lariciresinol and pinoresinol

This paper provides an overview on activity, stereospecificity, expression and regulation of pinoresinol-lariciresinol reductases in plants. These enzymes are shared by the pathways to all 8-8' lignans derived from pinoresinol. Pinoresinol-lariciresinol reductases (PLR) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols. They catalyze two successive reduction steps leading to the production of lariciresinol or secoisolariciresinol from pinoresinol. Two secoisolariciresinol enantiomers can be synthetized with different fates. Depending on the plant species, these enantiomers are either final products (e.g., in the flaxseed where it is stored after glycosylation) or are the starting point for the synthesis of a wide range of lignans, among which the aryltetralin type lignans are used to semisynthesize anticancer drugs such as Etoposide

Topics: Butylene Glycols; Furans; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Lignans; Oxidoreductases; Plant Proteins; Plants

Pinoresinol-lariciresinol reductases (PLRs) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols, and this represents the entry point for the synthesis of 8-8' lignans and contributes greatly to their structural diversity. Of particular interest has been the determination of how differing substrate specificities are achieved with these enzymes. Here, we present crystal structures of IiPLR1 from Isatis indigotica and pinoresinol reductases (PrRs) AtPrR1 and AtPrR2 from Arabidopsis thaliana, in the apo, substrate-bound and product-bound states. Each structure contains a head-to-tail homodimer, and the catalytic pocket comprises structural elements from both monomers. β4 loop covers the top of the pocket, and residue 98 from the loop governs catalytic specificity. The substrate specificities of IiPLR1 and AtPrR2 can be switched via structure-guided mutagenesis. Our study provides insight into the molecular mechanism underlying the substrate specificity of PLRs/PrRs and suggests an efficient strategy for the large-scale commercial production of the pharmaceutically valuable compound lariciresinol.

Topics: Arabidopsis; Arabidopsis Proteins; Butylene Glycols; Catalytic Domain; Crystallography, X-Ray; Furans; Isatis; Lignans; Models, Molecular; Mutagenesis, Site-Directed; Oxidoreductases; Phylogeny; Plant Proteins; Protein Engineering; Protein Multimerization; Static Electricity; Substrate Specificity

Pinoresinol/lariciresinol reductase (PLR), an NADPH-dependent reductase that catalyzes the sequential reduction of pinoresinol into secoisolariciresinol via Lariciresinol, can lead to the structural and stereochemical diversity of lignans. The relationship between substrate-selective reaction of PLR and sequence homology still remains unclear. In this study, we focused on the contribution of the variable region between PLRs in determining substrate selectivity. Here, two CsPLRs (CsPLR1 and CsPLR2) were identified in the tea plant (Camellia sinensis var. sinensis cv. Shuchazao). In vitro enzymatic assays showed that CsPLR1 could convert (+)- and (-)-pinoresinol into lariciresinol or secoisolariciresinol, whereas CsPLR2 catalyzed (+)-pinoresinol enantioselectively into (-)-secoisolariciresinol. Homology modeling and site-directed mutagenesis were used to examine the role of a variable loop in catalysis and substrate selectivity. The L174I mutant in CsPLR1 lost the capacity to reduce either (+)- or (-)-pinoresinol but retained the ability to catalyze the reduction of (-)-lariciresinol. These findings provide a basis for better understanding of the substrate-selective reaction of PLR.

Topics: Butylene Glycols; Camellia sinensis; Furans; Lignans; Mutagenesis, Site-Directed; Oxidoreductases; Sequence Homology, Amino Acid; Substrate Specificity

Sixteen lignanoids were isolated from an aqueous extract of the commonly used Chinese traditional medicine Dangshen, the dried roots of Codonopsis pilosula, by using a combination of various chromatographic techniques, including silica gel, macroporous adsorbent resin, MCI resin, sephadex LH-20, and reversed phase semi-preparative HPLC. On the basis of spectral data analysis, their structures were elucidated and identified as（-）-（7R,7’R,8R,8’S）-4,4’-dihydroxy-3,3’,5,5’,7-pentamethoxy-2,7’-cyclolignane（1）,（-）-（7R,8S）- dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranosyl-（1’’’→2’’）-β-D-glucopyranoside（2）,（-）-（7R,8S）- dihydrodehydrodiconiferyl alcohol（3）,（+）-（7S,8R）-dehydrodiconiferyl alcohol（4）,（+）-balanophonin（5）,（+）- demethoxypinoresinol（6）,（+）-pinoresinol（7）,（+）-epipinoresinol（8）,（-）-syringaresinol（9）,（-）-medioresinol（10）,（-）-lariciresinol（11）,（-）-secoisolariciresinol（12）,（-）-ent-isolariciresinol（13）,（+）-（7S,8S）-3-methoxy-3’,7- expoxy-8,4’-neolignan-4,9,9’-triol（14）,（+）-（7S,8R）-3’,4-dihydroxy-3-methoxy-8,4’-neolignan（15）, and（-）-（7R,8R）-3’,4-dihydroxy-3-methoxy-8,4’-neolignan（16）. All these compounds were isolated from C. pilosula for the first time, while compound 1 is a new natural product of 2,7’-cyclolignan and 2 is a new 4’,7-epoxy- 8,3’-neolignan diglucoside. Compound 12 showed activity against Fe(2+)-cysteine induced rat liver microsomal lipid peroxidation with an inhibition ratio of（63.4 ± 8.3） % at 1×10(-5) mol·L(-1).

