Structural characteristics of oxalate-soluble polysaccharides of Sosnowsky's hogweed ( Heracleum sosnowskyi Manden)

Structural characterization and immunomodulatory activity analysis of a novel pectic polysaccharide extracted from Tetrastigma hemsleyanum Diels et Gilg and its hydrolysis products

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a rare traditional Chinese medicine with high medicinal value and T. hemsleyanum polysaccharides (THPs) have attracted increasing attention in recent years. However, detailed structural and functional insights into THPs remain limited. Here, a novel pectic polysaccharide (STHP4) with an average molecular weight (Mw) of 119 kDa was extracted and purified from the aboveground part of T. hemsleyanum. Structurally, STHP4 was mainly composed of galacturonic acid, glucuronic acid, and galactose, with minor glucose, rhamnose, arabinose, and mannose, and its primary backbone was 1,4-GalA. Pectinase treatment of STHP4 yields two distinct fractions: STHP4-1 and STHP4-2. STHP4-1 shared the same types of monosaccharides with STHP4, except for the absence of glucose, but had a broad Mw distribution (9.9 to 251 kDa). Another product, STHP4-2, a mixture of oligosaccharides and free monosaccharides, has a Mw of 1.387 kDa. Their structures were further elucidated via methylation analysis and NMR spectra. Furthermore, STHP4-1 exhibited superior immune regulatory effects on macrophages, including increased nitric oxide release and elevated interleukin-6, interleukin-1β, and tumor necrosis factor α expression. These findings suggest that STHP4-1 might be the core active domain of STHP4, and both STHP4 and STHP4-1 are potential immune enhancers.

Extraction optimization, purification, characterization, and hypolipidemic activities of polysaccharide from pumpkin

Polysaccharides derived from pumpkin have garnered increasing interest due to their diverse biological activities. In this study, pumpkin polysaccharides were extracted using an ultrasound-assisted extraction method, optimized via response surface methodology. The optimal extraction conditions were identified as follows: a solid-liquid ratio of 1:60 (g/mL), an extraction time of 1.9 h, an extraction temperature of 62 °C, and an ultrasonic power of 286 W. Under these conditions, the total carbohydrate content in pumpkin polysaccharides reached 71.14 ± 1.53 %, closely aligning with the predicted value. Post extraction, the polysaccharides were purified using DEAE Sepharose Fast Flow and Sephadex G-100 columns, resulting in a pure fraction termed PPS3. Structural analysis revealed that PPS3, with a molecular mass of 5.96 × 104 Da, consisted of mannose, glucosamine hydrochloride, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose in a molar ratio of 0.005:0.004:0.041:0.013:0.545:0.004:0.241:0.147, respectively. The backbone primarily contained →4)-α-D-GalpA-6-OMe-(1→ residue with several branched chains. Functionally, PPS3 demonstrated potent in vitro hypolipidemic activities. These findings elucidated the structural characteristics of pumpkin polysaccharides and suggested their potential as natural hypolipidemic agents.

Structure characteristics of a novel pectic polysaccharide from Fructus Corni and its protective effect on alcoholic fatty liver

Alcoholic fatty liver disease (AFLD) is characterized by the accumulation of hepatic lipid and has no effective treatment yet. Fructus Corni is a traditional Chinese medicinal herb, and its extractions have demonstrated hepatoprotective properties. We hypothesize that the polysaccharides in Fructus Corni might have therapeutic effects on AFLD. In this study, we isolated a novel homogeneous polysaccharide, APFC-2 (Mw= 63.0 kDa), from the Fructus Corni, and its structure was elucidated by monosaccharide composition, methylation analysis, partial acid hydrolysis, and NMR spectra. APFC-2 is a pectic polysaccharide characterized by a backbone of T-β-Galp-(1 → 6)-β-Galp-(1 → 3,6)-β-Galp-(1 → [4)-α-GalpA-OMe-(1 → 4)-α-GalpA-(1→]m → [2,4)-α-Rhap-(1 → 4)-α-GalpA-(1→]n, with branches comprising T-Araf-(1→, →3)-α-Araf-(1→, →3,5)-α-Araf-(1→, and →5)-α-Araf-(1→. In vivo experiments indicated that APFC-2 could significantly reduce hepatic steatosis, fasting triglyceride, and cholesterol levels in AFLD mice. Cell proliferation and Oil Red O staining results showed that APFC-2 concentration-dependently increased cell viability and significantly improved lipid metabolism in vitro. Mechanistically, APFC-2 markedly inhibited the formation of lipid both in vitro and in vivo through activating liver kinase B1 (LKB1) and then regulating adenosine 5'-monophosphate-activated protein kinase (AMPK)-SREBP-1 and AMPK-PPAR-α pathways. This research provides a theoretical basis for the potential application of Fructus Corni pectic polysaccharide as a specific activator of LKB1 for treating AFLD.

