Search Results (105)

Pectin oligosaccharides are promising natural bioactive ingredients, while traditional preparation methods suffer from harsh conditions and environmental drawbacks. Herein, an eco-friendly alkaline hydrogen peroxide degradation method was applied to produce apple pectin oligosaccharides (APOSs), followed by ethanol precipitation. The structural features and antioxidant potential of APOSs were comprehensively characterized. Galacturonic acid (58.2%) was determined as the dominant monosaccharide, along with minor galactose, arabinose, and rhamnose. Sixteen oligosaccharides consisting of homogalacturonan fragments and RG-I hetero-oligosaccharides were identified using NMR, FTIR and UPLC/Q-TOF-MS. In vitro assays demonstrated excellent radical-scavenging capacities of APOSs. The DPPH and ABTS scavenging rates reached 84.6% (10 mg/mL) and 96.2% (9 mg/mL), respectively. This study provides a feasible green strategy for APOS fabrication and clarifies its antioxidant potential, supporting the industrial application of APOS as a high-efficiency natural antioxidant in functional foods. Full article

Tracheoid idioblasts in Nepenthes are anatomically specialized cells that differ distinctly from surrounding tissues in morphology, wall structure, and staining properties. Their presence has been documented in both vegetative organs, such as roots and stems, and in highly modified carnivorous leaves that form pitchers. We tested the hypothesis that if tracheoid idioblasts function to reinforce the mechanical strength of Nepenthes pitchers or to protect them from animal damage, they exhibit a secondary cell wall composition comparable to that of sclerenchyma or xylem cells, particularly with respect to its lignin and hemicellulose components. We assessed the localization of cell wall components in gland cell walls using histochemical tests, immunolabeling, and confocal microscopy. Light and scanning electron microscopy were used to reveal the tracheoid idioblast structure. Two species were examined: Nepenthes albomarginata T.Lobb ex Lindl. and Nepenthes bicalcarata Hook. f. In both species, giant tracheoid idioblasts with helical bands of secondary wall material were found throughout the pitchers. Negative phloroglucinol, fuchsin, and safranin staining test results demonstrated the absence of lignins in the tracheoid idioblast secondary cell walls. A histochemical test showed that the wall thickenings of the tracheoid idioblasts contained polysaccharides and cellulose and were rich in unsubstituted or low-substituted xylans, resembling the secondary cell walls of sclerenchyma and xylem cells. Our results suggest that tracheoid idioblasts with a helical secondary wall that is rich in xylans but not lignified most likely function as elastic reinforcing elements that increase the mechanical integrity of the organ while maintaining its flexibility and ability to undergo reversible deformation. Furthermore, tracheoid idioblasts may provide defense against herbivory. Full article

Plant polysaccharides can exert immunomodulatory activities. In this study we provided chemical characterization of wheat cell culture-derived polysaccharides (WCCPS) and assessed their capacity to modulate inflammatory responses in mouse macrophages. The total sample (T-010) contained arabinogalactans, arabinans, glucans and xyloglucans. Fractionation by anion-exchange chromatography rendered a bound acidic fraction (B-010) and an unbound neutral fraction (UB-010). The B-010 fraction was enriched in arabinogalactans and arabinans, with some galactans, homogalacturonans, and arabinoxylans. The neutral UB-010 fraction was composed of glucans and xyloglucans. None of the WCCPS preparations triggered cytokine production on their own, but each potentiated different macrophage responses to bacterial lipopolysaccharide (LPS). The total WCCPS in T-010 increased LPS-induced tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6 secretion, whereas the acidic arabinogalactan-rich fraction B-010 boosted IL-6 release and selectively upregulated nitric oxide synthase 2 (Nos2) and cholesterol 25-hydroxylase (Ch25h) expression in response to LPS. In contrast, the neutral UB-010 fraction enhanced IL-6 levels and induced Nos2 expression without altering Ch25h expression. These results suggest that WCCPS can modulate distinct aspects of the inflammatory response, with their effects shaped by their composition and structural features. Future research will focus on elucidating the molecular mechanisms underlying the immunomodulatory activity of WCCPS. Full article

