Physicochemical properties, immunostimulatory activity of the Lachnum polysaccharide and polysaccharide-dipeptide conjugates

An inulin-type polysaccharide from Atractylodis Macrocephalae Rhizoma can relieve psoriasis

Atractylodis Macrocephalae Rhizoma (AMR), an herb often found in compounded remedies for psoriasis, is rich in polysaccharides. However, the beneficial effects of AMR polysaccharides on psoriasis remain obscure. In this study, an inulin-type fructan-labelled AMP was extracted from the AMR. AMP has a molecular weight of 5.84 kDa and comprises fructose, glucose, and arabinose at a molar ratio of 93:5:2. Methylation and NMR analyses revealed that AMP comprises a linear backbone of 2,6-linked Fruf or 1,2-linked Fruf with branching 1,2,6-linked Fruf and terminates in T-Glcp. Animal studies verified that AMP can improve imiquimod-induced psoriasis-like skin lesions and downregulate the Il-17a, Il-23, Il-22, Il-6, Il-12, and Tnf-α gene expression. Furthermore, we elucidated the underlying mechanisms using cellular experiments. The ability of AMP to inhibit hyperproliferation and the overexpression of TNF-α, IL-6, and IL-23 genes in human immortal keratinocyte cells (HaCaT) stimulated by lipopolysaccharide was demonstrated. These results indicate that AMP may directly target keratinocytes to suppress excessive proliferation and contribute to anti-inflammatory responses, potentially by blocking the activation of the PI3K/AKT/mTOR pathway. In summary, AMP has demonstrated potential as a prospective treatment strategy for psoriasis.

Dictyophora indusiata polysaccharide attenuated LPS-induced intestinal inflammation of mice via the TLR4/JNK signaling pathway

BACKGROUND

Dictyophora indusiata polysaccharide is an important bioactive component of D. indusiata, playing an important role in alleviating inflammation. The present study aimed to investigate the anti-inflammatory effect and mechanism of D. indusiata polysaccharide on lipopolysaccharide (LPS)-induced intestinal inflammation in mice.

RESULTS

Our results indicated that D. indusiata polysaccharide ameliorated intestinal inflammation of mice by increasing the body weight, the number of goblet cells and decreasing inflammatory cell infiltration. In addition, D. indusiata polysaccharide significantly up-regulated expression of ZO-1, Occuldin mRNA, which were 2.55-fold and 2.28-fold higher than the LPS group, respectively. In particular, D. indusiata polysaccharide effectively inhibited the Toll-like receptor 4 (TLR4)/ c-Jun NH2-terminal kinase (JNK) signalling pathway which was 0.34-fold and 0.49-fold of gene expression and 0.41-fold and 0.39-fold of protein expression in the LPS group, respectively.

CONCLUSION

The results of the present study suggested that D. indusiata polysaccharide exerted anti-inflammatory and intestinal protective effects by inhibiting the TLR4/JNK signaling pathway, which will provide a basis for the potential value of D. indusiata polysaccharide as prebiotics in food applications. © 2024 Society of Chemical Industry.

Protective Effects of Polysaccharide of Atractylodes Macrocephala Koidz against Porcine Aortic Valve Endothelial Cells Damage Induced by di (2-ethylhexyl) Phthalate

The activation, injury, and dysfunction of endothelial cells are considered to be the initial key events in the development of atherosclerosis. Di (2-ethylhexyl) phthalate (DEHP), a prevalent organic pollutant, can cause damage to multiple organs. Polysaccharide of Atractylodes macrocephala Koidz (PAMK) is a bioactive compound extracted from A. macrocephala Koidz with various biological activities. This study investigates the protective effects of PAMK on porcine aortic valve endothelial cells (PAVEC) damaged by DEHP. PAVECs treated with DEHP alone or with PAMK showed reduced cell apoptosis and death in PAMK-pretreated cells. PAMK up-regulated Bcl-2 expression and down-regulated Bax protein, suppressing apoptosis. Flow cytometry analysis demonstrated that PAMK protected PAVECs from DEHP-induced damage. These findings suggest that PAMK inhibits cell apoptosis and protects against DEHP damage in endothelial cells.