Topics: Animals; Butylene Glycols; Codonopsis; Drugs, Chinese Herbal; Furans; Lignans; Microsomes, Liver; Molecular Structure; Plant Extracts; Plant Roots; Rats

A candidate gene for phenylcoumaran benzylic ether reductase in Arabidopsis thaliana encodes a peptide with predicted functional activity and plays a crucial role in secondary metabolism. Phenylcoumaran benzylic ether reductase (PCBER) is thought to be an enzyme crucial in the biosynthesis of 8-5'-linked neolignans. Genes of the enzyme have been isolated and characterized in several plant species. In this study, we cloned cDNA and the 5'-untranslated region of one PCBER candidate gene (At4g39230, designated AtPCBER1) from Arabidopsis thaliana. At the amino acid level, AtPCBER1 shows high sequence identity (64-71 %) with PCBERs identified from other plant species. Expression analyses of AtPCBER1 by reverse transcriptase-polymerase chain reaction and histochemical analysis of transgenic plants harboring the 5'-untranslated region of AtPCBER1 linked with gus coding sequence indicate that expression is induced by wounding and is expressed in most tissues, including flower, stem, leaf, and root. Catalytic analysis of recombinant AtPCBER1 with neolignan and lignans in the presence of NADPH suggests that the protein can reduce not only the 8-5'-linked neolignan, dehydrodiconiferyl alcohol, but also 8-8' linked lignans, pinoresinol, and lariciresinol, with lower activities. To investigate further, we performed metabolomic analyses of transgenic plants in which the target gene was up- or down-regulated. Our results indicate no significant effects of AtPCBER1 gene regulation on plant growth and development; however, levels of some secondary metabolites, including lignans, flavonoids, and glucosinolates, differ between wild-type and transgenic plants. Taken together, our findings indicate that AtPCBER1 encodes a polypeptide with PCBER activity and has a critical role in the biosynthesis of secondary metabolites in A. thaliana.

Topics: Arabidopsis; Arabidopsis Proteins; Biocatalysis; Flavonoids; Furans; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Glucosinolates; Lignans; Metabolomics; Oxidoreductases; Phenols; Phylogeny; Plants, Genetically Modified; Principal Component Analysis; Reverse Transcriptase Polymerase Chain Reaction; Tandem Mass Spectrometry

Nanoparticles, including gold nanoparticles (AuNP), have been used in imaging in cancer treatment and as therapeutic agents and drug delivery vehicles. Particularly lignans, also called phytoestrogens, have strong effects on the treatment of carcinomas due to their antiestrogenic, antiangiogenic and proapoptotic mechanism. The aim of this study is to investigate the antiproliferative effects of three lignans-AuNP conjugates, pinoresinol (PINO), lariciresinol (LARI) and secoisolariciresinol (SECO), on the MCF-7 cell lines. For this purpose, first, thiolated β-cyclodextrin (β-CD) was synthesized to achieve a surface modification of AuNP, and then the β-CD modified AuNP was characterized using the transmission electron microscopy (TEM), UV-Visible and Nuclear Magnetic Resonance (NMR) spectroscopy. Then, the selected lignans were conjugated to the β-CD-modified AuNP, and the antiproliferative effect of these conjugates was monitored. The results suggest that when compared to their non-conjugated forms, the AuNP-bound lignan conjugates prevented the proliferation of the MCF-7 cells significantly. Therefore, these AuNP-conjugated derivatives can be new candidate agents for breast cancer therapy.

