Pectic Polysaccharides Research Articles

Extraction, characterization, and rheology of Opuntia ficus indica cladode polysaccharides

In this study, hot water extraction was applied to obtain water-soluble pectin of Opuntia ficus indica (OFI) cladode. The yield was found 0.18–0.06% in fresh-weight with the degree of esterification at 48 ± 1.25% expressing that extracted polysaccharide has low-methoxyl (LM) pectin features. Some properties of OFI cladode pectin and commercial LM pectin were investigated. Infrared spectrums of the samples were found mostly similar by having major pectin constituents. 0.25, 0.5, 1, 2 and 3% w/v solutions were prepared for rheological properties at 25, 30, 35 and 40°C. Solutions prepared both using commercial pectin (CP) and OCP represented Newtonian behavior at applied shear rate region. More than 1% w/v concentration, CP showed higher thickening property compared to OCP solutions at various temperatures where CP samples were heavier compared to OCP. The activation energy of OCP solutions was higher than CP meaning that CP had stronger interaction between molecules by representing better stability. Novelty impact statement Opuntia ficus indica (OFI) is well known as the fruit part, however, the cladode part has a great potential for food use as a polysaccharide source. Cladode is rich in water-soluble pectic polysaccharides and there is no commercial cladode pectin available on the market. OFI cladode can be used as a cheap source of low-methoxyl pectin with some modifications due to the application area.

Pectic polysaccharides from Biluochun Tea: A comparative study in macromolecular characteristics, fine structures and radical scavenging activities in vitro

In this study, two acidic Biluochun Tea polysaccharides (BTP-A11 and BTP-A12) were investigated comparatively, which mainly consisted of Rha, Ara, Gal and GalA, possibly suggesting their pectic nature. Structurally, their galacturonan backbones composed of →4)-α-D-GalpA-(1→ and →2)-α-L-Rhap-(1→ were revealed similar, while Ara- and Gal-based branches attached to the O-2 of →2)-α-L-Rhap-(1→ were in distinctive types, proportions, extensibilities and branching degrees. This could lead to their different macromolecular characteristics, where BTP-A11 with higher Mw presented a more hyper-branched chain conformation and relatively higher structural flexibility/compactness, thereby resulting in a lower exclusion effect and an insufficient hydrodynamic volume. Besides, better radical scavenging activities in vitro were also determined for Gal-enriched BTP-A11, where a larger surface area containing more H-donating groups were related to its higher Mw, more hyper-branched conformation, lower DM and higher DA. Therefore, the understanding of structure-property-activity relationships was improved to some degrees for acidic Biluochun Tea polysaccharides, which could be potentially required for more applications in food, medical and cosmetic fields.

Rheological and gelling properties of Nicandra physalodes (Linn.) Gaertn. pectin in acidic media

Nicandra physalodes (Linn.) Gaertn. polysaccharide (NPGP) was previously recognized as a pectic polysaccharide, with a high galacturonic acid content (87.8%) and a low methoxylation degree (28%). In the present study, it was found that NPGP can form self-supporting gels when cooling its heated solutions (2.0%, w/v) acidified by citric acid. It was demonstrated that the decrease in pH led to the suppression in electrostatic repulsions between the pectin chains, thereby promoting pectin chain-chain association mainly through hydrogen bonding. As the pH decreased from 3.2 to 2.4, the gel strength and gel thermal stability were continuously increased. Moreover, it was shown that sucrose addition slightly promoted the gelation and gel thermal stability of NPGP, but the effect of monovalent ions (Na+) and divalent ions (Ca2+) was not significant. Conclusively, our results indicate that NPGP is a new gelling polysaccharide that shows great potential in formulation of acidic gel foods.

Isolation, Chemical Characterization and Antioxidant Activity of Pectic Polysaccharides of Fireweed (Epilobium angustifolium L.).

