Acetate Esters Research Articles

Synthesis and structural characterization of xylan acetate ester and its antinephritic effects in rats with experimental chronic kidney disease

Acetic acid has been shown to be effective in chronic kidney disease (CKD). However, it is a low-molecular-weight compound that allows it to be absorbed in the upper digestive tract so that it cannot function in colon. To overcome these deficiencies, an acetate-releasing xylan derivative, xylan acetate ester (XylA), was synthesized and selected in this study for its potential in the treatment of CKD. IR, NMR and HPGPC were used to characterize the structure of XylA and its antinephritic effects was evaluated in vivo. The results showed that acetate was successfully grafted onto the C-2 and C-3 positions of xylan and with a molecular weight at 69157 Da. XylA treatments could relieve the symptoms of CKD in an adenine-induced chronic renal failure (CRF) model and an adriamycin-induced focal segmental glomerulosclerosis (FSGS) model in SD rats. Further study indicated that XylA could upregulate the short-chain fatty acids (SCFAs) in vitro and vivo. Nevertheless, the relative abundance of Phascolarctobacterium in colon was increased after XylA treatment. XylA could upregulate G-protein-coupled receptor 41 (GPR41) expression, inhibit glomerular cell apoptosis and promoting proliferation. Our study expands the application of xylan and provides a new idea for the treatment of CKD with acetic acid.

Microbial community and volatile metabolites related to the fermentation degree of salted fermented chili peppers

Salted fermented chili pepper (SFCP) is a fermented vegetable with unique flavors, and its flavors vary in different regions of China. However, in-depth investigations of its microbial community and their relationship to the volatile metabolites are scarce. Our work investigated the microbial community and volatile metabolites in 14 SFCP samples from nine regions around China by both culture-dependent and high-throughput sequencing methods. Five samples were dominated by Lactobacillus, Weissella, and Pediococcus, whereas nine of the samples were dominated by Pseudomonas and Enterobacter microbes. Two types of sufficient-fermentation and slight-fermentation were suggested based on the microbial community and water activity (aw). Three samples from Guizhou province were included in the sufficient-fermentation type with aw > 0.75 and culturable lactic acid bacteria, whereas the other 11 samples were intergrated into the slight-fermentation type with aw ≤ 0.75 and unculturable lactic acid bacteria. The Lactobacillaceae, comprised of unclassified Lactobacillaceae, Lactobacillus, and Pediococcus, positively correlated with the characteristic flavor formation. The sufficient-fermentation type showed enriched in valencene, 2-methyl-naphthalene, pentadecanoic acid 3-methylbutyl ester, and acetic acid hexyl ester, generating wood, floral and fruit flavors. These findings help us to select the appropriate functional bacteria for high-quality SFCP.

More to legs than meets the eye: Presence and function of pheromone compounds on heliothine moth legs.

Chemical communication is ubiquitous in nature and chemical signals convey species-specific messages. Despite their specificity, chemical signals may not be limited to only one function. Identifying alternative functions of chemical signals is key to understanding how chemical communication systems evolve. Here, we explored alternative functions of moth sex pheromone compounds. These chemicals are generally produced in, and emitted from, dedicated sex pheromone glands, but some have recently also been found on the insects' legs. We identified and quantified the chemicals in leg extracts of the three heliothine moth species Chloridea (Heliothis) virescens, Chloridea (Heliothis) subflexa and Helicoverpa armigera, compared their chemical profiles and explored the biological function of pheromone compounds on moth legs. Identical pheromone compounds were present on the legs in both sexes of all three species, with no striking interspecies or intersex differences. Surprisingly, we also found pheromone-related acetate esters in leg extracts of species that lack acetate esters in their female sex pheromone. When we assessed gene expression levels in the leg tissue, we found known and putative pheromone-biosynthesis genes expressed, which suggests that moth legs may be additional sites of pheromone production. To determine possible additional roles of the pheromone compounds on legs, we explored whether these may act as oviposition-deterring signals, which does not seem to be the case. However, when we tested whether these chemicals have antimicrobial properties, we found that two pheromone compounds (16:Ald and 16:OH) reduce bacterial growth. Such an additional function of previously identified pheromone compounds likely coincides with additional selection pressures and, thus, should be considered in scenarios on the evolution of these signals.

Design, synthesis, docking, and antidepressant activity evaluation of isatin derivatives bearing Schiff bases.

