Isolation of a lectin binding rhamnogalacturonan-I containing pectic polysaccharide from pumpkin

Structural characterization and antioxidant activity mechanism of the ferulic acid-rich subfraction from sugar beet pectin

The feruloylated sugar chain in sugar beet pectin (SBP) is a natural polyphenol-polysaccharide complex. Its low abundance often leads to be neglected, thereby hindering its bioactivity and mechnism research. In this study, SBP-3 A, a novel feruloylated polysaccharide fragment, was isolated from sugar beet pectin utilizing enzymatic digestion. The presence of ferulic acid on SBP-3 A was confirmed through high-performance liquid chromatography (HPLC), with a mass fraction of 22.5 μg/mg. The average molecular weight was determined to be 33.31 kDa. Methylation analysis, and nuclear magnetic resonance (NMR) spectra revealed that SBP-3 A is a heteroglycan with the main chain structure of →2)-α-Rhap-(1 → 4)-α-GalpA-(1 → 2)-α-Rhap-(1→, and the branched chain structure of ferulic acid (FA) → 3,4)-β-Galp-(1 → 2,4)-α-Rhap-(1→. Subsequently, the antioxidant activity of SBP-3 A was evaluated using the Caenorhabditis elegans (C. elegans). SBP-3 A improved antioxidant enzymes and non-enzymatic defense system, decreased reactive oxygen species levels, and up-regulated the mRNA expression of sod-3, skn-1, and daf-16, while down-regulated the expression of age-1 in C. elegans. Moreover, SBP-3 A modulated the gut flora by favorably affecting the abundances of Lactobacillus, Ligilactobacillus, and Akkermansia, thereby enhancing antioxidant capacity in C. elegans. Consequently, the aforementioned findings support the potential application of SBP-3 A as a functional food for treating oxidative stress-related illnesses.

Structure characterization and gelling properties of RG-I-enriched pectins extracted from citrus peels using four different methods

To facilitate the application of rhamnogalacturonan-I (RG-I)-enriched pectins (RGPs) as novel, healthy, and gelling food additives, this study compared the structural characteristics and gelling properties of RGPs extracted from citrus peel via four methods (alkali: AK, high-temperature/pressure: TP, citric acid: CA, and enzyme-assisted: EA extractions). AK and CA yielded pectins with the highest RG-I proportions (54.8 % and 51.9 %, respectively) by disrupting the homogalacturonan region; TP and EA increased the RG-I proportions by ~10 %. Among the four methods, AK induced the lowest degree of esterification (DE) (6.7 %) and longer side chains that form strong entanglement, contributing to its highest gel hardness. The relatively low DE (18.5 %) of CA RGP facilitated stable gel formation. Notably, its highly branched RG-I region afforded more intramolecular hydrophobic interactions, making a more highly cross-linked gel network of better gel resilience. In contrast, TP induced the highest DE (57 %) and curved molecular chains; it inhibited Ca2+ binding, entanglement, and intramolecular hydrophobic interactions, and thus no gel formed. EA RGP was associated with the lowest molecular size, rendering it more difficult for Ca2+ to form links, which resulted no gel. These findings offer insights into the relationship among the extraction methods, molecular structures, and gelling properties of RGPs.

Ultrasonic-assisted extraction, analysis and properties of purple mangosteen scarfskin polysaccharide and its acetylated derivative

Purple mangosteen scarfskin polysaccharide has many important physiological functions, but its preparation method, structure, and function need further exploration. A polysaccharide was obtained from mangosteen scarfskin by ultrasonic-assisted extraction and purified. On this basis, its structure and physicochemical properties were investigated. The Congo red experiment was used to determine whether it has a triple helix conformation. The structure of purple mangosteen scarfskin polysaccharide was further analyzed by infrared spectroscopy and nuclear magnetic analysis. The antioxidant activities of the above three polysaccharides were studied by related experiments. It was found that the monosaccharide composition of purple mangosteen scarfskin polysaccharide mainly contained a large amount of arabinose, a small amount of rhamnoose and a very small amount of galacturonic acid, and its core main chain was composed of 1,4-α-arabinose. It did not have this spatial configuration. After the acetylation of purple mangosteen scarfskin polysaccharide, the acetylated derivative with a degree of substitution of 0.33 was obtained. It was found that they had certain scavenging and inhibiting effects on hydroxyl radicals and lipid peroxidation, and their activities were related to the concentration of polysaccharides. Meanwhile, the antioxidant activity of the polysaccharide was significantly enhanced after the modified treatment of acetylation, which indicated that chemical modification could effectively improve some activities of polysaccharide. The above studies provided some reference value for the further research and development of purple mangosteen scarfskin polysaccharide.

Organoleptic modulation functions and physiochemical characteristics of mannoproteins: Possible correlations and precise applications in modulating color evolution and orthonasal perception of wines

Mannoproteins have traditionally been recognized as effective wine organoleptic modulators, however, ambiguous understanding of the relationship between their organoleptic functions and physiochemical characteristics often lead to inappropriate application in winemaking. To reveal the possible role the physiochemical characteristics of mannoproteins play in modulating wine color and aroma properties, three water-soluble mannoproteins (MP1, MP2, MP3) with different physiochemical characteristics have been prepared, and accelerated red wine aging, malvidin pigments formation experiments, accelerated aroma release experiments have been designed to observe their organoleptic modulating functions in this research. Results suggest that the phenolic/chromatic stability of red wines could be enhanced by MP3, probably due to its low steric hindrance potential, high reactivity, and good hydro-alcoholic stability conferred by its high Mannan/Glucan ratio (8.68), abundant hydrophobic/hydrophilic amino acids (65.29 % of total protein), and low/medium molecular weight level (30.71-57.77 kDa), respectively, which protected the phenolic compounds and promoted the formation of pyranoanthocyanins. Mannoproteins could modulate the volatility of aroma compounds by expelling or retention effects, which depended on the duration of mannoprotein application (the expelling effect was firstly observed possibly because of the significant adsorption of free H2O by MPs) and the types of mannoproteins. MP1 and MP2 were prone to retain and expel aroma compounds, respectively, probably due to their medium/high molecular weight levels (60.48-135.39 kDa) that conferred abundant interacting sites, and the high proportion of hydrophobic and hydrophilic components in MP1 (97.71 % polysaccharides of total mannoprotein, 34.58 % hydrophobic amino acids of total protein) and MP2 (97.96 % polysaccharides of total mannoprotein, 28.36 % hydrophobic amino acids of total protein) guaranteed a relatively higher interacting frequency with aroma compounds and free H2O molecules, respectively.