Topics: beta-Cyclodextrins; Butylene Glycols; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Furans; Gold; Humans; Ligands; Lignans; MCF-7 Cells; Metal Nanoparticles; Molecular Structure; Organogold Compounds; Structure-Activity Relationship; Tumor Cells, Cultured

To study the chemical constituents in the stem bark of Styrax perkinsiae.. The chemical constituents were separated and purified by chromatographic methods after solvent extraction and identified by spectroscopic analyses.. Ten lignans were isolated from the stem bark of Styrax perkinsiae and identified as following: pinoresinol 4-O-β-D-glucopyranoside (1), matairesinoside (2), styraxlignolide B (3), 3- (β-D-glucopyranosyloxymethyl)-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl )-7-methoxy-(2R , 3S) -dihydrobenzofuran (4), burselignan (5), (+) -neo-olivil (6), threo-1-(4-hydroxy-3-methoxyphenyl )-2-[ 4-(3-hydroxypropyl)-2-methoxyphenoxy]-1, 3-propanediol (7), erythro-1-(4-hydroxy-3-methoxyphenyl )-2-[ 4-(3-hydroxypropyl )-2-methoxyphenoxy ] -1 ,3-propanediol (8), isolariciresinol(9) and (+) -lariciresinol (10).. Compounds 5 - 10 are isolated from the plants of Styrax genus for the first time.

Topics: Furans; Lignans; Lignin; Naphthols; Plant Bark; Plant Extracts; Styrax

In the present study, we evaluated the anti-inflammatory properties of several plant lignans most commonly distributed in foods. 7-Hydroxymatairesinol (HMR) and its major isomer 7-hydroxymatairesinol 2 (HMR2), lariciresinol, secoisolariciresinol, and pinoresinol, isolated from Norway spruce knots were examined.. We investigated the anti-inflammatory effects of lignans on tumor necrosis factor-α-treated human aortic endothelial cells by measuring the expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 by cell ELISA and the adhesion of U937 monocytes to activated endothelial cells using a cell adhesion assay. Among the lignans studied, HMR and HMR2 significantly reduced intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 levels as well as the adhesion of U937 to endothelial cells. To further characterize the molecular mechanisms involved in this regulation, the effect of HMR and HMR2 on nuclear factor-κB, SAPK/c-Jun NH2-terminal kinase and extracellular signal regulated kinase phosphorylation was assessed.. Our results demonstrated that the lignans HMR and HMR2, dominant in cereals such as in wheat, triticale, oat, barley, millet, corn bran, and in amaranth whole grain, exhibit strong anti-inflammatory properties in endothelial cells, at least in part, through attenuation of nuclear factor-κB and extracellular signal regulated kinase phosphorylation.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Aorta; Butylene Glycols; Cell Adhesion; Cells, Cultured; Endothelial Cells; Furans; Humans; Intercellular Adhesion Molecule-1; Lignans; MAP Kinase Kinase 4; Monocytes; NF-kappa B; Picea; PPAR gamma; Receptors, Estrogen; Vascular Cell Adhesion Molecule-1

RNAi technology was applied to down regulate LuPLR1 gene expression in flax (Linum usitatissimum L.) seeds. This gene encodes a pinoresinol lariciresinol reductase responsible for the synthesis of (+)-secoisolariciresinol diglucoside (SDG), the major lignan accumulated in the seed coat. If flax lignans biological properties and health benefits are well documented their roles in planta remain unclear. This loss of function strategy was developed to better understand the implication of the PLR1 enzyme in the lignan biosynthetic pathway and to provide new insights on the functions of these compounds. RNAi plants generated exhibited LuPLR1 gene silencing as demonstrated by quantitative RT-PCR experiments and the failed to accumulate SDG. The accumulation of pinoresinol the substrate of the PLR1 enzyme under its diglucosylated form (PDG) was increased in transgenic seeds but did not compensate the overall loss of SDG. The monolignol flux was also deviated through the synthesis of 8-5' linked neolignans dehydrodiconiferyl alcohol glucoside (DCG) and dihydro-dehydrodiconiferyl alcohol glucoside (DDCG) which were observed for the first time in flax seeds.

