Pectin Interaction with Immune Receptors is Modulated by Ripening Process in Papayas

Intestinal lymphatic transport of Smilax china L. pectic polysaccharide via Peyer's patches and its uptake and transport mechanisms in mononuclear phagocytes

Recently, the intestinal lymphatic transport based on Peyer's patches (PPs) is emerging as a promising absorption pathway for natural polysaccharides. Herein, the aim of this study is to investigate the PP-based oral absorption of a pectic polysaccharide from Smilax china L. (SCLP), as well as its uptake and transport mechanisms in related immune cells. Taking advantages of the traceability of fluorescently labeled SCLP, we confirmed that SCLP could be absorbed into PPs and captured by their mononuclear phagocytes (dendritic cells and macrophages) following oral administration. Subsequently, the systematic in vitro study suggested that the endocytic mechanisms of SCLP by model mononuclear phagocytes (BMDCs and RAW264.7 cells) mainly involved caveolae-mediated endocytosis, macropinocytosis and phagocytosis. More importantly, SCLP directly binds and interacts with toll-like receptor 2 (TLR2) and galectin 3 (Gal-3) receptor, and was taken up by mononuclear phagocytes in receptor-mediated manner. After internalization, SCLP was intracellularly transported primarily through endolysosomal pathway and ultimately localized in lysosomes. In summary, this work reveals novel information and perspectives about the in vivo fate of SCLP, which will contribute to further research and utilization of SCLP and other pectic polysaccharides.

Assessing high-temperature and pressure extraction of bioactive water-soluble polysaccharides from passion fruit mesocarp

The mesocarp (albedo) of passion fruit is considered a waste product but rich in soluble fibers, especially pectins. Biological activity and health benefits of pectins have recently emerged, especially in colorectal cancer and attenuating inflammation. Pectin conventional extraction often uses mineral acids, which can be hazardous to the environment, and alternatives can be costly. Here, we assessed a high-temperature and pressure method to extract pectin from the passion fruit albedo and evaluated the differences from the water-soluble fractions extracted. HPSEC, HPAEC, FTIR-ATR, and HSQC-NMR were performed to identify and confirm the highly methylated homogalacturonan structures. The heat-modified samples showed a decreased molecular size compared to the untreated sample. Colorectal cancer cell lines showed reduced viability after being treated with different doses of modified samples, with two of them, LW-MP3 and 4, showing the most potent effects. All samples were detected inside cells by immunofluorescence assay. It was observed that LW-MP3 and 4 upregulated the p53 protein, indicating cell-cycle arrest and the cleaved caspase-9 in one of the cell lines, with LW-MP4 enhancing cell death by apoptosis. Since the modified samples were composed of hydrolyzed homogalacturonans, those probably were the responsible structures for these anti-cancer effects.

Sugar-sweetened beverage but not diluted cloudy apple juice consumption induces post-prandial endotoxemia in healthy adults

Sugar beverages are discussed as critical in the development of metabolic endotoxemia. Here, employing a cross-over design study we assessed the effect of diluted cloudy apple juice (AJ), an iso-caloric and -sweetened placebo (P), or water (W) on post-prandial endotoxemia in healthy, normal weight adults. After obtaining fasting blood, 19 healthy men and women consumed 500 mL AJ, P, or W in a randomized order and blood was taken 120 and 180 min later. Caco-2 cells were incubated with the beverages. Markers of intestinal barrier function were assessed. The intake of P but not of AJ or W was associated with a significant increase in TLR2 ligands and bacterial endotoxin in serum after 120 min and 180 min, respectively. P but not AJ significantly increased bacterial toxin permeation in Caco-2 cells. Our results suggest that the effects of sugar-sweetened beverages on markers of intestinal barrier function markedly differ from those of fruit juices.

Effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice

Pectins are dietary fibers that are attributed with several beneficial immunomodulatory effects. Depending on the degree of esterification (DE), pectins can be classified as high methoxyl pectin (HMP) or low methoxyl pectin (LMP). The aim of this study was to investigate the effects of pectin methyl-esterification on intestinal microbiota and its immunomodulatory properties in naive mice. Supplementation of the diet with LMP or HMP induced changes in the composition of the intestinal microbiota in mice toward Bacteroides, which was mainly promoted by HMP. Metabolome analysis of stool samples from pectin-fed mice showed a different effect of the two types of pectin on the levels of short-chain fatty acids and bile acids, which was consistent with highly efficient in vivo fermentation of LMP. Analysis of serum antibody levels showed a significant increase in IgG and IgA levels by both pectins, while FACS analysis revealed a decrease of infiltrating inflammatory cells in the intestinal lamina propria by HMP. Our study revealed that the structural properties of the investigated pectins determine fermentability, effects on microbial composition, metabolite production, and modulation of immune responses. Consumption of HMP preferentially altered the gut microbiota and suppressed pro-inflammatory immune responses, suggesting a beneficial role in inflammatory diseases.

