RESUMEN

Considering an ever-growing global population, which hit 8 billion people in the fall of 2022, it is essential to find solutions to avoid croplands competition between human food and animal feed. Agricultural co-products such as soybean meals have become important components of the circular economy thanks to their use in animal feed. Their implementation was made possible by the addition of exogenous enzymes in the diet of monogastric animals, especially fungal carbohydrate-active enzymes (CAZymes). Here, we describe a time-course production and analysis of Aspergillus terreus secretomes for the identification of CAZymes able to enhance the digestibility of soybean meals. Functional assays revealed that the release of nutrients and the degradation of pectins in soybean meals can be tightly interconnected. Using a comparative proteomics approach, we identified several fungal pectin-degrading enzymes leading to increased assimilable nutrients in the soluble fraction of soybean meals. Our results reinforce the importance of deconstructing pectic polysaccharides in feedstuffs and contribute to sharpen our understanding of the fungal enzymatic interplays involved in pectin hydrolysis.IMPORTANCEIn the present study, we developed a strategy to identify the key fungal enzymatic activities involved in the improvement of soybean meal (SBM) digestibility. Our data unravel the importance of pectin degradation for the release of nutrients from SBM and provide some insights regarding the degradation of rhamnogalacturonan-I (RG-I) by ascomycetes. Indeed, the hydrolysis of pectins and RG-I by human microbiota is well documented in the literature, but our knowledge of the fungal CAZymes at play for the degradation of soybean pectins remains hitherto underexplored. Due to its wide use in animal feed, improving the digestibility of SBM by enzymatic treatments is a current challenge for feed additive suppliers. Since non-starch polysaccharides and pectins have often been reported for their anti-nutritional role in SBM, we believe this study will provide new avenues toward the improvement of enzymatic cocktails for animal nutrition and health.

Asunto(s)

Alimentación Animal , Aspergillus , Glycine max , Pectinas , Aspergillus/metabolismo , Aspergillus/enzimología , Pectinas/metabolismo , Glycine max/metabolismo , Alimentación Animal/análisis , Proteínas Fúngicas/metabolismo , Digestión

RESUMEN

This study aimed to investigate the structural characteristics and intracellular mechanisms of polysaccharides (MP-PE-I) purified from a crabapple (Malus prunifolia) enzymatic hydrolysate (MP-PE). Activity-guided fractionation revealed that MP-PE-I was the active moiety and significantly reduced the production and gene expression of pro-inflammatory factors in interleukin (IL)-1ß-treated intestinal epithelial cells (Caco-2). Moreover, MP-PE-I downregulated the phosphorylation and nuclear localization of proteins involved in the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways, as evidenced by immunoblotting and immunofluorescence analysis. In antagonistic studies with specific inhibitors of the MAPK and NF-κB pathways, IL-6 inhibition was significantly regulated by p38; IL-8 by IκBα, JNK, and p38; and monocyte chemoattractant protein-1 (MCP-1) by JNK, p38, and ERK. Additionally, MP-PE-I significantly decreased the mRNA and protein expression of IL-1 receptor type 1. Chemical and structural characteristic analyses showed that MP-PE-I is a polysaccharide rich in rhamnogalacturonan (RG)-I and plays a crucial role in intestinal immunomodulation. To our knowledge, this is the first study to demonstrate the intestinal immunomodulatory activity, intracellular mechanisms, and structural characteristics of RG-I-rich polysaccharides isolated from crabapples.

Asunto(s)

Interleucina-1beta , Pectinas , Polisacáridos , Pectinas/farmacología , Pectinas/química , Pectinas/aislamiento & purificación , Humanos , Interleucina-1beta/metabolismo , Interleucina-1beta/genética , Polisacáridos/farmacología , Polisacáridos/química , Polisacáridos/aislamiento & purificación , Inflamación/inducido químicamente , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , Células CACO-2 , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , FN-kappa B/metabolismo , Hidrólisis , Proteínas Quinasas Activadas por Mitógenos/metabolismo