Topics: Butylene Glycols; Flax; Furans; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Gene Knockdown Techniques; Glucosides; Lignans; Oxidoreductases; Plant Proteins; Plants, Genetically Modified; RNA Interference; Seeds

Bacterial genes for the degradation of major dilignols produced in lignifying xylem are expected to be useful tools for the structural modification of lignin in plants. For this purpose, we isolated pinZ involved in the conversion of pinoresinol from Sphingobium sp. strain SYK-6. pinZ showed 43-77% identity at amino acid level with bacterial NmrA-like proteins of unknown function, a subgroup of atypical short chain dehydrogenases/reductases, but revealed only 15-21% identity with plant pinoresinol/lariciresinol reductases. PinZ completely converted racemic pinoresinol to lariciresinol, showing a specific activity of 46±3 U/mg in the presence of NADPH at 30°C. In contrast, the activity for lariciresinol was negligible. This substrate preference is similar to a pinoresinol reductase, AtPrR1, of Arabidopsis thaliana; however, the specific activity of PinZ toward (±)-pinoresinol was significantly higher than that of AtPrR1. The role of pinZ and a pinZ ortholog of Novosphingobium aromaticivorans DSM 12444 were also characterized.

Topics: Arabidopsis; Arabidopsis Proteins; Bacterial Proteins; Furans; Genes, Bacterial; Lignans; Lignin; Molecular Structure; Oxidoreductases; Recombinant Fusion Proteins; Sequence Homology, Amino Acid; Species Specificity; Sphingomonadaceae; Substrate Specificity

Higher intake of lignans, diphenolic plant compounds, may reduce the risk of certain types of cancer and cardiovascular diseases. We assessed the dietary intake of four lignans: matairesinol, secoisolariciresinol, lariciresinol and pinoresinol. Furthermore, for the breads we supplemented the data with two more lignans: syringaresinol and medioresinol. Study subjects were 172 men and 97 women aged 40-75 years, residing in Riga, the capital of Latvia, all living at home, eating habitual food. Median total lignan intake was 2259 (range 1169-5759) μg/day. Secoisolariciresinol contributed 58% and syringaresinol 22% of lignan intake. Bread was the major food source of lignans in men (86%), whereas in women it was bread (57%) and flaxseed (35%).

Topics: Adult; Aged; Bread; Butylene Glycols; Cardiovascular Diseases; Diet; Feeding Behavior; Female; Flax; Furans; Humans; Latvia; Lignans; Male; Middle Aged; Neoplasms; Phenols; Phytoestrogens; Plant Extracts; Sex Factors

Secoisolariciresinol diglucoside (SDG), the main phytoestrogenic lignan of Linum usitatissimum, is accumulated in the seed coat of flax during its development and pinoresinol-lariciresinol reductase (PLR) is a key enzyme in flax for its synthesis. The promoter of LuPLR1, a flax gene encoding a pinoresinol lariciresinol reductase, contains putative regulatory boxes related to transcription activation by abscisic acid (ABA). Gel mobility shift experiments evidenced an interaction of nuclear proteins extracted from immature flax seed coat with a putative cis-acting element involved in ABA response. As ABA regulates a number of physiological events during seed development and maturation we have investigated its involvement in the regulation of this lignan synthesis by different means. ABA and SDG accumulation time courses in the seed as well as LuPLR1 expression were first determined in natural conditions. These results showed that ABA timing and localization of accumulation in the flax seed coat could be correlated with the LuPLR1 gene expression and SDG biosynthesis. Experimental modulations of ABA levels were performed by exogenous application of ABA or fluridone, an inhibitor of ABA synthesis. When submitted to exogenous ABA, immature seeds synthesized 3-times more SDG, whereas synthesis of SDG was reduced in immature seeds treated with fluridone. Similarly, the expression of LuPLR1 gene in the seed coat was up-regulated by exogenous ABA and down-regulated when fluridone was applied. These results demonstrate that SDG biosynthesis in the flax seed coat is positively controlled by ABA through the transcriptional regulation of LuPLR1 gene.

Topics: Abscisic Acid; Butylene Glycols; Flax; Furans; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genes, Plant; Lignans; Oxidoreductases; Plant Growth Regulators; Plants, Genetically Modified; Seeds

To separate and identify chemical constituents from Coptis chinensis.. The compounds were separated and purified by various chromatographic techniques. Their structures were identified on the basis of their physicochemical properties using spectral techniques such as NMR and MS.. Thirteen compounds were separated from ethanol extracts of C. chinensis, including seven lignans, three simple phenylpropanoids, two flavones and one phenolic acid, and identified as erythro-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (1), threo-guaiacylglycerol-8-O-4'-(coniferyl alcohol) ether (2), (+)-pinoresinol (3), (+)-medioresinol (4), (+)-lariciresinol (5), (+)-5'-methoxylariciresinol (6), (+)-isolariciresinol (7), chlorogenic acid (8), ferulic acid (9), Z-octadecyl caffeate (10), rhamnetin (11), wogonin (12), and vanillic acid (13).. Compounds 1, 2, 4, 6, 10-13 were separated from the genus Coptis for the first time.