Structural analysis and in vitro fermentation characteristics of an Avicennia marina fruit RG-I pectin as a potential prebiotic

Avicennia marina (Forssk.) Vierh. is a highly salt-tolerant mangrove, and its fruit has been traditionally used for treating constipation and dysentery. In this study, a pectin (AMFPs-0-1) was extracted and isolated from this fruit for the first time, its structure was analyzed, and the effects on the human gut microbiota were investigated. The results indicated that AMFPs-0-1 with a molecular weight of 798 kDa had a backbone consisting of alternating →2)-α-L-Rhap-(1→ and →4)-α-D-GalpA-(1→ residues and side chains composed of →3-α-L-Araf-(1→-linked arabinan with a terminal β-L-Araf, →5-α-L-Araf-(1→-linked arabinan, and →4)-β-D-Galp-(1→-linked galactan that linked to the C-4 positions of all α-L-Rhap residues in the backbone. It belongs to a type I rhamnogalacturonan (RG-I) pectin but has no arabinogalactosyl chains. AMFPs-0-1 could be consumed by human gut microbiota and increase the abundance of some beneficial bacteria, such as Bifidobacterium, Mitsuokella, and Megasphaera, which could help fight digestive disorders. These findings provide a structural basis for the potential application of A. marina fruit RG-I pectic polysaccharides in improving human intestinal health.

The characteristics of polysaccharide composition of red wines in China: Effects of grape varieties, origins and winemaking techniques

In this work, the polysaccharide profile of different grapes and red wines in China was studied and the influences of two common winemaking techniques on the components of wine were analyzed. The soluble polysaccharide content in the skins of native grape species in China (non-Vitis vinifera grapes) was significantly higher than that of Vitis vinifera species, while the terroir effect on V. vinifera varieties was limited. The combination of the enzyme preparation and the addition of mannoproteins (MPs) at the beginning of alcoholic fermentation (MP1 + E) could increase the contents of MPs and acid polysaccharides (APS) compared to the control wines. Meanwhile, better color characteristics and higher level of anthocyanin derivatives were observed. However, MP1 + E treatment reduced the content of polysaccharides rich in arabinose and galactose (PRAGs) due to enzymatic hydrolysis. The study will provide useful information for winemakers to regulate the wine polysaccharide profile.

Comparing the differences in quality profiles and antioxidant activity in seven pumpkin cultivars (Cucurbita moschata and Cucurbita maxima) at harvest and during postharvest storage

Pumpkin, nutritious vegetable, is renowned for its extended shelf life. In this study, seven pumpkin cultivars from Cucurbita moschata and Cucurbita maxima were comparatively characterized for 25 physiochemical quality factors, starch granule structures, antioxidant activity, and correlations at 0-60 days of postharvest (dop). The findings revealed that sucrose and carotenoid contents increased in C. moschata, while they initially increased and then decreased in C. maxima. Additionally, acidity, primarily driven by malic acid, decreased in C. maxima but increased in C. maxima. The starch content of C. moschata and C. maxima reached its maximum value at 30 dop and 20 dop, respectively. The DPPH radical scavenging activity correlated with the carotenoid content in both pumpkin species. Conclusively, C. moschata demonstrated improved nutritional and quality at 20-30 dop, while C. maxima exhibited higher commercial suitability at 10-20 dop. The findings suggested that pumpkin storage was crucial for quality improvement.

Fiber from elicited butternut pumpkin (Cucurbita moschata D. cv. Ariel) modulates the human intestinal microbiota dysbiosis

Elicited pumpkin was evaluated as a potential daily consumption product able to modulate the gut microbiota. An in vitro dynamic colonic fermentation performance with microbiota from obese volunteers was used. Prebiotic effects were observed after the pumpkin treatment. Bifidobacterium abundance was maintained during the treatment period whereas Lactobacillus increased in the transversal and descending colon. Conversely, Enterobacteriaceae and Clostridium groups were more stable, although scarce decreasing trends were observed for same species. Increments of Lactobacillus acidophilus and Limosilactobacillus fermentum (old Lactobacillus fermentum) were observed in the whole colonic tract after the treatment period. However, modulatory effects were mainly observed in the transversal and descending colon. Diverse bacteria species were increased, such as Akkermansia muciniphila, Bacteroides dorei, Cloacibacillus porcorum, Clostridium lactatifermentans, Ruminococcus albus, Ruminococcus lactaris, Coprococcus catus, Alistipes shahii or Bacteroides vulgatus. The prebiotic effect of the elicited pumpkin was provided by the fiber of the pumpkin, suggesting a release of pectin molecules in the transversal and distal colonic tract through low cellulosic fiber degradation, explaining the increases in the total propionic and butyric acid in these colonic sections. Also, a possible modulatory role of carotenoids from the sample was suggested since carotenes were found in the descending colon. Hence, the results of this research highlighted pumpkin as a natural product able to modulate the microbiota towards a healthier profile.

Effects of synergistic action on rheological and thermal properties of potato starch complexes co-gelatinized with caffeic acid and squash polysaccharides extracted with water and subcritical water

In order to broaden the application range of squash polysaccharide (WESP/SWESP) and caffeic acid (CAA) and improve the quality of potato starch (PS) products, the effects of WESP/SWESP and CAA on the gelatinization, rheology, thermodynamics, microstructure and in vitro digestion of PS were investigated. Meanwhile, the synergistic effect of WESP/SWESP and CAA on PS was further analyzed. Differently, due to WESP and SWESP had different monosaccharide composition and structure, they had different effects on the system. Pasting properties results showed that the presence of WESP/SWESP and CAA significantly reduced the peak viscosity, trough viscosity, breakdown viscosity and final viscosity of PS, especially under the combined action. In rheological tests, all sample gels belonged to the pseudoplastic fluids and weak gel system (tan δ < 1). Besides, thermodynamic properties revealed that WESP/SWESP and CAA synergistic effect had better retrogradation delay effect. In the ternary system, WESP/SWESP, CAA and PS can form a new network structure and improve the stability of the gel system. In addition, the results of infrared spectroscopy, Raman spectroscopy, x-ray diffraction and scanning electron microscopy exhibited that the ternary system can promote the accumulation and winding of the spiral structure of PS chain, and make the structure of PS gel network more orderly and stable. Furthermore, compared with PS gel, the ternary system had lower RDS and higher SDS and RS content, suggesting that the addition of WESP/SWESP and CAA at the same time was more conducive to reducing the hydrolysis rate of PS. This work revealed the interaction between WESP/SWESP, CAA and PS, which improved the physicochemical and digestive properties of PS. It will provide a theoretical basis for improving the quality of potato starch-related products and developing functional foods.

