cas 458-35-5, CONIFERYL ALCOHOL | Articles data

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Two-Step One-Pot Synthesis of Pinoresinol from Eugenol in an Enzymatic Cascade
The phytoestrogen pinoresinol is a high-value compound that has a protective effect against diverse health disorders, and thus is of interest for the pharmaceutical industry. Isolation of pinoresinol from plants suffers from low yields, and its chemical synthesis involves several work-up steps. In this study we devised a novel two-step one-pot enzymatic cascade combining a vanillyl-alcohol oxidase and a laccase for the production of pinoresinol from eugenol via the intermediate coniferyl alcohol. Along with the well-characterized vanillyl-alcohol oxidase from Penicillium simplicissimum used to catalyze the oxidation of eugenol, enzyme screening revealed three bacterial laccases that were appropriate for the synthesis of pinoresinol from coniferyl alcohol. The cascade was optimized regarding enzyme ratios, pH value, and the presence of organic solvents. Under optimized conditions, pinoresinol concentration achieved 4.4 mM (1.6 gl-1), and this compound was isolated and analyzed. Increasing value: The high-value compound pinoresinol is synthesized in a two-step one-pot process combining the vanillyl-alcohol oxidase from Penicillium simplicissimum (PsVAO) and a bacterial laccase starting from the inexpensive substrate eugenol. tBME=tert-butyl methyl ether.
Ricklefs, Esther,Girhard, Marco,Koschorreck, Katja,Smit, Martha S.,Urlacher, Vlada B.
p. 1857 - 1864
(2015)
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Allylation of a lignin model phenol: A highly selective reaction under benign conditions towards a new thermoset resin platform
The lack of aromatic material constituents derived from renewable resources poses a problem to meet the future demands of a more sustainable society. Lignin is the most abundant source of aromatic structures found in nature and is a highly interesting source for material applications. Development of controlled chemical modification routes of lignin structures are crucial in order to further develop this area. In this study allyl chloride is used to selectively modify a lignin phenol in the presence of other lignin functionalities, i.e. aliphatic hydroxyls and conjugated alkenes, under mild reaction conditions in quantitative yields. For this, coniferyl alcohol was used as a model compound in the present study. The modification was carried out in ethanol as the synthesis media. Studies on the effect of reaction time and temperature revealed optimum conditions allowing for a quantitative yield without any detectable levels of byproducts as studied with NMR, FT-IR and FT-Raman. The thermal stability of the formed product was determined to be up to at least 160 °C through DSC measurements. In addition, as a proof of concept, the use of the allylated monomer to form crosslinked films using free radical thiol-ene polymerization was demonstrated.
Jawerth,Lawoko,Lundmark,Perez-Berumen,Johansson
p. 96281 - 96288
(2016)
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On the role of the monolignol γ-carbon functionality in lignin biopolymerization
In order to investigate the importance of the monomeric γ-carbon chemistry in lignin biopolymerization and structure, synthetic lignins (dehydrogenation polymers; DHP) were made from monomers with different degrees of oxidation at the γ-carbon, i.e., carb
Holmgren, Anders,Norgren, Magnus,Zhang, Liming,Henriksson, Gunnar
p. 147 - 155
(2009)
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COMPOUNDS HAVING HEPATIAL DISEASE EFFECTIVE
The invention discloses a compound with a hepatopathy curative effect, and the compound is a compound shown as a general formula (I), an optical isomer or pharmaceutically acceptable salt thereof, canbe applied to treatment or prevention of hepatopathy, particularly to drugs for treating or preventing fatty liver, liver fibrosis or liver cirrhosis, and has a good application prospect.
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Paragraph 0114-0115; 0118

(2021/01/29)

Non-plasmonic Ni nanoparticles catalyzed visible light selective hydrogenolysis of aryl ethers in lignin under mild conditions
Light-driven catalysis on catalytically versatile group VIII metals, which has been widely used in thermal catalysis, holds great potential in solar-to-chemical conversion. We report a novel photocatalysis process for the selective hydrogenolysis of aryl ethers in lignin on a heterogeneous catalyst of non-precious Ni nanoparticles supported on ZrO2. Three aryl ether bonds in lignin were successfully cleaved under mild conditions with excellent conversion and good to excellent selectivity under visible light irradiation. We also used solar irradiation to demonstrate a significant reduction in the total energy consumption. The light irradiation excited interband transitions in Ni nanoparticles and the resultant energetic electrons enhanced the activity of reductive cleavage of the aryl ethers. Its application potential was illustrated by the depolymerization of dealkaline lignin to give a total monomer yield of 9.84 wt% with vanillin, guaiacol, and apocynin as the three major products.
Baeyens, Jan,Li, Peifeng,Ouyang, Yixuan,Sarina, Sarina,Su, Haijia,Xiao, Gang,Zhao, Yilin,Zhu, Huai-Yong
supporting information
p. 7780 - 7789
(2021/10/12)

METHOD OF FORMING MONOMERS AND FURFURAL FROM LIGNOCELLULOSE
The present disclosure relates to a method of producing monophenolicmonomers and furfural from lignocellulosic biomass beating the biomass in a solvent together with a zeolite based catalyst.
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Page/Page column 17; 18

(2020/06/05)

Controllable synthesis of 2- And 3-aryl-benzomorpholines from 2-aminophenols and 4-vinylphenols
We present herein a method for the controllable synthesis of 3-aryl-benzomorpholine and 2-aryl-benzomorpholine cycloadducts via cross-coupling/annulation between electron-rich 2-aminophenols and 4-vinylphenols. Molecular oxygen was successfully used in the reaction as the terminal oxidant and the complete inversion of chemoselectivity was achieved by the adjustment of the solvents and bases at room temperature.
Dong, Kui,Jin, Xiao-Ling,Chen, Shihao,Wu, Li-Zhu,Liu, Qiang
supporting information
p. 7941 - 7944
(2020/08/14)

Consolidated production of coniferol and other high-value aromatic alcohols directly from lignocellulosic biomass
Sustainable production of fine chemicals and biofuels from renewable biomass offers a potential alternative to the continued use of finite geological oil reserves. However, in order to compete with current petrochemical refinery processes, alternative biorefinery processes must overcome significant costs and productivity barriers. Herein, we demonstrate the biocatalytic production of the versatile chemical building block, coniferol, for the first time, directly from lignocellulosic biomass. Following the biocatalytic treatment of lignocellulose to release and convert ferulic acid with feruloyl esterase (XynZ), carboxylic acid reductase (CAR) and aldo-keto reductase (AKR), this whole cell catalytic cascade not only achieved equivalent release of ferulic acid from lignocellulose compared to alkaline hydrolysis, but also displayed efficient conversion of ferulic acid to coniferol. This system represents a consolidated biodegradation-biotransformation strategy for the production of high value fine chemicals from waste plant biomass, offering the potential to minimize environmental waste and add value to agro-industrial residues.
Tramontina, Robson,Galman, James L.,Parmeggiani, Fabio,Derrington, Sasha R.,Bugg, Timothy D. H.,Turner, Nicholas J.,Squina, Fabio M.,Dixon, Neil
supporting information
p. 144 - 152
(2020/01/13)