Ultrasonic-Assisted Extraction, Structural Characteristics, and Antioxidant Activities of Polysaccharides from Alpinia officinarum Hance

Alpinia officinarum Hance, a well known agricultural product in the Lei Zhou peninsula, is generally rich in polysaccharides. In order to enhance the use of A. officinarum Hance polysaccharides (AOP) in functional food, AOP was extracted using an ultrasonic-assisted extraction method, and the ultrasonic extraction parameters of AOP was optimized. Furthermore, this study investigated the physicochemical and antioxidant activities of AOPs. In addition, the structural properties were preliminarily determined using Fourier-transform infrared spectroscopy (FTIR), high performance size exclusion chromatography, and a Zetasizer. Ultimately, this study explored the mechanism underlying the antioxidant activities of AOP. The results showed that the optimal ultrasonic-assisted extraction parameters were as follows: ultrasonic time, 6 min; ratio of water to material, 12 mL/g; and ultrasonic power, 380 W. Under these conditions, the maximum yield of AOPs was 5.72%, indicating that ultrasonic-assisted extraction technology is suitable for extracting AOPs due to the reduced time and water usage. Additionally, AOPs were purified using graded alcohol precipitation, resulting in three fractions (AOP30, AOP50, and AOP70). AOP30 had the lowest molecular weight of 11.07 kDa and mainly consisted of glucose (89.88%). The half inhibitory concentration (IC50) value of AOP30 and AOP70 was lower than that of AOP50 in the ability to scavenge the ABTS radical, while a reverse trend was observed in reducing ferric ions. Notably, the antioxidant activities of AOPs were highly correlated with their polydispersity index (Mw/Mn) and Zeta potential. AOP30, a negatively charged acidic polysaccharide fraction, exhibited electron donating capacities. Additionally, it displayed strong antioxidant abilities through scavenging 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals and reducing ferric ions. In conclusion, the present study suggests that AOP30 could be developed as an antioxidant ingredient for the food industry.

Regulation on Pathway Metabolic Fluxes to Enhance Colanic Acid Production in Escherichia coli

Colanic acid (CA) is a natural polysaccharide macromolecule with rich and unique biological properties and is a promising candidate for use in food and cosmetics. To date, the efficient biosynthesis of CA and the influence of product accumulation on the strains used have yet to be precisely investigated. Herein, bottlenecks in the CA metabolic pathway were untangled by finely regulating the expression of manA, cpsG, fcl, and rcsA. Engineered strains produced CA at >1 g/L in shake flasks without dependence on cold temperatures, and it was verified in a 1 L bioreactor with a titer up to 18.64 g/L within 24 h. The accumulation of CA caused a decrease in the saturated fatty acid content (represented by C16:0 and C18:0) in the cell membrane. This study demonstrated pathway engineering for efficient CA production in cell factories and provided insights into the barriers and solutions faced in the biosynthesis of natural products.

Gastroprotective effect of the Lachnum polysaccharide and polysaccharide-dipeptide conjugates against gastric ulcer

Polysaccharides from Lachnum have many important biological activities. The LEP2a-dipeptide derivative (LAG) was obtained by carboxymethyl modification and alanyl-glutamine modification of LEP2a, an extracellular polysaccharide component of Lachnum. Mice with acute gastric ulcers were treated with 50 (low doses) and 150 (high doses) mg/kg, and their therapeutic effects were evaluated from the aspects of pathological damage to gastric tissue, oxidative stress response and inflammatory signal cascade reaction. High doses of LAG and LEP2a significantly inhibited pathological damage to the gastric mucosa, increased the activities of SOD and GSH-Px, and decreased the levels of MDA, and MPO. LEP-2A and LAG could also inhibit the production of proinflammatory factors and reduce the inflammatory response. They significantly decreased the levels of IL-6, IL-1β and TNF-α, while upregulated the level of PGE2 at high doses. LAG and LEP2a inhibited the protein expression of p-JNK, p-ERK, p-P38, p-IKK, p-IKB α and p-NF-KBP65. LAG and LEP2a protect the gastric mucosa in mice with ulcers by improving oxidative stress, blocking the MAPK/NF-κB pathway and inhibiting the production of inflammatory factors, and the anti-ulcer activity of LAG is superior to that of LEP2a.