Structural characterization and prebiotic activity of rhamnogalacturonan-I rich pumpkin pectic polysaccharide extracted by alkaline solution

The present study aimed to investigate the structural and physicochemical characteristics of alkali-extracted pectic polysaccharide (AkPP) and to evaluate its prebiotic effects. AkPP was obtained from pumpkin pulp using an alkaline extraction method. AkPP, which had a molecular weight (Mw) of mainly 13.67 kDa and an esterification degree of 9.60%, was composed mainly of galacturonic acid (GalA), rhamnose (Rha), galactose, and arabinose. The ratio of the homogalacturonan (HG) region to the rhamnogalacturonan-I (RG-I) region in AkPP was 48.74:43.62. In the nuclear magnetic resonance spectrum, the signals indicating α-1,4-linked D-GalA, α-1,2-linked L-Rha, α-1,2,4-linked L-Rha residues were well resolved, demonstrating the presence of the HG and RG-I regions in its molecular structure. Collectively, AkPP was low methoxyl pectin rich in the RG-I region with short side chains and had a low Mw. Thermal analysis revealed that AkPP had good thermal stability. Compared to inulin, AkPP more effectively promoted the proliferation of Lactobacillus acidophilus, Lacticaseibacillus rhamnosus GG, Lacticaseibacillus casei, and Lacticaseibacillus paracasei and the production of lactic, acetic, and propionic acids. This study presents the unique structural features of AkPP and provides a scientific basis for further investigation of the potential of AkPP as a promising prebiotic.

Breaking barriers: How modified citrus pectin inhibits galectin-8

Inhibition of galectin-3-mediated interactions by modified citrus pectin (MCP) could affect several rate-limiting steps in cancer metastasis, but the ability of MCP to antagonize galectin-8 function remains unknown. We hypothesized that MCP could bind to galectin-8 in addition to galectin-3. In this study, a combination of gradual ethanol precipitation and DEAE-Sepharose Fast Flow chromatography was used to isolate several fractions from MCP. The ability of these fractions to antagonize galectin-8 function was studied as well as the primary structure and initial structure-function relationship of the major active component MCP-30-3. The results showed that MCP-30-3 (168 kDa) was composed of Gal (13.8%), GalA (63.1%), GlcA (13.0%), and Glc (10.1%). MCP-30-3 could specifically bind to galectin-8, with an MIC value of 0.04 mg mL-1. After MCP-30-3 was hydrolyzed by β-galactosidase or pectinase, its binding activity was significantly reduced. These results provide new insights into the interaction between MCP structure and galectin function, as well as the potential utility in the development of functional foods.

Characterization of chemical and sensory properties of Cabernet Sauvignon and Marselan wines made by flash détente technique

This study aimed to characterize the sensory profiles of wines produced using the flash détente (FD) technique and to identify the flavor compounds contributing to the sensory characteristics. The FD technique was applied to two major grape varieties, Cabernet Sauvignon and Marselan, from the Changli region of China to produce high-quality wines with aging potential. Compared to the traditional macerated wines, the FD wines showed greater color intensity, mainly due to the higher levels of anthocyanins. Regarding the aroma characteristics, FD wines were found to have a more pronounced fruitness, especially fresh fruit note, which was due to the contribution of higher concentration of esters. Concurrently, FD wines showed an increased sweet note which was associated with increased lactones and furanones. In addition, FD wines exhibited reduced green and floral notes due to lower levels of C6 alcohols and C13-norisoprenoids. With regard to mouthfeel, FD wines presented greater astringency and bitterness, which was due to the higher levels of phenolics. The total concentration of condensed tannins and condensed tannins for each degree of polymerization was considerably higher in FD wines due to the strong extraction of the FD technique. A significant increase in grape-derived polysaccharides and glycerol was also found in FD wines, contributing to a fuller body. This study contributed to an increase in the knowledge of the Changli region and demonstrated that the FD technique could be applied to the wine production in this region to address the negative impacts of rainfall in individual vintages.

Comprehensive Assessment of Polysaccharides Extracted from Squash by Subcritical Water under Different Conditions

The effects of subcritical water microenvironment on the physiochemical properties, antioxidant activity and in vitro digestion of polysaccharides (SWESPs) from squash were investigated. After single-factor experiments, twenty samples were successfully prepared at different extraction temperatures (110, 130, 150, 170 and 190 °C) and extraction times (4, 8, 12 and 16 min). Under a low temperature environment, the whole process was mainly based on the extraction of SWESP. At this time, the color of SWESP was white or light gray and the molecular mass was high. When the temperature was 150 °C, since the extraction and degradation of SWESP reached equilibrium, the maximum extraction rate (18.67%) was reached at 150 °C (12 min). Compared with traditional methods, the yield of squash SWESP extracted by subcritical water was 3-4 times higher and less time consuming. Under high temperature conditions, SWESPs were degraded and their antioxidant capacity and viscosity were reduced. Meanwhile, Maillard and caramelization reactions turned the SWESPs yellow-brown and produced harmful substances. In addition, different SWESPs had different effects on in vitro digestion. In brief, SWESPs prepared under different conditions have different structures and physicochemical properties, allowing the obtainment of the required polysaccharide. Our results show that squash polysaccharides prepared in different subcritical water states had good development potential and application in the food industry.

Identification of carbohydrate in Polygonatum kingianum Coll. et Hemsl and inhibiting oxidative stress

The specific structure of Polygonatum kingianum Coll. et Hemsl polysaccharide (PKP) has been rarely reported. In this study, an inulin-type fructan PKP-1, was extracted and purified from Polygonatum kingianum Coll. et Hemsl, and its structural characteristics and antioxidants activity were evaluated. The molecular weights of PKP-1 was determined to be 4.802 kDa. Monosaccharide composition analysis evidenced that PKP-1 was composed of galactose, glucose and fructose in a molar ratio of 0.8 %:7.2 %:92.0 %. Glycosidic linkage and Nuclear Magnetic Resonance (NMR) analysis revealed that PKP-1 exhibited a primary sugar residue linkage of →1-β-d-Fruf-2→2,6-β-d-Fruf-1→, where β-d-Fruf-2→ acts as the side chain and links to the C-6 position of →2,6-β-d-Fruf-1→. In vitro antioxidant activity assays demonstrated that PKP-1 enhanced the mitigation of hepatic oxidative stress in HepG2 cells induced by free fatty acids. This effect was marked by increased enzymatic activities of superoxidase dismutase (SOD) and catalase (CAT), along with elevated glutathione (GSH) levels. These findings indicate that PKP-1 could be used as a potential natural antioxidant.