This study investigates the extraction of pectic polysaccharides from rapeseed meal (RSM) using both conventional and enzyme-assisted techniques, and the obtained pectic polysaccharide fractions will be used later to produce prebiotic pectic oligosaccharides (POS). A two-step process was developed, involving enzymatic treatment with Alcalase^® 2.4 L for 2 h and Cellic^® CTec3 HS preparations for 24 h, followed by ammonium oxalate extraction, which effectively isolated two pectic polysaccharide-enriched fractions: PP-EAE (first step) and the resulting Ca-bound pectic polysaccharides fraction (CaPP-EAE) (second step). Both fractions exhibited a bimodal molecular weight profile, indicative of the presence of long-chain polysaccharides alongside oligosaccharides. CaPP-EAE compositional analysis revealed that the fraction contained 56.8% galacturonic acid (GalA), low methyl-esterified (LM) pectins with 53.2% homogalacturonan (HG) and 30.2% rhamnogalacturonan I (RG-I) domains, featuring side chains of arabinan, arabinogalactan, and galactan. Subsequent enzymatic treatment with 0.5% (v/v) of Pectinex^® Ultra Passover for 30 min transformed these fragments into a mixture of short-chain POS. Importantly, the produced short-chain POS fraction demonstrated enhanced prebiotic activity, particularly for bacterial strains of the family Lactobacillaceae, compared to a yeast strain. These findings provide a sustainable, biorefinery-compatible approach for extracting and modifying RSM polysaccharides, supporting the development of structurally defined POS as novel prebiotics. Full article

Polysaccharides are natural polymers that are widely found in medicinal plants. Structurally, they are complex molecules composed of long chains of monosaccharide units linked by glycosidic bonds. Modern pharmacological research shows that the bioactivity of polysaccharides is closely related to their monosaccharide composition. This review summarises the monosaccharide composition of 210 polysaccharides from 72 medicinal plants. They were classified into 10 types through principal component analysis (glucans; homogalacturonan; galactans; arabinogalactans; mannans; glucomannans; arabinans; xylans; fructans; rhamnogalacturonan-I). The relationship between monosaccharide composition and biological activity was further analysed. The results are as follows: glucans make significant contributions to immunomodulation, antioxidant activity, and gut microbiota regulation; galactans are crucial for antioxidant effects, immunomodulation, and gut microbiota regulation; mannans play a key role in immunomodulation, antitumor activity, and neuroprotection; fructans are vital for gut microbiota regulation, immunomodulation, and antioxidant effects; and pectins exhibit notable immunomodulatory, antioxidant, and hypoglycaemic properties. Consequently, developing polysaccharides from medicinal plant resources based on their monosaccharide composition is expected to speed up the search for polysaccharides with high biological activity and provide a theoretical reference for polysaccharide research. Full article

Dodder (Cuscuta campestris) is a parasitic plant that causes severe economic losses to crops such as mung bean (Vigna radiata), although some species, including tomato (Solanum lycopersicum), exhibit varying degrees of resistance. Dodder parasitism begins with the development of the haustorium, whose endophytic primordium undergoes intrusive growth to penetrate host tissues. While the cell walls of endophytic cells are essential for invasion, the sequential changes occurring in these cell walls are not fully understood. This study aims to characterize cell wall modifications in Cuscuta campestris haustoria during parasitism of a susceptible host (Vigna radiata) and a resistant host (Solanum lycopersicum ‘Minibel’), using histochemical and immunohistochemical approaches focused on homogalacturonan (HG) and arabinogalactan proteins (AGPs). In both hosts, AGPs and HG (predominantly in their demethylesterified form) increased in the host-facing epidermal walls, the aligned file cells of the haustoria, and the boundary layer surrounding the haustorial cone. The boundary layer was enriched in AGPs and initially showed massive HG deposition, later incorporating lignin and callose. In tomato, lignin-based resistance was associated with the outermost cortical cells and did not substantially affect the overall dynamics of the dodder cell walls. These findings highlight the central role of coordinated cell wall remodeling in dodder invasion and reveal broadly similar developmental trajectories of HG and AGPs in haustoria formed on susceptible and resistant hosts. Full article

