- Acyl glycosides lignans, coumarins, and terpenes from the stems of Erycibe obtusifolia
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Nine new acyl glycosides, obtusifosides A-I (1-9), and eight known compounds have been isolated from an EtOH extract of the stems of Erycibe obtusifolia. Their structures were elucidated on the basis of a spectroscopic data analysis (NMR, HRESIMS, and CD) and chemical evidence. The hepatoprotective effects of some of the compounds from d-galactosamine-induced cytotoxicity in HL-7702 hepatic cells were evaluated. Compounds 1, 10, 11, 13, 16, and 17 showed significant hepatoprotective activities compared with the positive control bicyclol at concentrations of 1 × 10-5 M.
- Liu, Zhao-Zhen,Zhan, Zhi-Lai,Liu, Fu,Yang, Ya-Nan,Feng, Zi-Ming,Jiang, Jian-Shuang,Zhang, Pei-Cheng
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- ADMET polymerization of biobased monomers deriving from syringaresinol
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Renewable α,ω-dienes have been prepared from syringaresinol, a naturally occurring bisphenol deriving from sinapyl alcohol, and further studied as monomers in ADMET polymerizations. Polymerization was optimized according to catalyst loading and reaction conditions (in mass vs. in solvent), and led to polymers with molecular weight up to 14.1 kDa. Thermal analyses of these new polymers showed excellent thermal stabilities (257-360 °C) and tunable Tg (18-70 °C) depending on the structure of the starting α,ω-diene monomer.
- Hollande, Louis,Jaufurally, Abdus Samad,Ducrot, Paul-Henri,Allais, Florent
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- Neuritogenesis of herbal (+)- and (-)-syringaresinols separated by chiral HPLC in PC12h and neuro2a Cells
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Syringaresinol isolated from Epimedium koreanum NAKAI and Magnolia officinalis REHB. et WILS. was subjected to optical resolution by chiral HPLC to give (+)- and (-)-enantiomers. The two syringaresinol enantiomers, as well as a mixture of their glucosides, showed dose-dependent neuritogenesis in a concentration range from 0.24 to 24 μM in PC12h cells.
- Chiba, Kenzo,Yamazaki, Matsumi,Umegaki, Emiko,Ming, Run Li,Zhen, Wen Xu,Terada, Sumio,Taka, Michihiro,Naoi, Noriyuki,Mohri, Tetsuro
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- Dirigent Proteins Guide Asymmetric Heterocoupling for the Synthesis of Complex Natural Product Analogues
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Phenylpropanoids are a class of abundant building blocks found in plants and derived from phenylalanine and tyrosine. Phenylpropanoid polymerization leads to the second most abundant biopolymer lignin while stereo- and site-selective coupling generates an array of lignan natural products with potent biological activity, including the topoisomerase inhibitor and chemotherapeutic etoposide. A key step in etoposide biosynthesis involves a plant dirigent protein that promotes selective dimerization of coniferyl alcohol, a common phenylpropanoid, to form (+)-pinoresinol, a critical C2 symmetric pathway intermediate. Despite the power of this coupling reaction for the elegant and rapid assembly of the etoposide scaffold, dirigent proteins have not been utilized to generate other complex lignan natural products. Here, we demonstrate that dirigent proteins from Podophyllum hexandrum in combination with a laccase guide the heterocoupling of natural and synthetic coniferyl alcohol analogues for the enantioselective synthesis of pinoresinol analogues. This route for complexity generation is remarkably direct and efficient: three new bonds and four stereocenters are produced from two different achiral monomers in a single step. We anticipate our results will enable biocatalytic routes to difficult-to-access non-natural lignan analogues and etoposide derivatives. Furthermore, these dirigent protein and laccase-promoted reactions of coniferyl alcohol analogues represent new regio- and enantioselective oxidative heterocouplings for which no other chemical methods have been reported.
- Kim, Stacie S.,Sattely, Elizabeth S.
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supporting information
p. 5011 - 5021
(2021/05/04)
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- Pinoresinol-lariciresinol reductase: Substrate versatility, enantiospecificity, and kinetic properties
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Two western red cedar pinoresinol-lariciresinol reductase (PLR) homologues were studied to determine their enantioselective, substrate versatility, and kinetic properties. PLRs are downstream of dirigent protein engendered, coniferyl alcohol derived, stereoselective coupling to afford entry into the 8- and 8′-linked furofuran lignan, pinoresinol. Our investigations showed that each PLR homolog can enantiospecifically metabolize different furofuran lignans with modified aromatic ring substituents, but where phenolic groups at both C4/C4′ are essential for catalysis. These results are consistent with quinone methide intermediate formation in the PLR active site. Site-directed mutagenesis and kinetic measurements provided additional insight into factors affecting enantioselectivity and kinetic properties. From these data, PLRs can be envisaged to allow for the biotechnological potential of generation of various lignan skeleta, that could be differentially “decorated” on their aromatic ring substituents, via the action of upstream dirigent proteins.