Dietary fiber as a wide pillar of colorectal cancer prevention and adjuvant therapy

Colorectal cancer is the third most incident and second most lethal type of cancer worldwide. Lifestyle and dietary patterns are the key factors for higher disease development risk. The dietary fiber intake from fruits and vegetables, mainly formed by food hydrocolloids, can help to lower the incidence of this type of neoplasia. Different food polysaccharides have applications in anti-tumoral therapy, such as coadjuvant to mainstream drugs, carriage-like properties, or direct influence on tumoral cells. Some classes include inulin, β-glucans, pectins, fucoidans, alginates, mucilages, and gums. Therefore, it is fundamental to discuss colorectal cancer mechanisms and the roles played by different polysaccharides in intestinal health. Genetic, environmental, and immunological modulation of mutated pathways regarding colorectal cancer has been explored before. Microbial diversity, byproduct formation (primarily short-chain fatty acids), inflammatory profile control, and tumoral mutated pathways regulation are thoroughly explored mechanisms by which dietary fiber sources influence a healthy gut ambiance.

Ripe papaya pectins inhibit the proliferation of colon cancer spheroids and the formation of chemically induced aberrant crypts in rats colons

Pectins are a class of soluble polysaccharides that can have anticancer properties through several mechanisms. This study aimed to characterize the molecular structure of water-soluble fractions (WSF) derived from ripe and unripe papayas and assess their biological effects in two models: the 3D colon cancer spheroids to measure cell viability and cytotoxicity, and the in vivo model to investigate the inhibition of preneoplastic lesions in rats. WSF yield was slightly higher in ripe papaya, and both samples mainly consisted of pectin. Both pectins inhibited the growth of colon cancer HT29 and HCT116 spheroids. Unripe pectin disturbed HT29/NIH3T3 spheroid formation, decreased HCT116 spheroid viability, and increased spheroid cytotoxicity. Ripe pectin had a more substantial effect on the reduction of spheroid viability for HT29 spheroids. Furthermore, in vivo experiments on a rat model revealed a decrease in aberrant crypt foci (ACF) formation for both pectins and increased apoptosis in colonocytes for ripe papaya pectins. The results suggest potential anticancer properties of papaya pectin, with ripe pectin showing a higher potency.

Integrated Transcriptome and Proteome Analysis Reveals That Cell Wall Activity Affects Phelipanche aegyptiaca Parasitism

Phelipanche aegyptiaca can infect many crops, causing large agricultural production losses. It is important to study the parasitism mechanism of P. aegyptiaca to control its harm. In this experiment, the P. aegyptiaca HY13M and TE9M from Tacheng Prefecture and Hami City in Xinjiang, respectively, were used to analyze the parasitical mechanism of P. aegyptiaca by means of transcriptome and proteome analyses. The parasitic capacity of TE9M was significantly stronger than that of HY13M in Citrullus lanatus. The results showed that the DEGs and DEPs were prominently enriched in the cell wall metabolism pathways, including "cell wall organization or biogenesis", "cell wall organization", and "cell wall". Moreover, the functions of the pectinesterase enzyme gene (TR138070_c0_g), which is involved in the cell wall metabolism of P. aegyptiaca in its parasitism, were studied by means HIGS. The number and weight of P. aegyptiaca were significantly reduced when TR138070_c0_g1, which encodes a cell-wall-degrading protease, was silenced, indicating that it positively regulates P. aegyptiaca parasitism. Thus, these results suggest that the cell wall metabolism pathway is involved in P. aegyptiaca differentiation of the parasitic ability and that the TR138070_c0_g1 gene plays an important role in P. aegyptiaca's parasitism.