The aim of this study was to isolate pectins with antioxidant activity from the leaves of Epilobium angustifolium L. Two pectins, EA-4.0 and EA-0.8, with galacturonic acid contents of 88 and 91% were isolated from the leaves of E. angustifolium L. by the treatment of plant raw materials with aqueous hydrochloric acid at pH 4.0 and 0.8, respectively. EA-4.0 and EA-0.8 were found to scavenge the DPPH radical in a concentration-dependent manner at 17–133 μg/mL, whereas commercial apple pectin scavenged at 0.5–2 mg/mL. The antioxidant activity of EA-4.0 was the highest and exceeded the activity of EA-0.8 and a commercial apple pectin by 2 and 39 times (IC50—0.050, 0.109 and 1.961 mg/mL), respectively. Pectins EA-4.0 and EA-0.8 were found to possess superoxide radical scavenging activity, with IC50s equal to 0.27 and 0.97 mg/mL, respectively. Correlation analysis of the composition and activity of 32 polysaccharide fractions obtained by enzyme hydrolysis and anionic exchange chromatography revealed that the antioxidant capacity of fireweed pectins is mainly due to phenolics and is partially associated with xylogalacturonan chains. The data obtained demonstrate that pectic polysaccharides appeared to be bioactive components of fireweed leaves with high antioxidant activity, which depend on pH at their extraction.

The Role of Pectobacterium atrosepticum Exopolysaccharides in Plant–Pathogen Interactions

The phytopathogenic bacterium Pectobacterium atrosepticum (Pba), one of the members of the soft rot Pectobacteriaceae, forms biofilm-like structures known as bacterial emboli when colonizing the primary xylem vessels of the host plants. The initial extracellular matrix of the bacterial emboli is composed of the host plant’s pectic polysaccharides, which are gradually substituted by the Pba-produced exopolysaccharides (Pba EPS) as the bacterial emboli “mature”. No information about the properties of Pba EPS and their possible roles in Pba-plant interactions has so far been obtained. We have shown that Pba EPS possess physical properties that can promote the maintenance of the structural integrity of bacterial emboli. These polymers increase the viscosity of liquids and form large supramolecular aggregates. The formation of Pba EPS aggregates is provided (at least partly) by the acetyl groups of the Pba EPS molecules. Besides, Pba EPS scavenge reactive oxygen species (ROS), the accumulation of which is known to be associated with the formation of bacterial emboli. In addition, Pba EPS act as suppressors of the quantitative immunity of plants, repressing PAMP-induced reactions; this property is partly lost in the deacetylated form of Pba EPS. Overall, our study shows that Pba EPS play structural, protective, and immunosuppressive roles during Pba–plant interactions and thus should be considered as virulence factors of these bacteria.

Effect of the Olive Oil Extraction Process on the Formation of Complex Pectin-Polyphenols and Their Antioxidant and Antiproliferative Activities.

The aim of this research was to investigate the interaction of phenols and pectic polysaccharides during the olive oil extraction process. For this, pectin was extracted from fresh olive fruits and compared to the pectin isolated from the paste resulting from the extraction of the olive oil after milling with malaxation at 30 °C/30 min and subsequent centrifugation of the olive paste from the same lot of olive fruits in a system called ABENCOR (AB). The results indicate that these interactions were enhanced during the olive oil extraction process. In addition, the resulting AB extracts exhibited high antioxidant activity (ORAC) and strong antiproliferative activity in vitro against colon carcinoma Caco-2 cell lines compared to olive fruit extracts. The polyphenols associated mainly with the acidic pectin substance, with a higher content in AB extracts, seem to be responsible for these activities, and appear to maintain their activities in part after complexation. However, even in olive fruit extracts with smaller amounts of phenols in their compositions, pectic polysaccharides may also be involved in antioxidant and antiproliferative activities.

Mapping Pectic-Polysaccharide Epitopes in Cell Walls of Forage Chicory (Cichorium intybus) Leaves.