Topics: Caffeic Acids; Chlorogenic Acid; Coptis; Coumaric Acids; Ethanol; Flavanones; Flavones; Furans; Hydroxybenzoates; Lignans; Lignin; Naphthols; Quercetin; Vanillic Acid

Dietary lignans show some promising health benefits, but little is known about their fate and activities in the small intestine. The purpose of this study was thus to investigate whether plant lignans are taken up by intestinal cells and modulate the intestinal inflammatory response using the Caco-2 cell model. Six lignan standards [secoisolariciresinol diglucoside (SDG), secoisolariciresinol (SECO), pinoresinol (PINO), lariciresinol, matairesinol (MAT), and hydroxymatairesinol] and their colonic metabolites [enterolactone (ENL) and enterodiol] were studied. First, differentiated cells were exposed to SDG, SECO, PINO, or ENL at increasing concentrations for 4 h, and their cellular contents (before and after deconjugation) were determined by HPLC. Second, in IL-1β-stimulated confluent and/or differentiated cells, lignan effects were tested on different soluble proinflammatory mediators quantified by enzyme immunoassays and on the NF-κB activation pathway by using cells transiently transfected. SECO, PINO, and ENL, but not SDG, were taken up and partly conjugated by cells, which is a saturable conjugation process. PINO was the most efficiently conjugated (75% of total in cells). In inflamed cells, PINO significantly reduced IL-6 by 65% and 30% in confluent and differentiated cells, respectively, and cyclooxygenase (COX)-2-derived prostaglandin E(2) by 62% in confluent cells. In contrast, MAT increased significantly COX-2-derived prostaglandin E(2) in confluent cells. Moreover, PINO dose-dependently decreased IL-6 and macrophage chemoattractant protein-1 secretions and NF-κB activity. Our findings suggest that plant lignans can be absorbed and metabolized in the small intestine and, among the plant lignans tested, PINO exhibited the strongest antiinflammatory properties by acting on the NF-κB signaling pathway, possibly in relation to its furofuran structure and/or its intestinal metabolism.

Topics: 4-Butyrolactone; Anti-Inflammatory Agents; Butylene Glycols; Caco-2 Cells; Cell Differentiation; Chemokine CCL2; Chromatography, High Pressure Liquid; Cyclooxygenase 2; Furans; Glucosides; Humans; Interleukin-1beta; Interleukin-6; Interleukin-8; Intestines; Lignans; NF-kappa B; Plant Extracts; Signal Transduction

It has been suggested that lignan intake may decrease the risk for cardiovascular disease (CVD) by modifying traditional risk factors as well as aortic stiffness. However, the role of dietary lignans on the vascular system is largely unknown. The objective was to investigate whether dietary intake of plant lignans in a free-living population was associated with markers of vascular inflammation and function.. We performed a cross-sectional study in 242 (151 males) men and post-menopausal women. Anthropometric characteristics and lignan intake were evaluated. Soluble intercellular adhesion molecule-1 (sICAM-1), insulin, high-sensitive C-reactive protein, glucose, total cholesterol, HDL-cholesterol and triacylglycerols were measured in fasting blood samples. Brachial flow-mediated dilation (FMD) measurements were available for 101 subjects (56 males). Median (interquartile range) daily intake of matairesinol (MAT), secoisolariciresinol (SECO), pinoresinol (PINO), lariciresinol (LARI), and total lignans was 20.9 microg (17.4), 335.3 microg (289.1), 96.7 microg (91.1), 175.7 microg (135.8), and 665.5 microg (413.7), respectively, as assessed by 3-day weighed food record. Plasma concentrations of sICAM-1 (whole sample) significantly decreased (mean (95%CI) = 358 microg/L (320-401), 276 microg/L (252-303), 298 microg/L (271-326), and 269 microg/L (239-303), P per trend 0.013) and FMD values (FMD sub-group) significantly increased (4.1% (2.2-6.0), 5.7% (4.3-7.2), 6.4% (4.9-7.8), and 8.1% (6.3-10.0), P per trend 0.016) across quartiles of energy-adjusted MAT intake, even after adjustment for relevant clinical and dietary variables. Intake of SECO was also inversely related to plasma sICAM-1 (P per trend 0.018), but not to FMD values. No relationship between intake of PINO, LARI or total lignans and either sICAM-1 or FMD values was observed.. Higher MAT intakes in the context of a typical Northern Italian diet are associated to lower vascular inflammation and endothelial dysfunction, which could have some implications in CVD prevention.