Structural elucidation of novel pro-inflammatory polysaccharides from Daphne mezereum L

Daphne mezereum L., an important medicinal plant in Scandinavian folk medicine, was used to treat ailments such as diarrhea, swelling and stomach pain. A range of natural compounds have been isolated, but little attention has been given to the polysaccharides in this plant. Previous work in our group have shown that a polysaccharide enriched fraction from the bark of D. mezereum exhibited pro-inflammatory effects. To pursue this further, the aim of the present work was to isolate and characterize these polysaccharides. From the ethanol-precipitate of a water extract, one neutral (DMP-NF) and one acidic (DMP-AF) fraction was isolated by anion-exchange chromatography. GC, GC-MS and 1D- and 2D-NMR were used to characterize the polysaccharide structures. DMP-NF appeared to be a mixture of arabinan, arabinogalactan and hemicelluloses such as xyloglucan, mannan and xylan. DMP-AF contained a pectic polysaccharide mainly consisting of an unusually long homogalacturonan backbone. Enzymatic treatment by pectinase of DMP-AF yielded DMP-ED, which contained a rhamnogalacturonan-I backbone with arabinan, galactan and arabinogalactan side chains. Both DMP-NF and DMP-ED induced IFN-γ and TNF-α secretion in peripheral blood mononuclear cells (PBMCs), DMP-ED being the most potent fraction. DMP-AF was less active, which might be due to a less sterically available rhamnogalacturonan-I domain.

Dietary fiber pectin: challenges and potential anti-inflammatory benefits for preterms and newborns

Pectins, a class of dietary fibers abundant in vegetables and fruits, have drawn considerable interest due to their potential anti-inflammatory properties. Numerous studies have indicated that incorporating pectins into infant formula could be a safe strategy for alleviating infant regurgitation and diarrhea. Moreover, pectins have been shown to modulate cytokine production, macrophage activity, and NF-kB expression, all contributing to their anti-inflammatory effects. Despite this promising evidence, the exact mechanisms through which pectins exert these functions and how their structural characteristics influence these processes remain largely unexplored. This knowledge is particularly significant in the context of gut inflammation in developing preterm babies, a critical aspect of necrotizing enterocolitis (NEC), and in children and adults dealing with inflammatory bowel disease (IBD). Our mini review aims to provide an up-to-date compilation of relevant research on the effects of pectin on gut immune responses, specifically focusing on preterms and newborns. By shedding light on the underlying mechanisms and implications of pectin-mediated anti-inflammatory properties, this review seeks to advance our knowledge in this area and pave the way for future research and potential therapeutic interventions.

Nature's soothing solution: Harnessing the potential of food-derived polysaccharides to control inflammation

Reducing inflammation by diet is a major goal for prevention or lowering symptoms of a variety of diseases, such as auto-immune reactions and cancers. Natural polysaccharides are increasingly gaining attention due to their potential immunomodulating capacity. Structures of those molecules are highly important for their effects on the innate immune system, cytokine production and secretion, and enzymes in immune cells. Such polysaccharides include β-glucans, pectins, fucoidans, and fructans. To better understand the potential of these immunomodulatory molecules, it is crucial to enhance dedicated research in the area. A bibliometric analysis was performed to set a starting observation point. Major pillars of inflammation, such as pattern recognition receptors (PRRs), enzymatic production of inflammatory molecules, and involvement in specific pathways such as Nuclear-factor kappa-B (NF-kB), involved in cell transcription, survival, and cytokine production, and mitogen-activated protein kinase (MAPK), a regulator of genetic expression, mitosis, and cell differentiation. Therefore, the outcomes from polysaccharide applications in those scenarios are discussed.

Unveiling Plant-Based Pectins: Exploring the Interplay of Direct Effects, Fermentation, and Technological Applications in Clinical Research with a Focus on the Chemical Structure

Pectin, a plant-derived polysaccharide, possesses immense technological and biological application value. Several variables influence pectin's physicochemical aspects, resulting in different fermentations, interactions with receptors, and other functional properties. Some of those variables are molecular weight, degree of methylation and blockiness, and monosaccharide composition. Cancer cell cytotoxicity, important fermentation-related byproducts, immunomodulation, and technological application were found in cell culture, animal models, and preclinical and clinical assessments. One of the greater extents of recent pectin technological usage involves nanoencapsulation methods for many different compounds, ranging from chemotherapy and immunotherapy to natural extracts from fruits and other sources. Structural modification (modified pectin) is also utilized to enhance the use of dietary fiber. Although pectin is already recognized as a component of significant importance, there is still a need for a comprehensive review that delves into its intricate relationships with biological effects, which depend on the source and structure of pectin. This review covers all levels of clinical research, including cell culture, animal studies, and clinical trials, to understand how the plant source and pectin structures influence the biological effects in humans and some technological applications of pectin regarding human health.

