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

An in-depth review: Unraveling the extraction, structure, bio-functionalities, target molecules, and applications of pectic polysaccharides

Pectic polysaccharides have long been a challenging subject of research in the field of macromolecular science, given their complex structures and wide range of biological effects. However, the extensive exploration of pectic polysaccharides has been limited due to the intricacy of their structures. In this comprehensive review, we aim to provide a thorough summary of the existing knowledge on pectic polysaccharides, with a particular focus on aspects such as classification, extraction methodologies, structural analysis, elucidation of biological activities, and exploration of target molecules and signaling pathways. By conducting a comprehensive analysis of existing literature and research achievements, we strive to establish a comprehensive and systematic framework that can serve as a reference and guide for further investigations into pectic polysaccharides. Furthermore, this review delves into the applications of pectic polysaccharides beyond their fundamental attributes and characteristics, exploring their potential in fields such as materials, food, and pharmaceuticals. We pay special attention to the promising opportunities for pectic polysaccharides in the pharmaceutical domain and provide an overview of related drug development research. The aim of this review is to facilitate a holistic understanding of pectic polysaccharides by incorporating multifaceted research, providing valuable insights for further in-depth investigations into this significant polymer.

A review: Polysaccharides targeting mitochondria to improve obesity

Polysaccharides are one of the most important and widely used bioactive components of natural products, which can be used to treat metabolic diseases. Natural polysaccharides (NPs) have been the subject of much study and research in the field of treating obesity in recent years. Studies in the past have demonstrated that mitochondria are important for the initiation, progression, and management of obesity. Additionally, NPs have the ability to improve mitochondrial dysfunction via a variety of mechanisms. This review summarized the relationship between the structure of NPs and their anti-obesity activity, focusing on the anti-obesity effects of these compounds at the mitochondrial level. We discussed the association between the structure and anti-obesity action of NPs, including molecular weight, monosaccharide composition, glycosidic linkage, conformation and extraction methods. Furthermore, NPs can demonstrate a range of functions in adipose tissue, including but not limited to improving the mitochondrial oxidative respiratory chain, inhibiting oxidative stress, and maintaining mitochondrial mass homeostasis. The purpose of this work is to acquire a thorough understanding of the function that mitochondria play in the anti-obesity effects of NPs and to offer fresh insights for the investigation of how NPs prevent obesity and the creation of natural anti-obesity medications.

Size exclusion chromatography and asymmetrical flow field-flow fractionation for structural characterization of polysaccharides: A comparative review

Natural polysaccharides exhibit a wide range of biological activities, which are closely related to their structural characteristics, including their molecular weight distribution, size, monosaccharide composition, glycosidic bond types and spatial conformation, etc. Size exclusion chromatography (SEC) and asymmetrical flow field-flow fractionation (AF4), as two potent separation techniques, both harbor potential for continuous development and enhancement. This manuscript reviewed the fundamental principles and separation applications of SEC and AF4. The structural information and spatial conformation of polysaccharides can be obtained using SEC or AF4 coupled with multiple detectors. In addition, this manuscript elaborates in detail on the shear degradation of samples such as polysaccharides separated by SEC. In addition, the abnormal elution that occurs during the application of the two methods is also discussed. Both SEC and AF4 possess considerable potential for ongoing development and refinement, thereby offering increased possibilities and opportunities for polysaccharide separation and characterization.

Extraction methods, chemical compositions, molecular structure, health functions, and potential applications of tea polysaccharides as a promising biomaterial: a review

Tea polysaccharides (TPS) have attracted much attention due to their multiple biological activities, excellent biocompatibility and good biodegradability, creating a wide range of potential applications in the food and pharmaceutical industries. However, the high molecular weight and complexity of TPS components have restricted its purification and bioactivity, limiting its potential applications. In this review, the effects of various extraction methods, tea processing, and degree of fermentation on the composition and structure of TPS were thoroughly investigated to overcome this dilemma. Through a comprehensive analysis of in vivo and in vitro studies, the health benefits of TPS are discussed in detail, including antioxidant, anti-obesity, modulation of gut microbial communities, and anticancer bioactivities. Typical structural characterization techniques of TPS are also summarized, and interactions with common food components are discussed in depth, providing a deeper perspective on the overall knowledge of TPS. Finally, this review offers an extensive overview of the wide range of applications of TPS, including its strong emulsifying properties and bio-accessibility, in various fields such as food nutrition, drug delivery, encapsulation films, and emulsifiers. This review aims to provide a theoretical basis for the profound development of TPS for productive utilization.

