Sinapyl Alcohol Research Articles

EPR imaging of sinapyl alcohol and its application to the study of plant cell wall lignification.

In bioimaging, bioorthogonal chemistry is most often used to visualize chemical reporters by fluorescence in their native environment. Herein, we show that TEMPO-based probes can be ligated to monolignol reporters by Diels-Alder chemistry in plant cell walls, paving the way for the study of lignification by EPR spectroscopy and imaging.

Comparison of the NO heterogeneous reduction characteristics using biochars derived from three biomass with different lignin types

The properties of biochars derived from three biomass with different lignin types were analyzed by low-pressure nitrogen gas adsorption (LP-N 2GA), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. In this study, the heterogeneous reduction characteristics of NO by Chinese fir biochar (FB), elm biochar (EB) and bamboo biochar (BB) were compared. The reaction temperature increases from room temperature to 1073 K at a fixed heating rate of 10 K/min. Results show that the main stage of heterogeneous NO reduction with three kinds of biochars can be divided into two zones: dynamic control zone and diffusion control zone. The lignin composed of coniferyl alcohol and sinapyl alcohol derivative units will form more oxygen-containing functional groups and hydroxyl groups on EB and BB surfaces. Among the three biochars in the dynamic control zone, EB showed the highest NO reduction rate (2.69 ppm/K) and the strongest oxidation resistance. The lignin composed of a polymer with coniferyl alcohol as a basic unit form the well-developed pore characteristic of FB. The adsorption performance of FB is the best, which improves the reduction of NO in diffusion control zone.

Research on serum metabolomics of ovariectomized rats and intervention effect of Cuscuta chinensis on metabolic pattern

As a traditional Chinese medicine of invigorating the kidney, Cuscuta chinensis (CC) can be applied in improving the deficiency of kidney qi in menopausal women and regulating the level of estrogen. Previously, it was found that the ethanol extract of CC had an estrogen-like effect. In this study, the metabolic profile and metabolic pathways of rats in sham, ovariectomized model and CC groups were analyzed using UPLC-TOFMS-based metabolomics and the pattern recognition technology. The serum endogenouse metabolites could be well differentiated in different group, indicating significant differences of metabolic profiles. CC had an reverse adjustment effect on 14 differential metabolites of ovariectomized rats, including sinapyl alcohol, deoxycholic acid, prostaglandin B2, prostaglandin I2, dihydrosphingosine, choline, pentadecanoic acid, arachidonic acid, 1-stearoyl-Sn-Glycerol-3-Phosphocholine, palmitoleic acid, palmitic acid, vaccenic acid, oleic acid and stearic acid. Furthermore, these differential metabolites were categorized into several major pathways, such as biosynthesis of unsaturated fatty acids, lycerophospholipid metabolism and arachidonic acid metabolism. Therefore, it could be concluded that the estrogen-like effect of CC was related to the lipid metabolism to some extent. The research results provide useful help for the in-depth research and development of CC.

Purification and characterization of peroxidases from garden cress sprouts and their roles in lignification and removal of phenol and p-chlorophenol.

The study aims to evaluate the relation between peroxidases of day-6 garden cress sprouts and phenolic compounds. Three cationic, three anionic, and two unbounded peroxidases were separated from day-6 garden cress sprouts. Cationic (GCP1) and anionic (GCP2) peroxidases were purified with molecular masses of 25 and 40kDa, respectively. The Km values of GCP1 toward H2 O2 and guaiacol were lower than GCP2. The anionic GCP2 exhibited high affinity toward some lignin monomers, sinapyl alcohol, coniferyl alcohol, cinnamic and ferulic acids. Therefore, GCP2 is considered as a lignin peroxidase and contributed in lignin synthesis. The activity of GCP1 and GCP2 was stable at a wide pH range 5.5-8.0 and 6.0-7.5, respectively. Both peroxidases showed the same thermal stability range 20-50°C. GCP2 was more resistant against the effect of metal ions than GCP1. GCP2 showed high ability to remove of phenol and p-chlorophenol from effluent compared to GCP1. PRACTICAL APPLICATIONS: Generally, garden cress is used as a test plant to conduct biomonitoring of pollution in urban soil on a wide scale because of its simplicity, sensitivity, and cost-effectiveness. Peroxidase is an important antioxidant enzyme, which elevated when plant subjected to pollution. Recently, we reported that the increase of peroxidase activity was strongly correlated with high phenolic content and antioxidant activity during the germination of garden cress. In the present study, anionic peroxidase GCP2 may play an important role in lignification process and removal of phenol and p-chlorophenol from polluted soil/wastewater as well as resisted the harmful effect of heavy metals. Cationic peroxidase GCP1, as a natural scavenger, had high affinity toward H2 O2 coupled to oxidation of some plant phenolic compounds suggesting its role in consuming of excess H2 O2 .