RESUMEN

The impact of pectin structure on carotenoid bioaccessibility is still uncertain. This study aims to investigate how the different pectic polymers affected the bioaccessibility of carotenoids in a simulated juice model during static in vitro digestion. This study includes homogalacturonan (HG), which is a linear pectic polymer, rhamnogalacturonan-I (RG-I), which is a branched pectic polymer, and rhamnogalacturonan (RG), which is a diverse pectic polymer rich in RG-I, rhamnogalacturonan-II (RG-II), and xylogalacturonan domains. Juice models without pectin had the highest carotenoid bioaccessibility, suggesting pectin has negative effects on carotenoid bioaccessibility. During the intestinal phase, systems with HG showed the highest viscosity, followed by systems with RG and systems with RG-I. Systems with RG-I had lower carotenoid bioaccessibility than systems with HG and RG-II. Both the percentage of RG-I and the average side chain length of RG-I had negative correlations with carotenoid bioaccessibility. RG-I side chains with more arabinose and/or galactose might cause lower carotenoid bioaccessibility in this juice model system. This study offers valuable insights into the relationship between pectin structure and carotenoid bioaccessibility in a simulated juice model, highlighting the importance of considering pectin composition for maximizing carotenoid bioaccessibility and potential health benefits in fruit-based beverages.

Asunto(s)

Carotenoides , Jugos de Frutas y Vegetales , Pectinas , Pectinas/química , Carotenoides/química , Carotenoides/metabolismo , Jugos de Frutas y Vegetales/análisis , Viscosidad , Disponibilidad Biológica , Modelos Biológicos , Digestión , Humanos

RESUMEN

Pectic polysaccharides are one of the most vital functional ingredients in quinoa microgreens, which exhibit numerous health-promoting benefits. Nevertheless, the detailed information about the structure-function relationships of pectic polysaccharides from quinoa microgreens (QMP) remains unknown, thereby largely restricting their applications as functional foods or fortified ingredients. Therefore, to unveil the possible structure-function relationships of QMP, the mild alkali de-esterification was utilized to modify QMP, and then the correlations of esterification degrees of native and modified QMPs to their biological functions were systematically investigated. The results showed that the modified QMPs with different esterification degrees were successfully prepared by the mild alkali treatment, and the primary chemical structure (e.g., compositional monosaccharides and glycosidic linkages) of the native QMP was overall stable after the de-esterified modification. Furthermore, the results revealed that the antioxidant capacity, antiglycation effect, prebiotic potential, and immunostimulatory activity of the native QMP were negatively correlated to its esterification degree. In addition, both native and modified QMPs exerted immunostimulatory effects through activating the TLR4/NF-κB signaling pathway. These results are conducive to unveiling the precise structure-function relationships of QMP, and can also promote its applications as functional foods or fortified ingredients.

Asunto(s)

Antioxidantes , Chenopodium quinoa , Esterificación , Chenopodium quinoa/química , Relación Estructura-Actividad , Antioxidantes/química , Antioxidantes/farmacología , Antioxidantes/análisis , Pectinas/química , Polisacáridos/química , Prebióticos , Animales , Ratones , Alimentos Funcionales , Células RAW 264.7 , FN-kappa B/metabolismo

RESUMEN

Pectin and its derivatives have been shown to modulate immune signaling as well as gut microbiota in preclinical studies, which may constitute the mechanisms by which supplementation of specific pectic polysaccharides confers protection against viral respiratory infections. In a double-blind, placebo-controlled rhinovirus (RV16) challenge study, healthy volunteers were randomized to consume placebo (0.0 g/day) (N = 46), low-dose (0.3 g/day) (N = 49) or high-dose (1.5 g/day) (N = 51) of carrot derived rhamnogalacturonan-I (cRG-I) for eight weeks and they were subsequently challenged with RV-16. Here, the effect of 8-week cRG-I supplementation on the gut microbiota was studied. While the overall gut microbiota composition in the population was generally unaltered by this very low dose of fibre, the relative abundance of Bifidobacterium spp. (mainly B. adolescentis and B. longum) was significantly increased by both doses of cRG-1. Moreover, daily supplementation of cRG-I led to a dose-dependent reduction in inter- and intra-individual microbiota heterogeneity, suggesting a stabilizing effect on the gut microbiota. The severity of respiratory symptoms did not directly correlate with the cRG-I-induced microbial changes, but several dominant groups of the Ruminococcaceae family and microbiota richness were positively associated with a reduced and hence desired post-infection response. Thus, the present results on the modulation of the gut microbiota composition support the previously demonstrated immunomodulatory and protective effect of cRG-I during a common cold infection.