Topics: Aged; Biomarkers; Butylene Glycols; Cardiovascular Diseases; Cross-Sectional Studies; Diet; Diet Records; Diet, Mediterranean; Endothelium, Vascular; Female; Furans; Hemodynamics; Humans; Inflammation; Italy; Lignans; Male; Middle Aged; Phytoestrogens; Surveys and Questionnaires; Vascular Diseases

Due to their peculiar stereochemistry and numerous biological activities, lignans are of widespread interest. As only a few biosynthetic steps have been clarified to date, we aimed to further resolve the molecular basis of lignan biosynthesis. To this end, we first established that the biologically active lignan (-)-hinokinin could be isolated from in vitro cultures of Linum corymbulosum. Two hypothetical pathways were outlined for the biosynthesis of (-)-hinokinin. In both pathways, (+)-pinoresinol serves as the primary substrate. In the first pathway, pinoresinol is reduced via lariciresinol to secoisolariciresinol by a pinoresinol-lariciresinol reductase, and methylenedioxy bridges are formed later. In the second pathway, pinoresinol itself is the substrate for formation of the methylenedioxy bridges, resulting in consecutive production of piperitol and sesamin. To determine which of the proposed hypothetical pathways acts in vivo, we first isolated several cDNAs encoding one pinoresinol-lariciresinol reductase (PLR-Lc1), two phenylcoumaran benzylic ether reductases (PCBER-Lc1 and PCBER-Lc2), and two PCBER-like proteins from a cDNA library of L. corymbulosum. PLR-Lc1 was found to be enantiospecific for the conversion of (+)-pinoresinol to (-)-secoisolariciresinol, which can be further converted to give (-)-hinokinin. Hairy root lines with significantly reduced expression levels of the plr-Lc1 gene were established using RNAi technology. Hinokinin accumulation was reduced to non-detectable levels in these lines. Our results strongly indicate that PLR-Lc1 participates in (-)-hinokinin biosynthesis in L. corymbulosum by the first of the two hypothetical pathways via (-)-secoisolariciresinol.

Topics: 4-Butyrolactone; Amino Acid Sequence; Benzodioxoles; Butylene Glycols; Cells, Cultured; Cloning, Molecular; Dioxoles; DNA, Complementary; Flax; Furans; Gene Expression; Gene Library; Genes, Plant; Lignans; Molecular Sequence Data; Oxidoreductases; Phylogeny; Plant Proteins; RNA, Plant; Sequence Alignment; Sequence Homology, Amino Acid

A cDNA encoding a pinoresinol-lariciresinol reductase PLR (PLR-Lp1) was isolated from a cell culture of Linum perenne Himmelszelt accumulating the arylnaphthalene lignan justicidin B. The recombinant PLR-Lp1 prefers (+)-pinoresinol in the first reaction step, but (-)-lariciresinol in the second step. Therefore, it is the first PLR described with opposite enantiospecificity within the two reaction steps catalysed by PLRs. Hairy root lines transformed with an ihpRNAi construct to suppress plr gene expression show less mRNA accumulation for the plr-Lp1 gene and PLR enzyme activity. Justicidin B accumulation was reduced down to 24% in comparison to control lines showing the involvement of PLR-Lp1 in the biosynthesis of justicidin B.

Topics: Base Sequence; Blotting, Southern; Catalysis; Cloning, Molecular; Dioxolanes; DNA, Plant; Escherichia coli; Flax; Furans; Gene Expression Regulation, Plant; Gene Silencing; Genes, Plant; Genome, Plant; Lignans; Plant Proteins; Plant Roots; RNA, Messenger

Plant lignans are converted to enterolignans that have antioxidant and weak estrogen-like activities, and therefore they may lower cardiovascular disease and cancer risks.. We investigated whether the intakes of 4 plant lignans (lariciresinol, pinoresinol, secoisolariciresinol, and matairesinol) were inversely associated with coronary heart disease (CHD), cardiovascular diseases (CVD), cancer, and all-cause mortality.. The Zutphen Elderly Study is a prospective cohort study in which 570 men aged 64-84 y were followed for 15 y. We recently developed a database and used it to estimate the dietary intakes of 4 plant lignans. Lignan intake was related to mortality with the use of Cox proportional hazards analysis.. The median total lignan intake in 1985 was 977 microg/d. Tea, vegetables, bread, coffee, fruit, and wine were the major sources of lignan. The total lignan intake was not related to mortality. However, the intake of matairesinol was inversely associated with CHD, CVD, and all-cause mortality (P