Experimental and theoretical investigations of lignin-urea-formaldehyde wood adhesive: Density functional theory analysis

In view of its chemical structure, lignin has recently become an interesting candidate for various applications. This work serves to optimize the isolation process of lignin from sugar industry by-product (bagasse can, molasses beet) applying alkali treatment. For this purpose, the effect of alkali and sulfuric acid concentrations have been studied ranging from 10% (w/v) to 20% (w/v) and 1.5 M–3 M, respectively. Moreover, the isolated lignins were characterized by different complementary analysis such as FT-IR and TGA/DTG.The aim behind this work is to reduce formaldehyde emissions and improving mechanical as well as physical properties of wood adhesive. Lignin was added with different ratios, as partial substitution, in urea-formaldehyde (UF) (5:95; 10:90; 13:87 and 15:85, w: w) and compared to commercial control UF (0:100). Furthermore, a theoretical calculation, using the density functional theory (DFT)/B3LYP method validated that the coniferyl alcohol (G), sinapyl alcohol (S) and paracoumaryl alcohol (H) can suck up on the energy of the orbital borders, electronic affinity, electronic chemical potential and thermodynamic properties. The results obtained showed that the efficiency of these molecules is influenced with different degrees by several descriptors. It was also found that the compounds G and S out of H studied were more efficient within the density functional theory (DFT) at the B3LYP/6–31 (d,p) computational level.

Reactive oxygen species-mediated the accumulation of suberin polyphenolics and lignin at wound sites on muskmelons elicited by benzo (1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester

• BTH rapidly stimulated ROS production at wound sites on muskmelons. • ROS elicited by BTH activated phenylpropanoid metabolism at wound sites. • BTH promoted SPP and lignin accumulation at wound sites. • DPI inhibited wound healing process promoted by BTH at wound sites. Benzo (1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) is the first synthetic nontoxic chemical elicitor that has induced resistance in fruit and vegetables against postharvest diseases. In this study, we treated artificially wounded muskmelon fruit ( Cucumis melo L. cv. Perfect) with 100 mg L -1 BTH. The results indicated that there was a significant accumulation of suberin polyphenolics and lignin at wound sites on the treated fruit as well as a noticeable decrease in weight loss of wounded fruit during healing. The BTH treatment also enhanced the activity of NADPH oxidase and superoxide dismutase, increasing the production of O 2 •- and H 2 O 2 . Moreover, BTH activated the activity of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate-CoA ligase, and cinnamyl alcohol dehydrogenase as well as elevating the levels of cinnamic acid, p -coumaric acid, caffeic acid, ferulic acid, sinapic acid, coniferyl alcohol, sinapyl alcohol, and lignin at the wound sites on the treated fruit. When we treated the BTH-treated muskmelons with 50 μmol L -1 diphenylene iodonium (DPI), the treatment partially inhibited the accumulation of polyphenolic substances and lignin at wound sites on the treated fruit, weakened the activity of NADPH oxidase and superoxide dismutase, and reduced the production of O 2 .- and H 2 O 2 . Furthermore, BTH combined with DPI treatment caused lower activity of key enzymes and lower level of metabolites in phenylpropanoid pathway compared with BTH treatment. Considering DPI as a reactive oxygen species inhibitor, we suggest that reactive oxygen species could be a second messenger for activating phenylpropanoid metabolism, as a consequence for promoting polyphenolic substances and lignin accumulation and reducing weight loss in the BTH-treated muskmelons during healing.