Asunto(s)

Suplementos Dietéticos , Microbioma Gastrointestinal , Voluntarios Sanos , Pectinas , Humanos , Pectinas/administración & dosificación , Pectinas/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Masculino , Adulto , Método Doble Ciego , Femenino , Adulto Joven , Rhinovirus/efectos de los fármacos , Persona de Mediana Edad , Heces/microbiología , Bifidobacterium/efectos de los fármacos

RESUMEN

Mucilage is a gelatinous and sticky hydrophilic polysaccharide released from epidermal cells of seed coat after the hydration of mature seeds and is composed primarily of unbranched rhamnogalacturonan I (RG-I). In this study, we produced a recombinant endo-RG-I hydrolase from Aspergillus aculeatus (AaRhgA) in the fission yeast Schizosaccharomyces pombe and examined its substrate preference for pyridylaminated (PA) RG-I with the various degrees of polymerization (DP). Recombinant AaRhgA requires PA-RG-I with a DP of 10 or higher for its hydrolase activity. We heterologously expressed the AarhgA gene under the strong constitutive promoter, cauliflower mosaic virus 35S promoter, in Arabidopsis thaliana. In a series of biochemical analyses of each mucilage fraction released from the water-imbibed seeds of the transgenic plants, we found the enhanced deposition of the transparent mucilage layer that existed in the peripheral regions of the adherent mucilage and was not stained with ruthenium red. This study demonstrated the feasibility of manipulating the mucilage organization by heterologous expression of the endo-RG-I hydrolase.

Asunto(s)

Arabidopsis , Aspergillus , Pectinas , Plantas Modificadas Genéticamente , Semillas , Arabidopsis/genética , Arabidopsis/metabolismo , Aspergillus/enzimología , Aspergillus/genética , Aspergillus/metabolismo , Pectinas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Plantas Modificadas Genéticamente/genética , Semillas/metabolismo , Mucílago de Planta/metabolismo , Mucílago de Planta/química , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Schizosaccharomyces/enzimología , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Regiones Promotoras Genéticas , Caulimovirus/genética , Caulimovirus/metabolismo , Glicósido Hidrolasas/metabolismo , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/química , Especificidad por Sustrato

RESUMEN

Background: Panax ginseng Meyer polysaccharides exhibit various biological functions, like antagonizing galectin-3-mediated cell adhesion and migration. Galectin-8 (Gal-8), with its linker-joined N- and C-terminal carbohydrate recognition domains (CRDs), is also crucial to these biological processes, and thus plays a role in various pathological disorders. Yet the effect of ginseng-derived polysaccharides in modulating Gal-8 function has remained unclear. Methods: P. ginseng-derived pectin was chromatographically isolated and enzymatically digested to obtain a series of polysaccharides. Biolayer Interferometry (BLI) quantified their binding affinity to Gal-8, and their inhibitory effects on Gal-8 was assessed by hemagglutination, cell migration and T-cell apoptosis. Results: Our ginseng-derived pectin polysaccharides consist mostly of rhamnogalacturonan-I (RG-I) and homogalacturonan (HG). BLI shows that Gal-8 binding rests primarily in RG-I and its ß-1,4-galactan side chains, with sub-micromolar KD values. Both N- and C-terminal Gal-8 CRDs bind RG-I, with binding correlated with Gal-8-mediated function. Conclusion: P. ginseng RG-I pectin ß-1,4-galactan side chains are crucial to binding Gal-8 and antagonizing its function. This study enhances our understanding of galectin-sugar interactions, information that may be used in the development of pharmaceutical agents targeting Gal-8.