The cell walls of forage chicory (Cichorium intybus) leaves are known to contain high proportions of pectic polysaccharides. However, little is known about the distribution of pectic polysaacharides among walls of different cell types/tissues and within walls. In this study, immunolabelling with four monoclonal antibodies was used to map the distribution of pectic polysaccharides in the cell walls of the laminae and midribs of these leaves. The antibodies JIM5 and JIM7 are specific for partially methyl-esterified homogalacturonans; LM5 and LM6 are specific for (1→4)-β-galactan and (1→5)-α-arabinan side chains, respectively, of rhamnogalacturonan I. All four antibodies labelled the walls of the epidermal cells with different intensities. JIM5 and JIM7, but not LM5 or LM6, labelled the middle lamella, tricellular junctions, and the corners of intercellular spaces of ground, xylem and phloem parenchyma. LM5, but not LM6, strongly labelled the walls of the few sclerenchyma fibres in the phloem of the midrib and lamina vascular bundles. The LM5 epitope was absent from some phloem parenchyma cells. LM6, but not LM5, strongly labelled the walls of the stomatal guard cells. The differential distribution of pectic epitopes among walls of different cell types and within walls may reflect the deposition and modification of these polysaccharides which are involved in cell wall properties and cell development.

Pectic polysaccharide from Smilax china L. ameliorated ulcerative colitis by inhibiting the galectin-3/NLRP3 inflammasome pathway

Ulcerative colitis (UC) is an inflammatory bowel disease that affects the colon and rectum. Although galectin-3 (Gal-3) has been reported to play a proinflammatory role in UC, it is unknown whether pectic polysaccharide, a Gal-3 inhibitor in tumor metastasis, can alleviate UC by inhibiting Gal-3. The aim of this study was to investigate the anti-inflammatory effects and underlying mechanisms of SCLP, a pectic polysaccharide purified from Smilax china L. in our previous work, on dextran sulfate sodium-induced UC in BALB/c mice. The results showed that SCLP could significantly improve symptoms, alleviate histopathological damage and reduce the secretion of inflammatory mediators in mice with UC. Analysis of the anti-colitis mechanisms indicated that SCLP could inhibit the Gal-3/NLRP3 inflammasome/IL-1β pathway by suppressing the expression of Gal-3 and the interaction of Gal-3 and NLRP3. Our results suggested that SCLP could be a promising candidate for prevention and treatment of UC.

Covalently linked pectin-arabinoglucuronoxylan complex from Siberian fir Abies sibirica Ledeb.

In this study, by NMR spectroscopy, first was proved that the pectic polysaccharides of Abies sibirica are covalently bound to arabinoglucuronoxylan (AGX). Namely, AGX is attached at the 4th position to the 1,2,4-α-L-Rha residues of the RG-I main chain, indicating the following fragment: …→2)-[(2,4-β-D-Xylp)-(1→4)]-[(α-D-GalpA-(1→2)]-α-L-Rhap-(1→4)-α-D-GalpA-(1→…. We present direct evidence of covalent attachment between C1 of 1,2,4-β-D-Xylp from arabinoglucuronoxylan and С4 of 1,2,4-α-L-Rhap from RG-I of pectin by detailed 2D NMR analyses. It can be concluded that the 1,2,4-α-L-Rhap residues, were substituted at the 4th position by 1,5-α-L-arabinan or 1,4-β-D-galactan or AGX. The discovery of this interglycosidic linkage between xylan and pectin contradicts the classical model of the cell wall, which describes networks of binding glycans and pectic polysaccharides as separate and independent of one another. We can conclude that pectin undoubtedly plays a more important supporting and cross-linking role in the cell wall than is commonly thought.