Improved Pd/Ru metal supported graphene oxide nano-catalysts for hydrodeoxygenation (HDO) of vanillyl alcohol, vanillin and lignin
Pd and Ru nanoparticles supported on graphene oxide (GO) [Pd?GO and Ru?GO] and bimetallic [Pd/Ru?GO] were prepared and well characterized by XRD, FT-IR, EDS, TEM, XPS and ICP-AES analyses. The prepared nano-catalysts were tested for hydrodeoxygenation (HDO) of lignin monomer molecules-vanillyl alcohol and vanillin. In comparison with previously reported methods, Ru?GO and bimetallic Pd/Ru?GO catalysts showed high activity and selectivity, under milder conditions, at room temperature and 145 psi H2 pressure, for the formation of p-creosol, a value added product, as a potential future biofuel with antibacterial and anti-insecticidal properties. The multifold advantages of both these catalysts are in terms of reduced catalyst loading with a lower metal content and ambient temperture conditions resulting in higher conversion of the starting material. Furthermore, the efficacy of the developed methodology using Ru?GO and bimetallic Pd/Ru?GO catalysts under the optimized conditions was tested on the phenolic components of commercial lignin obtained by photo-catalytic fragmentation using TiO2, to obtain a mixture after HDO which contained vanillyl alcohol and p-creosol among others, as indicated by HPLC-MS analysis.
Arora, Shalini,Gupta, Neeraj,Singh, Vasundhara
supporting information
p. 2018 - 2027
(2020/04/07)

Synthesis method of valerolactam alkaloid compound (by machine translation)
The invention discloses a synthesis method, of a valerolactam alkaloid compound. Comprising: 1) reacting thionyl chloride with methanol, then adding ferulic acid, synthesizing ferulic acid methyl ester; 2) reacting 2 -nitrogen hexanone with phosphorus pentachloride; 4) 3, 3 -dibromo -2 - azaltrexone reacts with hydrogen and sodium acetate under the action of potassium iodide to generate 3-bromo 3 -cyclohexanone; 3) reaction, and reacting with hydrogen -2 - and sodium acetate under the action of potassium iodide; and the like 3 -2 . 5) 4) The terpineol prepared in step 3 -) is reacted, with sodium hydroxide, with the terpineol prepared in step -2 2 -) to form a lactam alkaloid compound. The synthetic method has the advantages of accessible raw material sources, mild reaction conditions, and simple reaction process operation. (by machine translation)
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Paragraph 0029; 0042; 0047-0049

(2019/10/01)

Compound for treating or preventing hepatopathy (by machine translation)
The invention discloses a compound, an optical isomer or a pharmaceutically acceptable salt, an optical isomer or a pharmaceutically acceptable salt thereof for treating or preventing hepatopathy, and the compound, optical isomer or pharmaceutically acceptable salt thereof can be applied to the preparation of a medicine for treating or preventing liver diseases. (by machine translation)
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Paragraph 0122-0123; 0125

(2019/10/01)

Visible-Light-Driven Cleavage of C?O Linkage for Lignin Valorization to Functionalized Aromatics
Lignin is the most abundant source of renewable aromatics. Catalytic valorization of lignin into functionalized aromatics is attractive but challenging. Photocatalysis is a promising sustainable approach. The strategies for designing well-performing photocatalysts are desired but remain limited. Herein, a facile energy band engineering strategy for promoting the photocatalytic activity of zinc–indium–sulfide (ZnmIn2Sm+3) for cleavage of the lignol β-O-4 bond under mild conditions was developed. The energy band structure of ZnmIn2Sm+3 could be tuned by controlling the atomic ratio of Zn/In. It was found that Zn4In2S7 performed best for cleavage of the β-O-4 bond under visible-light irradiation, owing to its appropriate energy band structure for offering adequate visible-light absorption and suitable redox capability. Functionalized aromatic monomers with near 18.4 wt % yield could be obtained from organosolv birch lignin. Mechanistic studies revealed that the β-O-4 bond was efficiently cleaved mainly through a one-step redox-neutral pathway via a Cα radical intermediate. The thiol groups on the surface of Zn4In2S7 played a key role in cleavage of the β-O-4 bond.
Lin, Jinchi,Wu, Xuejiao,Xie, Shunji,Chen, Liangyi,Zhang, Qinghong,Deng, Weiping,Wang, Ye
p. 5023 - 5031
(2019/12/02)

Chemodivergent hydrogenolysis of eucalyptus lignin with Ni@ZIF-8 catalyst
Reductive catalytic fractionation (RCF) of lignocellulosic biomass, that is depolymerization of the native lignin component into well-defined monomeric phenols in the first step, offers an opportunity to utilize entire biomass components. Herein, we report that Ni@ZIF-8 can serve as a chemodivergent catalyst in RCF of eucalyptus sawdust, thus selectively producing phenolic compounds having either a propyl or propanol end-chain under different reaction conditions. In both cases, high yields of lignin monomers and a high degree of delignification were achieved, next to well-preserved carbohydrate pulp suitable for further processing. A mechanistic study using model compounds indicated that the dehydroxylation at the γ-position of the β-O-4 structure may be involved in the selectivity-controlling step.
Liu, Xue,Li, Helong,Xiao, Ling-Ping,Sun, Run-Cang,Song, Guoyong
supporting information
p. 1498 - 1504
(2019/03/26)

Microbial Production of Natural and Unnatural Monolignols with Escherichia coli
Phenylpropanoids and phenylpropanoid-derived plant polyphenols find numerous applications in the food and pharmaceutical industries. In recent years, several microbial platform organisms have been engineered towards producing such compounds. However, for the most part, microbial (poly)phenol production is inspired by nature, so naturally occurring compounds have predominantly been produced to date. Here we have taken advantage of the promiscuity of the enzymes involved in phenylpropanoid synthesis and exploited the versatility of an engineered Escherichia coli strain harboring a synthetic monolignol pathway to convert supplemented natural and unnatural phenylpropenoic acids into their corresponding monolignols. The performed biotransformations showed that this strain is able to catalyze the stepwise reduction of chemically interesting unnatural phenylpropenoic acids such as 3,4,5-trimethoxycinnamic acid, 5-bromoferulic acid, 2-nitroferulic acid, and a “bicyclic” p-coumaric acid derivative, in addition to six naturally occurring phenylpropenoic acids.
Aschenbrenner, Jennifer,Marx, Patrick,Pietruszka, J?rg,Marienhagen, Jan
p. 949 - 954
(2019/02/26)