TLR 2/1 interaction of pectin depends on its chemical structure and conformation

Citrus pectins have demonstrated health benefits through direct interaction with Toll-like receptor 2. Methyl-ester distribution patterns over the homogalacturonan were found to contribute to such immunomodulatory activity, therefore molecular interactions with TLR2 were studied. Molecular-docking analysis was performed using four GalA-heptamers, GalA₇Me⁰, GalA₇Me^1,6, GalA₇Me^1,7 and GalA₇Me^2,5. The molecular relations were measured in various possible conformations. Furthermore, commercial citrus pectins were characterized by enzymatic fingerprinting using polygalacturonase and pectin-lyase to determine their methyl-ester distribution patterns. The response of 12 structurally different pectic polymers on TLR2 binding and the molecular docking with four pectic oligomers clearly demonstrated interactions with human-TLR2 in a structure-dependent way, where blocks of (non)methyl-esterified GalA were shown to inhibit TLR2/1 dimerization. Our results may be used to understand the immunomodulatory effects of certain pectins via TLR2. Knowledge of how pectins with certain methyl-ester distribution patterns bind to TLRs may lead to tailored pectins to prevent inflammation.

Liquid-liquid and liquid-solid separation in self-assembled chitosan-alginate and chitosan-pectin complexes

The complexation between two oppositely charged polyelectrolytes (PE) can lead liquid-liquid (complex coacervates, CC) or liquid-solid (solid precipitates, SP) phase separations. Herein, the effect of pH (2-11) and ionic strength (I, 0.05-1.0 M KCl) on the associative interactions between chitosan (QL)-alginate (SA) and QL-Pectin (Pec), polysaccharides widely used in biotechnology field, is described. pH and I, exhibited significant effect on the structure and phase transitions by modifying the ionization degree (α), pk_a, and associative interactions between PE. Onset of binding was established at pH_c 9, while continued acidification (pH_τ 5.8) led to simultaneous CC and SP exhibiting a maximum turbidity in both systems. At pH_δ 4.0, QL-Pec showed preferably CC structures whereas QL-SA maintained the CC and SP structures. At pH_ω 2, the associative interactions were suppressed due to the low ionization of Pec and SA. I (1.0 M) significantly diminished the interactions in QL-Pec due to charge screening. Molecular weight, second virial coefficient, hydrodynamic size, ionizable groups, and persistence length of polyion, influenced on the phase behavior of QL-Pec and QL-SA systems. Therefore, CC and SP are found simultaneously in both systems, their transitions can be modulated by intrinsic and environmental conditions, expanding the functional properties of complexed polysaccharides.

Ultrasonication, immune activity, and photocrosslinked microgel formation of pectic polysaccharide isolated from root bark of Ulmus davidiana var. japonica (Rehder) Nakai

The root bark of Ulmus davidiana var. japonica (Rehder) Nakai (Japanese elm) has been used for inflammatory disease treatments. In this work, we isolated pectic polysaccharides from the root bark of U. davidiana (UDP) and explored the immune activities of intact and ultrasonicated UDP on human macrophages. The UDP-treated macrophages showed a proinflammatory response, indicating classical activation via Toll-like receptor-mediated recognition. For hydrogel formation, the ultrasonicated UDP was modified with methacrylate groups, then subjected to photocrosslinking. The formed bulk hydrogel was pulverized into microgels by homogenization, and the microgel size was modulated for macrophage phagocytosis. The UDP microgel-treated macrophages displayed microgel internalization and classical activation that involved upregulation of M1 polarization markers (IL6, TNF-α, and CCR7), indicating that the microgel can be used as a carrier for macrophage-targeted drug delivery.

Immune-instructive copolymer scaffolds using plant-derived nanoparticles to promote bone regeneration

Background

Age-driven immune signals cause a state of chronic low-grade inflammation and in consequence affect bone healing and cause challenges for clinicians when repairing critical-sized bone defects in elderly patients.