- Davin, Laurence B.,Hwang, Julianne K.,Lewis, Norman G.,Moinuddin, Syed G. A.
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- Profiling of the formation of lignin-derived monomers and dimers from: Eucalyptus alkali lignin
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Lignin is a renewable and the most abundant aromatic source that can be used for extensive chemicals and materials. Although approximately 50 million tons of lignin are produced annually as a by-product of the pulp and paper industry, it is currently underutilized. It is important to know the structural features of technical lignin when considering its application. In this work, we have demonstrated the formation of low-molecular-weight constituents from hardwood (Eucalyptus) lignin, which produces much more low-molecular-weight constituents than softwood (spruce) lignin, after a chemical pulping process, and analyzed the micromolecular compositions in the alkali lignin after fractionation by dichloromethane (DCM) extraction. By applying analytical methods (gel-permeation chromatography, 2D NMR and GC-MS) with the aid of evidence from authenticated compounds, a great treasure trove of lignin-derived phenolic compounds from Eucalyptus alkali lignin were disclosed. Except for some common monomeric products, as many as 15 new lignin-derived monomers and dimers including syringaglycerol, diarylmethane, 1,2-diarylethanes, 1,2-diarylethenes, (arylvinyl ether)-linked arylglycerol dimers and isomeric syringaresinols were identified in the DCM-soluble fraction. Regarding the formation and evolution of the Cα-condensed β-aryl ether structure, a novel route that is potentially responsible for the high content of β-1 diarylethenes and diarylethanes in the lignin low-molecular-weight fraction, in addition to the β-1 (spirodienone) pathway, was proposed. This work not only provides novel insights into the chemical transformation of S-G lignin during the alkali pulping process, but also discovered lignin-derived phenolic monomers and dimers that can potentially be used as raw materials in the chemical or pharmaceutical industries. This journal is
- Hu, Zhenhua,Li, Suxiang,Lu, Fachuang,Shi, Lanlan,Wang, Chen,Yue, Fengxia,Zhang, Han,Zhao, Chengke
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supporting information
p. 7366 - 7375
(2020/11/18)
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- Biomimetic Oxidation of Monolignol Acetate and p-Coumarate by Silver Oxide in 1,4-Dioxane
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Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of ?3-acylated monolignols with Ag2O was studied to understand the effect of ?3-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave ?3-acylated and α-acylated β-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced ?3-acylated β-O-4 and ?3-acylated tetralin β-β dimers in 53 and 16% yields, respectively. Only the sinapyl alcohol moiety in sinapyl p-coumarate reacted, and the p-coumarate moiety remained unchanged, suggesting that p-coumaric acid is not incorporated into the lignin backbone in the acylated lignins. All of the ?3-acylated monolignols used in this study produced the ?3-acylated β-O-4 dimers, which suggests that the ?3-acylated monolignols act as lignin monomers. The relatively high yields of the β-O-4 dimers indicate that Ag2O oxidation of the monolignols can be used as an easy method for synthesizing the β-O-4 dimer model compounds.
- Hamada, Masahiro,Kishimoto, Takao,Nakajima, Noriyuki,Urabe, Daisuke,Yamashita, Ayana
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p. 2124 - 2131
(2020/03/06)
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- Syringaresinol inhibits UVA-induced MMP-1 expression by suppression of mapk/ap-1 signaling in hacat keratinocytes and human dermal fibroblasts
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Ultraviolet (UV) irradiation induces detrimental changes in human skin which result in photoaging. UV-induced intracellular changes cause degradation of extracellular matrix (ECM). UV-stimulated cleavage of collagen in ECM occurs via matrix metalloproteinases (MMPs). (±)syringaresinol (SYR), a phytochemical which belongs to the lignan group of polyphenols, was investigated for its ability to reverse the UVA-induced changes in human HaCaT keratinocytes and dermal fibroblasts (HDFs) in vitro. Effect of SYR on UVA-induced changes was investigated by production and activation of MMPs and its transcriptional upstream effectors; mitogen-activated protein kinases (MAPKs) and pro-inflammatory mediators. Levels of expression were determined using ELISA, RT-PCR and immunoblotting. UVA irradiation stimulated the production of MMP-1 and inhibited collagen production. SYR treatment suppressed MMP-1 and enhanced collagen production in UVA-irradiated HaCaT keratinocytes and HDFs. SYR repressed the UV-induced phosphorylation of p38, ERK and JNK MAPKs in HaCaT keratinocytes while only suppressing JNK phosphorylation in HDFs. In addition, SYR was able to inhibit UVA-induced production of inflammatory cytokines; TNF-α, COX-2, IL-1β and IL-6. Moreover, SYR suppressed the activator protein-1 (AP-1), a heterodimer of phosphorylated transcription factors c-Jun and c-Fos. SYRtreatment decreased nuclear levels of activated c-Fos and c-Jun as a mechanism to inhibit UVAinduced transcriptional activities leading to MMP-1 production. In conclusion, current results demonstrated that SYR could inhibit UVA-induced upregulation of MMP-1 by suppressing MAPK/AP-1 signaling in HaCaT keratinocytes and HDFs. Therefore, SYR was suggested as a potential compound with antiphotoaging properties against UVA-induced skin aging.