Depression is a prevalent psychiatric disorder. Treatment of depression is still a challenge due to the lack of response of some patients to a variety of available medications and side effects. Isatin is an interesting molecule with diversified biological effects. It also participates in many synthetic reactions, as a precursor molecule. In this study, a new series of N-alkyl and N-benzyl isatin derivatives bearing Schiff bases were synthesized and screened for antidepressant activities in mice. The synthesis was initiated by N-alkylation and N-benzylation of isatin by an alkylation reaction to give N-substituted isatins. 2-(Benzyloxy) benzohydrazide derivatives were synthesized by treating methyl2-hydroxybenzoate with benzyl bromide or 4-chlorobenzyl bromide which was followed by a reaction with hydrazine hydrate to provide acid hydrazide derivatives. The final compounds were obtained by condensation of N-substituted isatins with 2-(benzyloxy) benzohydrazide derivatives as Shiff-base products. Compounds were evaluated for antidepressant activities in mice by the locomotor activity, marble burying test, and forced swimming test. Monoamine oxidase-A (MAO-A) enzyme has been used for molecular docking studies. Compounds 8b and 8e in both doses, and 8 c in the lower dose, reduced immobility time during the forced swimming test relative to the control group. All preparations reduced the number of marbles buried compared with the control group. The highest docking score was -11.01 kcal/mol for compound 8e. N-Benzylated-isatin (8b, 8e) and N- acetic acid ethyl ester -isatin derivatives (8c) showed more effective antidepressant activity compared with N-phenyl acetamide isatin derivatives. Docking results relatively confirm the pharmacological results.

Torulaspora delbrueckii Strain Behaviour within Different Refermentation Strategies for Sparkling Cider Production

Torulaspora delbrueckii is known for improving the aroma quality in wine and beer, but information for cider manufacturing is scarce. We explored the behaviour of two commercial strains of T. delbrueckii in apple juice fermentation to produce cider and sparkling cider. The influence of the strain, method, and strain–method interaction on the physicochemical parameters of cider was analysed by enzymatic and chromatographic assays. The data were subjected to an analysis of variance and a principal component analysis. Both strains also showed regular fermentation kinetics under pressure. Ethanol, lactic acid, acetic acid, and glycerol were produced with significant differences between strains and production methods. Then, 26 volatile compounds were identified, with higher alcohols being the quantitatively most abundant group. Strain A was associated with a higher production of methyl butanol, 2-phenyl ethanol, and butyric, propionic, and succinic acid esters, while strain B was associated with higher amounts of hexanoic acid, and acetate and valerate esters. In addition, 13 compounds showed significant differences between methods, and 14 were influenced by the method–strain interaction. Our findings encourage the further investigation of the application of T. delbrueckii as a solo player to produce ciders with a unique flavour.

Research on the kinetics and degradation pathways of gaseous acetic acid ester organics

ABSTRACT Designed to meet the specific needs of the printing industry exhaust gas emissions, this paper proposes a method for the degradation of gaseous acetic acid ester organics that is environmentally friendly, safe, and simple to use: micro-nano cavitation technology. In the process of using micro-nano cavitation technology to degrade acetic acid ester organics, the products in the degradation process were analyzed by gas chromatography-mass (GC-MS) spectrometry, and the degradation pathways of acetic acid ester organics were identified. Under high temperatures and high pressure caused by cavitation collapse, the C–C bond and C–O bond on the main chain of organic matter are cleaved to form low molecular products. Low-molecular intermediate products are continuously produced as the reaction advances, and these intermediate products are further oxidized and decomposed into carbon dioxide and water. Besides, the factors that influence the degradation rate of acetic acid ester organics were investigated. Based on the experimental data, acetic acid esters can degrade with the greatest efficiency when their initial concentration is 200 ± 50 mg/m3 and their treatment time is 20∼30 min. Moreover, the experiment was optimized using the response surface method. The results suggested that for an initial concentration of 155.544 mg/m3 and a reaction time of 21.961 min, the best degradation rate was 0.251 min−1. Micro-nano cavitation technology is a novel and promising technology for the degradation of volatile organic compounds, with a wide range of practical applications.