Methods

Poly(l-lactide-co-ɛ-caprolactone) (PLCA) scaffolds are functionalized with plant-derived nanoparticles from potato, rhamnogalacturonan-I (RG-I), to investigate their ability to modulate inflammation in vitro in neutrophils and macrophages at gene and protein levels. The scaffolds’ early and late host response at gene, protein and histological levels is tested in vivo in a subcutaneous rat model and their potential to promote bone regeneration in an aged rodent was tested in a critical-sized calvaria bone defect. Significant differences were tested using one-way ANOVA, followed by a multiple-comparison Tukey’s test with a p value ≤ 0.05 considered significant.

Results

Gene expressions revealed PLCA scaffold functionalized with plant-derived RG-I with a relatively higher amount of galactose than arabinose (potato dearabinated (PA)) to reduce the inflammatory state stimulated by bacterial LPS in neutrophils and macrophages in vitro. LPS-stimulated neutrophils show a significantly decreased intracellular accumulation of galectin-3 in the presence of PA functionalization compared to Control (unmodified PLCA scaffolds). The in vivo gene and protein expressions revealed comparable results to in vitro. The host response is modulated towards anti-inflammatory/ healing at early and late time points at gene and protein levels. A reduced foreign body reaction and fibrous capsule formation is observed when PLCA scaffolds functionalized with PA were implanted in vivo subcutaneously. PLCA scaffolds functionalized with PA modulated the cytokine and chemokine expressions in vivo during early and late inflammatory phases. PLCA scaffolds functionalized with PA implanted in calvaria defects of aged rats downregulating pro-inflammatory gene markers while promoting osteogenic markers after 2 weeks in vivo.

Conclusion

We have shown that PLCA scaffolds functionalized with plant-derived RG-I with a relatively higher amount of galactose play a role in the modulation of inflammatory responses both in vitro and in vivo subcutaneously and promote the initiation of bone formation in a critical-sized bone defect of an aged rodent. Our study addresses the increasing demand in bone tissue engineering for immunomodulatory 3D scaffolds that promote osteogenesis and modulate immune responses.

Recent patents on water-soluble polysaccharides for advanced drug delivery, tissue engineering and regenerative medicine

Water-soluble polysaccharides have unique properties and have found wide application in the design of advanced drug-delivery systems and the biofabrication of tissue engineered scaffolds in regenerative medicine. This patent review provides a concise incursion into the mechanisms that define the key properties of water-soluble polysaccharides that have found embodiment within active patents recently granted (2020-2021). In addition, the relationship between their solubility and structural features such as molecular weight, ionic profile, degree of branching/crosslinking, side-chain flexibility and the presence/modification of functional groups that have been discusses. An assimilation of patents in which water-soluble polysaccharides are central to the design of therapeutic interventions applied to specialized treatments in oncology, infectious diseases and neuronal disorders is provided.

The Complex Biological Effects of Pectin: Galectin-3 Targeting as Potential Human Health Improvement?

Galectin-3 is the only chimeric representative of the galectin family. Although galectin-3 has ubiquitous regulatory and physiological effects, there is a great number of pathological environments where galectin-3 cooperatively participates. Pectin is composed of different chemical structures, such as homogalacturonans, rhamnogalacturonans, and side chains. The study of pectin's major structural aspects is fundamental to predicting the impact of pectin on human health, especially regarding distinct molecular modulation. One of the explored pectin's biological activities is the possible galectin-3 protein regulation. The present review focuses on revealing the structure/function relationship of pectins, their fragments, and their biological effects. The discussion highlighted by this review shows different effects described within in vitro and in vivo experimental models, with interesting and sometimes contradictory results, especially regarding galectin-3 interaction. The review demonstrates that pectins are promissory food-derived molecules for different bioactive functions. However, galectin-3 inhibition by pectin had been stated in literature before, although it is not a fully understood, experimentally convincing, and commonly agreed issue. It is demonstrated that more studies focusing on structural analysis and its relation to the observed beneficial effects, as well as substantial propositions of cause and effect alongside robust data, are needed for different pectin molecules' interactions with galectin-3.

Effects of pectins on colorectal cancer: targeting hallmarks as a support for future clinical trials

The intake of dietary fibers has been associated with a reduction in the risk of colorectal cancer.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.

Screening of potential tropical fruits in protecting endothelial dysfunction in vitro

Background

High consumption of antioxidant-rich fruits and vegetables reduces the endothelial damage involved in cardiovascular disease pathogenesis.