Physicochemical properties and protective effects on UVA-induced photoaging in Hs68 cells of Pleurotus ostreatus polysaccharides by fractional precipitation

The development of natural ingredients protecting skin from UVA-induced photoaging is widely expected. The present study investigated the physicochemical properties, antioxidant, moisturizing, collagenase and elastase inhibitory activities, and protective effect on UVA-induced photoaging in Hs68 cells of Pleurotus ostreatus polysaccharides (POPs). POP-40, POP-60, and POP-80 were extracted by gradient precipitation of 40 %, 60 %, and 80 % ethanol, which could be prepared in large quantities. The results showed that POPs had good DPPH and ABTS radical scavenging abilities, water retention capacity, and collagenase and elastase inhibition effects. POP-80 had the best efficacy. Further determined the anti-inflammatory and antisenescence activities of POPs in Hs68 cells. The results indicated that after UVA irradiation, the contents of ROS, senescent cells, NF-κB activity, and proinflammatory cytokines increased in Hs68 cells. However, cells pretreated with 50 μg/mL POPs significantly decreased the contents of ROS and the number of senescent cells, reduced NF-κB activity, and inhibited IL-6 and TNF-α production. There was no significant difference in reducing the accumulation of ROS and senescent cells between POP-80 and the common anti-inflammatory substance quercetin. The results suggested that POP-80 may be potential cosmeceutical ingredients as it can protect Hs68 cells from photodamage.

Acetyl-glucomannan from Dendrobium officinale: Structural modification and immunomodulatory activities

To understand the mechanisms of immunomodulatory effect, Dendrobium Officinale polysaccharides (DOP) were treated by ultrasound and mild base separately to generate fractions of various weight-average molecular weight (Mw) and degrees of acetylation (DA). The structural features, conformational properties, functional properties and immunomodulatory activities of original and modified DOPs were investigated. Ultrasonic treatment decreased the Mw and apparent viscosity and improved the water solubility of DOP. Mild base treatment remarkably reduced the DA and the water solubility, while the overall apparent viscosity was increased. Conformational analysis by triple-detector high performance size-exclusion chromatography showed that the molecular chain of DOP turned more compact coil conformation with decreased DA. Results from the macrophages RAW 264.7 analysis showed that samples sonicated for 200 min (Mw 34.2 kDa) showed the highest immune-regulation effects. However, the immunomodulatory effects of the samples after de-acetylation were all compromised compared to the original DOP. This study inspires further research to establish the structural-immunomodulatory relationships, which promote the application of DOP in both the food and medicine fields.

Structure and bioactivity of polysaccharide from a subseafloor strain of Schizophyllum commune 20R-7-F01

Fungal polysaccharide is a kind of biomacromolecule with multiple biological activities, which has a wide application prospect and may play an important role in organisms to cope with extreme environments. Herein, we reported an extracellular polysaccharide (EPS) produced by Schizophyllum commune 20R-7-F01 that was isolated from subseafloor sediments at ~2 km below the seafloor, obtained during expedition 337. The monosaccharide of EPS was glucose and its molecular weight was 608.8 kDa. Methylation and NMR analysis indicated that the backbone of the EPS was (1 → 3)-β-D-glucan with a side chain (1 → 6) β-D-glucan linking at every third residue. Bio-active assays revealed that the EPS had potent antioxidant activity and could promote RAW264.7 cells viability and phagocytosis. These results suggest that fungi derived from sediments below seafloor are important and new source of polysaccharides and may be involved in the adaptation of fungi to anoxic subseafloor extreme ecosystem.

Polysaccharides from Hericium erinaceus Fruiting Bodies: Structural Characterization, Immunomodulatory Activity and Mechanism

Five fractions from crude Hericium erinaceus polysaccharides (HEPs), including HEP-1, HEP-2, HEP-3, HEP-4 and HEP-5, were obtained through column chromatography with a DEAE Cellulose-52 column and Sephadex G-100 column. The contents of total carbohydrates and uronic acid in HEPs were 53.36% and 32.56%, respectively. HEPs were mainly composed of Fuc, Gal and Glu in a molar ratio of 7.9:68.4:23.7. Its chemical structure was characterized by sugar and methylation analysis, along with ¹H and ¹³C NMR spectroscopy. HEP-1 contains the backbone composed of (1→6)-linked-galactose with branches attached to O-2 of some glucose. The immunological activity assay indicated that HEP-1 significantly promoted the production of nitric oxide, interleukin-6, interleukin-10, interferon-γ and tumor necrosis factor-α and the phosphorylation of signaling molecules. Collectively, these results suggested that HEP-1 could improve immunity via NF-κB, MAPK and PI3K/Akt pathways. Hericium erinaceus polysaccharides might be explored as an immunomodulatory agent for use in dietary supplements.