- Joo, Yung Hyup,Karadeniz, Fatih,Ko, Jaeyoung,Kong, Chang-Suk,Oh, Jung Hwan
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- METHOD FOR PREPARING FUROFURAN LIGNAN COMPOUND
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The present invention relates to a method for preparing a furofuran lignan compound, comprising a step of selecting and alkylating an epoxy alcohol compound and an optical isomer thereof. (+)-furofuran lignan and (?)-furofuran lignan, as well as an optical isomer thereof, can be selectively prepared by means of the method.
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Paragraph 0036; 0037; 0044; 0045
(2015/03/16)
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- The synthesis and analysis of advanced lignin model polymers
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If the lignin-first biorefinery concept becomes a reality, high quality lignins close in structure to native lignins will become available in large quantities. One potential way to utilise this renewable material is through depolymerisation to aromatic chemicals. This will require the development of new chemical methods. Here, we report the synthesis and characterisation of advanced lignin model polymers to be used as tools to develop these methods. The controlled incorporation of the major linkages in lignin is demonstrated to give complex hardwood and softwood lignin model polymers. These polymers have been characterised by 2D HSQC NMR and GPC analysis and have been compared to isolated lignins.
- Lancefield,Westwood
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p. 4980 - 4990
(2015/11/16)
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- New lignans from the aerial parts of Rudbeckia laciniata
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Three new furofuran lignans, (+)-4,4′-O-diangeloylpinoresinol (1), (+)-4,4′-O-diangeloylmedioresinol (2), and (+)-4,4′-O- diangeloylsyringaresinol (3), together with the known compound (+)-syringaresinol, were isolated from the MeOH extract of Rudbeckia l
- Lee, Seung Young,Woo, Kyeong Wan,Kim, Chung Sub,Lee, Dong Ung,Lee, Kang Ro
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p. 320 - 325
(2013/03/28)
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- Novel tetrahydrofuran structures derived from β-β-coupling reactions involving sinapyl acetate in Kenaf lignins
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Free radical coupling of sinapyl γ-acetate or cross-coupling between sinapyl acetate and sinapyl alcohol yields novel tetrahydrofuran β-β-(cross-)coupled dehydrodimers. Such substructures are therefore anticipated in naturally acetylated lignins, e.g. in Kenaf, if sinapyl acetate is a component of the lignin monomer pool. The DFRC (derivatization followed by reductive cleavage) method, modified by replacing all acetyl reagents and solvents with their propionyl analogs (DFRC′), allows the analysis of naturally acetylated lignins. DFRC′ treatment of the sinapyl acetate-derived dimers or crossed dimers gave diagnostic products that retain at least one acetate group on a sidechain γ-position; the products have been authenticated by comparison of their mass spectra and GC retention times with those of synthesized compounds. DFRC′ of Kenaf lignins produces the same diagnostic products as from the dimers, implicating the presence of the various tetrahydrofuran units in Kenaf lignins. With data from the model compounds in hand, NMR analysis of Kenaf lignins elegantly confirms the presence of such substructures in the polymer, establishing that acetates on Kenaf lignins arise through incorporation of sinapyl acetate, as a lignin precursor, via enzyme-mediated radical coupling mechanisms. The Royal Society of Chemistry 2008.
- Lu, Fachuang,Ralph, John
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experimental part
p. 3681 - 3694
(2009/02/05)
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- In vivo anti-inflammatory and antinociceptive effects of liriodendrin isolated from the stem bark of Acanthopanax senticosus
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In the present study, liriodendrin isolated by activity-guided fractionation from the ethyl acetate (EtOAc) extracts of the stem bark of Acanthopanax senticosus, was evaluated for anti-inflammatory and antinociceptive activities. Liriodendrin (5, 10 mg/kg/day, p.o.) significantly inhibited the increase of vascular permeability induced by acetic acid in mice and reduced an acute paw edema induced by carrageenan in rats. When the analgesic activity was measured by the acetic acid-induced writhing test and hot plate test, liriodendrin showed a dose-dependent inhibition in animal models. In addition, syringaresinol, the hydrolysate of liriodendrin, more potently inhibited the LPS-induced production of NO, PGE2 and TNF-α production of macrophages than liriodendrin. Consistent with these observations, the expression level of iNOS and COX-2 enzyme was decreased by syringaresinol in a concentration-dependent manner. These results suggest that the anti-inflammatory and antinociceptive effects of liriodendrin after oral administration were attributable to the in vivo transformation to syringaresinol, which may function as the active constituent.