Response surface methodology for optimization of enzymatic acylation of (R)‐(‒)‐linalool application to essential oils

AbstractThe essential oils of Lavender (Lavandula angustifolia) and Tropical Basil (Ocimum basilicum) are characteristically high in both linalool and linalyl acetate esters, key constituents determining essential oil (EO) quality and activity. The enrichment of these products in linalyl acetate has a great interest in the industry. Herein, we report the production of linalyl acetate using the free lipase PPL as a catalyst in a solvent‐free medium. Parametric studies referring response surface methodology (RSM) were applied to optimize the conversion. The optimal experimental condition for (R)‐linalool acylation (temperature at 60°C, catalyst amount at 150 mg, volume of acetic anhydride at 1 mL, and reaction time at 5 days) was obtained from an experimental design analysis. Under these conditions, the enzymatic acylation was carried out for both pure linalool, Lavandula angustifolia and O. basilicum essential oils as substrates. 24.94% conversion of pure linalool to linalyl acetate was obtained; however, essential oils gave lower conversions (conv = 13%).

Analysis of Microbial Diversity and Metabolites in Sauerkraut Products with and without Microorganism Addition

The microbial compositions and metabolites of fermented sauerkraut with and without the addition of microorganisms have been compared. The OTU clustering, nonvolatile compounds, volatile compounds and associations between bacterial taxa and metabolites were analyzed by 16S rRNA high-throughput sequencing technology, ultra performance liquid chromatography (UPLC), gas chromatography ion mobility mass spectrometry (GC-IMS) and the O2PLS model studies. The results showed that at the phylum level, the microbial species in the four sauerkraut types consisted mainly of the phyla Firmicutes and Proteobacteria, but different modes of microbial addition formed their own unique microbial communities. There were significant differences in the microbial communities among different northeast China sauerkraut samples, and different microbial communities exerted similar effects to inhibit Firmicutes production. At the genus level, sauerkraut without added microorganisms had the lowest microbial diversity. A total of 26 amino acids and 11 organic acids were identified and were more abundant in nonmicrobially fermented sauerkraut; 88 volatile organic compounds were identified in the 4 types of sauerkraut, with the microbially fermented sauerkraut being richer in alcohols, esters and acids. Different brands of sauerkraut contain their own unique flavor compounds. Cystine and tyrosine, ascorbic acid and acetic acid, and alcohols and esters are closely related to a wide range of microorganisms in sauerkraut. Elucidating the correlations among microbiota and metabolites will help guide future improvements in sauerkraut fermentation processes.

Orthoamide und Iminiumsalze, CIX. Umsetzungen von Orthoamiden der Alkincarbonsäuren mit Diolen, Ethandithiol und CH-aciden Nitroverbindungen

AbstractOrthoamides of alkyne carboxylic acids17react with 1,2- and 1,3-dioles to give vinylogous cyclic urea acetals. Analogous reactions with ethandithiol deliver vinylogous thioureas. The condensation of orthoamides17with 3,5-dimethyl-4-nitroisoxazol affords 1,1-diamino-butadiene derivatives. From nitro acetaldehyde diethylacetal and orthoamides17can be prepared reactive vinylogous urea acetals, which condense with cyano-acetic acid ester under formation of 7,7-diamino-2,4,6-hexatrienecarboxylic acid esters. 5,5-Bis(dimethylamino)-2-nitro-2,4-butadienecarboxylic acid esters, which are accessible from the orthoamides17and nitro acetic ester, cyclize to give 5-dimethylamino-pyrrole-2-carboxylic acid esters on treatment with zinc/acetic acid.

Sonoluminescence intensity and ultrasonic cavitation temperature in organic solvents: Effects of generated radicals

Ultrasonic cavitation in organic solvents remains poorly understood in contrast with aqueous systems, largely because of complexities related to solvent decomposition. In this study, we sonicated different types of organic solvents (i.e. linear alkanes, aliphatic alcohols, aromatic alcohols, and acetate esters) under argon saturation. The average temperature of the cavitation bubbles was estimated using the methyl radical recombination method. We also discuss the effects of the physical properties of the solvents, such as vapor pressure and viscosity, on the cavitation temperature. The average cavitation bubble temperature and sonoluminescence intensity were higher in organic solvents with lower vapor pressure; for aromatic alcohols, these values were particularly high. It was found that the specific high sonoluminescence intensities and average cavitation temperatures exhibited in aromatic alcohols are caused by the highly resonance-stable generated radicals. The results obtained in this study are very useful for acceleration of sonochemical reaction in organic solvents, which are indispensable for organic synthesis and material synthesis.