Highly dynamic, coordinated, and stage-specific profiles are revealed by a multi-omics integrative analysis during tuberous root development in cassava

Cassava (Manihot esculenta) is an important starchy root crop that provides food for millions of people worldwide, but little is known about the regulation of the development of its tuberous root at the multi-omics level. In this study, the transcriptome, proteome, and metabolome were examined in parallel at seven time-points during the development of the tuberous root from the early to late stages of its growth. Overall, highly dynamic and stage-specific changes in the expression of genes/proteins were observed during development. Cell wall and auxin genes, which were regulated exclusively at the transcriptomic level, mainly functioned during the early stages. Starch biosynthesis, which was controlled at both the transcriptomic and proteomic levels, was mainly activated in the early stages and was greatly restricted during the late stages. Two main branches of lignin biosynthesis, coniferyl alcohol and sinapyl alcohol, also functioned during the early stages of development at both the transcriptomic and proteomic levels. Metabolomic analysis further supported the stage-specific roles of particular genes/proteins. Metabolites related to lignin and flavonoid biosynthesis showed high abundance during the early stages, those related to lipids exhibited high abundance at both the early and middle stages, while those related to amino acids were highly accumulated during the late stages. Our findings provide a comprehensive resource for broadening our understanding of tuberous root development and will facilitate future genetic improvement of cassava.

Subcritical Methanol Extraction of the Stone of Japanese Apricot Prunus mume Sieb. et Zucc.

The pits of Japanese apricot, Prunus mume Sieb. et Zucc., which are composed of stones, husks, kernels, and seeds, are unused by-products of the processing industry in Japan. The processing of Japanese apricot fruits generates huge amounts of waste pits, which are disposed of in landfills or, to a lesser extent, burned to form charcoal. Mume stones mainly consist of cellulose, hemicellulose, and lignin. Herein, we attempted to solubilize the wood-like carapace (stone) encasing the pit by subcritical fluid extraction with the aim of extracting useful chemicals. The characteristics of the main phenolic constituents were elucidated by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) analyses. The degrees of solubility for various treatments (190 °C; 3 h) were determined as follows: subcritical water (54.9%), subcritical 50% methanol (65.5%), subcritical 90% methanol (37.6%), subcritical methanol (23.6%), and subcritical isopropyl alcohol (14.4%). Syringaldehyde, sinapyl alcohol, coniferyl alcohol methyl ether, sinapyl alcohol methyl ether, 5-(hydroxymethyl)-2-furfural, and furfural were present in the subcritical 90% methanol extract. Coniferyl and sinapyl alcohols (monolignols) are source materials for the biosynthesis of lignin, and syringaldehyde occur in trace amounts in wood. Our current findings provide a solubilization method that allows the main phenolic constituents of the pits to be extracted under mild conditions. This technique for obtaining subcritical extracts shows great potential for further applications.

Overexpression of ZePrx in Nicotiana tabacum Affects Lignin Biosynthesis Without Altering Redox Homeostasis.

Class III plant peroxidases (Prxs) are involved in the oxidative polymerization of lignins. Zinnia elegans Jacq. Basic peroxidase (ZePrx) has been previously characterized as capable of catalyzing this reaction in vitro and the role in lignin biosynthesis of several of its Arabidopsis thaliana homologous has been previously confirmed. In the present work, ZePrx was overexpressed in Nicotiana tabacum to further characterize its function in planta with particular attention to its involvement in lignin biosynthesis. Since Prxs are known to alter ROS levels by using them as electron acceptor or producing them in their catalytic activity, the impact of this overexpression in redox homeostasis was studied by analyzing the metabolites and enzymes of the ascorbate-glutathione cycle. In relation to the modification induced by ZePrx overexpression in lignin composition and cellular metabolism, the carbohydrate composition of the cell wall as well as overall gene expression through RNA-Seq were analyzed. The obtained results indicate that the overexpression of ZePrx caused an increase in syringyl lignin in cell wall stems, suggesting that ZePrx is relevant for the oxidation of sinapyl alcohol during lignin biosynthesis, coherently with its S-peroxidase nature. The increase in the glucose content of the cell wall and the reduction of the expression of several genes involved in secondary cell wall biosynthesis suggests the occurrence of a possible compensatory response to maintain cell wall properties. The perturbation of cellular redox homeostasis occurring as a consequence of ZePrx overexpression was kept under control by an increase in APX activity and a reduction in ascorbate redox state. In conclusion, our results confirm the role of ZePrx in lignin biosynthesis and highlight that its activity alters cellular pathways putatively aimed at maintaining redox homeostasis.