Electrochemical Dimerization of Phenylpropenoids and the Surprising Antioxidant Activity of the Resultant Quinone Methide Dimers
A simple method for the dimerization of phenylpropenoid derivatives is reported. It leverages electrochemical oxidation of p-unsaturated phenols to access the dimeric materials in a biomimetic fashion. The mild nature of the transformation provides excellent functional group tolerance, resulting in a unified approach for the synthesis of a range of natural products and related analogues with excellent regiocontrol. The operational simplicity of the method allows for greater efficiency in the synthesis of complex natural products. Interestingly, the quinone methide dimer intermediates are potent radical-trapping antioxidants; more so than the phenols from which they are derived—or transformed to—despite the fact that they do not possess a labile H-atom for transfer to the peroxyl radicals that propagate autoxidation.
Romero, Kevin J.,Galliher, Matthew S.,Raycroft, Mark A. R.,Chauvin, Jean-Philippe R.,Bosque, Irene,Pratt, Derek A.,Stephenson, Corey R. J.
supporting information
p. 17125 - 17129
(2018/12/04)

Rhodium-Catalyzed Synthesis of α,β-Unsaturated Ketones through Sequential C-C Coupling and Redox Isomerization
A novel Rh(I)-catalyzed sequential C-C coupling and redox isomerization between allylic alcohols and 1,3-dienes has been accomplished. This versatile protocol provides expeditious access to a broad range of polysubstituted α,β-unsaturated ketones with excellent atom economy and regioselectivity.
Li, Hong-Shuang,Guo, Guili,Zhang, Rui-Ze,Li, Fei
supporting information
p. 5040 - 5043
(2018/08/24)

Comparative transcriptomics analysis for gene mining and identification of a cinnamyl alcohol dehydrogenase involved in methyleugenol biosynthesis from asarum sieboldii miq
Asarum sieboldii Miq., one of the three original plants of TCM ASARI RADIX ET RHIZOMA, is a perennial herb distributed in central and eastern China, the Korean Peninsula, and Japan. Methyleugenol has been considered as the most important constituent of Asarum volatile oil, meanwhile asarinin is also employed as the quality control standard of ASARI RADIX ET RHIZOMA in Chinese Pharmacopeia. They both have shown wide range of biological activities. However, little was known about genes involved in biosynthesis pathways of either methyleugenol or asarinin in Asarum plants. In the present study, we performed de novo transcriptome analysis of plant tissues (e.g., roots, rhizomes, and leaves) at different developmental stages. The sequence assembly resulted in 311,597 transcripts from these plant materials, among which 925 transcripts participated in ‘secondary metabolism’ with particularly up to 20.22% of them falling into phenylpropanoid biosynthesis pathway. The corresponding enzymes belong to seven families potentially encoding phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-monooxygenase (C4H), p-coumarate 3-hydroxylase (C3H), caffeoyl-CoA O-methyltransferase (CCoAOMT), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD), and eugenol synthase (EGS). Moreover, 5 unigenes of DIR (dirigent protein) and 11 unigenes of CYP719A (719A subfamily of cytochrome P450 oxygenases) were speculated to be involved in asarinin pathway. Of the 15 candidate CADs, four unigenes that possessed high FPKM (fragments per transcript kilobase per million fragments mapped) value in roots were cloned and characterized. Only the recombinant AsCAD5 protein efficiently converted p-coumaryl, coniferyl, and sinapyl aldehydes to their corresponding alcohols, which are key intermediates employed not only in biosynthesis of lignin but also in that of methyleugenol and asarinin. qRT-PCR revealed that AsCAD5 had a high expression level in roots at three developmental stages. Our study will provide insight into the potential application of molecular breeding and metabolic engineering for improving the quality of TCM ASARI RADIX ET RHIZOMA.
Liu, Jinjie,Xu, Chong,Zhang, Honglei,Liu, Fawang,Ma, Dongming,Liu, Zhong
(2018/12/13)

A xylenol orange-based screening assay for the substrate specificity of flavin-dependent para-phenol oxidases
Vanillyl alcohol oxidase (VAO) and eugenol oxidase (EUGO) are flavin-dependent enzymes that catalyse the oxidation of para-substituted phenols. This makes them potentially interesting biocatalysts for the conversion of lignin-derived aromatic monomers to value-added compounds. To facilitate their biocatalytic exploitation, it is important to develop methods by which variants of the enzymes can be rapidly screened for increased activity towards substrates of interest. Here, we present the development of a screening assay for the substrate specificity of para-phenol oxidases based on the detection of hydrogen peroxide using the ferric-xylenol orange complex method. The assay was used to screen the activity of VAO and EUGO towards a set of twenty-four potential substrates. This led to the identification of 4-cyclopentylphenol as a new substrate of VAO and EUGO and 4-cyclohexylphenol as a new substrate of VAO. Screening of a small library of VAO and EUGO active-site variants for alterations in their substrate specificity led to the identification of a VAO variant (T457Q) with increased activity towards vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol) and a EUGO variant (V436I) with increased activity towards chavicol (4-allylphenol) and 4-cyclopentylphenol. This assay provides a quick and efficient method to screen the substrate specificity of para-phenol oxidases, facilitating the enzyme engineering of known para-phenol oxidases and the evaluation of the substrate specificity of novel para-phenol oxidases.
Ewing, Tom A.,Van Noord, Aster,Paul, Caroline E.,Van Berkel, Willem J. H.
(2018/01/18)

Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol
Herein we describe a one-pot microwave-assisted method for the synthesis of cinnamic acid and coumarin derivatives. The synthesis begins with an aldehyde synthon, and the chosen reaction conditions determine whether a cinnamic acid or coumarin derivative is formed. A regioselective Claisen rearrangement was also efficiently incorporated into the synthetic sequence to further increase the complexity of the product. Notably, this approach provides high product yields and selectivities without the need of a phenol protecting group.
Konrádová, Daniela,Kozubíková, Hana,Dole?al, Karel,Pospí?il, Ji?í
p. 5204 - 5213
(2017/09/29)