Structure and properties of acidic polysaccharides isolated from Massa Medicata Fermentata: Neuroprotective and antioxidant activity

Massa Medicata Fermentata (MMF) is a fermented food with therapeutic effects. Previous studies suggested that after stir-frying, the uronic acid content in MMF crude polysaccharides increases, and the pH value decreases, which is caused by the change in acidic polysaccharides. However, the detailed physicochemical properties and structure-activity correlation of the acidic polysaccharides in MMF have not been fully explored. In this study, two acidic polysaccharides (SMMFAP and CMMFAP) were isolated from the MMF and its stir-fried product, respectively. Their structural characteristics and bioactivities were comparatively studied, and the structure-activity correlation was examined. Our findings revealed that the SMMFAP had a higher average Mw and higher Gal and Man content than the CMMFAP. Both the SMMFAP and CMMFAP were mainly composed of Xyl, Man, and Gal residues, whereas the CMMFAP had fewer linkage types. Additionally, the CMMFAP exhibited stronger neuroprotective activity than the SMMFAP owing to its higher content of 1,6-linked-Galp, while the SMMFAP exhibited better antioxidant activity, which might be related to its higher average Mw. Our findings suggest that acidic polysaccharides may be the active substances that cause differences in effectiveness between the sheng and chao MMF. Furthermore, the research qualified the SMMFAP and CMMFAP with different potential applications.

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.

Research on the Impact of Deep Eutectic Solvent and Hot-Water Extraction Methods on the Structure of Polygonatum sibiricum Polysaccharides

Deep eutectic solvent (DES) and hot-water extraction (HWE) methods were utilized to extract polysaccharides from Polygonatum sibiricum, referred to as DPsP and WPsP, respectively. The extracted polysaccharides were purified using the Superdex-200 dextran gel purification system, resulting in three components for each type of polysaccharide. The structures of these components were characterized. The molecular weight analysis revealed that DPsP components had slightly larger molecular weights compared with WPsP, with DPsP-A showing a slightly higher dispersity index and broader molecular weight distribution. The main monosaccharide components of both DPsP and WPsP were mannose and glucose, while DPsP exhibited a slightly greater variety of sugar components compared with WPsP. FTIR analysis demonstrated characteristic polysaccharide absorption peaks in all six PSP components, with a predominance of acidic pyranose sugars. NMR analysis revealed the presence of pyranose sugars, including rhamnose and sugar aldehyde acids, in both DPsP-B and WPsP-A. DPsP-B primarily exhibited β-type glycosidic linkages, while WPsP-A predominantly displayed α-type glycosidic linkages, with a smaller fraction being β-type. These findings indicated differences in monosaccharide composition and structure between PSPs extracted using different methods. Overall, this study provided experimental evidence for future research on the structure-function relationship of PSPs.

The digestive behavior of pectin in human gastrointestinal tract: a review on fermentation characteristics and degradation mechanism

Pectin is widely spread in nature and it develops an extremely complex structure in terms of monosaccharide composition, glycosidic linkage types, and non-glycosidic substituents. As a non-digestible polysaccharide, pectin exhibits resistance to human digestive enzymes, however, it is easily utilized by gut microbiota in the large intestine. Currently, pectin has been exploited as a novel functional component with numerous physiological benefits, and it shows a promising prospect in promoting human health. In this review, we introduce the regulatory effects of pectin on intestinal inflammation and metabolic syndromes. Subsequently, the digestive behavior of pectin in the upper gastrointestinal tract is summarized, and then it will be focused on pectin's fermentation characteristics in the large intestine. The fermentation selectivity of pectin by gut bacteria and the effects of pectin structure on intestinal microecology were discussed to highlight the interaction between pectin and bacterial community. Meanwhile, we also offer information on how gut bacteria orchestrate enzymes to degrade pectin. All of these findings provide insights into pectin digestion and advance the application of pectin in human health.

Polysaccharides from Oudemansiella radicata residues attenuate carbon tetrachloride-induced liver injury

In addition to fruiting bodies and mycelia, the mushroom residues have also been demonstrated to be rich in polysaccharides which have attracted academic attentions owing to their extensive bioactivities. Therefore, the present work aimed to investigate the potential hepatoprotective effects of Oudemansiella radicata residues polysaccharides (RPS). Our results demonstrated that RPS showed significantly protective effects against carbon tetrachloride (CCl₄)-induced liver injury, and the possible mechanisms may be related with the predominant bioactivities of RPS containing anti-oxidation by activating the Nrf2 signal pathways, anti-inflammation by inhibiting NF-κB signal pathways and reducing the release of inflammatory cytokines, anti-apoptosis by regulating Bcl-2/Bax pathway, and anti-fibrosis by inhibiting the expressions of TGF-β1, Hyp and α-SMA, respectively. These findings suggested that RPS, a typical β-type glycosidic pyranose-polysaccharides, could be used as promising diet supplement or medication for the adjunctive treatment of hepatic diseases, and also contributed to promoting the recyclable utilization of mushroom residues.

Development of Galectin-3 Targeting Drugs for Therapeutic Applications in Various Diseases

Galectin-3 (Gal3) is one of the most studied members of the galectin family that mediate various biological processes such as growth regulation, immune function, cancer metastasis, and apoptosis. Since Gal3 is pro-inflammatory, it is involved in many diseases that are associated with chronic inflammation such as cancer, organ fibrosis, and type 2 diabetes. As a multifunctional protein involved in multiple pathways of many diseases, Gal3 has generated significant interest in pharmaceutical industries. As a result, several Gal3-targeting therapeutic drugs are being developed to address unmet medical needs. Based on the PubMed search of Gal3 to date (1987-2023), here, we briefly describe its structure, carbohydrate-binding properties, endogenous ligands, and roles in various diseases. We also discuss its potential antagonists that are currently being investigated clinically or pre-clinically by the public and private companies. The updated knowledge on Gal3 function in various diseases could initiate new clinical or pre-clinical investigations to test therapeutic strategies, and some of these strategies could be successful and recognized as novel therapeutics for unmet medical needs.

A critical review of RG-I pectin: sources, extraction methods, structure, and applications

In recent years, RG-I pectin isolated by low-temperature alkaline extraction methods has attracted the attention of a large number of researchers due to its huge health benefits. However, studies on other applications of RG-I pectin are still lacking. In this study, we summarized the sources (e.g. potato pulp, sugar beet pulp, okra, apple pomace, citrus peel, pumpkin, grapefruit, ginseng, etc.), extraction methods, fine structure and applications of RG-I pectin in physiological activities (e.g. anti-cancer, anti-inflammatory, anti-obesity, anti-oxidation, immune regulation, prebiotics, etc.), emulsions, gels, etc. These neutral sugar side chains not only endow RG-I pectin with various physiological activities but the entanglement and cross-linking of these side chains also endow RG-I pectin with excellent emulsifying and gelling properties. We believe that this review can not only provide a comprehensive reading for new workers interested in RG-I pectin, but also provide a valuable reference for future research directions of RG-I pectin.

