Research

Jump to: Review

13 pages, 1625 KiB

Open AccessArticle

Topochemical Engineering of Cellulose—Carboxymethyl Cellulose Beads: A Low-Field NMR Relaxometry Study

by Pieter De Wever, Rodrigo de Oliveira-Silva, João Marreiros, Rob Ameloot, Dimitrios Sakellariou and Pedro Fardim

Molecules 2021, 26(1), 14; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26010014 - 22 Dec 2020

Cited by 8 | Viewed by 3298

Abstract

The demand for more ecological, highly engineered hydrogel beads is driven by a multitude of applications such as enzyme immobilization, tissue engineering and superabsorbent materials. Despite great interest in hydrogel fabrication and utilization, the interaction of hydrogels with water is not fully understood. [...] Read more.

The demand for more ecological, highly engineered hydrogel beads is driven by a multitude of applications such as enzyme immobilization, tissue engineering and superabsorbent materials. Despite great interest in hydrogel fabrication and utilization, the interaction of hydrogels with water is not fully understood. In this work, NMR relaxometry experiments were performed to study bead–water interactions, by probing the changes in bead morphology and surface energy resulting from the incorporation of carboxymethyl cellulose (CMC) into a cellulose matrix. The results show that CMC improves the swelling capacity of the beads, from 1.99 to 17.49, for pure cellulose beads and beads prepared with 30% CMC, respectively. Changes in water mobility and interaction energy were evaluated by NMR relaxometry. Our findings indicate a 2-fold effect arising from the CMC incorporation: bead/water interactions were enhanced by the addition of CMC, with minor additions having a greater effect on the surface energy parameter. At the same time, bead swelling was recorded, leading to a reduction in surface-bound water, enhancing water mobility inside the hydrogels. These findings suggest that topochemical engineering by adjusting the carboxymethyl cellulose content allows the tuning of water mobility and porosity in hybrid beads and potentially opens up new areas of application for this biomaterial. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Figure 1

9 pages, 2390 KiB

Open AccessCommunication

Comparative Studies on Regioselectivity of α- and β-Linked Glucan Tosylation

by Andreas Koschella, Thomas Heinze, Antje Tied, Katja Geitel, Chih-Ying Chien and Tadahisa Iwata

Molecules 2020, 25(22), 5382; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25225382 - 17 Nov 2020

Cited by 2 | Viewed by 2240

Abstract

Alpha- and beta-linked 1,3-glucans have been subjected to conversion with p-toluenesulfonic acid (tosyl) chloride and triethylamine under homogeneous reaction conditions in N,N-dimethyl acetamide/LiCl. Samples with a degree of substitution of tosyl groups (DS_Ts) of up to 1.91 [...] Read more.

Alpha- and beta-linked 1,3-glucans have been subjected to conversion with p-toluenesulfonic acid (tosyl) chloride and triethylamine under homogeneous reaction conditions in N,N-dimethyl acetamide/LiCl. Samples with a degree of substitution of tosyl groups (DS_Ts) of up to 1.91 were prepared by applying 5 mol reagent per mole repeating unit. Hence, the reactivity of α-1,3-glucan is comparable with cellulose and starch, while the β-1,3-linked glucan curdlan is less reactive. The samples dissolve in aprotic dipolar media independent of the DS_Ts and possess a solubility in less polar solvents that depends on the DS_Ts. NMR studies on the tosyl glucans and of the peracylated derivatives showed a preferred tosylation of position 2 of the repeating unit. However, the selectivity is less pronounced compared with starch. It could be concluded that the α-configurated glycosidic bond directs tosyl groups towards position 2. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Graphical abstract

20 pages, 3181 KiB

Open AccessArticle

Influence of Partial Acid Hydrolysis on Size, Dispersity, Monosaccharide Composition, and Conformation of Linearly-Branched Water-Soluble Polysaccharides

by Cristina Lupo, Samy Boulos and Laura Nyström

Molecules 2020, 25(13), 2982; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25132982 - 29 Jun 2020

Cited by 14 | Viewed by 3995

Abstract

The effect of partial acid hydrolysis on the physical and chemical properties of galactomannan, arabinoxylan, and xyloglucan was investigated. Polysaccharides were treated at 50 °C with hydrochloric acid for 3–48 h. Portions of isopropanol (i-PrOH) were added sequentially to the hydrolyzates, [...] Read more.