Analysis of volatile compounds production kinetics: A study of the impact of nitrogen addition and temperature during alcoholic fermentation.

Among the different compounds present in the must, nitrogen is an essential nutrient for the management of fermentation kinetics, also playing a major role in the synthesis of fermentative aromas. Fermentation temperature is yet another variable that affects fermentation duration and the production of fermentative aromas in wine. The main objective of this study was thus to evaluate the combined effects of nitrogen addition-at the start of the fermentation process or during the stationary phase-at different fermentation temperatures on both fermentation kinetics and aroma synthesis kinetics. To study the impact of these three parameters simultaneously, we used an innovative transdisciplinary approach associating an online GC-MS system with an original modeling approach: a Box-Behnken experimental design combined with response surface modeling and GAM modeling. Our results indicated that all three factors studied had significant effects on fermentation and aroma production kinetics. These parameters did not impact in the same way the different families of volatile compounds. At first, obtained data showed that reduction of ester accumulation in the liquid phase at high temperature was mainly due to important losses by evaporation but also to modifications of yeast metabolic capabilities to synthetize these compounds. In a noticeable way, optimal temperature changed for liquid accumulation of the two classes of esters-23°C for acetate ester and 18°C for ethyl esters-because biological impact of temperature was different for the two chemical families. Moreover, the study of these three factors simultaneously allowed us to show that propanol is not only a marker of the presence of assimilable nitrogen in the medium but above all a marker of cellular activity. Finally, this work enabled us to gain a deeper understanding of yeast metabolism regulation. It also underlines the possibility to refine the organoleptic profile of a wine by targeting the ideal combination of fermentation temperature with initial and added nitrogen concentrations. Such observation was particularly true for isoamyl acetate for which interactions between the three factors were very strong.

Larvicidal Activity of Ethyl Acetate Leaf Extract of Aegle marmelos (L.) Correa Against Aedes aegypti

Aegle marmelos leaf contains secondary metabolites that have bioinsecticidal effects. This study aimed to analyze phytoconstituents of the ethyl acetate extract of Aegle marmelos leaves, its larvicidal activity, and its effects on histopathological changes of the midgut of Aedes aegypti larvae. The ethyl acetate extract was obtained from the concentrated maceration of the leaf powder and analyzed with GCMS. The instar III or IV larvae were used and divided into six groups where each group was exposed to an extract with a concentration of 1%; 4%; 8% and 16%, and one other control group without exposure to such extract. The histopathology of larval midgut was prepared, stained with Hematoxyllin-Eosin, and observed using light microscopy. GC-MS analysis revealed that the extracts contain 8 compounds, Oleic acid, 9-Hexadecenoic acid, Cis-1,3-Eicosenoic acid, Dasycarpidan-1-methanol, acetate (ester), Digitoxin, Z-(13,14-epoxy)tetradeg-11-en-ol acetate; 2,3-dimethyl-5-trifluoromethyl-1-phen-1,4-diol, ethyl iso-allocholate. Probit test revealed that the LC50 value of ethyl acetate extract of Aegle marmelos leaves was 3.917% and histopathological results are damage to brush borders, nucleus and nucleolus, epithelial cells, and hypertrophy of the gastric caeca. The leaf ethyl acetate extract from Aegle marmerlos can be considered as a probable natural insecticide to kill Aedes aegypti. Aegle marmelos can be applied as natural insecticide to eradicate the population of Ae. aegypti.

Sorption Properties of PET Copolyesters and New Approach for Foaming with Filament Extrusion Additive Manufacturing

The mass transfer process of binary esters of acetic acid in polyethylene terephthalate (PET), polyethylene terephthalate with a high degree of glycol modification (PETG), and glycol-modified polycyclohexanedimethylene terephthalate (PCTG) was studied. It was found that the desorption rate of the complex ether at the equilibrium point is significantly lower than the sorption rate. The difference between these rates depends on the type of polyester and temperature and allows the accumulation of ester in the volume of the polyester. For example, the stable content of acetic ester in PETG at 20 °C is 5 wt.%. The remaining ester, which has the properties of a physical blowing agent, was used in the filament extrusion additive manufacturing (AM) process. By varying the technological parameters of the AM process, foams of PETG with densities ranging from 150 to 1000 g/cm3 were produced. Unlike conventional polyester foams, the resulting foams are not brittle.