RESUMEN

Pectin, a complex polysaccharide found in plant cell walls, plays a crucial role in various industries due to its functional properties. The diluted alkali-soluble pectin (DASP) fractions that result from the stepwise extraction of apples and carrots were studied to evaluate their structural and rheological properties. Homogalacturonan and rhamnogalacturonan I, in different proportions, were the main pectin domains that composed DASP from both materials. Atomic force microscopy revealed that the molecules of apple DASP were longer and more branched. A persistence length greater than 40 nm indicated that the pectin molecules deposited on mica behaved as stiff molecules. The weight-averaged molar mass was similar for both samples. Intrinsic viscosity values of 194.91 mL·g-1 and 186.79 mL·g-1 were obtained for apple and carrot DASP, respectively. Rheological measurements showed greater structural strength for apple-extracted pectin, whereas carrot pectin was characterized by a higher linear viscoelasticity limit. This comparison showed that the pectin fractions extracted by diluted alkali are structurally different and have different rheological properties depending on their botanical origin. The acquired insights can enhance the customized use of pectin residue and support further investigations in industries relying on pectin applications.

Asunto(s)

Daucus carota , Malus , Malus/química , Álcalis , Pectinas/química , Polisacáridos

RESUMEN

Tartary buckwheat green leaves are considered to be among the most important by-products in the buckwheat industry. Although Tartary buckwheat green leaves are abundant in pectic polysaccharides, their potential applications in the food industry are quite scarce. Therefore, to promote their potential applications as functional or fortified food ingredients, both deep-eutectic-solvent-assisted extraction (DESE) and high-pressure-assisted deep eutectic solvent extraction (HPDEE) were used to efficiently and selectively extract pectic polysaccharides from Tartary buckwheat green leaves (TBP). The results revealed that both the DESE and HPDEE techniques not only improved the extraction efficiency of TBP but also regulated its structural properties and beneficial effects. The primary chemical structures of TBP extracted using different methods were stable overall, mainly consisting of homogalacturonan and rhamnogalacturonan-I (RG-I) pectic regions. However, both the DESE and HPDEE methods could selectively extract RG-I-enriched TBP, and the proportion of the RG-I pectic region in TBP obviously improved. Additionally, both the DESE and HPDEE methods could improve the antioxidant and anti-glycosylation effects of TBP by increasing its proportion of free uronic acids and content of bound polyphenolics and reducing its molecular weight. Moreover, both the DESE and HPDEE methods could partially intensify the immunostimulatory effect of TBP by increasing its proportion of the RG-I pectic region. These findings suggest that DES-based extraction techniques, especially the HPDEE method, can be promising techniques for the efficient and selective extraction of RG-I-enriched TBP.

RESUMEN

Glycosylation is a method that enhances the functional properties of proteins by covalently attaching sugars to them. This study aimed at preparing three conjugates (WP-HG, WP-SBP, and WP-RGI) by dry heating method to research the influence of different pectin structures on the functional properties of WP and characterize properties and structures of these conjugates. The research results manifested that the degree of glycosylation (DG) of HG, SBP and RGI were 13.13 % ± 0.07 %, 23.27 % ± 0.3 % and 36.39 % ± 0.3 % respectively, suggesting that the increase of the number of branch chains promoted the glycosylation reaction. The formation of the conjugate was identified by the FT-IR spectroscopy technique. And SEM showed that WP could covalently bind to pectin, resulting in a smoother and denser surface of the conjugates. The circular dichroism analysis exhibited that the glycosylation reaction altered the secondary structure of WP and decreased the α-Helix content. This structural change in the protein spatial conformation led to a decrease in the hydrophobicity of protein surface. But the addition of pectin further regulated the hydrophilic-hydrophobic ratio on the surface of the protein, thus improving the emulsification properties of WP. In addition, the glycosylation could improve the stability of the emulsion, giving it a smaller droplet size, higher Zeta-potential and more stable properties. In a word, this study pointed out the direction for the application of different pectin structures in the development of functional properties of glycosylation products in food ingredients.