Enzymatic Specific Production and Chemical Functionalization of Phenylpropanone Platform Monomers from Lignin
Enzymatic catalysis is an ecofriendly strategy for the production of high-value low-molecular-weight aromatic compounds from lignin. Although well-definable aromatic monomers have been obtained from synthetic lignin-model dimers, enzymatic-selective synthesis of platform monomers from natural lignin has not been accomplished. In this study, we successfully achieved highly specific synthesis of aromatic monomers with a phenylpropane structure directly from natural lignin using a cascade reaction of β-O-4-cleaving bacterial enzymes in one pot. Guaiacylhydroxylpropanone (GHP) and the GHP/syringylhydroxylpropanone (SHP) mixture are exclusive monomers from lignin isolated from softwood (Cryptomeria japonica) and hardwood (Eucalyptus globulus). The intermediate products in the enzymatic reactions show the capacity to accommodate highly heterologous substrates at the substrate-binding sites of the enzymes. To demonstrate the applicability of GHP as a platform chemical for bio-based industries, we chemically generate value-added GHP derivatives for bio-based polymers. Together with these chemical conversions for the valorization of lignin-derived phenylpropanone monomers, the specific and enzymatic production of the monomers directly from natural lignin is expected to provide a new stream in “white biotechnology” for sustainable biorefineries.
Ohta, Yukari,Hasegawa, Ryoichi,Kurosawa, Kanako,Maeda, Allyn H.,Koizumi, Toshio,Nishimura, Hiroshi,Okada, Hitomi,Qu, Chen,Saito, Kaori,Watanabe, Takashi,Hatada, Yuji
p. 425 - 433
(2017/02/05)

Asymmetric Organocatalytic Stepwise [2+2] Entry to Tetra-Substituted Heterodimeric and Homochiral Cyclobutanes
An asymmetric synthesis of tetra-substituted cyclobutanes involving an organocatalytic, stepwise [2+2]-cycloaddition is described. The secondary-amine-catalyzed method allows for the hetero-dimerization of two different cinnamic-acid-derived sub-units, opening a novel one-step assembly to densely functionalized, head-to-tail coupled dimeric cyclobutanes in high enantiomeric excess. A series of selective synthetic interconversions in these sensitive cycloadducts is also described.
Nielsen, Alex J.,Jenkins, Hilary A.,McNulty, James
supporting information
p. 9111 - 9115
(2016/07/14)

MELANIN GENERATION INHIBITOR AND WHITENING AGENT
PROBLEM TO BE SOLVED: To provide a melanin generation inhibitor and a whitening agent that are excellent in whitening effect and also excellent in safety and temporal stability. SOLUTION: The invention provides a melanin generation inhibitor containing a compound represented by formula [1] as an active ingredient, a whitening agent, as well as a melanin generation inhibiting method and a whitening method by applying such agents to the skin. (R1, R2, R4, and R5 are each independently H, a hydroxyl group, an alkyl group of C1-4, or -O-C(=O)R6; R6 is an alkyl group of C1-4; R3 is H, an alkyl group of C1-4, or -C(=O)R7; and R7 is an alkyl group of C1-8.) SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0092; 0093

(2017/04/20)

Anti selective glycolate aldol reactions of (: S)-4-isopropyl-1-[(R)-1-phenylethyl]imidazolidin-2-one: application towards the asymmetric synthesis of 8-4′-oxyneolignans
The anti selective glycolate aldol reactions of (S)-4-isopropyl-1-[(R)-1-phenylethyl]imidazolidin-2-one auxiliary have been standardized with high yields and excellent diastereoselectivities on various substituted aryl, allyl and alkyl aldehydes. The optimized reaction conditions were employed for the stereoselective synthesis of oxyneolignans.
Gangar, Mukesh,Ittuveetil, Avinash,Goyal, Sandeep,Pal, Anang,Harikrishnan,Nair, Vipin A.
p. 102116 - 102126
(2016/11/09)

Enzymatic production of oroxylin A and hispidulin using a liverwort flavone 6-O-methyltransferase
Oroxylin A and hispidulin, compounds which are abundant in both Scutellaria and liverwort species, are important lead compounds for the treatment of ischemic cerebrovascular disease. Their enzymatic synthesis requires an O-methyltransferase able to interact with the related flavonoid's 6-OH group, but such an enzyme has yet to be identified in plants. Here, the gene encoding an O-methyltransferase (designated PaF6OMT) was isolated from the liverwort species Plagiochasma?appendiculatum. A test of alternative substrates revealed that its strongest preferences were baicalein and scutellarein, which were converted into, respectively, oroxylin A and hispidulin. Allowed a sufficient reaction time, the conversion rate of these two substrates was, respectively, 90% and 100%. PaF6OMT offers an enzymatic route to the synthesis of oroxylin A and hispidulin.
Zhang, Yu-Ying,Xu, Rui-Xue,Gao, Shuai,Cheng, Ai-Xia
p. 2619 - 2628
(2017/01/14)

Biocatalytic Properties and Structural Analysis of Eugenol Oxidase from Rhodococcus jostii RHA1: A Versatile Oxidative Biocatalyst
Eugenol oxidase (EUGO) from Rhodococcus jostii RHA1 had previously been shown to convert only a limited set of phenolic compounds. In this study, we have explored the biocatalytic potential of this flavoprotein oxidase, resulting in a broadened substrate scope and a deeper insight into its structural properties. In addition to the oxidation of vanillyl alcohol and the hydroxylation of eugenol, EUGO can efficiently catalyze the dehydrogenation of various phenolic ketones and the selective oxidation of a racemic secondary alcohol—4-(1-hydroxyethyl)-2-methoxyphenol. EUGO was also found to perform the kinetic resolution of a racemic secondary alcohol. Crystal structures of the enzyme in complexes with isoeugenol, coniferyl alcohol, vanillin, and benzoate have been determined. The catalytic center is a remarkable solvent-inaccessible cavity on the si side of the flavin cofactor. Structural comparison with vanillyl alcohol oxidase from Penicillium simplicissimum highlights a few localized changes that correlate with the selectivity of EUGO for phenolic substrates bearing relatively small p-substituents while tolerating o-methoxy substituents.
Nguyen, Quoc-Thai,de Gonzalo, Gonzalo,Binda, Claudia,Rioz-Martínez, Ana,Mattevi, Andrea,Fraaije, Marco W.
p. 1359 - 1366
(2016/08/31)

The synthesis and analysis of advanced lignin model polymers
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
supporting information
p. 4980 - 4990
(2015/11/16)