Structural Characterization and In Vitro Fermentation Properties of Polysaccharides from Dragon Fruit (Hylocereus undatus)

Dragon fruit offers numerous health benefits and is widely consumed. However, research on its polysaccharides, crucial constituents of the fruit, remains limited. The study aimed to characterize the structural and biological properties of SDFP-2, a polysaccharide isolated from dragon fruit. Structural analyses revealed that SDFP-2, with a molecular mass of 8.08 × 104 Da, consisted of mannose, glucosamine hydrochloride, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose in a molar ratio of 0.181:0.250:16.544:12.762:3.793:0.739:51.014:14.716. SDFP-2 comprises HG-type and RG-I-type pectic structures, along with an arabinogalactan structure characterized by a main chain of →6)-β-D-Galp-(1→6)-β-D-Galp-(1→, with side chains attached at the O-3 position of the 1,6-β-galactose residues. Functionally, SDFP-2 exhibited notable hypolipidemic and hypoglycemic properties in HepG2 cell assays, significantly reducing lipid accumulation and enhancing glucose metabolism by restoring key glycolytic enzyme activities. In vitro fermentation with fecal microbiota demonstrated SDFP-2's ability to modulate gut microbial composition, elevating beneficial short-chain fatty acid production, including acetate, propionate, and butyrate. This microbial shift favored SCFA producers, such as Coprococcus eutactus and Roseburia intestinalis, while diminishing pro-inflammatory bacteria like Escherichia-Shigella, underscoring SDFP-2's prebiotic potential. These findings elucidated SDFP-2 as a promising dietary intervention for metabolic regulation and intestinal health enhancement.

Preparation and structural characteristics of polysaccharides from loquat peel waste, and their preliminary bioactivities

BACKGROUND

Loquat peel, often as food waste, is a valuable source of bioactive polysaccharides. However, study of such polysaccharides is insufficient, leaving a significant gap in understanding their preparation, structure and bioactivities.

RESULTS

In this study, three types of loquat peel polysaccharides (LPWP, LPHP and LPNP) were sequentially extracted using hot water, HCl and NaOH solutions, respectively. Among them, LPWP was the purest, with a yield of 3.4% and molecular weight of 470.6 kDa, and it differed from LPHP and LPNP in structure, as evidenced by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy, which demonstrated that LPWP consisted of more arabinose (Ara) but less galacturonic acid, rhamnose and galactose, with molar percentages of 71.3%, 23.3%, 3.5% and 1.9%, respectively. Besides, LPWP also exhibited superior antioxidant and antihyperglycemic activities in vitro, particularly in inhibiting α-amylase and α-glucosidase. Methylation and nuclear magnetic resonance analysis confirmed that LPWP was a methyl-esterified pectic polysaccharide rich in branched arabinan, as evidenced by the notable proportion of α-Ara residues, including T-α-Araf, 1,5-α-Araf and 1,2,3,5-α-Araf, with molar percentages of 27.1%, 23.1% and 10.2%, respectively. AFM imaging further revealed its branched-chain morphology and aggregation behavior.