Asunto(s)

Pectinas , Proteína de Suero de Leche/química , Pectinas/química , Glicosilación , Espectroscopía Infrarroja por Transformada de Fourier , Emulsiones/química

RESUMEN

BACKGROUND AND AIMS: The softening of ripening fruit involves partial depolymerization of cell-wall pectin by three types of reaction: enzymic hydrolysis, enzymic elimination (lyase-catalysed) and non-enzymic oxidative scission. Two known lyase activities are pectate lyase and rhamnogalacturonan lyase (RGL), potentially causing mid-chain cleavage of homogalacturonan and rhamnogalacturonan-I (RG-I) domains of pectin respectively. However, the important biological question of whether RGL exhibits action in vivo had not been tested. METHODS: We developed a method for specifically and sensitively detecting in-vivo RGL products, based on Driselase digestion of cell walls and detection of a characteristic unsaturated 'fingerprint' product (tetrasaccharide) of RGL action. KEY RESULTS: In model experiments, potato RG-I that had been partially cleaved in vitro by commercial RGL was digested by Driselase, releasing an unsaturated tetrasaccharide ('ΔUA-Rha-GalA-Rha'), taken as diagnostic of RGL action. This highly acidic fingerprint compound was separated from monosaccharides (galacturonate, galactose, rhamnose, etc.) by electrophoresis at pH 2, then separated from ΔUA-GalA (the fingerprint of pectate lyase action) by thin-layer chromatography. The 'ΔUA-Rha-GalA-Rha' was confirmed as 4-deoxy-ß-l-threo-hex-4-enopyranuronosyl-(1→2)-l-rhamnosyl-(1→4)-d-galacturonosyl-(1→2)-l-rhamnose by mass spectrometry and acid hydrolysis. Driselase digestion of cell walls from diverse ripe fruits [date, sea buckthorn, cranberry, yew (arils), mango, plum, blackberry, apple, pear and strawberry] yielded the same fingerprint compound, demonstrating that RGL had been acting in vivo in these fruits prior to harvest. The 'fingerprint' : (galacturonate + rhamnose) ratio in digests from ripe dates was approximately 1 : 72 (mol/mol), indicating that ~1.4 % of the backbone Rha→GalA bonds in endogenous RG-I had been cleaved by in-vivo RGL action. CONCLUSIONS: The results provide the first demonstration that RGL, previously known from studies of fruit gene expression, proteomic studies and in-vitro enzyme activity, exhibits enzyme action in the walls of soft fruits and may thus be proposed to contribute to fruit softening.

Asunto(s)

Pared Celular , Frutas , Pectinas , Polisacárido Liasas , Polisacárido Liasas/metabolismo , Frutas/enzimología , Pared Celular/metabolismo , Pectinas/metabolismo

RESUMEN

Plant cell wall polysaccharides, including xylan, mannan, xyloglucan, and pectins, are often acetylated and members of the domain of unknown function 231 (DUF231)/trichome birefringence-like (TBL) family have been shown to be O-acetyltransferases mediating the acetylation of xylan, mannan, and xyloglucan. However, little is known about the O-acetyltransferases responsible for pectin acetylation. In this report, we biochemically characterized a suite of Arabidopsis DUF231/TBL proteins for their roles in pectin acetylation. We generated 24 TBL recombinant proteins in mammalian cells and demonstrated that 10 of them were able to transfer acetyl groups from acetyl-CoA onto the pectins homogalacturonan (HG) or rhamnogalacturonan-I (RG-I), and thus were named pectin O-acetyltransferase 1 to 10 (POAT1 to 10). It was found that POAT2,4,9,10 specifically acetylated HG and POAT5,6 acetylated RG-I, whereas POAT1,3,7,8 could act on both HG and RG-I. The acetylation of HG and RG-I by POATs was further corroborated by hydrolysis with pectin acetylesterases and by nuclear magnetic resonance spectroscopy. In addition, mutations of the conserved GDS and DXXH motifs in POAT3 and POAT8 were shown to lead to a loss of their ability to acetylate HG and RG-I. Furthermore, simultaneous RNA interference downregulation of POAT1,3,6,7,8 resulted in reduced cell expansion, impaired plant growth, and decreased pectin acetylation. Together, our findings indicate that these POATs are pectin O-acetyltransferases involved in acetylation of the pectin polysaccharides HG and RG-I.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Xilanos/metabolismo , Ramnogalacturonanos/análisis , Ramnogalacturonanos/metabolismo , Mananos/metabolismo , Acetilación , Birrefringencia , Tricomas/metabolismo , Pectinas/metabolismo , Polisacáridos/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Acetiltransferasas/genética , Acetiltransferasas/metabolismo , Catálisis , Pared Celular/metabolismo