Protective effects of six different pectic polysaccharides on DSS-induced IBD in mice

Administration of pectic polysaccharides is a therapeutic strategy in the management of gut inflammation. However, the knowledge about the effects of different dietary sources and structure are missing. This study explored the protective effects of six different pectic polysaccharides from Goji berry (G), dragon fruit (D), lemon (L), pomelo (P), potato (T) and raspberry (R) in dextran sulfate sodium (DSS)-induced colitis mice. D mainly contained rhamnogalacturonan (RG) backbone; L had high amount of arabinan sidechains; P was a high-esterified homogalacturonan (HG) pectic polysaccharide; the primary domain in T was galactan sidechains; R and G had the composition of arabinan: galactan: RG: HG = 19: 28: 15: 22 and 36: 17: 21: 14. Our results suggested that G and R were the most effective in alleviating colitis via alleviating tissue damage, promoting the index of immune organs, suppressing the production of TNF-α, IL-1β and IL-17, improving antioxidant status and promoting the total amount of SCFAs. Similarly, the administration of L alleviated colitis mainly by increasing the fermentation products without changes in the composition pattern of SCFAs. The secretion of IL-6 might be suppressed by pectic polysaccharides containing high amount of arabinan sidechains, while anti-inflammatory cytokines and intestinal barrier function tend to be regulated by pectic polysaccharides rich in galactan. In conclusion, pectic polysaccharide containing diversified structural domains (homogeneous proportion of HG, RG, arabinan, and galactan) might be the most effective in alleviating gut inflammation. This unprecedented report revealed the anti-inflammatory effects of different pectic polysaccharides, which was critical for the reasonable selection of dietary fiber to prevent gut inflammation.

Pectic polysaccharides extracted from sesame seed hull: Physicochemical and functional properties

The objective of the present investigation was to extract pectic polysaccharides from sesame seed hull and to determine their physicochemical and functional characteristics. The pectic polysaccharides in the seed hull were extracted with HCl and then collected at three ethanol concentrations of 30% (SSP30), 50% (SSP50), and 90% (SSP90). We found that SSP30 represented 75.6% of the total polysaccharides, and that it contained 76.39% galacturonic acid, with many HG domains and few short side chains in the RG-I domains. SSP30 exhibited the strongest hydroxyl radical scavenging activity among the three fractions, and was better able to stabilize the emulsions. Higher Mw pectic polysaccharides were firstly precipitated at lower ethanol concentrations, and the Mw of the precipitated pectic polysaccharides decreased with increasing ethanol concentration. These results provide important information on the structure and functional characteristics of sesame hull polysaccharides. This information can contribute to the future development of sesame hull polysaccharides for industrial purposes.

Structural changes of lignin-carbohydrate complexes (LCCs) from Chinese quince fruits during the sequential fractionation of pectic and hemicellulosic polysaccharides

Chinese quince (Chaenomeles sinensis) fruits offer a potential source of pectin and hemicellulose. However, the existence of lignin-carbohydrate complexes (LCCs) can negatively impact the extraction of pectin and hemicellulose. In this work, LCCs were sequentially fractionated from Chinese quince during the removal of pectin and hemicellulose. The structures of LCCs were characterized by HPAEC, FT-IR, GPC, Py-GC/MS, TGA and 2D HSQC NMR. The results showed that the carbohydrate content and molecular weight of LCCs was found to be changed significantly after the removal of hemicellulose (KSH). The lignin in Björkman LCCs was found to be linked mainly to galactan and fructan, whereas the lignin LCC-AcOHs was found to be linked mainly to arabinan after the removal of KSH. The isolation of carbonate-soluble pectin (NSP) increased thermal stability of Björkman LCC fraction, however, the isolation of chelator-soluble pectin (CSP) increased the thermal stability of LCC-AcOHs. The S/G ratios of LCC-AcOHs increased and large amounts of S-type lignin released during sequential fractionation of pectin and hemicellulose. These results will be beneficial for understanding the mechanisms of pectin and hemicellulose isolation, thereby facilitating the potential application of Chinese quince as a valuable natural resource for food and other industries.

The graft framework: Quantitative changes in cell wall matrix polysaccharides throughout the tomato graft union formation

Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion.

