma1 may be an important mechanism for an antiproliferative effect on the human cancer cells. Therefore, these inhibitors may be utilized as cancer chemotherapeutic and chemopreventive agents.

Animals↗
PubMed2004

Inhibitory lignans against NFAT transcription factor from Acanthopanax koreanum.

Three lignans isolated from the roots of A. koreanum (Araliaceae), namely eleutheroside E (1), tortoside A (2), and hemiariensin (4), were evaluated for their ability to inhibit NFAT transcription factor. Of these compounds, compound 4, possessing a diarylbutane skeleton, exhibited potent inhibitory activity against NFAT transcription factor (IC50: 36.3 +/- 2.5 microM). However, the activities of 1 (IC50: > 500 microM) and 2 (IC50: 136.1 +/- 9.4 microM), which possess bisaryldioxabicyclooctane skeletons, were lower. As the lignan derivatives of the same skeletons, hinokinin (5) and (-)-yatein (6) with diarylbutane skeletons and (+)-syringaresinol (3) with a bisaryldioxabicyclooctane skeleton were also studied for their inhibitory effects on NFAT transcription factor.

Buffers↗
PubMed2005

Furofuran lignans from a callus culture of Cichorium intybus.

Three new and one known furofuran lignans--syringaresinol derivatives--along with the known phenylpropanoids cichoriin and syringin were isolated from a callus tissue of Cichorium intybus. The compounds were characterised by spectral methods. This is the first report on the presence of furofuran lignans in Cichorium species.

Biochemistry↗
PubMed2005

Suitability of a batch in vitro fermentation model using human faecal microbiota for prediction of conversion of flaxseed lignans to enterolactone with reference to an in vivo rat model.

BACKGROUND: In vitro fermentation models have been used widely for studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas the suitability of these methods for enterolactone (ENL) formation has received less attention. AIM: The aim was to study the suitability of an in vitro fermentation model for prediction of bioconversion of lignans to ENL, to compare the approach with that of an in vivo rat model and to study the SCFA formation in both models. METHODS: Predigested samples of rye bran (R), flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal control were incubated in an in vitro fermentation model using human faecal microbiota. In the in vivo experiment rats consumed a non-fibre control diet (C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone, or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA concentrations were measured from in vitro faecal fermentation samples and from the intestinal contents of rats. Plasma ENL concentrations from rats were also measured. RESULTS: The highest ENL production was found in vitro with the F supplement (areas under curve: 740 +/- 4, 7,500 +/- 400, 2,600 +/- 500 and 1,520 +/- 70 nmol x h for the R, F, R&F supplements and faecal control, respectively). In vivo, the concentration of ENL in caecal digesta from flaxseed meal was significantly (P < 0.05) enhanced by the presence of rye bran (medians 261, 407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation was found between the models regarding ENL production, possibly due to different responses to the presence of rye bran matrix, differences in microbiota or application of a batch in the in vitro fermentation model. Rye bran supplementation enhanced butyrate production both in vitro and in vivo. CONCLUSION: In vitro fermentation and the in vivo rat models responded differently to the presence of rye bran and no correlation with regard to the ENL formation from flaxseed lignans was observed.

4-Butyrolactone↗
PubMed2005

Enhancement of lignan biosynthesis in suspension cultures of Linum nodiflorum by coronalon, indanoyl-isoleucine and methyl jasmonate.

The effect of the two synthetic elicitors coronalon and indanoyl-isoleucine and of methyl jasmonate (MeJA) on the accumulation and biosynthesis of lignans by cell suspension cultures of Linum nodiflorum (Linaceae) was investigated. The production of 6-methoxypodophyllotoxin (MPTOX) could be increased more than tenfold, the maximal content reaching up to over 2.5% of the cell dry weight. The highest yield was achieved by administering 50 microM of the synthetic elicitors on the fourth day and extracting the products on the tenth day of the culture period. An additional lignan accumulated in elicitor-treated cultures. Its structure was elucidated by extensive 1D and 2D NMR measurements, revealing its identity as 5'-demethoxy-MPTOX (5'-dMPTOX). Its average content amounted up to over 5% of the cell dry weight. Growth was only slightly affected by the addition of the elicitors. Methyl jasmonate exerted a moderate stimulating effect on the L. nodiflorum cells with MPTOX and 5'-dMPTOX contents going up to 1.4 and 2.1% of the cell dry weight, respectively. The activities of deoxypodophyllotoxin 6-hydroxylase and beta-peltatin 6-O-methyltransferase, two enzymes involved in MPTOX biosynthesis, were increased up to 21.9-fold and 14.6-fold, respectively, in the treated cultures.

Acetates↗
PubMed1999

The metabolism and distribution of sesame lignans (sesamin and episesamin) in rats.

In this study, we examined the distribution and metabolism of refined sesame oil lignans (sesamin and episesamin) in rat. For 8 wk rats were fed the diet including 0.5% (w/w) sesame lignans (sesamin and episesamin) with 5% (w/w) corn oil or eicosapentaenoic acid (EPA)-rich oil. The concentrations of sesamin and episesamin in rat liver after their administration for 8 wk were very low; both of them were less than 0.5 microgram/g liver. These were observed in both oil groups although the fatty acid compositions of dietary oils were completely different. No significant difference existed in lymphatic absorption between sesamin and episesamin. To investigate the distribution of sesamin and episesamin in rats, the concentrations of sesamin and episesamin were determined in tissues and serum within 24 h after administration to rats. Sesamin and episesamin may be, at first, incorporated into the liver and then transported to the other tissues (lung, heart, kidney, and brain). They are lost from the body within 24 h after administration. There was no significant difference in lymphatic absorption between sesamin and episesamin, but the amount of sesamin was significantly lower than that of episesamin in all tissues and serum. These results suggest that sesamin is absorbed in lymph the same as episesamin, but that sesamin is subsequently metabolized faster by the liver.

Animals↗
PubMed1986

Evidence that mammalian lignans show endogenous digitalis-like activities.

Enterolactone, a lignan that has been identified in biological samples from man and several mammals, shares with ascorbic acid and cardiac glycosides a gamma-butyrolactone. It displaces 3H-ouabain from its binding sites on cardiac digitalis receptor and inhibits, dose dependently, the Na+, K+-ATPase activity of human and guinea-pig heart. The time dependence of this inhibition resembles that of dihydroouabain, a cardiac glycoside in which the lactone ring does not contain conjugated double bonds. The active concentrations of enterolactone as inhibitor of Na+,K+-ATPase are in the 10(-4) M range and, at those concentrations, the cross-reactivity with antidigoxin antibodies is low. Lignans may contribute to the putative digitalis-like activity found in tissues, blood and urine of several mammals including man.

4-Butyrolactone↗