Pulsed-ozonolysis assisted oxidative treatment of forestry biomass for lignin fractionation

Lignocellulosic biomass has been used to produce biomolecules of industrial interest through thermochemical, biological, and chemical transformation. However, few works have been developed over lignin fractionation to obtain monolignols with commercial potentials, such as sinapyl, coniferyl, and p-coumaryl alcohols. This study is focused on developing a thermochemical method to delignify biomass. Additionally, an oxidative treatment with ozone was studied to increase the release of monolignol compounds. The results showed that with 30 sec of ozonation in liquid samples from softwood sawdust a total concentration of 368.50 ± 0.73 mg/kg of monolignols was released after microwave-assisted extraction (256.5 ± 0.51 mg/kg of sinapyl alcohol and 112 ± 0.22 mg/kg of coniferyl alcohol) and 629.20 ± 0.21 mg/kg was released after thermal treatment (453.70 ± 0.15 mg/kg of sinapyl alcohol and 175.5 ± 0.06 mg/kg of coniferyl alcohol). For p-coumaryl alcohol, 16.32 mg/kg was obtained only in hardwood samples. The results of the present study showed that ozonolysis improves monolignols release from forestry residues.

Understanding the formation of phenolic monomers during fractionation of birch wood under supercritical ethanol over iron based catalysts

The liquefaction of biomass in ethanol, at the critical point, has high potential due to low temperature and pressure (243 °C, 63 bar) when compared with water (374 °C, 220 bar). The current study deals with the fractionation of birch wood powder which was liquefied under supercritical ethanol over acidic or non-acidic catalysts, 5 wt % Fe-Beta-H-150 and 5 wt % Fe–SiO2, respectively. Based on the results, the reaction mechanism for the formation of lignin degradation products was proposed. The main phenolic product was isoeugenol over 5 wt % Fe-Beta-H-150 while intermediate products, i.e. such as coniferyl, and sinapyl alcohol, 4-propenyl syringol, syringaresinol, as well as syringyldehyde reacted rapidly further. The thermodynamic analysis was performed by Joback approach and using Gibbs-Helmholtz equation supporting the obtained results.

Enzymatic-assisted polymerization of the lignin obtained from a macroalgae consortium, using an extracellular laccase-like enzyme (Tg-laccase) from Tetraselmis gracilis

In the past decade, Mexican coasts have received an enormous influx of macroalgae species, producing serious environmental and public health concerns. Here, we developed a green methodology to generate a new polymer from the lignin contained in the macroalgae. The methodology consists in lignin extraction-by-boiling and its subsequent polymerization with a laccase-like enzyme from the green algae Tetraselmis gracilis (Tg-laccase). Mass spectrometry revealed the presence of guaiacyl (G), p-hydroxyphenyl (H), and sinapyl alcohol as the main monolignols in the lignin from Sargassum sp. On the other hand, MALDI-TOF spectra shows an increase in the size of the lignin chain after enzymatic polymerization process with Tg-laccase. Besides, the characterization of the novel polymer -using 1H NMR, FTIR, SEC-FPLC, and UV/Vis- allowed establishing that during the polymerization process there is a decrease in the number of phenolic groups as well as loss of aromatic protons, which allowed proposing a polimerizacion mechanism. This methodology could be promising in the development of a new lignin-based polymer and would open a new direction for the environmental management of the macroalgae on the Mexican beaches.

Lignin Monomers from beyond the Canonical Monolignol Biosynthetic Pathway: Another Brick in the Wall

Lignin is conventionally defined as being formed by the oxidative polymerization of three main monolignols, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol, that are derived from the general phenylpropanoid biosynthetic pathway. Many other phenolic compounds that are also derived from the phenylpropanoid pathway are also known to perform as genuine lignin monomers in many plants, as is the case of the monolignol ester conjugates, phenolic compounds arising from the truncated biosynthesis of monolignols, or ferulate esters. Recent investigations, however, have indicated that phenolic compounds arising from beyond the canonical phenylpropanoid pathway, namely flavonoids, hydroxystilbenes, and hydroxycinnamic amides, may also behave as authentic lignin monomers and are incorporated into the lignin in some plants, further challenging the traditional definition of lignin. This is the case of the flavone tricin that is incorporated into the lignin of grasses and other monocots, the hydroxystilbene piceatannol (together with resveratrol and isorhapontigenin, at lower levels) that has been found in the lignins of palm fruit shells, their respective O-glucosides (astringin, piceid, and isorhapontin) that are present in the lignin of Norway spruce bark, or the ferulic amides feruloyltyramine, incorporated into the lignin of tobacco and potato tubers, and diferuloylputrescine, which appears to be incorporated into maize kernel lignin. These valuable compounds are potentially available in high amounts and at low cost and may be obtained from the waste products from the processing of agricultural or forest biomass.

Phytotoxic effect of Alhagi maurorum on the growth and physiological activities of Pisum sativum L.