Physical, Anatomical, and Biochemical Composition of Skins Cell Walls from Two Grapevine Cultivars (Vitis vinifera) of Champagne Region Related to Their Susceptibility to Botrytis cinerea during Ripening

This work investigated the structural, biochemical, and molecular characteristics of grape skin cell wall during ripening, related to susceptibility to Botrytis cinerea. The comparative study between the two main grape cultivars in Champagne region, Pinot noir and Chardonnay, quantified: (1) the maturity and physical profile of grape skin; (2) the morphological characteristics; (3) soluble pectic polysaccharides located in grape skin cell walls; and (4) the gene expression of the two main degrading enzymes (VvPME1 and VvPG1) and PME activity. During the maturation period, the grape skins of the two cultivars appear different in their structure and composition. Chardonnay is characterized by higher relative humidity (RH) and level of VvPG1 expression, lower disease incidence and penetrometry values, and thicker cell walls than Pinot noir skins. Thus, the cell wall composition is sufficiently different between grape varieties from the same area to allow their discrimination and could be used to better manage the harvest date.

Sequential extraction and analysis of cell wall polysaccharides from Inula viscosa leaves and stems

Inula viscosa (syn Dittrichia viscosa) (sticky fleabane) from the Asteraceae family, is well-known for its pharmacological activities. In this research, anatomical characterization of leaves and stems of Inula viscosa plants revealed a considerable heterogeneity in their cell walls. Cell walls were isolated separately from leaves and stems and subjected to sequential extractions with boiling water, oxalate ammonium, KOH and NaOH solutions. The four polysaccharide fractions obtained were comparatively analysed using gas chromatography-flame ionization detector (GC-FID) and Fourier Transform Infrared–Attenuated Total Reflectance (ATR-FTIR) spectroscopy. The findings showed that the polysaccharides were unevenly distributed in the two organs. ATR-FTIR data reflected a higher proportion of pectins in stems relative to leaves in both fractions. Pectic fractions (hot water soluble and oxalate soluble fractions) seemed to be mainly composed by homogalacturonan and rhamnogalacturonan, with a residual presence of inulin. Hemicellulose (KOH and NaOH) fractions, instead, were rich in xylans, and still contained a low proportion of pectic polysaccharides. ATR-FTIR data pointed to a higher proportion of xylans in stems than in leaves. Finally, attending the molecular mass of cell wall polysaccharides from leaves, pectin fractions showed the presence of populations of polysaccharides with lower molecular masses than those of hemicellulose fractions.

Steam drying markedly increases the solubility of feruloylated arabinan-rich pectic polysaccharide in sugar beet pulp

Three sugar beet pulp samples, which were dried by different methods (drum-dried, steam-dried, and shelf-dried), were prepared and hot water extractions (90 °C, 6 h) were performed to compare the pectic polysaccharide yield. The steam-dried pulp yielded 34.1 g of pectic polysaccharides per 100 g of dry matter. This represented about twice the yield of the other techniques, with a recovery of about 60% of the estimated amount contained in the raw material. The pectic polysaccharide obtained from the steam-dried pulp by hot water extraction and dialysis contained larger amount of arabinose (32.4 g/ 100 g solids) as constituent sugars than that of commercial beet pectin. The weight-average molecular mass was 175 kDa, which was lower than that of commercial beet pectin (538 kDa) and most of the extracted feruloyl group were bound to this polysaccharide. These characteristics were similar to those of pectic polysaccharides obtained previously by autoclave extraction from wet beet pulp. It was presumed that the pectic polysaccharides contained in sugar beet pulp were partially hydrolyzed and solubilized under pressurized and high temperature conditions (0.25–0.3 MPa, 150–180 °C) during steam drying, making them easier to extract. Using steam-dried pulp as a raw material, feruloylated arabinan-rich pectic polysaccharides can be efficiently obtained by hot water extraction under non-pressurized conditions without acid addition.

Evaluation of antitumor metastasis via immunostimulating activities of pectic polysaccharides isolated from radish leaves

We investigated the antimetastatic effects of polysaccharides (RWP) isolated from radish leaves by hot water extraction and ethanol precipitation. From the sugar composition analysis, RWP was estimated to be a pectic polysaccharide. Peritoneal macrophages stimulated with RWP significantly augmented the production of various cytokines. In an assay for natural killer (NK) cell activity, both intravenous (i.v.) and oral administration of RWP significantly enhanced NK cells cytotoxicity against YAC-1 lymphoma. In an experiment on lung metastasis of Colon26-M3.1 carcinoma, prophylactic i.v. and oral administration of RWP inhibited metastasis by 77.2% and 55.0%, respectively, at 1000 μg/mouse. Furthermore, pretreatment with anti-asialo GM1 for NK cells depletion partly suppressed the inhibitory effect of RWP on lung metastasis. Thus, our study results suggest that RWP has superior antimetastatic activity, and this effect is related to the activation of various immune factors.