Multifunctional novel Diallyl disulfide (DADS) derivatives with β-amyloid-reducing, cholinergic, antioxidant and metal chelating properties for the treatment of Alzheimer's disease
A series of novel Diallyl disulfide (DADS) derivatives were designed, synthesized and evaluated as chemical agents, which target and modulate multiple facets of Alzheimer's disease (AD). The results showed that the target compounds 5a-l and 7e-m exhibited significant anti-Aβ aggregation activity, considerable acetylcholinesterase (AChE) inhibition, high selectivity towards AChE over butyrylcholinesterase (BuChE), potential antioxidant and metal chelating activities. Specifically, compounds 7k and 7l exhibited highest potency towards self-induced Aβ aggregation (74% and 71.4%, 25 μM) and metal chelating ability. Furthermore, compounds 7k and 7l disaggregated Aβ fibrils generated by Cu2+-induced Aβ aggregation by 80.9% and 78.5%, later confirmed by transmission electron microscope (TEM) analysis. Besides, 7k and 7l had the strongest AChE inhibitory activity with IC50 values of 0.056 μM and 0.121 μM, respectively. Furthermore, molecular modelling studies showed that these compounds were capable of binding simultaneously to catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. All the target compounds displayed moderate to excellent antioxidant activity with ORAC-FL values in the range 0.546-5.86 Trolox equivalents. In addition, absorption, distribution, metabolism and excretion (ADME) profile and toxicity prediction (TOPKAT) of best compounds 7k and 7l revealed that they have drug like properties and possess very low toxic effects. Collectively, the results strongly support our assertion that these compounds could provide good templates for developing new multifunctional agents for AD treatment.
Manral, Apra,Saini, Vikas,Meena, Poonam,Tiwari, Manisha
p. 6389 - 6403
(2015/10/05)

Synthesis and bioactivity of tripolinolate A from Tripolium vulgare and its analogs
A new coniferol derivative, named as tripolinolate A (1), and 11 known compounds (2-12) were isolated from whole plants of Tripolium vulgare Nees. The structure of this new compound was determined as 4-(2S-methylbutyryl)-9-acetyl-coniferol based on its NMR and HRESIMS spectral analyses. A simple and efficient method was designed to prepare tripolinolate A and its 19 analogs including nine new chemical entities for bioactive assay. Tripolinolate A and its analog 4,9-diacetyl-coniferol were found to be the two most active compounds that significantly inhibited the proliferation of different cancer cell lines with IC50 values ranging from 0.36 to 12.9 μM and induced apoptosis in tumor cells. Structure-activity relationship analysis suggested that the molecular size of acyl moieties at C-4 and C-9 position might have an effect on the activity of this type of coniferol derivatives.
Chen, Lu,Liang, Ying,Song, Tengfei,Anjum, Komal,Wang, Wenling,Yu, Siran,Huang, Haocai,Lian, Xiao-Yuan,Zhang, Zhizhen
p. 2629 - 2633
(2015/06/08)

A biocompatible alkene hydrogenation merges organic synthesis with microbial metabolism
Organic chemists and metabolic engineers use orthogonal technologies to construct essential small molecules such as pharmaceuticals and commodity chemicals. While chemists have leveraged the unique capabilities of biological catalysts for small-molecule production, metabolic engineers have not likewise integrated reactions from organic synthesis with the metabolism of living organisms. Reported herein is a method for alkene hydrogenation which utilizes a palladium catalyst and hydrogen gas generated directly by a living microorganism. This biocompatible transformation, which requires both catalyst and microbe, and can be used on a preparative scale, represents a new strategy for chemical synthesis that combines organic chemistry and metabolic engineering. Reduction to practice: A hydrogenation reaction has been developed that employs hydrogen generated in situ by a microorganism and a biocompatible palladium catalyst to reduce alkenes on a synthetically useful scale. This type of transformation, which directly combines tools from organic chemistry with the metabolism of a living organism for small-molecule production, represents a new strategy for chemical synthesis.
Sirasani, Gopal,Tong, Liuchuan,Balskus, Emily P.
p. 7785 - 7788
(2014/08/05)

SYNTHESIS OF CATECHIN AND EPICATECHIN CONJUGATES
The present invention relates generally to catechin and epicatechin conjugates of formula (I). For example, a chemical synthesis process for the preparation of catechin and epi-catechin compounds, in particular of catechin and epi-catechin conjugates is disclosed. A further aspect of the invention pertains to new catechin and epi-catechin conjugate compounds.
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Page/Page column 13

(2013/03/26)

Synthesis of catechin and epicatechin conjugates
The present invention relates generally to catechin and epicatechin conjugates of formula (I). For example, a chemical synthesis process for the preparation of catechin and epi-catechin compounds, in particular of catechin and epi-catechin conjugates is disclosed. A further aspect of the invention pertains to new catechin and epi-catechin conjugate compounds.
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Paragraph 0035

(2013/03/26)

In vitro analysis of the monolignol coupling mechanism using dehydrogenative polymerization in the presence of peroxidases and controlled feeding ratios of coniferyl and sinapyl alcohol
In this study, dehydrogenative polymers (DHP) were synthesized in vitro through dehydrogenative polymerization using different ratios of coniferyl alcohol (CA) and sinapyl alcohol (SA) (10:0, 8:2, 6:4, 2:8, 0:10), in order to investigate the monolignol coupling mechanism in the presence of horseradish peroxidase (HRP), Coprinus cinereus peroxidase (CiP) or soybean peroxidase (SBP) with H2O2, respectively. The turnover capacities of HRP, CiP and SBP were also measured for coniferyl alcohol (CA) and sinapyl alcohol (SA), and CiP and SBP were found to have the highest turnover capacity for CA and SA, respectively. The yields of HRP-catalyzed DHP (DHP-H) and CiP-catalyzed DHP (DHP-C) were estimated between ca. 7% and 72% based on the original weights of CA/SA in these synthetic conditions. However, a much lower yield of SBP-catalyzed DHP (DHP-S) was produced compared to that of DHP-H and DHP-C. In general, the DHP yields gradually increased as the ratio of CA/SA increased. The average molecular weight of DHP-H also increased with increasing CA/SA ratios, while those of DHP-C and DHP-S were not influenced by the ratios of monolignols. The frequency of β-O-4 linkages in the DHPs decreased with increasing CA/SA ratios, indicating that the formation of β-O-4 linkages during DHP synthesis was influenced by peroxidase type.
Moon, Sun-Joo,Kwon, Mi,Choi, Donha,Won, Keehoon,Kim, Yong Hwan,Choi, In-Gyu,Choi, Joon Weon
p. 15 - 21
(2012/11/13)