CONCLUSION

This study highlights the potential of loquat peel polysaccharides as a bioactive ingredient with significant antioxidant and antihyperglycemic properties, particularly LPWP, which was found as a methyl-esterified pectic polysaccharide with abundant-branched arabinan. Our work provides valuable insights into the application of loquat peel polysaccharides in functional foods. © 2024 Society of Chemical Industry.

Ultrasound-assisted extraction, purification, structural characterization, and hypoglycemic activities of a polysaccharide from Momordica charantia L

Polysaccharides from Momordica charantia L. (MCP) have attracted interest for their diverse biological activities. This study investigated the ultrasound-assisted extraction of MCP, optimizing conditions using response surface methodology. The optimal extraction parameters were a material-liquid ratio of 1:4 (g/mL), a temperature of 74 °C, an extraction time of 2.4 h, and an ultrasonic power of 296 W, resulting in a total carbohydrate content of 40.22 ± 1.69 %, closely matching theoretical predictions. Following extraction, MCP was purified using DEAE Sepharose Fast Flow anion exchange and Sephadex G-100 dextran gel chromatography, isolating a pure polysaccharide fraction, MCPS-3. Structural analysis revealed that MCPS-3, with a molecular mass of 93.796 kDa, consisted of rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose in molar ratios of 10.66:3.66:258.0:1.0:51.0:9.338. Methylation and NMR analyses suggested that MCPS-3 was a complex polysaccharide, predominantly homogalacturonan domains with rhamnogalacturonan I side chains. In functional assays, MCPS-3 demonstrated inhibition of α-amylase and α-glucosidase activities. Additionally, in insulin-resistant HepG2 cells, MCPS-3 improved glucose consumption, increased glycogen content, and enhanced the activities of hexokinase and pyruvate kinase. These findings provided insights into the structural properties of MCPS-3 and underscored its potential as a natural compound with significant hypoglycemic activity.

Purification, structural identification, in vitro hypoglycemic activity and digestion characteristics of polysaccharides from the flesh and peel of wampee (Clausena lansium)

In this study, two polysaccharides were isolated from the flesh and peel of wampee, termed as PWP-F and PWP-P respectively, and their structural characteristics, in vitro antioxidant and hypoglycemic activities and digestion were investigated. Results indicated the molecular weight of PWP-F was higher than that of PWP-P and they were both mainly composed of galactose and arabinose. Both polysaccharides exhibited α-type and β-type glycosidic linkages based on FTIR analysis. NMR spectroscopy revealed that PWP-F mainly consisted of α-Araf-(1→, →3,5)-α-Araf-(1→, →2,5)-α-Araf-(1→, →4) → β-Galp-(1 → and α-GalpA-(1→, while PWP-P was composed of α-Araf-(1→, →3)-α-Araf-(1→, →5)-α-Araf-(1→, →3,6) → β-Galp-(1→ and α-GalpA-(1→. Scanning electron microscopy showed that PWP-P had more porous surface structure compared to PWP-F. Moreover, PWP-P exhibited superior antioxidant activity and significant inhibition of both α-glucosidase and α-amylase compared to PWP-F. Specifically, PWP-P demonstrated mixed inhibition against α-glucosidase and α-amylase. In vitro digestion results showed the molecular weight, polysaccharide and reducing sugar content of PWP-F and PWP-P decreased after simulative gastrointestinal digestion. Overall, PWP-P has great potential as a kind of new antioxidant and hypoglycemic agent.

Physicochemical Characterization, Antioxidant and Anticancer Activity Evaluation of an Acidic Polysaccharide from Alpinia officinarum Hance