RESUMEN

In this work, the effects of four different extraction methods, acid (HCl), alkali (NaOH), enzymes (cellulase/pectinase), and buffer (pH 7.0) on the physicochemical properties and functionalities of burdock pectin were systematically investigated and compared. Buffer extraction gave a low yield (2.8 %) and is therefore limited in its application. The acid treatment hydrolyzed the neutral sidechains and gave a homogalacturonan content of 72.6 %. By contrast, alkali and enzymes preserved the sidechains while degrading the polygalacturonan backbone, creating a rhamnogalacturonan-I dominant structure. The branched structure, low molecular weight, and high degree of methylation (42.3 %) contributed to the interfacial adsorption, emulsifying capacity, and cellular antioxidant activity of the enzyme-extracted product. For the acid-extracted product, the strong intramolecular electrostatic repulsion restricted the formation of a contact interface to prevent coalescence of the emulsion. In addition, they did not have sufficient reducing ends to scavenge free radicals. Although a high branching size (5.0) was adopted, the low degree of methylation (19.5 %) affected the emulsifying capacity of the alkali-extracted products. These results provide useful information for pectic polysaccharides production with tailored properties.

Asunto(s)

Arctium , Arctium/química , Pectinas/química , Polisacáridos/química , Antioxidantes/farmacología , Antioxidantes/química , Álcalis

RESUMEN

Plant rhamnogalacturonan lyases (RGLyases) cleave the backbone of rhamnogalacturonan I (RGI), the "hairy" pectin and polymer of the disaccharide rhamnose (Rha)-galacturonic acid (GalA) with arabinan, galactan or arabinogalactan side chains. It has been suggested that RGLyases could participate in remodeling cell walls during fruit softening, but clear evidence has not been reported. To investigate the role of RGLyases in strawberry softening, a genome-wide analysis of RGLyase genes in the genus Fragaria was performed. Seventeen genes encoding RGLyases with functional domains were identified in Fragaria × ananassa. FaRGLyase1 was the most expressed in the ripe receptacle of cv. Chandler. Transgenic strawberry plants expressing an RNAi sequence of FaRGLyase1 were obtained. Three transgenic lines yielded ripe fruits firmer than controls without other fruit quality parameters being significantly affected. The highest increase in firmness achieved was close to 32%. Cell walls were isolated from ripe fruits of two selected lines. The amount of water-soluble and chelated pectins was higher in transgenic lines than in the control. A carbohydrate microarray study showed a higher abundance of RGI epitopes in pectin fractions and in the cellulose-enriched fraction obtained from transgenic lines. Sixty-seven genes were differentially expressed in transgenic ripe fruits when compared with controls. These genes were involved in various physiological processes, including cell wall remodeling, ion homeostasis, lipid metabolism, protein degradation, stress response, and defense. The transcriptomic changes observed in FaRGLyase1 plants suggest that senescence was delayed in transgenic fruits.

Asunto(s)

Fragaria , Fragaria/metabolismo , Frutas/genética , Frutas/metabolismo , Ramnogalacturonanos/metabolismo , Pectinas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Polisacárido Liasas/genética , Polisacárido Liasas/metabolismo , Pared Celular/metabolismo , Regulación de la Expresión Génica de las Plantas