Epicatechin B-ring conjugates: First enantioselective synthesis and evidence for their occurrence in human biological fluids
Herein, the first enantioselective total synthesis of a number of biologically relevant (-)-epicatechin conjugates is described. The success of this synthesis relied on (i) optimized conditions for the stereospecific cyclization step leading to the catechin C ring; on (ii) efficient conjugation reactions; and on (iii) optimized deprotection sequences. These standard compounds have been subsequently used to elucidate for the first time the pattern of (-)-epicatechin conjugates present in four different human biological fluids following (-)-epicatechin absorption.
Romanov-Michailidis, Fedor,Viton, Florian,Fumeaux, René,Lévèques, Antoine,Actis-Goretta, Lucas,Rein, Maarit,Williamson, Gary,Barron, Denis
supporting information; experimental part
p. 3902 - 3905
(2012/09/22)

Identification and initial SAR of silybin: An Hsp90 inhibitor
Through Hsp90-dependent firefly luciferase refolding and Hsp90-dependent heme-regulated eIF2α kinase (HRI) activation assays, silybin was identified as a novel Hsp90 inhibitor. Subsequently, a library of silybin analogues was designed, synthesized and evaluated. Initial SAR studies identified the essential, non-essential and detrimental functionalities on silybin that contribute to Hsp90 inhibition.
Zhao, Huiping,Brandt, Gary E.,Galam, Lakshmi,Matts, Robert L.,Blagg, Brian S.J.
scheme or table
p. 2659 - 2664
(2011/06/22)

Characterization of two isozymes of coniferyl alcohol dehydrogenase from Streptomyces sp. NL15-2K
We purified two isozymes of coniferyl alcohol dehydrogenase (CADH I and II) to homogeneity from cellfree extracts of Streptomyces sp. NL15-2K. The apparent molecular masses of CADH I and II were determined to be 143 kDa and 151 kDa respectively by gel filtration, whereas their subunit molecular masses were determined to be 35,782.2 Da and 37,597.7 Da respectively by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Thus, it is probable that both isozymes are tetramers. The optimum pH and temperature for coniferyl alcohol dehydrogenase activity were pH 9.5 and 45 °C for CADH I and pH 8.5 and 40 °C for CADH II. CADH I oxidized various aromatic alcohols and allyl alcohol, and was most efficient on cinnamyl alcohol, whereas CADH II exhibited high substrate specificity for coniferyl alcohol, and showed no activity as to the other alcohols, except for cinnamyl alcohol and 3-(4-hydroxy-3-methoxyphenyl)- 1-propanol. In the presence of NADH, CADH I and II reduced cinnamaldehyde and coniferyl aldehyde respectively to the corresponding alcohols.
Nishimura, Motohiro,Kohno, Kunie,Nishimura, Yoshio,Inagaki, Masanori,Davies, Julian
experimental part
p. 1770 - 1777
(2012/02/02)

Biotransformation of isoeugenol catalyzed by growing cells of Pseudomonas putida
Growing cells of Pseudomonas putida transformed isoeugenol after 5 days of incubation to give mainly vanillin, eugenol, 4-(E)-(3-hydroxyprop-1-enyl)-2- methoxyphenol and the dimeric molecule (+)-4-[2,3-dihydro-7-methoxy-3-methyl-5- (E)-(1-propenyl)-2-benzofuranyl]-2-methoxyphenol (licarin A). The formation of the latter compound from isoeugenol by biotransformation with P. putida is reported here for the first time.
Vasudevan, Sangeetha,Bhat, Sujata V.
experimental part
p. 147 - 150
(2011/12/15)

Cinnamyl alcohols and methyl esters of fatty acids from Wedelia prostrata callus cultures
Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) (1) and hexadecanoic acid methyl ester (methyl palmitate) (2), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol (3), coniferyl alcohol (4), p-coumaryl alcohol (5) and coniferyl alcohol 4-O-glucoside (coniferin) (6), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic and chemical methods, while the other compounds were identified by gas chromatography-mass spectrometry and thin layer chromatography in comparison with standards.
Abd El-Mawla, Ahmed M.A.,Farag, Salwa F.,Beuerle, Till
experimental part
p. 45 - 52
(2011/03/22)

Growth inhibitory activities of oxyprenylated and non-prenylated naturally occurring phenylpropanoids in cancer cell lines
A series of 25 selected oxyprenylated natural phenylpropanoids were synthesized, and their growth inhibitory activities were evaluated in vitro together with 14 other commercially available non-alkylated compounds belonging to the same chemical series. The compounds were tested on six human cancer cell lines using MTT colorimetric assays. The data reveal that of the six chemical groups (G) studied, coumarins (G1), cinnamic and benzoic acids (G2), chalcones (G3), acetophenones (G4), anthraquinones (G5), and cinnamaldehydes and cinnamyl alcohols (G6), G2-related compounds displayed the weakest growth inhibitory activities in vitro, whereas G5-related compounds displayed the highest activities. Quantitative videomicroscopy analyses were then carried out on human U373 glioblastoma cells, which are characterized by various levels of resistance to different pro-apoptotic stimuli. These analyses revealed that compounds 20 (4,2′,4′-trihydroxychalcone), and 30 and 31 (two cinnamaldehydes) were cytostatic and able to overcome the intrinsic resistance of U373 cancer cells to pro-apoptotic stimuli.
Bruyre, Céline,Genovese, Salvatore,Lallemand, Benjamin,Ionescu-Motatu, Alexandra,Curini, Massimo,Kiss, Robert,Epifano, Francesco
scheme or table
p. 4174 - 4179
(2011/08/06)

A continuous, quantitative fluorescent assay for plant caffeic acid o-methyltransferases
Plant caffeic acid O-methyltransferases (COMTs) use S-adenosylmethionine (ado-met), as a methyl donor to transmethylate their preferred (phenolic) substrates in vivo, and will generally utilize a range of phenolic compounds in vitro. Collazo et al. (Anal. Biochem. 2005, 342, 86-92) have published a discrete, end-point fluorescence assay to detect histone methyltransferases using S-adenosyl homocysteine hydrolase and adeonsine deaminase as coupling enzymes and a thiol-specific fluorophore, Thioglo1, as the detecting reagent. Using this previous assay as a guide, we have developed and validated a facile, sensitive and real-time fluorescence assay for characterizing plant COMTs and in the process simplified the original assay as well by obviating the need for adenosine deaminase in the assay, and simultaneously converting an end-point assay into a continuous one. Our assay has been used to kinetically characterize recombinant sorghum COMT (Bmr-12) a key enzyme involved in cell wall lignification, and analyze COMT activity in maturing tillers from switchgrass plants. Data indicated that the calculated Km and Vmax values for the recombinant sorghum COMT using different substrates in the fluorescent assay were similar to published values for COMT enzymes from other plant species. Native COMT activity was greatest in internodes at the top of a tiller and declined in the more basal internodes. This new assay should have broad applicability for characterizing COMTs and potentially other plant methlytransferases that utilize ado-met as a methyl donor. This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.
Palmer, Nathan A.,Sattler, Scott E.,Saathoff, Aaron J.,Sarath, Gautam
experimental part
p. 5220 - 5226
(2011/08/05)