Lemon gum: Non-toxic arabinogalactan isolated from Citrus × latifolia with antiproliferative property against human prostate adenocarcinoma cells

Lemon gum (LG) obtained from Citrus × latifolia in Brazil was isolated and characterized. In addition, gum biocompatibility was evaluated in vitro and in vivo by Galleria mellonella and mice model. The cytotoxicity against tumor cells was also evaluated. The ratio of arabinose:galactose: rhamnose:4-OMe-glucuronic acid was 1:0.65:0.06:0.15. Small traces of protein were detected, emphasizing the isolate purity. Molar mass was 8.08 × 10⁵ g/mol, with three different degradation events. LG showed antiproliferative activity against human prostate adenocarcinoma cancer cells, with percentage superior to 50 %. In vivo toxicity models demonstrated that LG is biocompatible polymer, with little difference in the parameters compared to control group. These results demonstrate advance in the study of LG composition and toxicity, indicating a potential for several biomedical and biotechnological future applications.

Structural and biochemical insight into a modular β-1,4-galactan synthase in plants

Rhamnogalacturonan I (RGI) is a structurally complex pectic polysaccharide with a backbone of alternating rhamnose and galacturonic acid residues substituted with arabinan and galactan side chains. Galactan synthase 1 (GalS1) transfers galactose and arabinose to either extend or cap the β-1,4-galactan side chains of RGI, respectively. Here we report the structure of GalS1 from Populus trichocarpa, showing a modular protein consisting of an N-terminal domain that represents the founding member of a new family of carbohydrate-binding module, CBM95, and a C-terminal glycosyltransferase family 92 (GT92) catalytic domain that adopts a GT-A fold. GalS1 exists as a dimer in vitro, with stem domains interacting across the chains in a 'handshake' orientation that is essential for maintaining stability and activity. In addition to understanding the enzymatic mechanism of GalS1, we gained insight into the donor and acceptor substrate binding sites using deep evolutionary analysis, molecular simulations and biochemical studies. Combining all the results, a mechanism for GalS1 catalysis and a new model for pectic galactan side-chain addition are proposed.

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (Mw) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

Structural Characterization of Polysaccharides from Coriandrum sativum Seeds: Hepatoprotective Effect against Cadmium Toxicity In Vivo

Coriandrum sativum is one of the most widespread curative plants in the world, being vastly cultivated in arid and semi-arid regions as one of the oldest spice plants. The present study explored the extraction of polysaccharides from Coriandrum sativum seeds and the evaluation of their antioxidant potential and hepatoprotective effects in vivo. The polysaccharide from coriander seeds was extracted, and the structural characterization was performed by FT-IR, UV-vis, DSC, NMR (1D and 2D), GC-MS, and SEC analysis. The polysaccharide extracted from Coriandrum sativum (CPS) seeds was characterized to evaluate its antioxidant and hepatoprotective capacities in rats. Results showed that CPS was composed of arabinose, rhamnose, xylose, mannose, fructose, galactose, and glucose in molar percentages of 6.2%, 3.6%, 8.8%, 17.7%, 5.2%, 32.9%, and 25.6%, respectively. Further, CPS significantly hindered cadmium-induced oxidation damage and exercised a protective effect against Cd hepatocytotoxicity, with a considerable reduction in MDA production and interesting CAT and SOD enzyme levels. Results suggest that CPS might be employed as a natural antioxidant source.

Structural diversity and physicochemical properties of polysaccharides isolated from pumpkin (Cucurbita moschata) by different methods

Natural polysaccharides were isolated and purified from Cucurbita moschata by hot water extraction and mild acid-base sequential extraction. Chemical and instrumental studies revealed that hot water-extracted and mild acid-extracted polysaccharides with molecular masses of 48 kDa and 85 kDa were both pectic polysaccharides with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) domains, while mild acid-extracted polysaccharide was more dominated by branched RG-I with higher contents of galactose (10.59 %) and arabinose (8.08 %). Furthermore, mild acid-extracted polysaccharide exhibited better thickening and emulsifying properties, likely due to its larger molecular mass and higher branching degree. Mild base-extracted polysaccharide with a molecular mass of 18 kDa was a glucan-like polysaccharide. It showed the strongest thermostability and gel behavior among these pumpkin polysaccharides, likely attributed to its unique network structure stabilized by substantial intra/intermolecular hydrogen bonds. This study aimed to establish the structure-property relationships between these structurally diverse pumpkin polysaccharides from different extraction methods and provided theoretical foundations for their targeted application in foods.

Immunomodulatory Effects of an Aqueous Extract of Black Radish on Mouse Macrophages via the TLR2/4-Mediated Signaling Pathway

Here, we determined the immunostimulatory effects of black radish (Raphanus sativus ver niger) hot water extract (BRHE) on a mouse macrophage cell line (RAW 264.7) and mouse peritoneal macrophages. We found that BRHE treatment increased cell proliferation, phagocytic activity, nitric oxide (NO) levels, cytokine production, and reactive oxygen species synthesis. Moreover, BRHE increased the expression of the following immunomodulators in RAW 264.7 cells and peritoneal macrophages: pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), iNOS, and COX-2. BRHE treatment significantly up-regulated the phosphorylation of components of the mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), Akt, and STAT3 signaling pathways. Further, the effects of BRHE on macrophages were significantly diminished after the cells were treated with the TLR2 antagonist C29 or the TLR4 antagonist TAK-242. Therefore, BRHE-induced immunostimulatory phenotypes in mouse macrophages were reversed by multiple inhibitors, such as TLR antagonist, MAPK inhibitor, and Akt inhibitor indicating that BRHE induced macrophage activation through the TLR2/4-MAPK-NFκB-Akt-STAT3 signaling pathway. These results indicate that BRHE may serve as a potential immunomodulatory factor or functional food and provide the scientific basis for the comprehensive utilization and evaluation of black radish in future applications.

Alternative Utilization of Vegetable Crop: Pumpkin Polysaccharide Extract and Their Efficacy on Skin Hydration

Traditional pumpkin (Cucurbita moschata) and Japanese pumpkin (C. maxima) consist of natural polysaccharides. From a scientific basis, natural polysaccharides could be applied to improve hydration in the cosmetic field. The purified polysaccharide was extracted and deproteinized with the CaCl2 method. Japanese pumpkin showed the higher value of physicochemical properties including yield (12.96 ± 0.60%), total polysaccharide content (0.89 ± 0.04 mg/mL), swelling capacity (4.00 ± 0.00%), swelling index (1.04 ± 0.00%), solubility (126.67 ± 5.77%), viscosity (1.25 ± 0.00 cps), water capacity (0.93 ± 0.15 g/g) and oil absorption capacity (5.93 ± 0.06 g/g) than traditional pumpkin. Additionally, Japanese pumpkin (IC50 9.30 ± 0.58 µg/mL) provided higher antioxidant activity by DPPH assay than traditional pumpkin (IC50 9.98 ± 0.25 µg/mL). The evaluation of efficacy on skin hydration in fifteen Thai volunteers indicated that Japanese pumpkin showed non-skin irritation. An extract concentration of 0.05–0.1% showed a significantly increased effect in moisturizing ability according to concentration (p < 0.05). This result supported that it was safe and effective to use as a moisturizer for cosmetic products.