- Jung, Hyun-Ju,Park, Hee-Juhn,Kim, Ryung-Gue,Shin, Kyoung-Min,Ha, Joohun,Choi, Jong-Won,Kim, Hyoung Ja,Lee, Yong Sup,Lee, Kyung-Tae
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p. 610 - 616
(2007/10/03)
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- Phenolic glycosides from rhizomes of Smilax glabra
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A new lignan glycoside, (+)-syringaresinol 4-O-β-D-glucopyranosyl-(1→6) -β-D-glucopyranoside (1), together with twelve known compounds, were isolated from the rhizomes of Smilax glabra. The structure was established on the basis of chemical and spectroscopic methods.
- Yuan, Jiuzhi,Li, Wei,Koike, Kazuo,Chen, Yingjie,Nikaido, Tamotsu
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p. 1633 - 1637
(2007/10/03)
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- Clay catalysed convenient isomerization of natural furofuran lignans under microwave irradiation
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The naturally occuring furofuron lignans, (+)-sesamin, (+)-eudesmin, (+)-syringaresinol and (+)-yangambin underwent rapid isomerization to their corresponding C-7 epimers under microwave irradiation in the presence of montmorillonite KSF as catalyst.
- Das,Madhusudhan,Venkataiah
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p. 4001 - 4006
(2007/10/03)
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- SYNTHESIS OF BIOLOGICALLY ACTIVE TETRAHYDROFUROFURANLIGNAN-(SYRINGIN, PINORESINOL)- MONO- AND BIS-GLYCOSIDES
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The naturally occuring tetrahydrofurofuran-lignan-(syringaresinol, pinoresinol)-mono- and bis-glucosides were synthesized and their structures thereby confirmed.Key Word Index - Ligan-glucosides; synthesis; syringaresinol and pinoresinol glucosides.
- Vermes, Barbara,Seligmann, Otto,Wagner, Hildebert
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p. 3087 - 3090
(2007/10/02)
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- Studies on the constituents of the bark of Kalopanax pictus Nakai
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Five new compounds, kalopanaxsaponin G (2) and kalopanaxins A (6), B (8), C (11) and D (13), were isolated from the bark of Kalopanax pictus together with nine known compounds, kalopanaxsaponins A (1) and B (5), pericarpsaponin P(J3) (3), hederasaponin B (4), syringin (7), protocatechuic acid (9), coniferin (10), liriodendrin (=dl-syringaresinol di-O-glucopyranoside) (12), glucosyringic acid (14) and chlorogenic acid (15). The structures of the new compounds were characterized as hederagenin 28-O-α-L-rhamnopyranosyl(1→4)-β-D-glucopyranosyl(1→6)-β-D- glucopyranoside (2), ferulylaldehyde (=coniferylaldehyde) 4-O-β-D-glucopyranoside (6), coniferin 6'-O-(4-O-α-L-rhamnopyranosyl)-syringate (8), 2-methoxyhydroquinone 4-O-[6-O[(4-O-α-L-rhamnopyranosyl)-syringyl]-β-D-glucopyranoside (11) and coniferyl alcohol 4-O-β-D-apiofuranosyl(1→2)-β-D-glucopyranoside (=coniferin 2'-O-β-D-apiofuranoside) (13).
- Sano,Sanada,Ida,Shoji
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p. 865 - 870
(2007/10/02)
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- The Constituents of Eucommia ulmoides OLIV. I. Isolation of (+)-Medioresinol Di-O-β-D-glucopyranoside
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A new lignan diglycoside was isolated from the bark of Eucommia ulmoides OLIV. (Eucommiaceae) and its structure was established as (+)-medioresinol di-O-β-D-glucopyranoside (1) by means of chemical and spectral studies. (+)-Pinoresinol di-O-β-D-glucopyranoside (2),liriodendrin (3) and (+)-pinoresinol O-β-D-glucopyranoside (4) were also isolated.Keywords - Eucommia ulmoides; lignan; (+)-medioresinol di-O-β-D-glucoside; (+)-pinoresinol di-O-β-D-glucoside; (+)-pinoresinol O-β-D-glucoside; liriodendrin; (13)C-NMR
- Deyama, Takeshi
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p. 2993 - 2997
(2007/10/02)
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