The relationship between polysaccharide structure and its antioxidant activity needs to be systematically elucidated

Polysaccharides have a wide range of applications due to their excellent antioxidant activity. However, the low purity and unclear structure of polysaccharides have led some researchers to be skeptical about the antioxidant activity of polysaccharides. The current reports on the structure-activity relationship of polysaccharides are sporadic, so there is an urgent need to systematically summarize the antioxidant effects of polysaccharides with clear structures and the relationships between the structures to provide a scientific basis for the development and application of polysaccharides. This paper will systematically elucidate the structure-activity relationship of antioxidant polysaccharides, including the molecular weight, monosaccharide composition, glycosidic linkage, degree of branching, advanced conformation and chemical modification. For the first time, the antioxidant activity of polysaccharides is related to their chemical structure through histogram and radar map, and further studies using principal component analysis and cluster analysis. We critically discussed how the source, chemical structure and chemically modified groups of polysaccharides significantly contribute to their antioxidant activity and summarized the current research status and shortcomings of the structure-activity relationship of antioxidant polysaccharides. This review provides a theoretical basis and new perspective for further research on the structure-activity relationship of antioxidant polysaccharides and the development of natural antioxidants.

Structure characterization and protective effect against UVB irradiation of polysaccharides isolated from the plateau plant Gentiana dahurica Fisch

Gentiana dahurica Fisch. (G. dahurica) is one of the legitimate sources of Qinjiao in Traditional Chinese Medicine (TCM) and grows on high-altitude plateaus. Plants develop unique biochemical accumulations to resist plateau conditions, especially the strong UV irradiation. Thus, this study aimed to investigate the polysaccharide of G. dahurica (GDP), its structure and its activity against UVB irradiation. Four GDPs were isolated and two of them were subjected to structural elucidation. The results suggested that GDP-1 has 53.5 % Ara and 30.8 % GalA as its main monosaccharides, with a molecular weight (Mw) of 23 kDa; the GDP-2 has 33.9 % Ara and 48.5 % GalA, with a Mw of 82 kDa. Methylation and NMR spectroscopy analysis revealed that GDP-1 contains →5)-α-Araf-(1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1 → 3,4)-α-GalpA-(6-OMe)-(1→ as the main chain, the branches of GalA (with esterification), and the terminal Ara; the GDP-2 contains →4)-α-GalpA-(1 → 4)-α-GalpA-(6-OMe)-(1 → 5)-α-Araf-(1 → 3,5)-α-Araf-(1→ as the main chain, the branches of →5)-α-Araf-(1-5)-α-Araf, and the terminal GalA. Both GDP-1 and GDP-2 exhibited concentration-dependent antioxidant activity against DPPH, ABTS and hydroxyl radicals. Moreover, GDPs significantly attenuated the decreases in viability and proliferation of HaCaT cells after UVB irradiation. They can scavenge reactive oxygen species (ROS) and improve the activities of endogenous antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH). The potential mechanism explored by flow cytometry assays of cell apoptosis and cell cycle distribution suggested that GDPs exert protective effects against UVB irradiation by reducing ROS and attenuating S phase cell arrest. In brief, the GDP-1 and GDP-2 are α-1,3- and α-1,4- arabinogalacturonan, respectively. The high content of Ara could be attributed to biochemical accumulation in resisting to the plateau environment and to prevent UVB irradiation-related damage in cells. These findings provide insight into authentic medicinal herbs and the development of GDPs in the modern pharmaceutical and cosmetics industry.

Efficient extraction of pectic polysaccharides from thinned unripe kiwifruits by deep eutectic solvent-based methods: Chemical structures and bioactivities

To promote the potentially industrial applications of thinned unripe kiwifruits, two deep eutectic solvent-based methods, including deep eutectic solvent-assisted extraction (DAE) and microwave-assisted deep eutectic solvent extraction (MDE), were optimized for the extraction of polysaccharides from thinned unripe kiwifruits (YKP). Results showed that the yields of YKP-D prepared by DAE and YKP-DM prepared by MDE were extremely higher than YKP-H prepared by hot water extraction. Furthermore, YKP-H, YKP-D, and YKP-DM were mainly composed of pectic polysaccharides, including homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. Besides, both YKP-D and YKP-DM exhibited stronger antioxidant, anti-glycosylation, and immunomodulatory effects than those of YKP-H, and their higher contents of uronic acids and bound polyphenols as well as lower molecular weights could partially contribute to their bioactivities. Overall, these results revealed that the developed MDE method could be utilized as a promising method for highly efficient extraction of YKP with superior beneficial effects.