AHP-3a, a triple-helix acidic polysaccharide isolated from Alpinia officinarum Hance, was evaluated for its anticancer and antioxidant activities. The physicochemical properties and structure of AHP-3a were investigated through gel permeation chromatography, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The weight-average molecular weight of AHP-3a was 484 kDa, with the molar percentages of GalA, Gal, Ara, Xyl, Rha, Glc, GlcA, and Fuc being 35.4%, 21.4%, 16.9%, 11.8%, 8.9%, 3.1%, 2.0%, and 0.5%, respectively. Based on the results of the monosaccharide composition analysis, methylation analysis, and NMR spectroscopy, the main chain of AHP-3a was presumed to consist of (1→4)-α-D-GalpA and (1→2)-α-L-Rhap residues, which is a pectic polysaccharide with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) structural domains containing side chains. In addition, the results of the antioxidant activity assay revealed that the ability of AHP-3a to scavenge DPPH, ABTS, and OH free radicals increased with an increase in its concentration. Moreover, according to the results from the EdU, wound healing, and Transwell assays, AHP-3a can control the proliferation, migration, and invasion of HepG2 and Huh7 hepatocellular carcinoma cells without causing any damage to healthy cells. Thus, AHP-3a may be a natural antioxidant and anticancer component.

The gut-liver axis perspective: Exploring the protective potential of polysaccharides from Cistanche deserticola against alcoholic liver disease

The primary objective of this study is to investigate the potential mechanism behind the protective effect of Cistanche deserticola polysaccharides (CP) against alcoholic liver disease (ALD). Multiple chromography techniques were employed to characterize CP from polysaccharide, the molecular weight distribution of polysaccharides, monosaccharide composition, isomeric hydrogen and isomeric carbon, in order to clarify the material basis of CP. To create the ALD mouse model, we utilized the well-established Lieber-DeCarli alcoholic liquid feed method. Findings from the study revealed that CP administration resulted in significant improvements in intestinal permeability, upregulation of barrier proteins expression, and reduced levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in mouse liver and serum. Additionally, CP treatment reduced the presence of inflammatory cytokines both in serum and liver while enhancing the activity of antioxidant enzymes in the liver. Furthermore, CP effectively reduced alcohol-induced oxidative damage by downregulating Keap1 protein levels in the liver, leading to increased expression of Nrf2 protein. The 16S rDNA sequencing results revealed that CP significantly restored the intestinal microbiota composition in ALD mice. These findings establish a strong association between gut microbiota and liver injury indicators, highlighting the potential of CP in preventing and treating ALD by modulating the gut-liver axis.

Isolation, characterization, trypsin inhibition, liver protective and antioxidant activities of arabinoxylan from Massa Medicata Fermentata and its processed products

Massa Medicata Fermentata (MMF) is a traditional Chinese medicine widely used in feed additives and human medicine. In this study, two neutral polysaccharides (SMMFP-1 and CMMFP-1) were isolated from two forms of MMF (sheng and chao MMF), and their structural characteristics and bioactivities were studied. The results showed that CMMFP-1 had higher average Mw compared with that of SMMFP-1. SMMFP-1 had a lower proportion of Ara, Xyl, GalA, and GlcA, but higher levels of Fuc, Gal, Man, and GulA. Compared with CMMFP-1, SMMFP-1 had a triple helix structure. SMMFP-1 had a layered structure, whereas CMMFP-1 had a curly layered structure. More glycosidic linkage types were found in SMMFP-1 than in CMMFP-1, and SMMFP-1 had a greater number of side chains. More importantly, SMMFP-1 showed better trypsin inhibition activity in vitro, liver-protective activity in vivo, and stronger antioxidant activity in vivo than CMMFP-1. Thus, arabinoxylans may be one of the active substances for different efficacies between MMF and its processed product. The results of this study facilitate the exploration of the correlation between the structural characteristics and biological functionalities of MMF arabinoxylans. Moreover, a theoretical basis is established for further study of the unique properties of arabinoxylans and their applications.