The digestive gland of Venus flytrap consists of various types of specialized cells. Secretory cells form two layers: the first is a more external outer layer and the second is an internal layer that is connected to stalk cells. Our goal was to check whether the position/location of cells is essential in terms of cell wall composition (whether cell wall microdomains exist). We also focused on the structure of cell wall ingrowths in secretory cells. To achieve this, the localization of the cell wall components in the cell walls of gland cells was performed using the immunolabeling technique and confocal microscopy. It has been found that cells within the gland head are not equal. Their location determines the composition of their cell walls in terms of the presence of various epitopes. The cell walls of the secretory cells in the outer layer were deficient in epitopes recognized by antibodies, including JIM5 (low methylesterified homogalacturonans), CCRC-M38 (low methylesterified homogalacturonans), LM5 (galactan), and CCRC-M48 (xyloglucan), which contrasted with the cell walls of the cells in the inner layer. In terms of the occurrence of pectic homogalacturonans, cell wall ingrowths constitute cell wall microdomains. The digestive glands of Dionaea muscipula exhibit pronounced cell wall microdomain organization, with distinct distributions of pectins, hemicelluloses, and arabinogalactan proteins across different glandular layers. These compositional differences reflect functional specialization in secretion, absorption, and structural support. Full article

Microbial degradation of pectin is a fundamental process for the carbon cycle and a strategic approach for treating industrial residues. This study characterizes a novel marine bacterium, Paenarthrobacter sp. FR1, isolated from East China Sea intertidal sediment, which exhibits the ability to utilize pectin. Its draft genome (4.83 Mb, 62.92% GC content) is predicted to encode 4498 protein-coding genes. Genomic analysis revealed a rich repertoire of Carbohydrate-Active Enzymes (CAZymes) crucial for this process, including 108 glycoside hydrolases (GHs), 7 polysaccharide lyases (PLs), 35 carbohydrate esterases (CEs), and 11 auxiliary activities (AAs). Genomic analysis provides supportive evidence that FR1 may target both homogalacturonan (HG) and rhamnogalacturonan (RG) pectin domains, potentially through complementary hydrolytic and oxidative pathways. Phylogenomic analysis based on Average Nucleotide Identity (ANI, 83.56%) and digital DNA-DNA Hybridization (dDDH, 27.8%) confirmed its status as a potential novel species. Notably, FR1 is a rare Paenarthrobacter isolate with innate pectinolytic capability, a characteristic not previously documented in this genus. This strain’s unique enzymatic machinery highlights its importance in marine carbon cycling and provides a valuable biotechnological resource for degrading pectin-rich wastes. Full article

Homogalacturonan (HG) methylesterification is a key determinant of plant cell wall (CW) structure and function, shaping growth, morphogenesis, and responses to biotic and abiotic stresses. This review highlights recent advances in the regulation of homogalacturonan (HG) methylesterification, focusing on the coordinated roles of pectin methylesterases (PMEs), pectin methylesterase inhibitors (PMEIs), transcription factors (TFs), and hormonal signals. We examine how these regulators interact within the CW microenvironment to modulate elasticity, porosity, and remodeling dynamics. Insights from immunolocalization and biomechanical studies reveal the spatiotemporal patterning of HG de-esterification and its integration with developmental and stress-adaptive signaling. Beyond basic biology, HG methylesterification dynamics directly influence traits such as fruit firmness, pathogen resistance, and stress tolerance, positioning HG methylesterification-related genes as promising targets for molecular breeding and biotechnological interventions. By integrating mechanistic understanding with genomic and phenotypic selection approaches, breeders can precisely tailor CW properties to enhance crop resilience and quality. A comprehensive view of HG methylesterification—from enzymatic control to mechanical feedback—offers a conceptual and practical framework for guiding crop improvement and sustainable agricultural practices. Full article