RESUMEN

This study aimed to investigate the mechanisms underlying intracellular signaling pathways in macrophages in relation to the structural features of rhamnogalacturonan (RG) I-type polysaccharide (PGEP-I) purified from Panax ginseng leaves. For this investigation, we used several specific inhibitors and antibodies against mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), and pattern recognition receptors (PRRs). Furthermore, we investigated the roles of component sugar chains on immunostimulating activity through a sequential enzymatic and chemical degradation steps. We found that PGEP-I effectively induced the phosphorylation of several MAPK- and NF-κB-related proteins, such as p38, cJun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p65. Particularly, immunocytochemistry analysis confirmed the PGEP-I-induced translocation of p65 into the nucleus. Furthermore, the breakdown of PGEP-I side chains and main chain during sequential enzymatic and chemical degradation reduced the PGEP-I-induced macrophage cytokine secretion activity. IL-6, TNF-α, and NO secreted by macrophages are associated with several signaling pathway proteins such as ERK, JNK, and NF-κB and several PRRs such as dectin-1, CD11b, CD14, TLR2, TLR4, and SR. Thus, these findings suggest that PGEP-I exerts potent macrophage-activating effects, which can be attributed to its typical RG-I structure comprising arabinan, type II arabinogalactan, and rhamnose-galacturonic acid repeating units in the main chain.

Asunto(s)

FN-kappa B , Panax , FN-kappa B/metabolismo , Ramnogalacturonanos/metabolismo , Azúcares/metabolismo , Azúcares/farmacología , Panax/química , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Polisacáridos/farmacología , Polisacáridos/metabolismo , Macrófagos

RESUMEN

This review article focuses on the multifaceted roles of pectin in cancer management, namely as an oncotherapeutic delivery vehicle and a pharmacological agent. Over the past decades, the potential of pectin as a novel therapeutical agent for the prevention and/or management of cancer has gained increasing interest. Pectin has been found to modulate different mechanisms involved in the onset and progression of carcinogenesis, such as galectin-3 inhibition, caspase-3-induced apoptosis, and autophagy. Elucidating the structure-activity relationship provides insight into the relationship between the structure of pectin and different mechanism/s. The bioactivity of pectin, with respect to its structure, was critically discussed to give a better insight of the relationship between the structure of the extracted pectin and the observed bioactive effects. The rhamnogalacturonan I part of the pectin chain was found to bind to galectin-3, associated with several cancer hallmarks. The anti-inflammatory and antioxidant potential of pectin were also described. The roles of pectin as a treatment enhancer and a drug delivery vehicle for oncotherapeutics were critically defined. The scientific findings presented in this paper are expected to highlight the potential and role of pectin recovered from various plant sources in preventing and managing cancer.

RESUMEN

The cellulose-enriched tertiary cell walls present in many plant fibers have specific composition, architecture, machinery of formation, and function. To better understand the mechanisms underlying their mode of action and to reveal the peculiarities of fibers from different plant species, it is necessary to more deeply characterize the major components. Next to overwhelming cellulose, rhamnogalacturonan I (RG-I) is considered to be the key polymer of the tertiary cell wall; however, it has been isolated and biochemically characterized in very few plant species. Here, we add RG-I to the list from the phloem fibers of the Phaseolus vulgaris stem that was isolated and analyzed by nuclear magnetic resonance (NMR), dynamic light scattering, and immunolabeling, both within tissue and as an isolated polymer. Additionally, fibers with tertiary cell walls from nine species of dicotyledonous plants from the orders Malphigiales, Fabales, and Rosales were labeled with RG-I-related antibodies to check the presence of the polymer and compare the in situ presentation of its backbone and side chains. The obtained results confirm that RG-I is an obligatory polymer of the tertiary cell wall. However, there are differences in the structure of this polymer from various plant sources, and these peculiarities may be taxonomically related.

Asunto(s)

Galactanos , Pectinas , Galactanos/química , Pectinas/química , Plantas , Celulosa , Pared Celular/química