Prebiotic potential of RG-I pectic polysaccharides from Citrus subcompressa by novel extraction methods

In the present study, the in vitro fermentation by human gut microbiota of alkali-extraction citrus pectin (AK) and high pressure-alkali-extraction citrus pectin (HPAK) were investigated. The monosaccharide composition analysis showed that both AK and HPAK had a high ratio of Rhamngalacturonan I (RG-I) structure. After 48 h of fermentation, 85%–86% of total carbohydrate was utilized by colonic microbiota. The pH value in the fecal fermentation liquid significantly decreased during fermentation. AK and HPAK significantly promoted the production of short-chain fatty acids, especially propionic and n-butyric acids. They also increased the abundance of potential beneficial genera (i.e. Bifidobacterium and Phascolarctobacterium) and decreased the abundance of potential harmful genera (Escherichia-Shigella and Klebsiella). All the results suggested that HPAK and AK are potentially sources of prebiotics in functional foods aimed at promoting gut health.

Structural characterization and anticoagulant activity of homogalacturonan from durian peel

Two novel pectic polysaccharides DZM-A (5.1 kDa) and DZM-B (160.8 kDa) were isolated from durian peel and purified by DEAE-52 column and Sephadex G-100 column. The structures of two polysaccharides were analyzed by infrared spectrum (IR), gas chromatography (GC) and nuclear magnetic resonance (NMR). It was deduced that DZM-A had a complicated main and branch chain with →4)-α-d-GalA-(1→, →5)-α-l-Araf-(1→ and →4,2)-α-l-Rha-(1→, a small amount of galactose and glucose. The structure of DZM-B was mainly composed of →4)-α-d-GalA-(1→. DZM-A showed anticoagulant effects through endogenous and exogenous coagulation pathways in vitro and in vivo. DZM-A could also regulate the content of ET-1 and eNOs, change the state of blood flow, and have anticoagulant effect in vivo.

A Pectin-Rich, Baobab Fruit Pulp Powder Exerts Prebiotic Potential on the Human Gut Microbiome In Vitro

Increasing insight into the impact of the gut microbiota on human health has sustained the development of novel prebiotic ingredients. This exploratory study evaluated the prebiotic potential of baobab fruit pulp powder, which consists of pectic polysaccharides with unique composition as compared to other dietary sources, given that it is rich in low methoxylated homogalacturonan (HG). After applying dialysis procedures to remove simple sugars from the product (simulating their absorption along the upper gastrointestinal tract), 48 h fecal batch incubations were performed. Baobab fruit pulp powder boosted colonic acidification across three simulated human adult donors due to the significant stimulation of health-related metabolites acetate (+18.4 mM at 48 h), propionate (+5.5 mM at 48 h), and to a lesser extent butyrate (0.9 mM at 48 h). Further, there was a trend of increased lactate levels (+2.7 mM at 6h) and reduced branched chain fatty acid (bCFA) levels (−0.4 mM at 48 h). While Bacteroidetes levels increased for all donors, donor-dependent increases in Bifidobacteria, Lactobacilli, and Firmicutes were observed, stressing the potential interindividual differences in microbial composition modulation upon Baobab fruit pulp powder treatment. Overall, Baobab fruit pulp powder fermentation displayed features of selective utilization by host microorganisms and, thus, has promising prebiotic potential (also in comparison with the ‘gold standard’ prebiotic inulin). Further research will be required to better characterize this prebiotic potential, accounting for the interindividual differences, while aiming to unravel the potential resulting health benefits.