Recent insights into the physicochemical properties, bioactivities and their relationship of tea polysaccharides

Tea polysaccharides (TPS) is receiving global concern in past years due to their therapeutic effects in many diseases such as obesity and diabetes. Many publications imply that the unique physicochemical properties and bioactivities of TPS are prerequisites for its use as a biofilm, drug carrier and emulsifier. Despite numerous healthy benefits, studies on the in-deep structure-activity relationship of TPS still not well explored and explained yet. The main reasons for the research limitation are attributed mainly to the unbreakable advanced structural research technology and the formation of TPS conjugates. The present review also summarizes some similar parameters in primary structure of TPS with better bioactivities, discusses the relationships between their physicochemical properties and bioactivities, and suggests that function-specific TPS would be obtained in the future if the links between preparation methods, physicochemical properties and bioactivities of TPS could be well understood and established.

Structural properties and biological activities of soluble dietary fibers rich in pectic-polysaccharides from different buckwheat green leaves

Buckwheat green leaves are commonly consumed as functional tea materials due to their various beneficial effects. Although buckwheat green leaves have abundant soluble dietary fibers (SDFs), the information about their structural properties and functional properties remains unknown, largely hindering their applications as functional/health products. Hence, to enhance the usage and application of SDFs from buckwheat green leaves as value-added health products, the structures and biological activities of SDFs derived from different buckwheat green leaves were investigated and compared. Results revealed that SDFs derived from Tartary buckwheat green leaves (TBSDF) and common buckwheat green leaves (CBSDF) were rich in complex pectic-polysaccharides, mainly composing of homogalacturonan (HG) and rhamnogalacturonan I (RG I) pectic domains. Besides, TBSDF had higher proportion of RG I pectic domains than that of CBSDF. Furthermore, the existence of a high content of complex pectic-polysaccharides in TBSDF and CBSDF could contribute to their various biological activities, such as antioxidant, antiglycation, fat/bile acid binding, anticancer, and prebiotic effects. These results can provide some new insights into further development of buckwheat green leaves and related SDFs as value-added health products.

Study on the structure, antioxidant activity and degradation pattern of polysaccharides isolated from lotus seedpod

The lotus (Nelumbo nucifera Gaertn.) is the largest aquatic vegetable in Asia. The lotus seedpod (LS) is an inedible part of the mature flower receptacle of the lotus plant. However, the polysaccharide isolated from the receptacle has been less studied. The purification of LS resulted in two polysaccharides (LSP-1 and LSP-2). Both polysaccharides were found to be medium-sized HG pectin, with a Mw of 74 kDa. Their structures were elucidated via GC-MS and NMR spectrum and proposed as the repeating sugar units of GalA connected via α-1,4-glycosidic linkage, with LSP-1 having a higher degree of esterification. They have certain content of antioxidant and immunomodulatory activities. The esterification of HG pectin would have an adverse effect on these activities. Furthermore, the degradation pattern and kinetics of LSPs by pectinase conformed to the Michaelis-Menten model. There is a large amount of LS, resulting from the by-product of locus seed production, and thus a promising source for the isolation of the polysaccharide. The findings of the structure, bioactivities, and degradation property provide the chemical basis for their applications in the food and pharmaceutical industries.

Impact of Six Extraction Methods on Molecular Composition and Antioxidant Activity of Polysaccharides from Young Hulless Barley Leaves

Young hulless barley leaves are gaining recognition for potential health benefits, and the method of extracting polysaccharides from them is critical for potential food industry applications. This study delves into a comparative analysis of six distinct fiber extraction techniques: hot water extraction; high-pressure steam extraction; alkaline extraction; xylanase extraction; cellulase extraction; and combined xylanase and cellulase extraction. This analysis included a thorough comparison of polysaccharide-monosaccharide composition, structural properties, antioxidant activities (DPPH, ABTS, and FRAP), and rheological properties among fibers extracted using these methods. The results underscore that the combined enzymatic extraction method yielded the highest extraction yield (22.63%), while the rest of the methods yielded reasonable yields (~20%), except for hot water extraction (4.11%). Monosaccharide composition exhibited divergence across methods; alkaline extraction yielded a high abundance of xylose residues, whereas the three enzymatic methods demonstrated elevated galactose components. The extracted crude polysaccharides exhibited relatively low molecular weights, ranging from 5.919 × 104 Da to 3.773 × 105 Da across different extraction methods. Regarding antioxidant activities, alkaline extraction yielded the highest value in the ABTS assay, whereas enzymatically extracted polysaccharides, despite higher yield, demonstrated lower antioxidant capacity. In addition, enzymatically extracted polysaccharides exerted stronger shear thinning behavior and higher initial viscosity.