The present work was conducted to evaluate the effect of aqueous extract of Alhagi maurorum at different rates (1, 5, 10, 15%, w/v) on the growth as well as some physiological parameters of pea (Pisum sativum L.). The pot experiment revealed that Alhagi maurorum aqueous extract reduced all growth parameters of pea plant along with photosynthesis pigments, insoluble sugars, total carbohydrate, total protein and total phenolics. On the other hand, soluble sugars, soluble protein, proline, flavonoids and antioxidant enzymes increased upon treatment with aqueous solution of Alhagi maurorum. The adverse effect of the extract on the growth of treated pea plants especially hydroquinone and sinapyl alcohol that were found in relatively high concentration in the extract were identified and quantified by the GC–MS of the methanolic extract of Alhagi maurorum.

Structural basis for monolignol oxidation by a maize laccase.

Plant laccases catalyse the oxidation of monolignols in lignification, a process reinforcing the cell wall of many different cell types that provide mechanical support, nutrient transportation and defence against pathogens in plants1. The isozymes display a broad range of substrate preferences. Here, the substrate preference of a laccase (ZmLac3) from Zea mays (maize) was characterized. The crystal structure of ZmLac3 revealed a compact and deep substrate-binding pocket, and the binding modes of sinapyl alcohol (SinA) and coniferyl alcohol (ConA) were solved. On the basis of structural data and kinetics analysis, we propose that the regionalization of polar and hydrophobic surfaces in the binding pocket of ZmLac3 is vital for defining the orientation of SinA/ConA binding. The extra methoxyl group in SinA makes substantial contributions to interactions between SinA and ZmLac3, which are absent in the ZmLac3-ConA complex. In summary, the polar and hydrophobic interactions between SinA/ConA and ZmLac3 determine the binding positions of the monolignols in ZmLac3. These results provide valuable insight about ZmLac3 catalysis and should aid industrial processes that use plant laccases.

Kraft lignin-based piezoresistive sensors: Effect of chemical structure on the microstructure of ultrathin carbon fibers

In an attempt to diversify lignin applications, in this study, electrospun mats composed of ultrathin carbon fibers from Eucalyptus globulus Lignin (EKL) and sugarcane bagasse Kraft lignin (BKL) capable of detecting certain human body motions were fabricated and their chemical structures fully investigated accordingly. Results suggested that the main chemical structure of EKL was slightly linear with sinapyl alcohol and coniferyl alcohol as the basic units and pinoresinol, arylglycerol-β-aryl ether, phenylcoumaran, with diphenylethane as the main linkages. The slightly linear EKL and cross-linked BKL tended to form amorphous carbon and graphite crystallites under the same heat treatment process respectively, thereby resulting in a large difference in the resistance of fabricated sensors. The amplitude of signals due to changes in the relative resistance (△R/R0) for EKL ultrathin carbon fiber (CF)-based sensor was approximately 9 × 104 during the finger bending process, while large (△R/R0 ~380) and small (△R/R0 < 10) relative resistance variations due to BKL-CF-based sensors were detected during the arm bending and finger pressing motions respectively.

Biomimetic Oxidation of Monolignol Acetate and p-Coumarate by Silver Oxide in 1,4-Dioxane.

Lignin acylated with acetate and/or p-coumarate is common in many herbaceous plants. Herein, the biomimetic oxidation of γ-acylated monolignols with Ag2O was studied to understand the effect of γ-acyl groups on monolignol polymerization. The oxidation of sinapyl acetate gave γ-acylated and α-acylated β-O-4 dimers in 71 and 9.5% yields, respectively. The oxidation of sinapyl p-coumarate produced γ-acylated β-O-4 and γ-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 γ-acylated monolignols used in this study produced the γ-acylated β-O-4 dimers, which suggests that the γ-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.