Effect of Hogweed Pectin on Rheological, Mechanical, and Sensory Properties of Apple Pectin Hydrogel

This study aims to develop hydrogels from apple pectin (AP) and hogweed pectin (HP) in multiple ratios (4:0; 3:1; 2:2; 1:3; and 0:4) using ionotropic gelling with calcium gluconate. Rheological and textural analyses, electromyography, a sensory analysis, and the digestibility of the hydrogels were determined. Increasing the HP content in the mixed hydrogel increased its strength. The Young’s modulus and tangent after flow point values were higher for mixed hydrogels than for pure AP and HP hydrogels, suggesting a synergistic effect. The HP hydrogel increased the chewing duration, number of chews, and masticatory muscle activity. Pectin hydrogels received the same likeness scores and differed only in regard to perceived hardness and brittleness. The galacturonic acid was found predominantly in the incubation medium after the digestion of the pure AP hydrogel in simulated intestinal (SIF) and colonic (SCF) fluids. Galacturonic acid was slightly released from HP-containing hydrogels during chewing and treatment with simulated gastric fluid (SGF) and SIF, as well as in significant amounts during SCF treatment. Thus, new food hydrogels with new rheological, textural, and sensory properties can be obtained from a mixture of two low-methyl-esterified pectins (LMPs) with different structures.

Structure-function relationships of pectic polysaccharides from broccoli by-products with in vitro B lymphocyte stimulatory activity

To study structure-function relationships of pectic polysaccharides with their immunostimulatory activity, broccoli by-products were used. Pectic polysaccharides composed by 64 mol% uronic acids, 18 mol% Ara, and 10 mol% Gal, obtained by hot water extraction, activated B lymphocytes in vitro (25-250 μg/mL). To disclose active structural features, combinations of ethanol and chromatographic fractionation and modification of the polysaccharides were performed. Polysaccharides insoluble in 80 % ethanol (Et80) showed higher immunostimulatory activity than the pristine mixture, which was independent of molecular weight range (12-400 kDa) and removal of terminal or short Ara side chains. Chemical sulfation did not promote B lymphocyte activation. However, the action of pectin methylesterase and endo-polygalacturonase on hot water extracted polysaccharides produced an acidic fraction with a high immunostimulatory activity. The de-esterified homogalacturonan region seem to be an important core to confer pectic polysaccharides immunostimulatory activity. Therefore, agri-food by-products are a source of pectic polysaccharide functional food ingredients.

Structural features and anticancer mechanisms of pectic polysaccharides: A review

The anticancer activity of pectic polysaccharides (PPs) was proved by numerous studies, and which also indicated that the bioactivity of PPs was closely related to its complicated structures. Based on the summary and analysis about structure characteristics and corresponding enzymatic process of the reported PPs, the anticancer mechanism and related structural features were systematically clarified. It was found that not only the direct effects on the cancer cells by proliferation inhibition or apoptosis, but also the regulation of immune system, gut microbiota and gut metabolism as indirect effects, jointly played important roles in the anticancer of PPs. Nevertheless, during the study of PPs as promising anticancer components, the exact structure-function relationship, digestion process in vivo, and comprehensive action mechanism are still not well understanding. With the unveiling of the proposed issues, it is believed that PPs are promising to be exploited as effective cancer therapy/adjunctive therapy drugs or functional foods.

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.

Structure of KOH-extractable polysaccharides of tree greenery of from Siberian fir Abies sibirica Ledeb

Polysaccharide AS_K was extracted with aqueous KOH from the Abies sibirica foliage. Pectin, xylan, AGPs and xyloglucan were isolated from AS_K by anion-exchange chromatography and Smith degradation, combined with enzymatic cleavage. Potential interactions between those polymers were examined. Since xylan, AGPs, RG-I and glucan were co-fractionated following complete removal of galacturonan (HG) with polygalacturonase, it can be inferred that the enzymatic cleavage of HG did not affect co-fractionation of cross-linking glycans, RG-I and AGPs. These were hypothesized to be bound via a covalent cross-link, as the removal of HG regions did not affect this complex. Given that pectin was represented solely by RG-I regions, it can be assumed that some of glucan, xylan and AGPs were associated directly with RG-I. Besides, the enzymatic hydrolysis eliminated most of xylose and rhamnose. This suggests implicitly that some of xylan was linked to RG-I.