Extraction and Purification, Structural Characterization and Biological Activity of a Polysaccharide, PRP-1, from Plumeria rubra

Polysaccharides derived from the flowers of Plumeria rubra (PRP) have shown a variety of beneficial effects on improving human health. However, the structural features and bioactivities of PRP remain unclear. A novel neutral polysaccharide (named PRP-1) with a molecular weight of 23 kDa was extracted and purified from the flowers of P. rubra. PRP-1 was consisted of arabinose, galactose, glucose, xylose and mannose, with a molar ratio of 1.49: 27.89: 50.24: 13.02: 7.36. The structural characterization based on the methylation and 1D/2D nuclear magnetic resonance analyses indicated that PRP-1 was composed of →4)-Glcp-(1→, →4,6)-Glcp-(1→, →4)-Galp-(1→, →2)-Galp-(1→, t-Gal(p), →4)-Manp-(1→, →4,6)-Manp-(1→, t-Man(p), →2)-Xylp-(1→, and t-Xyl(p). Scanning electron microscopy revealed that PRP-1 possess a compact three-dimensional curling network structure in the terms of morphology. PRP-1 exhibited anti-inflammatory activity, which have moderate inhibitory effects on TNF-α and IL-6 production in lipopolysaccharide (LPS)-induced RAW 264.7 cells. In addition, PRP-1 showed ABTS, OH radicals scavenging and the Fe2+ chelating effects in a concentration dependent manner. In α-glucosidase inhibition assay, PRP-1 did not exhibit inhibitory activity. Overall, these results provide a scientific basis for the utilization of the flowers of P. rubra as a potential functional food ingredient.

Comparison of Soluble Dietary Fibers Extracted from Ten Traditional Legumes: Physicochemical Properties and Biological Functions

Soluble dietary fibers (SDFs) exist as the major bioactive components in legumes, which exhibit various biological functions. To improve the potential applications of legume SDFs as healthy value-added products in the functional food industry, the physicochemical properties and biological functions of SDFs from ten selected traditional legumes, including mung bean, adzuki bean, red bean, red sword bean, black bean, red kidney bean, speckled kidney bean, common bean, white hyacinth bean, and pea, were studied and compared. Results showed that the physicochemical properties of SDFs varied in different species of legumes. All legume SDFs almost consisted of complex polysaccharides, which were rich in pectic-polysaccharides, e.g., homogalacturonan (HG) and rhamnogalacturonan I (RG I) domains. In addition, hemicelluloses, such as arabinoxylan, xyloglucan, and galactomannan, existed in almost all legume SDFs, and a large number of galactomannans existed in SDFs from black beans. Furthermore, all legume SDFs exhibited potential antioxidant, antiglycation, immunostimulatory, and prebiotic effects, and their biological functions differed relative to their chemical structures. The findings can help reveal the physicochemical and biological properties of different legume SDFs, which can also provide some insights into the further development of legume SDFs as functional food ingredients.

Physicochemical characteristics and biological activities of soluble dietary fibers isolated from the leaves of different quinoa cultivars

Quinoa leaf is consumed as a promising value-added vegetable in the diet. Although quinoa leaf is rich in soluble dietary fibers, the knowledge regarding their chemical structures and biological activities is still limited, which astricts their application in the functional food industry. Thus, to improve the precise use and application of soluble dietary fibers (SDFs) isolated from quinoa leaves in the food industry, the physicochemical structures and bioactivities of SDFs isolated from different quinoa leaves were systematically investigated. Results indicated that quinoa leaves were rich in SDFs, ranging from 3.30 % to 4.55 % (w/w). Quinoa SDFs were mainly composed of acidic polysaccharides, such as homogalacturonan and rhamnogalacturonan I, which had the molecular weights in the range of 4.228 × 10⁴ -7.059 × 10⁴ Da. Besides, quinoa SDFs exerted potential in vitro antioxidant activities, lipid and bile acid-adsorption capacities, immunoregulatory activities, and prebiotic effects, which might be partially associated with their molecular mass, content of uronic acid, and content of bound polyphenol. Collectively, these findings are beneficial to better understanding the chemical structures and bioactivities of SDFs extracted from different quinoa leaves, which can also provide a scientific basis for developing quinoa SDFs into functional foods in the food industry.