The effect of partial acid hydrolysis on the physical and chemical properties of galactomannan, arabinoxylan, and xyloglucan was investigated. Polysaccharides were treated at 50 °C with hydrochloric acid for 3–48 h. Portions of isopropanol (i-PrOH) were added sequentially to the hydrolyzates, resulting in fractions that were collected by centrifugation. As expected, a significant reduction of weight-average molecular weight (M_w) was observed with increasing hydrolysis time. Fractional precipitation was successfully applied to collect at least one polymer fraction with dispersity (Đ) close to one for each polysaccharide. The monosaccharide composition analysis showed that the partial hydrolysis usually lowered the relative amount of side chains, with the exception of galactomannan, where the composition remained largely unaffected. Estimation of the polymer conformation in solution, through evaluation of the Mark-Houwink parameter coefficient (α), confirmed that acid hydrolysis influenced the polysaccharides’ conformation. It was demonstrated that acid treatment in dilute solution followed by fractional isopropanol precipitation is a method, extendible to a variety of polysaccharides, to obtain materials of decreased molecular weight and low dispersity with slightly altered overall composition and conformation. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Figure 1

18 pages, 2507 KiB

Open AccessArticle

Immunomodulatory Effects of Lycium barbarum Polysaccharide Extract and Its Uptake Behaviors at the Cellular Level

by Le Feng, Xiao Xiao, Jing Liu, Junyan Wang, Nan Zhang, Tao Bing, Xiangjun Liu, Ziping Zhang and Dihua Shangguan

Molecules 2020, 25(6), 1351; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25061351 - 16 Mar 2020

Cited by 50 | Viewed by 3876

Abstract

Lycium barbarum L. is a widely used functional food and medicinal herb in Asian countries. L. barbarium polysaccharides (LBP) are considered as one of the major medicinal components of L. barbarium fruit and exhibits a wide range of biological activities. Here, we investigated [...] Read more.

Lycium barbarum L. is a widely used functional food and medicinal herb in Asian countries. L. barbarium polysaccharides (LBP) are considered as one of the major medicinal components of L. barbarium fruit and exhibits a wide range of biological activities. Here, we investigated the immunomodulatory effects of LBP and its uptake behaviors at the cellular level. LBP was prepared by water extraction and ethanol precipitation, and divided into two fractions based on the molecular weight distribution by ultrafiltration (LBP > 10 kDa and LBP < 10 kDa). The physicochemical properties of LBP and LBP fractions were well characterized. The LBP > 10 kDa fraction greatly enhanced the viability of macrophages RAW264.7 cells and induced cell polarization, but had weak effects to other tested tumor cell lines and normal cell line. This fraction could regulate the production of NO, TNF-α, IL-6 and ROS in RAW264.7 cells, suggesting both pro-inflammatory and anti-inflammatory effects. The dye-labeled LBP could be internalized into all tested cell lines and accumulated in lysosomes. The internalization of LBP in RAW264.7 cells is mainly through the clathrin-mediated endocytosis pathway. The Caco-2 intestinal transport experiment demonstrated that the dye labeled LBP could be transported through the Caco-2 cell monolayer (mimic intestinal epithelium) through clathrin-mediated endocytosis. These results demonstrate the immunomodulatory effects of LBP and its effective uptake by macrophages and intestine. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Graphical abstract

Review

Jump to: Research

37 pages, 2788 KiB

Open AccessReview

Comparisons of Isolation Methods, Structural Features, and Bioactivities of the Polysaccharides from Three Common Panax Species: A Review of Recent Progress

by Hongyu Qi, Zepeng Zhang, Jiaqi Liu, Zhaoqiang Chen, Qingxia Huang, Jing Li, Jinjin Chen, Mingxing Wang, Daqing Zhao, Zeyu Wang and Xiangyan Li

Molecules 2021, 26(16), 4997; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26164997 - 18 Aug 2021

Cited by 17 | Viewed by 3445

Abstract

Panax spp. (Araliaceae family) are widely used medicinal plants and they mainly include Panax ginseng C.A. Meyer, Panax quinquefolium L. (American ginseng), and Panax notoginseng (notoginseng). Polysaccharides are the main active ingredients in these plants and have demonstrated diverse pharmacological [...] Read more.