Insights into lignin primary structure and deconstruction from Arabidopsis thaliana COMT (caffeic acid O-methyl transferase) mutant Atomt1
The Arabidopsis mutant Atomt1 lignin differs from native lignin in wild type plants, in terms of sinapyl (S) alcohol-derived substructures in fiber cell walls being substituted by 5-hydroxyconiferyl alcohol (5OHG)-derived moieties. During programmed lignin assembly, these engender formation of benzodioxane substructures due to intramolecular cyclization of their quinone methides that are transiently formed following 8-O-4′ radical-radical coupling. Thioacidolytic cleavage of the 8-O-4′ inter-unit linkages in the Atomt1 mutant, relative to the wild type, indicated that cleavable sinapyl (S) and coniferyl (G) alcohol-derived monomeric moieties were stoichiometrically reduced by a circa 2:1 ratio. Additionally, lignin degradative analysis resulted in release of a 5OHG-5OHG-G trimer from the Atomt1 mutant, which then underwent further cleavage. Significantly, the trimeric moiety released provides new insight into lignin primary structure: during polymer assembly, the first 5OHG moiety is linked via a C8-O-X inter-unit linkage, whereas subsequent addition of monomers apparently involves sequential addition of 5OHG and G moieties to the growing chain in a 2:1 overall stoichiometry. This quantification data thus provides further insight into how inter-unit linkage frequencies in native lignins are apparently conserved (or near conserved) during assembly in both instances, as well as providing additional impetus to resolve how the overall question of lignin macromolecular assembly is controlled in terms of both type of monomer addition and primary sequence.
Moinuddin, Syed G. A.,Jourdes, Michael,Laskar, Dhrubojyoti D.,Ki, Chanyoung,Cardenas, Claudia L.,Kim, Kye-Won,Zhang, Dianzhong,Davin, Laurence B.,Lewis, Norman G.
experimental part
p. 3928 - 3946
(2010/09/17)

An enantiocomplementary dirigent protein for the enantioselective lacease-catalyzed oxidative coupling of phenols
(+)- or (-)-plnoreslnol: that Is the question. Which of the two enantiomeric lignans is formed during laccasecatalyzed phenol coupling of (E)-coniferyl alcohol (1) depends on the dirigent protein. In the presence of the first enantiocomplementary dirigent protein AtDIR6, (-)-2 is formed (78 % ee). Preferential formation of (+)-2 is observed in the presence of the dirigent protein FiDIR1, whereas only racemic 2 is formed in the absence of dirigent proteins
Pickel, Benjamin,Constantin, Mihaela-Anca,Pfannstiel, Jens,Conrad, Juergen,Beifuss, Uwe,Schaller, Andreas
supporting information; experimental part
p. 202 - 204
(2010/03/30)

Design, synthesis, and examination of neuron protective properties of alkenylated and amidated dehydro-silybin derivatives
A series of C7-O- and C20-O-amidated 2,3-dehydrosilybin (DHS) derivatives ((±)-1a-f and (±)-2), as well as a set of alkenylated DHS analogues ((±)-4a-f), were designed and de novo synthesized. A diesteric derivative ofDHS((±)-3) and two C23 esterifiedDHSanalogues ((±)-5a and (±)-5b) were also prepared for comparison. The cell viability of PC12 cells, Fe2+ helation, lipid peroxidation (LPO), free radical scavenging, and xanthine oxidase inhibition models were utilized to evaluate their antioxidative and neuron protective properties. The study revealed that the diether atC7-OHand C20-OHas well as the monoether at C7-OH, which possess aliphatic substituted acetamides, demonstrated more potent LPO inhibition and Fe2+chelation compared to DHS and quercetin. Conversely, the diallyl ether at C7-OH and C20-OH was more potent in protection of PC12 cells against H2O2-induced injury than DHS and quercetin. Overall, the more lipophilic alkenylated DHS analogues were better performing neuroprotective agents than the acetamidated derivatives. The results in this study would be beneficial for optimizing the therapeutic potential of lignoflavonoids, especially in neurodegenerative disorders such as Alzheimer's and Parkinson's disease.
Yang, Lei Xiang,Huang, Ke Xin,Li, Hai Bo,Gong, Jing Xu,Wang, Feng,Feng, Yu Bing,Tao, Qiao Feng,Wu, Yi Hang,Li, Xiao Kun,Wu, Xiu Mei,Zeng, Su,Spencer, Shawn,Zhao, Yu,Qu, Jia
supporting information; experimental part
p. 7732 - 7752
(2010/08/06)

Antiestrogenic constituents of the Thai medicinal plants Capparis flavicans and Vitex glabrata
Antiestrogenic compounds were investigated from Thai indigenous plants for galactogogues since estrogen is reported to suppress lactation in breastfeeding women. The aerial parts of the Thai medicinal plant Capparis flavicans, which has traditionally been
Luecha, Prathan,Umehara, Kaoru,Miyase, Toshio,Noguchi, Hiroshi
experimental part
p. 1954 - 1959
(2010/04/24)

A novel and efficient procedure for the preparation of allylic alcohols from α,β-unsaturated carboxylic esters using LiAlH4/BnCl
A new and efficient method for the reduction of α,β-unsaturated carboxylic esters to allylic alcohols utilizing LiAlH4/BnCl is described. Various α,β-unsaturated esters, including the coumarins bearing α,β-unsaturated lactone skeleton, can be converted smoothly into their corresponding allylic alcohols in high yields under mild conditions with short reaction times.
Wang, Xiaolong,Li, Xiaodong,Xue, Jijun,Zhao, Yuling,Zhang, Yumei
experimental part
p. 413 - 415
(2009/05/11)

Coniferyl alcohol glucoside from Astragalus bungeanus
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Alaniya,Kavtaradze,Mshvildadze,Lavoi,Pichette
p. 706 - 707
(2008/04/05)