The Therapeutic Potential of Plant Polysaccharides in Metabolic Diseases

Plant polysaccharides (PPS) composed of more than 10 monosaccharides show high safety and various pharmacological activities, including immunoregulatory, antitumor, antioxidative, antiaging, and other effects. In recent years, emerging evidence has indicated that many PPS are beneficial for metabolic diseases, such as cardiovascular disease (CVD), diabetes, obesity, and neurological diseases, which are usually caused by the metabolic disorder of fat, sugar, and protein. In this review, we introduce the common characteristics and functional activity of many representative PPS, emphasize the common risks and molecular mechanism of metabolic diseases, and discuss the pharmacological activity and mechanism of action of representative PPS obtained from plants including Aloe vera, Angelica sinensis, pumpkin, Lycium barbarum, Ginseng, Schisandra chinensis, Dioscorea pposite, Poria cocos, and tea in metabolic diseases. Finally, this review will provide directions and a reference for future research and for the development of PPS into potential drugs for the treatment of metabolic diseases.

Characterization of a novel polysaccharide from red ginseng and its ameliorative effect on oxidative stress injury in myocardial ischemia

BACKGROUND

Red ginseng (RG) was widely used as traditional Chinese medicine (TCM) or dietary supplement. However, few researches had been reported on the red ginseng polysaccharide (RGP).

METHODS

In this study, a novel heteropolysaccharide named RGP1-1 was fractionated sequentially by DEAE-52 column and Sephadex G-100 gel column. The primary structure of RGP1-1, including glycosyl linkages, molecular weight, monosaccharide composition, morphology and physicochemical property were conducted by nuclear magnetic resonance (NMR), gas chromatography-mass spectrometer (GC-MS), atomic force microscope (AFM), scanning electron microscope (SEM), differential scanning calorimetry-thermogravimetric analysis (DSC-TG) and so on. The effect of RGP1-1 in preventing and treating myocardial ischemia was evaluated by an animal model isoprenaline (ISO) induced mice.

RESULTS

RGP1-1, with a homogeneous molecular weight of 5655 Da, was composed of Glc and Gal in the ratio of 94.26:4.92. The methylation and NMR analysis indicated the backbone was composed of → 1)-Glcp-(4 → and → 1)-Galp-(4 →, branched partially at O-4 with α-D-Glcp-(1 → residue. Morphology and physicochemical property analysis revealed a triple-helical conformation, flaky and irregular spherical structure with molecule aggregations and stable thermal properties of RGP1-1. And it contained 6.82 mV zeta potential, 117.4 nm partical size and polymerization phenomenon. Furthermore, RGP1-1 possessed strong antioxidant activity in vitro and in vivo, RGP1-1 could decrease cardiomyocyte apoptosis and myocardium fibrosis of mice in histopathology and it could decrease significantly the serum levels of cardiac troponin (cTnI), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), malondialdehyde (MDA). Western blot analysis showed that RGP1-1 can increase the expression of main protein Nuclear factor E2-related factor 2(Nrf2), NAD(P)H:quinone oxidoreductase 1 (NQO1), heme oxygenase-1(HO-1) and kelch-like ECH-associated protein1(keap1) in oxidative stress injure progress, and therefore regulate the pathway of Nrf2/HO-1.

CONCLUSION

The above findings indicated that RGP1-1 had an improving effect on ISO-induced myocardial ischemia injury in mice, as novel natural antioxidant and heart-protecting drugs.

A review of sugar beet pectin-stabilized emulsion: extraction, structure, interfacial self-assembly and emulsion stability

In recent years, sugar beet pectin as a natural emulsifier has shown great potential in food and pharmaceutical fields. However, the emulsification performance depends on the molecular structure of sugar beet pectin, and the molecular structure is closely related to the extraction method. This review summarizes the extraction methods of pectin, structure characterization methods and the current research status of sugar beet pectin-stabilized emulsions. The structural characteristics of sugar beet pectin (such as degree of methylation, degree of acetylation, degree of blockiness, molecular weight, ferulic acid content, protein content, neutral sugar side chains, etc.) are of great significance to the emulsifying activity and stability of sugar beet pectin. Compared with traditional hot acid extraction method, ultrasonic-assisted extraction, microwave-assisted extraction, subcritical water-assisted extraction, induced electric field-assisted extraction and enzyme-assisted extraction can improve the yield of sugar beet pectin. At the same time, compared with harsh extraction conditions (too high temperature, too strong acidity, too long extraction time, etc.), mild extraction conditions can better preserve these emulsifying groups in sugar beet pectin molecules, which are beneficial to improve the emulsifying properties of sugar beet pectin. In addition, the interfacial self-assembly behavior of sugar beet pectin induced by the molecular structure is crucial to the long-term stability of the emulsion. This review provides a direction for extracting or modifying sugar beet pectin with specific structure and function, which is instructive for finding alternatives to gum arabic.

Extraction, purification, structural characterization, and gut microbiota relationship of polysaccharides: A review

Intestinal dysbiosis is one of the major causes of the occurrence of metabolic syndromes, such as obesity, diabetes, nonalcoholic fatty liver disease, and cardiovascular diseases. Polysaccharide-based microbial therapeutic strategies have excellent potential in the treatment of metabolic syndromes, but the underlying regulatory mechanisms remain elusive. Identification of the internal regulatory mechanism of the gut microbiome and the interaction mechanisms involving bacteria and the host are essential to achieve precise control of the gut microbiome and obtain valuable clinical data. Polysaccharides cannot be directly digested; the behavior in the intestinal tract is considered a "bridge" between microbiota and host communication. To provide a relatively comprehensive reference for researchers in the field, we will discuss the polysaccharide extraction and purification processes and chemical and structural characteristics, focusing on the polysaccharides in gut microbiota through the immune system, gut-liver axis, gut-brain axis, energy axis interactions, and potential applications.

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.

Structural Characterization of Polysaccharides in Waste Liquor Produced by Wet Decortication of Sesame Seeds

The wet decortication of sesame seeds produces wastewater containing diverse minerals and organic pollutants that could be valuable resources for the food industry. This investigation aimed to reclaim, purify, and characterize the polysaccharides contained in the waste liquor from the sesame decortication industry. The purified polysaccharide fractions were characterized using monosaccharide analysis, GPC (high-performance gel permeation chromatography), FT-IR (Fourier-transform infrared) spectroscopy, methylation analysis, 1D and 2D Nucleai Magnetic Resonance (NMR) analysis, and thermal analysis. Four fractions were found (SSP-1,-2,-3, -4), of which SSP-2 was proportionately the largest and most interesting. The backbone of SSP-2 is mainly composed of (1→2,4)-β-_D-Xylp residues with side chains connected to the O-4 position, with many T-β-_D-Galp and (1→5)-α-_L-Araf residues, and fewer (1→4)-α-_D-Glcp, (1→2)-α-_L-Rhap, T-α-_L-Araf, and (1→2)-β-_D-GlcpA residues. An efficient method for removing the polysaccharides would simplify wastewater treatment while finding a use for them would benefit the sesame, food, and pharmaceutical industries.