Characterization of pectin-xylan-glucan-arabinogalactan proteins complex from Siberian fir Abies sibirica Ledeb

Polysaccharide AS_K was isolated from the Abies sibirica foliage by extraction with an aqueous KOH solution. AS_K was shown to contain structurally different polymers such as arabinoglucuronoxylans, xyloglucans, glucomannans, arabinogalactan-proteins (AGPs). The pectic polysaccharides were also found in the alkaline extract of AS_K and were represented by regions of homogalactorunan and rhamnogalactouronan-I whose side sugar chains were made up chiefly of highly branched 1,5-α-l-arabinan. The potential couplings between those polysaccharides were examined. Our studies showed simultaneous elution of pectin, xyloglucans, arabinoglucuronoxylans and AGPs, indicating that pectins can be covalently bound to the other cell-wall polysaccharides. NMR spectroscopy results revealed that the polysaccharides obtained by ion-exchange chromatography almost had no free reducing ends. These findings corroborate the conclusion that pectin, AGPs, glucan and xylan are bound together. The existence of the covalently bound complex of pectin-xylan-xyloglucan-AGP is suggested herein. Pectin and xylan are hypothesized to be covalently linked through RG-I regions.

Isolation and structure characterization of a low methyl-esterified pectin from the tuber of Dioscorea opposita Thunb

A low methyl-esterified pectin (33.2% methyl-esterification degree) was isolated from the tuber of Dioscorea opposita Thunb., which was an edible and medicinal material in China. This pectin (M_w of 1.3 × 10⁴ g/mol) contained the ~59.1% homogalacturonan (HG) and ~38.1% highly branched rhamnogalacturonan I (RG-I) region with possible side chains embracing arabinogalactan II, arabinan or arabinogalactan I. The fragments including HG backbone consisting of → 4)-α-GalpA-(1 → and → 4)-α-GalpA-6-O-methyl-(1 → with molar ratio of ~2:1, and repeating unit of arabinogalactan II side chain composed of α-Araf-(1 → and → 3,6)-β-Galp-(1→, were speculated through methylation analysis and NMR spectra. However, the linkage pattern for RG-I backbone and side chains were indiscernible due to limited resolution of NMR spectra. Besides, the pectin adopted a flexible chain conformation in 0.1 M NaNO₃ solution. These results provided a structural basis for study on polysaccharide from D. opposite, which was benefit for development of functional food of yam.

Characterization of an antioxidant pectic polysaccharide from Platycodon grandiflorus

Platycodonis Radix is widely used as homology of medicine and food in China; polysaccharides are thought to be one of its functional constituents. In this study, a pectic polysaccharide, PGP-I-I, was obtained from the root of the traditional medicine plant Platycodon grandiflorus through ion exchange chromatography and gel filtration. This was characterized being mainly composed of 1,5-α-L-arabinan and both arabinogalactan type I (AG-I) and II chains linked to rhamnogalacturonan I (RG-I) backbone linked to longer galacturonan chains. In vitro bioactivity study showed that PGP-I-I could restore the intestinal cellular antioxidant defense under the condition of hydrogen peroxide (H2O2) treatment through promoting the expressions of cellular antioxidant genes and protect against oxidative damages.

Structural characteristics of oxalate-soluble polysaccharides from Norway spruce (Picea abies) foliage

Structurally different polymers were derived from Picea abies foliage by successive extraction with water (PA_W), HCl solution (PA_A) and (NH₄)₂C₂O₄ solution (PA_O). The P. abies foliage was found to contain basically low-methoxyl pectin extractable with an (NH₄)₂C₂O₄ solution. PA_W was shown to comprise primarily arabinogalactan-proteins (AGPs); PA_A was composed of mixed AGPs and pectic polysaccharides, with the latter prevailing; and polysaccharide PA_O isolated in the highest yield included chiefly pectic polysaccharides. The major constituents of PA_O were low-methoxyl and low-acetylated 1,4-α-d-galacturonan and partially acetylated RG-I. The sugar side chains of RG-I contained chiefly highly branched 1,5-α-l-arabinan and arabinogalactan type I as a minor constituent. RG-I whose side chains had 1,5-α-l-arabinan represented short regions alternating with non-acetylated and unmethylesterified galacturonan regions. In addition to pectins, polysaccharide PA_O contained AGPs, xylanes and glucomannans, indicating that these polysaccharides are in an intimate interaction.