Application of Steapsin lipase for bioconversion of glycerol acetates from glycerol

This work demonstrates the synthesis of glycerol acetate esters derived from glycerol through an esterification reaction catalyzed by lipase (Steapsin). Glycerol was esterified with acetic acid. The best conditions for the synthesis of glycerol acetates were 70 °C, molar ratio between glycerol and acetic acid was 1:10 and the catalyst concentration was 5 wt %. Glycerol (G) conversion reached 95–99% within 48–108 h of reaction. The yields of glycerol acetates were 22%, 59% and 19% of mono glycerol acetate (MGA), di glycerol acetate (DGA) and tri glycerol acetate (TGA) respectively. The obtained results demonstrated the efficiency of the reaction catalyzed by lipase and the feasibility of this method for the synthesis of glycerol acetates through bio-catalysis. This method of glycerol acetate synthesis was not described in the literature until now, giving this research an innovative edge.

Impact of Assimilable Nitrogen Supplementation on Saccharomyces cerevisiae Metabolic Response and Aromatic Profile of Moschofilero Wine.

The concentration of nitrogen in must is critical to yeast fermentation efficiency and wine aroma profile. The present work determined the effect of the amount of yeast assimilable nitrogen (YAN) on fermentation kinetics, aroma production, and gene expression patterns of the wine yeast Saccharomyces cerevisiae. Fermentations were performed under two different YAN concentrations of must. Acetate esters, linalool, and nerol appeared to be clearly affected by the different YAN levels. Real-time-PCR results revealed that the genes involved in ethyl and acetate esters production recorded, in general, higher transcript levels under high nitrogen supplementation. In addition, an up-regulation of the BGL2 and EXG1 genes, which are related to terpenes production, was observed in the case of high nitrogen content and it is well corresponded to the terpenol concentration found. Our study revealed the impact of nitrogen supplementation on yeast metabolism and its importance to adjust wine's aromatic composition and sensory profile.

Mild depolymerization of alkaline lignin in a formic acid-choline chloride type deep eutectic solvent system

Abstract The degradation of lignin can generate a variety of products with diverse applications. Lignin is abundant on earth; however, its high molecular weight and stable properties impede its development. Currently, acid-catalyzed degradation of lignin is a relatively common and promising catalytic method, particularly DES catalytic degradation, which is not only environmentally friendly but also features an excellent degradation effect. This report discusses the degradation mechanism and effect of the formic acid-choline chloride DES system for the degradation of alkaline lignin. According to fourier transform infrared spectroscopy (FTIR) and 1H-NMR spectroscopy, it is evident that the phenolic hydroxyl content of lignin increases after degradation, which indicates the cleavage of β-O-4′ ether bonds in the macromolecular structure. Gel permeation chromatography (GPC) was employed to determine the molecular weight of degraded lignin, and regenerated lignin with low molecular weight and low dispersibility was obtained. The minimum average molecular weight (M w ) was 2.3 × 103 g/mol. During the depolymerization process, it was also discovered that the repolymerization and degradation reactions formed a competitive relationship. The lignin oil contained primarily propanoic acid ethyl ester, acetic acid butyl ester, 2-methoxy-4-propyl phenol, 2-methoxy phenol, and apocynin, as determined by GC-MS.

Revalorization of Melon By-Product to Obtain a Novel Sparkling Fruity-Based Wine.

Fresh melons not meeting cosmetic standards were revaluated into sparkling melon-based wine. Firstly, still melon wine was elaborated and bottled into 750 mL bottles, closed with a crown seal, and stored for 10-weeks at 14 °C. The oenological parameters and polar compounds in must, still wine, and during the sparkling process were evaluated during the experiment. The volatile profile was qualified by GC-MS, and the odor activity value (OAV) and relative odor contribution (ROC) were measured for aroma characterization. Results show that sparkling wine resulted in 12% v/v ethanol. Certain amino acids contributed to the transformation and increase of volatile compounds via Ehrlich's pathway: leucine to isoamyl alcohol; valine to iso-butyl alcohol; and phenylalanine to phenethyl alcohol. The volatile compounds also increased after the first fermentation, principally in acetate and ethyl esters, and higher alcohols. Isoamyl acetate, ethyl decanoate, 3,6-nonadienyl acetate, and (E,Z)-nonadien-1-ol had the highest OAV and ROC values among the volatiles; this contributed to the sweet, fruity, banana, tropical, nutty and melon aroma in this sparkling wine. Sensory evaluation (100 to 40) was evaluated according to International Organisation of Vine and Wine compendium, the final product (10-week) scored 92 points, with great visual, nose, and taste values. This study demonstrates how by-products revalorization can provide new products such as this novel sparkling wine with a characteristic and distinctive aroma, good sensory acceptance and market potential.