Topics: Aged; Aged, 80 and over; Butylene Glycols; Cardiovascular Diseases; Cause of Death; Cohort Studies; Coronary Disease; Diet; Diet Surveys; Furans; Humans; Lignans; Male; Middle Aged; Multivariate Analysis; Neoplasms; Netherlands; Proportional Hazards Models; Prospective Studies; Wine

Enterolignans (enterodiol and enterolactone) can potentially reduce the risk of certain cancers and cardiovascular diseases. Enterolignans are formed by the intestinal microflora after the consumption of plant lignans. Until recently, only secoisolariciresinol and matairesinol were considered enterolignan precursors, but now several new precursors have been identified, of which lariciresinol and pinoresinol have a high degree of conversion. Quantitative data on the contents in foods of these new enterolignan precursors are not available. Thus, the aim of this study was to compile a lignan database including all four major enterolignan precursors. Liquid chromatography-tandem mass spectrometry was used to quantify lariciresinol, pinoresinol, secoisolariciresinol and matairesinol in eighty-three solid foods and twenty-six beverages commonly consumed in The Netherlands. The richest source of lignans was flaxseed (301,129 microg/100 g), which contained mainly secoisolariciresinol. Also, lignan concentrations in sesame seeds (29,331 microg/100 g, mainly pinoresinol and lariciresinol) were relatively high. For grain products, which are known to be important sources of lignan, lignan concentrations ranged from 7 to 764 microg/100 g. However, many vegetables and fruits had similar concentrations, because of the contribution of lariciresinol and pinoresinol. Brassica vegetables contained unexpectedly high levels of lignans (185-2321 microg/100 g), mainly pinoresinol and lariciresinol. Lignan levels in beverages varied from 0 (cola) to 91 microg/100 ml (red wine). Only four of the 109 foods did not contain a measurable amount of lignans, and in most cases the amount of lariciresinol and pinoresinol was larger than that of secoisolariciresinol and matairesinol. Thus, available databases largely underestimate the amount of enterolignan precursors in foods.

Topics: Beverages; Butylene Glycols; Databases, Factual; Edible Grain; Food Analysis; Fruit; Furans; Humans; Lignans; Netherlands; Plants, Edible; Seeds; Vegetables

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of the four major enterolignan precursors [secoisolariciresinol, matairesinol, lariciresinol, and pinoresinol] in foods. The method consists of alkaline methanolic extraction, followed by enzymatic hydrolysis using Helix pomatia (H. pomatia) beta-glucuronidase/sulfatase. H. pomatia was selected from several enzymes based on its ability to hydrolyze isolated lignan glucosides. After ether extraction samples were analyzed and quantified against secoisolariciresinol-d8 and matairesinol-d6. The method was optimized using model products: broccoli, bread, flaxseed, and tea. The yield of methanolic extraction increased up to 81%, when it was combined with alkaline hydrolysis. Detection limits were 4-10 microg/(100 g dry weight) for solid foods and 0.2-0.4 microg/(100 mL) for beverages. Within- and between-run coefficients of variation were 6-21 and 6-33%, respectively. Recovery of lignans added to model products was satisfactory (73-123%), except for matairesinol added to bread (51-55%).

Topics: Butylene Glycols; Chromatography, Liquid; Food Analysis; Furans; Hydrolysis; Lignans; Mass Spectrometry; Plants; Sensitivity and Specificity

Total extract of resin from Araucaria angustifolia was analyzed by gas chromatography/mass spectrometry and 32 lignans were identified. Lignan acetates are present in the resin and consist of four secoisolariciresinol acetates, six lariciresinol acetates, two 7'-hydroxylariciresinol acetates and an isolariciresinol acetate, which have hitherto not been reported in the plant kingdom. Shonanin and 7'-hydroxylariciresinol type lignans are also present in A. angustifolia resin. Lignans containing syringyl moieties, characteristic for angiosperms, occur in the resin and consist of 5-methoxylariciresinol-9-acetate, 5'-methoxylariciresinol-9-acetate, 5-methoxypinoresinol dimethyl ether and 5-methoxypinoresinol. This is noteworthy because syringyl moieties have only been reported for Thuja species (Cupressaceae) among the gymnosperms. The mass spectra of the various lignan trimethylsilyl derivatives are discussed with the interpretations of the fragmentation patterns.