Polysaccharide composition of an anticoagulant fraction from the aqueous extract of Marsypianthes chamaedrys (Lamiaceae)

Marsypianthes chamaedrys (Lamiaceae) is a medicinal plant popularly used against envenomation by snakebite. Pharmacological studies have shown that extracts of M. chamaedrys have antiophidic, anti-inflammatory and anticoagulant properties, supporting the ethnopharmacological use. In this study, an aqueous extract of aerial parts of M. chamaedrys showed anticoagulant activity in the activated partial thromboplastin time assay (0.54 IU/mg). The bioassay-guided fractionation using ethanol precipitation and gel filtration chromatography on Sephadex G-50 and Sephadex G-25 resulted in a water-soluble fraction with increased anticoagulant activity (Fraction F2-A; 2.94 IU/mg). A positive correlation was found between the amount of uronic acids and the anticoagulant potential of the active samples. Chemical and spectroscopic analyses indicated that F2-A contained homogalacturonan, type I rhamnogalacturonan, type II arabinogalactan and α-glucan. UV and FT-IR spectra indicated the possible presence of ferulic acid. Pectic polysaccharides and type II arabinogalactans may be contributing to the anticoagulant activity of the aqueous extract of M. chamaedrys in the APTT assay.

Structural characterization and anticomplement activity of an acidic polysaccharide containing 3-O-methyl galactose from Juniperus tibetica

A water-soluble acidic polysaccharide containing 3-O-methyl galactose, named YB-PS4, was isolated from the twigs and leaves of Juniperus tibetica Kom. Its structure was characterized by monosaccharide composition analysis, methylation, and NMR spectroscopy. It was concluded that YB-PS4 had a backbone composed of→2,4)-α-Rhap-(1→, →3,5)-α-Araf-(1→, →2,4)-α-Galp-(1 → and →4)-α-GalpA-(1→, with branches of →2)-α-Rhap-(1→,→3)-α-Araf-(1 → and →2)-3-O-Me-α-Galp-(1→. The possible repetitive units were speculated and further analyzed by oligosaccharide analysis. YB-PS4 showed inhibitory effects on complement activation through the classical pathway (CH₅₀ = 94.23 ± 8.90 μg/mL) and alternative pathway (AP₅₀ = 194.76 ± 9.20 μg/mL). Preliminary mechanism study indicated that it interacted with C1q, C2, C3, C4 and C5. These studies pointed a way to understand the active constituents of J. tibetica and provided scientific bases for YB-PS4 as a complement inhibitor.

New findings on green sweet pepper (Capsicum annum) pectins: Rhamnogalacturonan and type I and II arabinogalactans

Polysaccharides were extracted from sweet pepper (Capsicum annum) with hot water and named ANW (9% yield). Starch was precipitated by freeze-thaw treatment, while pectic polysaccharides (8% yield) remained soluble and consisted of GalA (67.0%), Rha (1.6%), Ara (6.4%), Xyl (0.3%), Gal (6.7%) and Glc (4.4%). A highly methoxylated homogalacturonan (HG, degree of methylesterification of 85% and degree of acetylation of 5%), and type I and type II arabinogalactans (AG-I and AG-II) were observed in NMR analyses. These were fractionated with Fehling's solution to give HG (5.5% yield) and AG fractions (0.6% yield). AG-I and AG-II were further separated by ultrafiltration. AG-II (0.2% yield) consisted of Ara (17.1%), Gal (36.0%), Rha (5.6%) and GalA (12.0%), had a molecular weight of 5.3×10⁴g/mol and methylation and ¹H/¹³C HSQC-DEPT-NMR analyses showed that it was anchored in type I rhamnogalacturonan. This is the first study that reports the presence of AG-I and AG-II in sweet pepper fruits.