Acute toxicity study of antibacterial organophilic bentonite incorporated with geranyl acetate in mice and geranyl acetate liberation in simulated gastric fluid

In the present study, the antibacterial property of the organophilic bentonite (Bent-ODA) and organophilic bentonite incorporated with geranyl acetate ester (Bent-ODA-GA) was evaluated against bacteria Staphylococcus aureus, Escherichia coli and Salmonella typhimurium. Oral acute toxicity of Bent-ODA-GA was evaluated in mice, by a single oral dose of 300 and 2000 mg kg−1. Animals were observed for any toxicity clinical signs or mortality for 15 days according to OECD 423 guidelines. The release assay of GA presents in Bent-ODA in simulated gastric fluid, pH 3.5 and pH 6.5 was also performed. Bent-ODA-GA composite presented antibacterial activity against S. aureus and S. typhimurium bacteria with 10.7 ± 0.6 mm and 2.2 ± 0.1 mm inhibition halo, respectively, which make it possible to associate the composite antimicrobial feature due to the ester presence. The composite did not reveal any toxicity signs or mortality in any animal for acute toxicity treatment during the 15 days observation period. The LD50 of Bent-ODA-DA was estimated to be greater than 2000 mg kg−1. It was also observed that geranyl acetate is released from Bent-ODA in concentrations lower than 0.03 mg kg−1 for pH 3.5 and 0.004 mg kg−1 for pH 6.5, which are lower than those that could cause some toxic effects in animals.

Thorough Characterization of ETHQB3.5, a QTL Involved in Melon Fruit Climacteric Behavior and Aroma Volatile Composition.

The effect of the QTL involved in climacteric ripening ETHQB3.5 on the fruit VOC composition was studied using a set of Near-Isogenic Lines (NILs) containing overlapping introgressions from the Korean accession PI 16375 on the chromosome 3 in the climacteric 'Piel de Sapo' (PS) genetic background. ETHQB3.5 was mapped in an interval of 1.24 Mb that contained a NAC transcription factor. NIL fruits also showed differences in VOC composition belonging to acetate esters, non-acetate esters, and sulfur-derived families. Cosegregation of VOC composition (23 out of 48 total QTLs were mapped) and climacteric ripening was observed, suggesting a pleiotropic effect of ETHQB3.5. On the other hand, other VOCs (mainly alkanes, aldehydes, and ketones) showed a pattern of variation independent of ETHQB3.5 effects, indicating the presence of other genes controlling non-climacteric ripening VOCs. Network correlation analysis and hierarchical clustering found groups of highly correlated compounds and confirmed the involvement of the climacteric differences in compound classes and VOC differences. The modification of melon VOCs may be achieved with or without interfering with its physiological behavior, but it is likely that high relative concentrations of some type of ethylene-dependent esters could be achieved in climacteric cultivars.

Investigation of chemical linkages between lignin and carbohydrates in cultured poplar cambium tissues via double isotope labeling

Lignin precursor labeled with 13C (coniferin-13Cα), carbohydrate precursor labeled with D (6,6-D2-glucose) were put into cambium tissue stripped from a growing poplar. The tissue was further cultured in vitro for 18d. Then, the isotopic abundance was determined. The results showed that the labeled precursors could be normally involved in the formation of new xylem. The labeled new xylem tissue was fractionated by ionic liquid DMSO/TBAH system to obtain two components: glucan-lignin complex (GL) and xylan-lignin complex (XL). The X-ray diffraction (XRD) results indicated that the crystalline form of cellulose in the GL component was transformed from type I to type II after the ionic liquid separation. Then the GL and XL were purified and modified by enzymatic and chemical methods, and their structures were elucidated by nuclear magnetic resonance (NMR) spectroscopy. The results showed that lignin subunits in the cultured tissues were mainly connected by β-5 and β-O-4 linkages, of which the β-O-4 substructure unit predominated. Lignin and carbohydrates were mainly connected by acetal bonds, ether bonds, and ester bonds. Combined with the carbohydrate composition and XRD analysis results, the GL components also confirmed the existence of acetal bonds, ester bonds and ether bonds between lignin and cellulose.