Polysaccharides of Salsola passerina: Extraction, Structural Characterization and Antioxidant Activity

The above-ground part of the Salsola passerine was found to contain ~13% (w/w) of polysaccharides extractable with water and aqueous solutions of ammonium oxalate and sodium carbonate. The fractions extracted with aqueous sodium carbonate solutions had the highest yield. The polysaccharides of majority fractions are characterized by similar monosaccharide composition; namely, galacturonic acid and arabinose residues are the principal components of their carbohydrate chains. The present study focused on the determination of antioxidant activity of the extracted polysaccharide fractions and elucidation of the structure of polysaccharides using nuclear magnetic resonance (NMR) spectroscopy. Homogalacturonan (HG), consisting of 1,4-linked residues of α-D-galactopyranosyluronic acid (GalpA), rhamnogalacturonan-I (RG-I), which contains a diglycosyl repeating unit with a strictly alternating sequence of 1,4-linked D-GalpA and 1,2-linked L-rhamnopyranose (Rhap) residues in the backbone, and arabinan, were identified as the structural units of the obtained polysaccharides. HMBC spectra showed that arabinan consisted of alternating regions formed by 3,5-substituted and 1,5-linked arabinofuranose residues, but there was no alternation of these residues in the arabinan structure. Polysaccharide fractions scavenged the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical at 0.2-1.8 mg/mL. The correlation analysis showed that the DPPH scavenging activity of polysaccharide fractions was associated with the content of phenolic compounds (PCs).

Structural Characterization and Macrophage Polarization-Modulating Activity of a Novel Polysaccharide from Large Yellow Tea

A novel homogeneous polysaccharide (LYP-S3) that promotes the M2 polarization of macrophages was obtained from large yellow tea by a bioactivity-guided sequential isolation procedure and activity evaluation in the present study. Structural characterization revealed that LYP-S3 has an average molecular weight of 28.6 kDa and is composed of rhamnose, arabinose, galactose, glucose, and galacturonic acid at the molar ratio of 8.08:11.66:11.77:3.96:58.02. The main backbone of LYP-S3 consists of →4)-α-d-GalpA-6-OMe-(1→, β-d-GalpA-(1→, →4)-β-d-Galp-(→1, and →β-d-Galp-(1→, and the branches are composed of α-l-Araf-(→1, →5)-α-l-Araf-(1→, →2,4)-β-l-Rhap-(1→, →2)-β-l-Rhap-(1→, and →4)-β-d-Glcp-(1→. An in vitro bioactivity evaluation assay showed that LYP-S3 remarkably reduced the expression of M1 macrophage markers and increased the expression of M2 macrophage markers. In addition, LYP-S3 inhibited adipocyte differentiation and adipogenesis in 3T3-L1 adipocytes and blocked macrophage migration toward 3T3-L1 adipocytes in the cocultures of bone-marrow-derived monocytes and 3T3-L1 adipocytes. Furthermore, LYP-S3 promoted the M2 polarization of macrophages in cocultures. These findings suggested that LYP-S3 has a potential function in preventing inflammation and obesity.

Effects of oxidation-based tea processing on the characteristics of the derived polysaccharide conjugates and their regulation of intestinal homeostasis in DSS-induced colitis mice

Different cultivars and processing technologies involved in producing tea result in the high heterogeneity of derived polysaccharide conjugates, which limits the understanding of their composition and structure, and biological activity. Here, raw tea leaves from the same cultivar were used to produce dried fresh tea leaves, green tea, and black tea, and three polysaccharide conjugates derived from dried fresh tea leaves (FTPS), green tea (GTPS), and black tea (BTPS) were prepared accordingly. Their physiochemical characteristics and bioactivities were investigated. The results showed that the oxidation during tea processing increased the phenolics and proteins while decreasing the GalA in the derived TPS conjugates; meanwhile, it reduced the molecular weight and particle size of BTPS but enhanced their antioxidant activity in vitro. Furthermore, all three TPS conjugates improved intestinal homeostasis by reducing TJ protein loss and inflammation and alleviated DSS-induced colitis symptoms in mice. In addition, the three TPS conjugates showed differential regulation of the intestinal microbiome and altered the produced SCFAs, which contributed to the prevention of colitis. Our findings suggest that TPS conjugates could be applied in colitis prevention in association with the regulation of gut microbiota, and their efficacy could be optimized by employing suitable tea processing technologies.