The Use of Endo-Cellulase and Endo-Xylanase for the Extraction of Apple Pectins as Factors Modifying Their Anticancer Properties and Affecting Their Synergy with the Active Form of Irinotecan

Pectin constitutes an essential component of dietary fiber. Modified pectins from various sources possess potent anticancer and immunomodulatory activities. In this study, two pectins isolated from apple pomace by Trichoderma enzyme treatment, PX (with endo-xylanase) and PCX (with both endo-cellulase and endo-xylanase), were studied in colon cancer cell lines (HCT 116, Caco-2, and HT-29). Both pectins reduced colon cancer cell viability, induced apoptosis, and increased intracellular amounts of reactive oxygen species. Additionally, synergy between pectin and an active form of irinotecan, SN-38, in all aspects mentioned above, was discovered. This drug is a common component of cytotoxic combinations recommended as treatment for colon cancer patients. PX and PCX demonstrated significant anti-inflammatory activity in lipopolysaccharide-stimulated cells. Interaction of apple pectins with galectin-3 and Toll-like Receptor 4 (TLR4) was suggested to be responsible for their anticancer and anti-inflammatory effect. Since PCX was more active than PX in almost all experiments, the role of the enzyme used to obtain the pectin for its biological activity was discussed. It was concluded that co-operation between both enzymes was needed to obtain the molecule of the most beneficial properties. The low molecular mass of PCX together with a high proportion of rhamnogalacturonan I (RG I) regions seemed to be crucial for its superior activity.

Homogalacturonan from squash: Characterization and tau-binding pattern of a sulfated derivative

A pectic polysaccharide (WAP) was isolated from squash and identified as a homogalacturonan with a molecular mass of 83.2 kDa by GPC, monosaccharide composition analysis, FT-IR and NMR spectra. Sulfation modification of WAP was carried out and a sulfated derivative (SWAP) was obtained with a substitution degree of 1.81. The NMR spectrum indicated that the sulfation modification mainly occurred at the C-2 and C-3 positions of galacturonan residues. The binding pattern of SWAP to tau K18 protein was observed in 2D 1H15N HSQC spectra of tau, which resembled the tau-heparin interaction, with R2 domain as the major binding region. These results suggest that SWAP has the potential to act as a heparin mimic to inhibit the transcellular spread of tau; thus natural polysaccharide from squash may be developed into therapies for AD and related tauopathies.

Ferroptosis Related Immunomodulatory Effect of a Novel Extracellular Polysaccharides from Marine Fungus Aureobasidium melanogenum

Marine fungi represent an important and sustainable resource, from which the search for novel biological substances for application in the pharmacy or food industry offers great potential. In our research, novel polysaccharide (AUM-1) was obtained from marine Aureobasidium melanogenum SCAU-266 were obtained and the molecular weight of AUM-1 was determined to be 8000 Da with 97.30% of glucose, 1.9% of mannose, and 0.08% galactose, owing to a potential backbone of α-D-Glcp-(1→2)-α-D-Manp-(1→4)-α-D-Glcp-(1→6)-(SO₃⁻)-4-α-D-Glcp-(1→6)-1-β-D-Glcp-1→2)-α-D-Glcp-(1→6)-β-D-Glcp-1→6)-α-D-Glcp-1→4)-α-D-Glcp-6→1)-[α-D-Glcp-4]₂₆→1)-α-D-Glcp and two side chains that consisted of α-D-Glcp-1 and α-D-Glcp-(1→6)-α-D-Glcp residues. The immunomodulatory effect of AUM-1 was identified. Then, the potential molecular mechanism by which AUM-1 may be connected to ferroptosis was indicated by metabonomics, and the expression of COX2, SLC7A11, GPX4, ACSL4, FTH1, and ROS were further verified. Thus, we first speculated that AUM-1 has a potential effect on the ferroptosis-related immunomodulatory property in RAW 264.7 cells by adjusting the expression of GPX4, regulated glutathione (oxidative), directly causing lipid peroxidation owing to the higher ROS level through the glutamate metabolism and TCA cycle. Thus, the ferroptosis related immunomodulatory effect of AUM-1 was obtained.

Physicochemical Characterization and Antioxidant and Hypolipidaemic Activities of a Polysaccharide From the Fruit of Kadsura coccinea (Lem.) A. C. Smith

Kadsura coccinea fruit, a novel fruit resource, has attracted wide interest, but the physicochemical characteristics and biological activities of its polysaccharides remain unclear. This study investigated the physicochemical properties of a polysaccharide extracted from K. coccinea fruit polysaccharide (KCFP) and evaluated its antioxidant and hypolipidaemic activities in vitro and in vivo. KCFP is an amorphous, thermally stable pectin heteropolysaccharide with an average molecular weight of 204.6 kDa that is mainly composed of mannose, rhamnose, glucose, galactose, xylose, arabinose, galacturonic acid (molar percentage >70%) and glucuronic acid. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assays and an iron reducing antioxidant power assay showed that KCFP has strong antioxidant capacity, while the bile acid binding assay showed that KCFP has hypolipidaemic potential in vitro. The antioxidant and hypolipidaemic activities of KCFP were further evaluated in high-fat diet-induced hyperlipidaemic mice. KCFP significantly increased the activities of superoxide dismutase, glutathione peroxidase and catalase, decreased the malondialdehyde content, significantly reduced the total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) levels, and increased the amount of high-density lipoprotein cholesterol (HDL-C). These findings suggest that KCFP could be used as a functional food to remedy oxidative damage and hyperlipidaemia.

Structures and immunomodulatory activity of one galactose- and arabinose-rich polysaccharide from Sambucus adnata

One galactose- and arabinose-rich polysaccharide isolated from Sambucus adnata was named SPS-1, which had an average molecular weight 138.52 kDa, and was composed of L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-galactose, and L-arabinose in a molar ratio of 0.6:0.4:0.1:4.9:4.0. The primary structure of SPS-1 was further analyzed through methylation and NMR spectroscopy. The results showed that SPS-1 had the structural characteristics of AG-II pectin. The immunoactivity test showed that SPS-1 activated the phosphorylation of MAPKs-related proteins and further elevated the expression levels of related nuclear transcription factors (IκBα and NF-κB p65) in the cells through the TLR2 and MyD88/TRAF6-dependent pathway, thereby significantly enhancing the phagocytosis of macrophages and stimulating the secretion of NO, IL-1β, IL-6, and TNF-α, which activated the RAW264.7 cells. Therefore, SPS-1, acting as an immunomodulator, is a potential drug for immunological diseases.