A series of silver-polygalacturonate complexes with improved structure and activity against bacterial infections was developed. Pure sodium polygalacturonate was obtained by saponification of a pectin precursor and identified by NMR as predominantly homogalacturonan (uronide content 95%). Polygalacturonate complexes with ionic and borohydride-reduced silver with a controllable metallic component were synthesized; the role of spontaneous Ag⁺ reduction was revealed. The presence of uniform 5 nm nanoparticles and negligible particulate by-products in the reduced complexes was verified. The complexes showed similar silver-normalized activity against non-resistant bacteria, irrespective of complex stoichiometry/silver state. Pharmaceutical silver proteinate with a similar nanoparticle profile exhibited the same silver-normalized activity, indicating the lack of a ligand effect. The Ag⁺ complex was more effective against some hospital drug-resistant strains. The cytotoxicity of the complexes depended on fibroblast type, silver state, ligand type, exposure time, presumably in association with cellular availability and glutathione depletion. The complexes were administered to rats with excisional wounds persistently infected with S. aureus. Swab/histological analyses of the treated wounds revealed decreased bacterial burden/tissue damage, along with promotion of wound contraction/closure and matrix formation. The nanoparticle complexes that were compared had similar antibacterial/regenerative effects, while the Ag⁺ complex demonstrated higher efficacy in vivo. These results encourage the use of the developed silver-polygalacturonate complexes as antibacterial substances. Full article

Glands from Nepenthes pitcher secrete various substances, including digestive enzymes, and absorb nutrients from digested prey. Due to the extreme specialization of these glands, they are an interesting model for studying secretory cells’ structure and activity. This study aimed to fill the gap in the literature concerning the immunocytochemistry of Nepenthes digestive glands in the major cell wall polysaccharides and glycoproteins. To do this, the localization of the cell wall components in the cell walls of glandular cells was performed using whole-mount immunolabeled glands of Nepenthes albomarginata. Also, we wanted to check to what extent the cuticles of glandular cells with discontinuities would be a barrier to the antibodies. The technique used allowed for the localization of de-esterified pectic homogalacturonans in the outer walls of gland cells. The remaining antibodies (which detect esterified pectins, hemicelluloses, and arabinogalactan protein) marked only debris or secretion residues on the gland or epidermal surfaces. Positive labeling with LM19 and CCRC-M38 antibodies suggests the presence of pectic homogalacturonan in the very superficial part of the glands’ cell walls, so they were easily accessible to antibodies. Full article

Flaxseed polysaccharides (FLP) are bioactive macromolecules with valuable functional properties and applications in the food, pharmaceutical, and packaging industries. This study focused on obtaining high-purity pectin from flaxseed cake using sustainable extraction with natural deep eutectic solvents (NADES) based on choline chloride (ChCl) and citric acid (CA) The ChCl/CA system (1:1) resulted in the LU3 extract, which provided the best outcome, yielding the highest pectin recovery (36.88 mg/g), elevated uronic acid content (30.33% of sample; 68.15% of saccharides), and the lowest protein contamination (11.46%), confirming superior pectin purity. Structural (UV-Vis, FT-IR, GC-MS, GPC, LH-20) identified homogalacturonan with xylogalacturonan domains (53% DM) and a molecular weight range of 14–500 × 10³ g/mol. Morphological and physicochemical characterization, including SEM/EDS imaging, zeta potential analysis, and rheological measurements, revealed that LU3 is an anionic, heterogeneous biopolymer exhibiting pH-dependent charge behavior. These properties underscore its potential as a safe and effective material for bio-industrial applications. Overall, the study demonstrates that NADES provide an eco-friendly and efficient medium for extracting high-quality pectin from flaxseed cake, offering a sustainable strategy for the valorization of flaxseed polysaccharides in bio-based products. Full article