Metabolic characterization of newly isolated Pseudomonas nitroreducens Jin1 growing on eugenol and isoeugenol
Newly isolated soil bacterium strain Jin1 was able to grow on both eugenol and isoeugenol each as sole source of carbon and energy. Based on bacterial 16S rDNA analysis, Jin1 belongs to Pseudomonas nitroreducens with a similarity of 98.92% (14/1297). P. nitroreducens Jin1 was found to biotransform eugenol and isoeugenol to vanillin by different pathways. Eugenol was biotransformed to vanillin through coniferyl alcohol and ferulic acid similarly to the pathway shown previously by Pseudomonassp. HR199 and vanillin produced from eugenol was rapidly metabolized to vanillic acid. Contrastively, Pseudomonas nitroreducens Jin1 did not appear to produce metabolic intermediates during the biotransformation of isoeugenol to vanillin which was finally biotransformed to vanillic acid with much slower rate. These results indicate that there seems to be different metabolic regulation systems for the biotransformation of eugenol and isoeugenol by this bacterium. Herein, we report on Pseudomonas nitroreducens Jin1, a novel bacterium that produces vanillin from eugenol and isoeugenol by two different metabolic pathways.
Unno, Tatsuya,Kim, Soo-Jin,Kanaly, Robert A.,Ahn, Joong-Hoon,Kang, Su-Il,Hur, Hor-Gil
experimental part
p. 8556 - 8561
(2009/09/29)

Characterization of the chemical composition of a byproduct from Siam benzoin gum
The mixture of bark and gum obtained after size-grading of Siam benzoin gum was studied to establish its potential application as a valuable new grade of the balsamic resin. An analysis of its volatile constituents by means of static headspace and SPME led to the identification of 26 and 50 compounds, respectively. Significant differences were observed in both the headspace composition and olfactory properties of the byproduct as compared to those of Siam benzoin gum. This prompted the further analysis of its volatile extract and its resinoid by GC techniques, resulting in the identification of 60 (99.5%) and 16 (89.1%) components, respectively. To examine the influence of bark pieces, different extracts obtained from the raw material and from a sorted sample were analyzed by GC and HPLC techniques. The chemical compositions and the yields determined for the two resinoids lead to the conclusion that this harvesting byproduct is a new grade of Siam benzoin gum, providing interesting olfactory notes that differ from those of other grades.
Castel, Cecilia,Fernandez, Xavier,Lizzani-Cuvelier, Louisette,Perichet, Christine,Lavoine, Sophie
p. 8848 - 8854
(2007/10/03)

Arabidopsis thaliana β-Glucosidases BGLU45 and BGLU46 hydrolyse monolignol glucosides
In higher plants, β-glucosidases belonging to glycoside hydrolase (GH) Family 1 have been implicated in several fundamental processes including lignification. Phylogenetic analysis of Arabidopsis thaliana GH Family 1 has revealed that At1g61810 (BGLU45), At1g61820 (BGLU46), and At4g21760 (BGLU47) cluster with Pinus contorta coniferin β-glucosidase, leading to the hypothesis that their respective gene products may be involved in lignification by hydrolysing monolignol glucosides. To test this hypothesis, we cloned cDNAs encoding BGLU45 and BGLU46 and expressed them in Pichia pastoris. The recombinant enzymes were purified to apparent homogeneity by ammonium sulfate fractionation and hydrophobic interaction chromatography. Among natural substrates tested, BGLU45 exhibited narrow specificity toward the monolignol glucosides syringin (Km, 5.1 mM), coniferin (Km, 7 mM), and p-coumaryl glucoside, with relative hydrolytic rates of 100%, 87%, and 7%, respectively. BGLU46 exhibited broader substrate specificity, cleaving salicin (100%), p-coumaryl glucoside (71%; Km, 2.2 mM), phenyl-β-d-glucoside (62%), coniferin (8%), syringin (6%), and arbutin (6%). Both enzymes also hydrolysed p- and o-nitrophenyl-β-d-glucosides. Using RT-PCR, we showed that BGLU45 and BGLU46 are expressed strongly in organs that are major sites of lignin deposition. In inflorescence stems, both genes display increasing levels of expression from apex to base, matching the known increase in lignification. BGLU45, but not BGLU46, is expressed in siliques, whereas only BGLU46 is expressed in roots. Taken together with recently described monolignol glucosyltransferases [Lim et al., J. Biol. Chem. (2001) 276, 4344-4349], our enzymological and molecular data support the possibility of a monolignol glucoside/β-glucosidase system in Arabidopsis lignification.
Escamilla-Trevino, Luis L.,Chen, Wei,Card, Marcella L.,Shih, Ming-Che,Cheng, Chi-Lien,Poulton, Jonathan E.
p. 1651 - 1660
(2008/02/12)

Isolation and biomimetic synthesis of anti-inflammatory stilbenolignans from Gnetum cleistostachyum
One new stilbenolignan, gnetucleistol F (1), and four known stilbenolignans, gnetofuran A (2), lehmbachol D (3), gnetifolin F (4) and gnetumontanin C (5) were isolated from the lianas of Gnetum cleistostachyum C. Y. CHENG (Gnetaceae). Their structures and relative configurations were determined by means of spectroscopic evidence. Compounds 1, 2, 3 and 4 were synthesized for the first time on the basis of their biogenetic pathway, and their possible biomimetical synthetic mechanisms were discussed. The pharmacological activities of all stilbenolignans have been tested. Among them, 1, 2, 3, 4 and 5 showed moderate inhibitory activities on TNF-α and 1 also showed potent inhibitory activity on malondialdehyde.
Yao, Chun-Suo,Lin, Mao,Wang, Lin
p. 1053 - 1057
(2007/10/03)

Non-enzymatic reduction of quinone methides during oxidative coupling of monolignols: Implications for the origin of benzyl structures in lignins
Lignin is believed to be synthesized by oxidative coupling of 4-hydroxyphenylpropanoids. In native lignin there are some types of reduced structures that cannot be explained solely by oxidative coupling. In the present work we showed via biomimetic model experiments that nicotinamide adenine dinucleotide (NADH), in an uncatalyzed process, reduced a β-aryl ether quinone methide to its benzyl derivative. A number of other biologically significant reductants, including the enzyme cellobiose dehydrogenase, failed to produce the reduced structures. Synthetic dehydrogenation polymers of coniferyl alcohol synthesized (under oxidative conditions) in the presence of the reductant NADH produced the same kind of reduced structures as in the model experiment, demonstrating that oxidative and reductive processes can occur in the same environment, and that reduction of the in situ-generated quinone methides was sufficiently competitive with water addition. In situ reduction of β-β-quinone methides was not achieved in this study. The origin of racemic benzyl structures in lignins therefore remains unknown, but the potential for simple chemical reduction is demonstrated here. The Royal Society of Chemistry 2006.
Holmgren, Anders,Brunow, Goesta,Henriksson, Gunnar,Zhang, Liming,Ralph, John
p. 3456 - 3461
(2008/09/16)