RESUMEN

The human gut microbiota is characterized by large interpersonal differences, which are not only linked to health and disease but also determine the outcome of nutritional interventions. In line with the growing interest for developing targeted gut microbiota modulators, the selectivity of a carrot-derived rhamnogalacturonan I (cRG-I) was compared to substrates with demonstrated low (inulin, IN) and high selectivity (xanthan, XA), at a human equivalent dose (HED) of 1.5 g/d. The high throughput of the ex vivo SIFR® technology, validated to generate predictive insights for clinical findings, enabled the inclusion of 24 human adults. Such an unprecedented high number of samples in the context of in vitro gut microbiota modelling allowed a coverage of clinically relevant interpersonal differences in gut microbiota composition and function. A key finding was that cRG-I supplementation (already at an HED of 0.3 g/d) lowered interpersonal compositional differences due to the selective stimulation of taxa that were consistently present among human adults, including OTUs related to Bacteroides dorei/vulgatus and Bifidobacterium longum (suspected keystone species), Bacteroides thetaiotaomicron, Bifidobacterium adolescentis and butyrate-producing taxa such as Blautia sp., Anaerobutyricum hallii, and Faecalibacterium prausnitzii. In contrast, both IN and XA treatments increased interpersonal compositional differences. For IN, this followed from its low specificity. For XA, it was rather the extremely high selectivity of XA fermentation that caused large differences between 15 responders and 9 nonresponders, caused by the presence/absence of highly specific XA-fermenting taxa. While all test compounds significantly enhanced acetate, propionate, butyrate, and gas production, cRG-I resulted in a significantly higher acetate (+40%), propionate (+22%), yet a lower gas production (-44%) compared to IN. cRG-I could thus result in overall more robust beneficial effects, while also being better tolerated. Moreover, owing to its remarkable homogenization effect on microbial composition and metabolite production, cRG-I could lead to more predictable outcomes compared to substrates that are less specific or overly specific.

Asunto(s)

Daucus carota , Microbioma Gastrointestinal , Adulto , Humanos , Propionatos , Butiratos

RESUMEN

Lotus leaf is effective in regulating glycolipid absorption and metabolism, but the roles of small-molecule compounds and polysaccharides are unknown. In this study, the small-molecule compounds including flavonoids, alkaloids, and polysaccharides were gradually isolated from lotus leaf infusion by multi-column chromatography and applied to in vitro activity verification and structural characterization. Although flavonoids and alkaloids were effective in inhibiting pancrelipase and α-glucosidase, polysaccharides more effectively bounded bile acids, inhibited cholesterol micelle solubility, and stimulated the growth of Bifidobacterium than lotus leaf infusion. Polysaccharides, presented as spherical conformation in water, were identified as rhamnogalacturonan I-enriched (93%) low-ester pectin with multiple branches mainly composed of arabinan, arabinogalactan-type II, and galactan formed by →3)-Galp-(1→, →5)-Araf-(1→ and →4)-Galp-(1→ residues. Polysaccharides, which were a key constituent of lotus leaf infusion in regulating glycolipid absorption and metabolism, should be paid more attention and developed as a functional food ingredient.

Asunto(s)

Alcaloides , Lotus , Lotus/química , Flavonoides/farmacología , Flavonoides/análisis , Polisacáridos/química , Pectinas/química , Alcaloides/análisis , Hojas de la Planta/química

RESUMEN

The structural characteristics of two water-extracted pectic polysaccharides from Fructus aurantii were investigated, and the impacts of their structures on the emulsifying stability were evaluated. FWP-60 (extracted by cold water and followed 60 % ethanol precipitation) and FHWP-50 (extracted by hot water and followed 50 % ethanol precipitation) were both high methyl-esterified pectins, which were composed of homogalacturonan (HG) and highly branched rhamnogalacturonan I (RG-I) regions. The weight-average molecular weight, methyl-esterification degree (DM) and HG/RG-I ratio of FWP-60 were 1200 kDa, 66.39 % and 4.45, respectively, which were 781 kDa, 79.10 % and 1.95 for FHWP-50. The methylation and NMR analysis of FWP-60 and FHWP-50 demonstrated that the main backbone consisted of different molar ratios of →4)-α-GalpA-(1 â†’ and →4)-α-GalpA-6-O-methyl-(1 →, and the side chains contained arabinan and galactan. Moreover, the emulsifying properties of FWP-60 and FHWP-50 were discussed. Compared with FHWP-50, FWP-60 had better emulsion stability. Overall, pectin had a linear HG domain and a small number of RG-I domain with short side chains to facilitate the stabilization of emulsions in Fructus aurantii. A comprehensive knowledge of the structure characteristic and emulsifying property would enable us to provide more information and theoretical guidance for the structure and emulsion preparation of Fructus aurantii pectic polysaccharides.

Asunto(s)

Pectinas , Agua , Agua/análisis , Emulsiones/análisis , Pectinas/química , Polisacáridos/química , Frutas/química