Objective

To evaluate the phytochemical content, antioxidant and scavenging activities (FRAP, ORAC, OH^•, HOCl, H₂O₂, and O₂ ^-), endothelial H₂O₂-cytoprotective effect, nitric oxide (NO) release activation potential, and endothelial wound healing properties of 10 tropical fruits, comprising pineapple, sugar apple, papaya fruit, longan, mangosteen, lychee, langsat, mango, rambutan, and guava.

Design

Experimental study. The experiments were conducted in vitro using endothelial cell line EA.hy926.

Results

The high performance liquid chromatography (HPLC) phytochemical analysis indicated the presence of gallic acid and quercetin in all fruits, along with the overall absence of ellagic acid. Chlorogenic acid was only detected in three fruits, that is, pineapple, ripe papaya, and guava. The antioxidant and scavenging activities of all fruits were concentration-dependent. Only the H₂O₂ scavenging activity exhibited broad positive associations with other ROS-scavenging activities. Sugar apple and unripe papaya induced a significant reduction in H₂O₂-induced cell death in endothelial cells while pineapple, sugar apple, longan, and langsat activated NO release.

Discussion

All the studied tropical fruits contained bioactive phytoantioxidants with wide ranges of antioxidant capacity and scavenging activities. The endothelial functional tests were relevant to the screening for fruits that may benefit cardiovascular health. Among the four fruits that promoted endothelial wound closure, only sugar apple and unripe papaya induced cell migration and vascular capillary-like tube formation.

Conclusion

Sugar apple and unripe papaya are potential functional fruits that can protect against oxidative cell death and enhance endothelial wound healing.

The Dietary Fiber Pectin: Health Benefits and Potential for the Treatment of Allergies by Modulation of Gut Microbiota

Purpose of Review

The incidence of allergies is increasing and has been associated with several environmental factors including westernized diets. Changes in environment and nutrition can result in dysbiosis of the skin, gut, and lung microbiota altering the production of microbial metabolites, which may in turn generate epigenetic modifications. The present review addresses studies on pectin-mediated effects on allergies, including the immune modulating mechanisms by bacterial metabolites.

Recent Findings

Recently, microbiota have gained attention as target for allergy intervention, especially with prebiotics, that are able to stimulate the growth and activity of certain microorganisms. Dietary fibers, which cannot be digested in the gastrointestinal tract, can alter the gut microbiota and lead to increased local and systemic concentrations of gut microbiota-derived short chain fatty acids (SCFAs). These can promote the generation of peripheral regulatory T cells (T_reg) by epigenetic modulation and suppress the inflammatory function of dendritic cells (DCs) by transcriptional modulation.

The dietary fiber pectin (a plant-derived polysaccharide commonly used as gelling agent and dietary supplement) can alter the ratio of Firmicutes to Bacteroidetes in gut and lung microbiota, increasing the concentrations of SCFAs in feces and sera, and reducing the development of airway inflammation by suppressing DC function.

Summary

Pectin has shown immunomodulatory effects on allergies, although the underlying mechanisms still need to be elucidated. It has been suggested that the different types of pectin may exert direct and/or indirect immunomodulatory effects through different mechanisms. However, little is known about the relation of certain pectin structures to allergies.

Self-Assembling pH-Responsive Nanoparticle Platform Based on Pectin-Doxorubicin Conjugates for Codelivery of Anticancer Drugs

Pharmaceutical science based on biological nanotechnology is developing rapidly in parallel with the development of nanomaterials and nanotechnology in general. Pectin is a natural polysaccharide obtainable from a wide range of sources. Here, we show that doxorubicin (DOX)-conjugated hydrophilic pectin (PET) comprising an amphiphilic polymer loaded with hydrophobic dihydroartemisinin (DHA) self-assemble into nanoparticles. Importantly, conjugated DOX and DHA could be released quickly in a weakly acidic environment by cleavage of the acid-sensitive acyl hydrazone bond. Confocal microscopy and flow cytometry confirmed that these PET-DOX/DHA nanoparticles efficiently delivered DOX into the nuclei of MCF-7 cells. Significant tumor growth reduction was monitored in a female C57BL/6 mouse model, showing that the PET-DOX/DHA nanoparticle-mediated drug delivery system inhibited tumor growth and may improve therapy. Thus, we have demonstrated that pectin may be useful in the design of materials for biomedical applications.