Panax spp. (Araliaceae family) are widely used medicinal plants and they mainly include Panax ginseng C.A. Meyer, Panax quinquefolium L. (American ginseng), and Panax notoginseng (notoginseng). Polysaccharides are the main active ingredients in these plants and have demonstrated diverse pharmacological functions, but comparisons of isolation methods, structural features, and bioactivities of these polysaccharides have not yet been reported. This review summarizes recent advances associated with 112 polysaccharides from ginseng, 25 polysaccharides from American ginseng, and 36 polysaccharides from notoginseng and it compares the differences in extraction, purification, structural features, and bioactivities. Most studies focus on ginseng polysaccharides and comparisons are typically made with the polysaccharides from American ginseng and notoginseng. For the extraction, purification, and structural analysis, the processes are similar for the polysaccharides from the three Panax species. Previous studies determined that 55 polysaccharides from ginseng, 18 polysaccharides from American ginseng, and 9 polysaccharides from notoginseng exhibited anti-tumor activity, immunoregulatory effects, anti-oxidant activity, and other pharmacological functions, which are mediated by multiple signaling pathways, including mitogen-activated protein kinase, nuclear factor kappa B, or redox balance pathways. This review can provide new insights into the similarities and differences among the polysaccharides from the three Panax species, which can facilitate and guide further studies to explore the medicinal properties of the Araliaceae family used in traditional Chinese medicine. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Figure 1

17 pages, 1008 KiB

Open AccessReview

Polysaccharide Structures and Their Hypocholesterolemic Potential

by Inês M. V. Silva, Fernanda Machado, Maria João Moreno, Cláudia Nunes, Manuel A. Coimbra and Filipe Coreta-Gomes

Molecules 2021, 26(15), 4559; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules26154559 - 28 Jul 2021

Cited by 31 | Viewed by 4207

Abstract

Several classes of polysaccharides have been described to have hypocholesterolemic potential, namely cholesterol bioaccessibility and bioavailability. This review will highlight the main mechanisms by which polysaccharides are known to affect cholesterol homeostasis at the intestine, namely the effect (i) of polysaccharide viscosity and [...] Read more.

Several classes of polysaccharides have been described to have hypocholesterolemic potential, namely cholesterol bioaccessibility and bioavailability. This review will highlight the main mechanisms by which polysaccharides are known to affect cholesterol homeostasis at the intestine, namely the effect (i) of polysaccharide viscosity and its influence on cholesterol bioaccessibility; (ii) on bile salt sequestration and its dependence on the structural diversity of polysaccharides; (iii) of bio-transformations of polysaccharides and bile salts by the gut microbiota. Different quantitative structure–hypocholesterolemic activity relationships have been explored depending on the mechanism involved, and these were based on polysaccharide physicochemical properties, such as sugar composition and ramification degree, linkage type, size/molecular weight, and charge. The information gathered will support the rationalization of polysaccharides’ effect on cholesterol homeostasis and highlight predictive rules towards the development of customized hypocholesterolemic functional food. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Figure 1

23 pages, 2204 KiB

Open AccessReview

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

by Rajarshi Ghosh, Daniel L. Bryant and Anthony L. Farone

Molecules 2020, 25(24), 5854; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25245854 - 11 Dec 2020

Cited by 29 | Viewed by 3783

Abstract

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major [...] Read more.

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

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures

Figure 1

31 pages, 5279 KiB

Open AccessReview

Multivalent Ions as Reactive Crosslinkers for Biopolymers—A Review

by Florian Wurm, Barbara Rietzler, Tung Pham and Thomas Bechtold

Molecules 2020, 25(8), 1840; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules25081840 - 16 Apr 2020

Cited by 35 | Viewed by 6335

Abstract

Many biopolymers exhibit a strong complexing ability for multivalent ions. Often such ions form ionic bridges between the polymer chains. This leads to the formation of ionic cross linked networks and supermolecular structures, thus promoting the modification of the behavior of solid and [...] Read more.

Many biopolymers exhibit a strong complexing ability for multivalent ions. Often such ions form ionic bridges between the polymer chains. This leads to the formation of ionic cross linked networks and supermolecular structures, thus promoting the modification of the behavior of solid and gel polymer networks. Sorption of biopolymers on fiber surfaces and interfaces increases substantially in the case of multivalent ions, e.g., calcium being available for ionic crosslinking. Through controlled adsorption and ionic crosslinking surface modification of textile fibers with biopolymers can be achieved, thus altering the characteristics at the interface between fiber and surrounding matrices. A brief introduction on the differences deriving from the biopolymers, as their interaction with other compounds, is given. Functional models are presented and specified by several examples from previous and recent studies. The relevance of ionic crosslinks in biopolymers is discussed by means of selected examples of wider use. Full article

(This article belongs to the Special Issue Polysaccharides: Structure-Function Relationships)

► Show Figures