Topics: Butylene Glycols; Furans; Gas Chromatography-Mass Spectrometry; Lignans; Lignin; Naphthols; Phenols; Pinus; Resins, Plant; Trimethylsilyl Compounds

Phytoestrogens of the lignan type are widely distributed in plant-derived food items and are believed to protect against hormone-dependent cancer. The richest known dietary source of lignans is flaxseed. Flaxseed has been reported to contain glycosides of secoisolariciresinol as the major lignan, together with small amounts of matairesinol, isolariciresinol, and pinoresinol. Secoisolariciresinol, but none of the other lignans, has so far been identified in pumpkin seeds. In the present study, two different methods for the hydrolysis of lignan glycosides are compared. Artifact formation and loss of lignans under acidic conditions were observed. Lariciresinol was identified by GC-MS analysis in two different types of flaxseed (Linum usitatissimum L. and Linum flavum L.) and in pumpkin seeds (Cucurbita pepo L.) for the first time. Likewise, the novel lignan demethoxy-secoisolariciresinol was tentatively identified in the flaxseed samples. Stereochemical analysis by chiral HPLC of several lignans isolated from flaxseed showed that secoisolariciresinol, matairesinol, and lariciresinol consisted predominantly of one enantiomer.

Topics: Butylene Glycols; Chromatography, High Pressure Liquid; Cucurbita; Flax; Furans; Gas Chromatography-Mass Spectrometry; Hydrogen-Ion Concentration; Hydrolysis; Lignans; Lignin; Seeds; Stereoisomerism

Intramolecular radical cyclization of suitably substituted epoxy ethers 4a-g using bis(cyclopentadienyl)titanium(III) chloride as the radical source resulted in trisubstituted tetrahydrofurano lignans and 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane lignans depending on the reaction conditions. The titanium(III) species was prepared in situ from commercially available titanocene dichloride and activated zinc dust in THF. Upon radical cyclization followed by acidic workup, epoxy olefinic ethers 4a-g afforded furano lignans dihydrosesamin 1a, lariciresinol dimethyl ether 1b, acuminatin methyl ether 1e, and sanshodiol methyl ether 1g directly and lariciresinol 1h, acuminatin 1i, and lariciresinol monomethyl ether 1j after removal of the benzyl protecting group by controlled hydrogenolysis of the corresponding cyclized products. The furofuran lignans sesamin 2a, eudesmin 2b, and piperitol methyl ether 2e were also prepared directly by using the same precursors 4a-f on radical cyclization followed by treatment with iodine and pinoresinol 2h, piperitol 2i, and pinoresinol monomethyl ether 2j after controlled hydrogenolysis of the benzyl protecting group of the corresponding cyclized products. Two naturally occurring acyclic lignans, secoisolariciresinol 5h and secoisolariciresinol dimethyl ether 5b, have also been prepared by exhaustive hydrogenolysis of 2h and 2b, respectively.

Topics: Alkylation; Catalysis; Chemistry, Organic; Cyclization; Dioxoles; Epoxy Compounds; Ethers, Cyclic; Flavonoids; Furans; Glycosides; Lignans; Lignin; Magnetic Resonance Spectroscopy; Molecular Structure; Stereoisomerism

Pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." This study establishes the first known catalytic function for the latter, as being able to engender the NADPH-dependent reduction of phenylcoumaran benzylic ethers. Accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. In this investigation, the phenylcoumaran benzylic ether reductase from the gymnosperm, Pinus taeda, was cloned, with the recombinant protein heterologously expressed in Escherichia coli. The purified enzyme reduces the benzylic ether functionalities of both dehydrodiconiferyl alcohol and dihydrodehydrodiconiferyl alcohol, with a higher affinity for the former, as measured by apparent Km and Vmax values and observed kinetic 3H-isotope effects. It abstracts the 4R-hydride of the required NADPH cofactor in a manner analogous to that of the pinoresinol-lariciresinol reductases and isoflavone reductases. A similar catalytic function was observed for the corresponding recombinant reductase whose gene was cloned from the angiosperm, Populus trichocarpa. Interestingly, both pinoresinol-lariciresinol reductases and isoflavone reductases catalyze enantiospecific conversions, whereas the phenylcoumaran benzylic ether reductase only shows regiospecific discrimination. A possible evolutionary relationship among the three reductase classes is proposed, based on the supposition that phenylcoumaran benzylic ether reductases represent the progenitors of pinoresinol-lariciresinol and isoflavone reductases.

Topics: Amino Acid Sequence; Base Sequence; Cloning, Molecular; DNA, Complementary; Furans; Lignans; Lignin; Molecular Sequence Data; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors; Sequence Homology, Amino Acid; Stereoisomerism; Trees