Dietary pectic substances enhance gut health by its polycomponent: A review

Pectic substances, one of the cell wall polysaccharides, exist widespread in vegetables and fruits. A surge of recent research has revealed that pectic substances can inhibit gut inflammation and relieve inflammatory bowel disease symptoms. However, physiological functions of pectins are strongly structure dependent. Pectic substances are essentially heteropolysaccharides composed of homogalacturonan and rhamnogalacturonan backbones substituted by various neutral sugar sidechains. Subtle changes in the architecture of pectic substances may remarkably influence the nutritional function of gut microbiota and the host homeostasis of immune system. In this context, developing a structure-function understanding of how pectic substances have an impact on an inflammatory bowel is of primary importance for diet therapy and new drugs. Therefore, the present review has summarized the polycomponent nature of pectic substances, the activities of different pectic polymers, the effects of molecular characteristics and the underlying mechanisms of pectic substances. The immunomodulated property of pectic substances depends on not only the chemical composition but also the physical structure characteristics, such as molecular weight (M_w ) and chain conformation. The potential mechanisms by which pectic substances exert their protective effects are mainly reversing the disordered gut microbiota, regulating immune cells, enhancing barrier function, and inhibiting pathogen adhesion. The manipulation of pectic substances on gut health is sophisticated, and the link between structural specificity of pectins and selective regulation needs further exploration.

Modulation of human gut microbiota by dietary fibers from unripe and ripe papayas: Distinct polysaccharide degradation using a colonic in vitro fermentation model

Dietary fibers (DFs) consumption promotes a healthier gut through colonic fermentation and the modulation of different types of gut bacteria. The aim of this study is to evaluate the production of short-chain fatty acids (SCFA), metabolization of polysaccharides, and changes in the bacterial profile related to DFs extracted from the pulp of unripe and ripe papayas, using a batch colonic in vitro fermentation model. Our results show that fermentation of DFs from papayas induce the production of SCFAs and are utilized in different ways by intestinal microbiota. DFs from ripe papayas showed faster degradation by human gut microorganisms due to higher level of water-soluble polysaccharides. The fermentation of unripe papaya fibers increased the abundance of microorganisms belonging to family Clostridiaceae and genera Coprobacillus, Bulleidia, and Slackia, whereas both fibers increased Clostridium and Bacteroides, showing fruit ripeness affects the fermentation pattern of fruit fibers and their probable beneficial health aspects.

Panax quinquefolius (North American Ginseng) Polysaccharides as Immunomodulators: Current Research Status and Future Directions

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major bioactive ingredients. However, most NAG reviews are focused on ginsenosides with little information on polysaccharides. NAG polysaccharides have demonstrated a therapeutic activity in numerous studies, in which many of the bioactivities involve regulation of the immune response. The purpose of this review is to summarize the structural features and the immunomodulatory properties of crude, partially purified, and pure polysaccharides isolated from NAG. Receptors of the innate immune system that potentially bind to NAG polysaccharides and the respective signal transduction pathways initiated by these compounds are discussed. Major challenges, recent innovations, and future directions in NAG polysaccharide research are also summarized.

The purification of pectin from commercial fruit flours results in a jaboticaba fraction that inhibits galectin-3 and colon cancer cell growth

Fruits are a prime source of nutrients, bioactive compounds, and dietary fibers. Some products available on the Brazilian market use fruit by-products and claim to have useful effects on human health due to their dietary fiber content. The study aimed to extract and purify the total (28-47 w/w yield) and soluble dietary fiber (4-7 w/w yield) from jaboticaba, papaya, and plum commercial flours sold in Brazil and to study the in vitro biological effects of the fractions. The purified water-soluble fractions consisted mainly of pectin-derived oligosaccharides (5-15 KDa molecular weight) with a negligible content of polyphenols, protein, ashes, and starch. Jaboticaba sample was 95% galacturonic acid while plum and papaya samples were 40% galacturonic acid and 40% galactose (mol%), approximately. The samples were tested for recombinant human galectin-3 inhibition and changes in the cell viability of human colorectal cancer cells. Only the jaboticaba sample inhibited galectin-3 and decreased HCT116 cell viability after 48 h of treatment (p ≤ 0.01) while the plum sample decreased the cell viability after 24 h treatment (p ≤ 0.05). The results obtained in this study demonstrate the relationship between the structure of the soluble fibers extracted from jaboticaba flour and the possible beneficial effects of their consumption.