Diversity of metabolite accumulation patterns in inner and outer seed coats of pomegranate: exploring their relationship with genetic mechanisms of seed coat development

The expanded outer seed coat and the rigid inner seed coat of pomegranate seeds, both affect the sensory qualities of the fruit and its acceptability to consumers. Pomegranate seeds are also an appealing model for the study of seed coat differentiation and development. We conducted nontarget metabolic profiling to detect metabolites that contribute to the morphological differentiation of the seed coats along with transcriptomic profiling to unravel the genetic mechanisms underlying this process. Comparisons of metabolites in the lignin biosynthetic pathway accumulating in seed coat layers at different developmental stages revealed that monolignols, including coniferyl alcohol and sinapyl alcohol, greatly accumulated in inner seed coats and monolignol glucosides greatly accumulated in outer seed coats. Strong expression of genes involved in monolignol biosynthesis and transport might explain the spatial patterns of biosynthesis and accumulation of these metabolites. Hemicellulose constituents and flavonoids in particular accumulated in the inner seed coat, and candidate genes that might be involved in their accumulation were also identified. Genes encoding transcription factors regulating monolignol, cellulose, and hemicellulose metabolism were chosen by coexpression analysis. These results provide insights into metabolic factors influencing seed coat differentiation and a reference for studying seed coat developmental biology and pomegranate genetic improvement.

Chemical constituents of the ethyl acetate extract from the leaf of mugwort (Artemisia vulgaris L.)

Introduction: Mugwort (Artemisia vulgaris L.) is a familiar herbal medicine and also a daily vegetable. It is one of the ingredients in the famous remedy "Cao ích mẫu" specializing in menstrual disorders or the omelet with mugwort that helps save blood flow to the brain to treat headaches. In both traditional medicine and the new drugs, diseases are usually treated by mugwort as diabetes, epilepsy combination for psychoneurosis, depression, irritability, insomnia, anxiety, and stress. To demonstrate the medicinal uses, the chemical constituents of this herbal were continually studied.&#x0D; Methods: The leaves of mugwort were collected in Ba Ria - Vung Tau province, Vietnam. The plant was identified by the late pharmacist and botanist Binh Duc Phan. A voucher specimen (AV001) was deposited in the herbarium of the Department of Organic Chemistry, VNUHCM–University of Science. Dried leaf powder of A. vulgaris (11 kg) was extracted with methanol and evaporated under reduced pressure to give a methanol extract (910 g), which was dissolved in methanol-water (1:9) and then successively partitioned with petroleum ether, chloroform, and ethyl acetate. From the previously researched ethyl acetate fraction, nine compounds were isolated: six known phenolic compounds (luteolin, 6-methoxyluteolin, eupatilin, o-coumaric acid, vanillic acid, and protocatechuic acid), sinapyl alcohol diisovalerate, vulgarin, and one new compound (artanoic acid).&#x0D; Results: In this research, ethyl acetate fraction was also studied. From subfraction EA4, six compounds were isolated by three skeletons: phenolic compounds (5,4′ -dihydroxyflavone and 4-hydroxyphenyl acetate), phenyl propanoid (methyl 2-O-b -D-glucopyranosylcoumarate and 2-O-b -D-glucopyranosylcoumaric acid) and uracil (5-methyluracil and uridine). The structure of the isolated compounds was determined to base on 1D, 2D NMR spectra, HR-ESI-MS, and comparison with published data.&#x0D; Conclusion: Particularly, four compounds (methyl 2-O-b -D-glucopyranosylcoumarate, 2-O-b -D-glucopyranosylcoumaric acid, 5-methyluracil, and uridine) were known for the first time from this species.&#x0D;

Soft template-based bismuth doped zinc oxide nanocomposites for photocatalytic depolymerization of lignin

Lignin depolymerization is a growing research area for the synthesis of aromatic molecules. In current studies, photocatalytic lignin depolymerization has been investigated by designing a series of soft template-based Zn0.95Bi0.05O nano-materials (SK1-SK5). Synthesized nano-materials were characterized by PXRD, SEM/EDX, BET, FTIR and utilized for photocatalytic lignin depolymerization in the presence of direct sunlight. Lignin depolymerization was monitored by UV–Visible Spectroscopy and catalytic pathway analyzed by different kinetic models. Percent depolymerization was studied for the effect of catalyst dose, starting lignin concentration and different temperatures. Pseudo second order was found the best fitted kinetic model indicating chemically rate controlled mechanism. Activation energy (Ea) for the reaction was found to be 11 kJ/mol that is remarkably lower than conventional lignin depolymerization i.e. 59.75 kJ/mol depicting better catalytic efficiencies of tested materials. Lignin depolymerization products were characterized by HPLC and FTIR Spectroscopy and their analysis indicated the conversion of lignin into smaller subunits like syringaldehyde, sinapyl alcohol, phthalates, and 4-hydroxy-benzoic acid. Specifically, phenol (21%) and 2-methoxy-4-methylphenol (16%) were detected by GCMS analysis in the products of lignin depolymerization by SK2.