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.

Functional Characterization of an Amaranth Natterin-4-Like-1 Gene in Arabidopsis thaliana

The functional characterization of an Amaranthus hypochondriacus Natterin-4-Like-1 gene (AhN4L-1) coding for an unknown function protein characterized by the presence of an aerolysin-like pore-forming domain in addition to two amaranthin-like agglutinin domains is herewith described. Natterin and nattering-like proteins have been amply described in the animal kingdom. However, the role of nattering-like proteins in plants is practically unknown. The results described in this study, obtained from gene expression data in grain amaranth and from AhN4L-1-overexpressing Arabidopsis thaliana plants indicated that this gene was strongly induced by several biotic and abiotic conditions in grain amaranth, whereas data obtained from the overexpressing Arabidopsis plants further supported the defensive function of this gene, mostly against bacterial and fungal plant pathogens. GUS and GFP AhN4L-1 localization in roots tips, leaf stomata, stamens and pistils also suggested a defensive function in these organs, although its participation in flowering processes, such as self-incompatibility and abscission, is also possible. However, contrary to expectations, the overexpression of this gene negatively affected the vegetative and reproductive growth of the transgenic plants, which also showed no increased tolerance to salinity and water-deficit stress. The latter despite the maintenance of significantly higher chlorophyll levels and photosynthetic parameters under intense salinity stress. These results are discussed in the context of the physiological roles known to be played by related lectins and AB proteins in plants.

Structural characterization and in vitro anti-inflammatory estimation of an unusual pectin linked by rhamnogalacturonan I and xylogalacturonan from lotus plumule

A novel homogenous polysaccharide LPWF together with its three acid hydrolysis products LPWF1-3 were isolated and prepared from lotus plumule (germs of Nelumbo nucifera). LPWF was composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), xylose (Xyl), and galacturonic acid (GalA) in the molar ratio of 7.3: 34.0: 7.0: 19.1: 32.6 with a molecular weight of 567.6 kDa. The structure of LPWF was elucidated by methylation and NMR analysis of LPWF1-3 and a follow-up structural assembling aided by high-resolution mass spectrometry mapping of oligosaccharides and ROSEY spectra. LPWF was characterized as an unusual pectin linked by rhamnogalacturonan I (RGI, composed of LPWF1-2) and xylogalacturonan (XGA, LPWF3). LPWF1 was an arabinan peeled from the RGI part with a 1,5-linked backbone branching on the O-2 position, while LPWF2 was the remaining part of RGI composed of Rha (36.1%), Gal (17.8%), and GalA (43.7%). LPWF3 was identified as the XGA part with a backbone of α-1,4-linked GalA and branches of mono-xylose substitutions on the O-3 of GalA. LPWF (25 μg/mL) demonstrated significant inhibitions on the expression of IL-1β, IL-6, and TNF-α in LPS-stimulated primary murine microglia cultures. LPWF1 and 2 showed selectively and significantly inhibitory activity against the expression of IL-1β.

Holistic review of polysaccharides isolated from pumpkin: Preparation methods, structures and bioactivities

Pumpkin polysaccharides have arrested researchers' attention in fields of food supplements for healthy product and traditional Chinese medicine due to their multiple bioactivities with non-toxic and highly biocompatible. This review emphatically summarized recent progresses in the primary and spatial structural features, various bioactivities, structure-to-function associations, different preparation techniques, and absorption characteristics across intestinal epithelial and in vivo bio-distribution of pumpkin polysaccharides. Additionally, current challenges and future trends in development of pumpkin polysaccharides were pointed out. We found that pumpkin polysaccharides were primary structure (e.g. glucan, galactoglucan, galactomannan, galactan, homogalacturonan (HG), and rhamnogalacturonan-Ι (RG-Ι)) and special structure diverse (e.g. hollow helix, linear, and sphere-like) and significant functional foods or therapeutic agents (e.g. oral hypoglycemic agents). Moreover, we found that the molecular weight (Mw), uronic acid, linkage types, and modifications all could affect their bioactivities (e.g. anti-oxidant, anti-coagulant, and anti-diabetic activities), and pumpkin polysaccharides may across intestinal epithelial into the blood reaching to target organs. Collectively, the structures diversity and pharmacological values of pumpkin polysaccharides support their therapeutic potentials and sanitarian functions.

Polyphenolic-protein-polysaccharide conjugates from Spica of Prunella vulgaris: Chemical profile and anti-herpes simplex virus activities

Previous studies showed that the water extract (PVW) from Spica of Prunella vulgaris Linn. (Labiatae) exerts anti-herpes simplex virus (HSV) activity. Evaluation the antiviral activity of the graded ethanol precipitations indicated that 30% ethanol precipitate (PVE30) was the active principle of water extract (PVW). Further activity-oriented separation of PVE30 through salting-out method revealed that the anti-HSV activity of P. vulgaris glycoconjugates (PVG) was more potent than PVE30 and PVW, 2-fold and 4-fold, respectively. UPLC-QTOF-MS/MS, FT-IR and NMR techniques identified PVG as a type of polyphenolic-protein-polysaccharides (PPPs) with an average molecular weight of 41.69 kDa. PVG was composed of dibenzylbutyrolactone lignan units, and rich in galacturonic acid, xylose, rhamnose, rhamnose, arabinose, glucose monosaccharide units, glutamic acid and aspartic acid. Further in vitro antiviral testing confirmed that PVG substantially and stably inhibited acyclovir (ACV) resistant HSV strains; its inhibitory action was even better than the positive control ACV. Overall, our findings support PVG as a potential drug resource for anti-HSV therapy.

Structural Characterization of a Neutral Polysaccharide from Cucurbia moschata and Its Uptake Behaviors in Caco-2 Cells

A neutral pumpkin polysaccharide (NPPc) was extracted from Cucurbia moschata and its structural characterization is performed. Moreover, uptake behaviors of an NPPC were investigated at the cellular level. The results showed that NPPc, an average molecular weight (Mw) of 9.023 kDa, was linear (1→4)-α-D-Glcp residues in the backbone, which branched point at O-6 position of (1→4,6)-α-D-Glcp. The side chain contained (1→6)-α-D-Glcp and terminal glucose. The cellular uptake kinetics results showed that the uptake of fluorescent-labeled NPPc was in time- and dose-dependent manners in Caco-2 cells. For subcellular localization of NPPc, it was accumulated in endoplasmic reticulum and mitochondrion. This study illustrates the characteristics on the uptake of NPPc and provides a rational basis for the exploration of polysaccharides absorption in intestinal epithelium.