Toll-like receptor 2-modulating pectin-polymers in alginate-based microcapsules attenuate immune responses and support islet-xenograft survival

Encapsulation of pancreatic islets in alginate-microcapsules is used to reduce or avoid the application of life-long immunosuppression in preventing rejection. Long-term graft function, however, is limited due to varying degrees of host tissue responses against the capsules. Major graft-longevity limiting responses include inflammatory responses provoked by biomaterials and islet-derived danger-associated molecular patterns (DAMPs). This paper reports on a novel strategy for engineering alginate microcapsules presenting immunomodulatory polymer pectin with varying degrees of methyl-esterification (DM) to reduce these host tissue responses. DM18-pectin/alginate microcapsules show a significant decrease of DAMP-induced Toll-Like Receptor-2 mediated immune activation in vitro, and reduce peri-capsular fibrosis in vivo in mice compared to higher DM-pectin/alginate microcapsules and conventional alginate microcapsules. By testing efficacy of DM18-pectin/alginate microcapsules in vivo, we demonstrate that low-DM pectin support long-term survival of xenotransplanted rat islets in diabetic mice. This study provides a novel strategy to attenuate host responses by creating immunomodulatory capsule surfaces that attenuate activation of specific pro-inflammatory immune receptors locally at the transplantation site.

Low methyl-esterified pectin protects pancreatic β-cells against diabetes-induced oxidative and inflammatory stress via galectin-3

Insufficient intake of dietary fibers in Western societies is considered a major contributing factor in the high incidence rates of diabetes. The dietary fiber pectin has been suggested to be beneficial for management of both Diabetes Type 1 and Type 2, but mechanisms and effects of pectin on insulin producing pancreatic β-cells are unknown. Our study aimed to determine the effects of lemon pectins with different degree of methyl-esterification (DM) on β-cells under oxidative (streptozotocin) and inflammatory (cytokine) stress and to elucidate the underlying rescuing mechanisms, including effects on galectin-3. We found that specific pectins had rescuing effects on toxin and cytokine induced stress on β-cells but effects depended on the pectin concentration and DM-value. Protection was more pronounced with low DM5 pectin and was enhanced with higher pectin-concentrations. Our findings show that specific pectins might prevent diabetes by making insulin producing β-cells less susceptible for stress.

An acidic polysaccharide (AGC3) isolated from North American ginseng (Panax quinquefolius) suspension culture as a potential immunomodulatory nutraceutical

Polysaccharides isolated from Panax quinquefolius roots are widely used as nutraceuticals due to their immunomodulatory properties. Despite their popularity, several challenges exist in isolating ginseng root polysaccharides such as batch-to-batch structural inconsistencies and bacterial endotoxin contamination. A plant tissue culture-based platform offers a potential solution to isolate natural polysaccharide fractions with consistent chemical characteristics and reduced endotoxin content. In this study, an acidic polysaccharide fraction (AGC3) with immunomodulatory properties was isolated from Panax quinquefolius suspension cultures. The heterogeneous fraction (molecular weight: 4.81 and 32.14 kDa), purified by anion exchange chromatography, was predominantly composed of galactose (>60%) along with the presence of rhamnose, arabinose, glucose, glucuronic acid and galacturonic acid. The major glycosidic linkages were found to be t-Galp (47.7%), 4-Galp (15.6%), 2,4-Rhap (8.1%), 6-Galp (8.1%) and 4-GalAp (6.8%). Structural analyses indicated the presence of a pectic rhamnogalacturonan I polysaccharide in AGC3. AGC3 significantly (p < 0.05) stimulated RAW 264.7 murine macrophage cells and primary murine splenocytes by enhancing the production of several immunomodulatory mediators such as IL-6, TNF-α, GM-CSF and MCP-1. The results also indicated the putative roles of NF-κB (p65/RelA) and MAPK (p38) signaling pathways in the immunostimulatory response. Additionally, AGC3 induced murine splenocyte proliferation, another major indicator of immunostimulation. Overall, AGC3 has the potential to be used as an immunostimulatory nutraceutical.

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American ginseng suspension culture as source of natural bioactive polysaccharides.

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Acidic polysaccharide, AGC3 displayed potent immunostimulatory properties.

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Putative mechanism of action includes NF-κB (p65/RelA) and MAPK (p38) pathways.

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AGC3 predominantly composed of RGI-type pectins.

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Potential nutraceutical that can be used as an exogenous immunomodulator.