Flooding can cause root hypoxia and can lead to significant agricultural losses. Therefore, understanding plant adaptations to flooding, including root aerenchyma development, is one important avenue for insuring future global food security. We investigated cell wall modifications during root aerenchyma formation in response to the prolonged 0–48 h flooding of Phaseolus coccineus, Pisum sativum, and Cicer arietinum seedlings. Using transmission electron microscopy, toluidine blue O (TBO) staining, and immunolabeling with antibodies targeting de-methyl-esterified homogalacturonan (DMEH), partially DMEH, and methyl-esterified homogalacturonan (MEH), we examined changes in cell wall composition. Transmission electron microscopy and TBO staining revealed degradation of cell walls and middle lamella, with accumulation of DMEH near flooding-induced aerenchyma cavities. Immunolabeling indicated increased DMEH epitope availability in flooded roots, suggesting a role in cell wall remodeling. Enzyme pretreatments, used to “unmask” homogalacturonan by removing cellulose and hemicellulose, revealed that specific forms of homogalacturonan, particularly DMEH complexed with calcium and MEH, are masked by these cell wall components. The study highlights the complex interplay of pectin, cellulose, and hemicellulose in cell wall degradation during aerenchyma development, providing insights into legume flooding stress responses. Full article

Nepenthes L. species (tropical pitcher plants) are a classic example of carnivorous plants. The Nepenthes traps are highly specialized pitchers with a zoned structure. On the outer surface of the pitcher, there are nectaries and various types of trichomes, including glandular trichomes. The main aim of our study was to examine these glandular trichome structures and check the distribution of the homogalacturonans (HGs) and hemicelluloses in the cell wall of trichome cells. The structure of Nepenthes bicalcarata Hook. f. and Nepenthes albomarginata T.Lobb ex Lindl. trichomes was analyzed using light and electron microscopy. The antibodies were used against the wall components [anti-pectic homogalacturonans (HGs): JIM5 (low methylesterified HGs), LM19 (low methylesterified HGs), CCRC-M38 (a fully de-esterified HGs), JIM7 (highly esterified HGs), LM20 (esterified HGs), LM5 (galactan) and anti-hemicelluloses: LM25 (xyloglucan), LM15 (galactoxyloglucan), CCRC-M138 (xylan), and LM10 antibody (xylan)]. The localization of the examined compounds was determined using immunohistochemistry techniques. The presence of endodermal and transfer cells supports the idea that peltate trichomes actively transport solutes. Also, the presence of pectic homogalacturonans and hydrophilic hemicelluloses indicates that water or aqueous solutions are transported through the trichomes’ cell walls. Our study supports the idea that these trichomes may act as hydathodes or hydropotes. Full article

C. macrophylla and C. tangutorum, collectively known as Shigecai in Chinese, are consumed as special and nutritious vegetables by the Tibetan, Qiang, and Yi communities in China. However, due to the insufficient knowledge of their phytochemical compositions and health benefits, the industrial utilization of these species in the food sector remains limited. Although Shigecai leaves contain substantial pectic polysaccharides, their chemical structures and biological activities remain unknown, which ultimately restricts their industrial utilization. Thus, to address this gap, this study systematically analyzed the chemical characteristics and biological functions of rhamnogalacturonan-I (RG-I)- enriched pectin from C. tangutorum (CTHDP) and C. macrophylla (CMHDP) leaves. The results demonstrate that Shigecai leaves are promising sources of RG-I-enriched pectin, with yields of 57.63–65.21 mg/g dry weight. In addition, both CTHDP and CMHDP exhibited highly similar chemical and structural properties, dominated by RG-I and homogalacturonan (HG) pectin regions, with RG-I ratios of 60.14–63.33 mol%. Furthermore, both samples demonstrated notable antioxidant ability, antiglycation activity, prebiotic potency, and immunoregulatory effects, which were strongly linked to their bound polyphenol content, uronic acid content, and molecular weight. These findings support the industrial utilization of Shigecai and establish Shigecai-derived RG-I-enriched pectin as a promising functional food ingredient. Full article