Exopolymer-Functionalized Nanoselenium from Bacillus subtilis SR41: Characterization, Monosaccharide Analysis and Free Radical Scavenging Ability

To provide a safe and effective supplement of the essential trace element selenium, we focused on the biosynthesis of nanoselenium (SeNPs) via probiotics. A novel kind of exopolymer-functionalized nanoselenium (SeEPS), whose average size was 67.0 ± 0.6 nm, was produced by Bacillus subtilis SR41, whereas the control consisted of exopolymers without selenium (EPS). Chemical composition analysis, Fourier transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC) confirmed that SeEPS and EPS shared similar polysaccharide characteristic groups, such as COO- and C=O, and contained not only 45.2–45.4% of sugars but also 23.5–24.7% of proteins and some lipids. Both SeEPS and EPS were primarily composed of mannose, amino glucose, ribose, glucose and galactose. Furthermore, to identify the biologically active component of SeEPS, three kinds of selenium particles with different stabilizers [Se(0), bovine serum albumin-Se and EPS-Se] were synthesized chemically, and their ability to scavenge free radicals in vitro was compared with that of SeEPS and EPS. The results revealed that EPS itself exhibited weak superoxide and hydroxyl radical scavenging abilities. Nevertheless, SeEPS had superior antioxidant properties compared to all other products, possibly due to the specific structure of SeNPs and exopolymers. Our results suggested that exopolymer-functionalized SeNPs with specific monosaccharide composition and structure could eventually find a potential application as an antioxidant.

Extraction, Purification, Physicochemical Properties, and Activity of a New Polysaccharide From Cordyceps cicadae

The polysaccharides from C. cicadae were extracted by ultrasonically-assisted enzymatic extraction (UAEE). Response surface analysis was used to determine the optimum parameters as follows: addition of enzymes, 0.71%; extraction temperature, 60°C; extraction time, 18 min; liquid-solid ratio, 46:1 (mL/g). The extraction yield of polysaccharide was 3.66 ± 0.87%. A novel polysaccharide fraction (JCH-a1) from C. cicadae was extracted and then purified by cellulose DEAE-32 and Sephadex G-100 anion exchange chromatography. The analysis results showed that the molar ratio of galactose, glucose, and mannose in JCH-a1 cells (60.7 kDa) was 0.89:1:0.39. JCH-a1 with a triple helix contains more α-glycosides and has strong thermal stability. Moreover, JCH-a1 showed strong antioxidant activity and acted as a strong inhibitor of α-glucosidase in vitro. In addition, JCH-a1 can prolong the lifespan of C. elegans. The present study might provide a basis for further study of JCH-a1 as an antioxidant and hypoglycemic food or drug.

Comparison of structural and antioxidant activity of polysaccharide extracted from truffles

As the main component of truffles, polysaccharides have a variety of biological activities such as anti-oxidation, anti-tumor, and hypoglycemic activity, and these activities are closely related to its structure. In this study, Tuber Aestivum crude polysaccharide (TACP) and Tuber Melanosporum crude polysaccharide (TMCP) were obtained from Tuber Aestivum and Tuber Melanosporum by using microwave-assisted hot water, and then the Sephadex G-200 column was utilized to further separate and purify Tuber Aestivum polysaccharide (TAP) and Tuber Melanosporum polysaccharide (TMP) from TACP and TMCP. The structural characterization results showed that the molecular weight of TAP was 2.18 × 10⁴  kDa, while TMP was 8.79 × 10³  kDa. Although the two polysaccharide components were mainly composed of mannose (Man) and glucose (Glc), the molar ratio of Man and Glc in TAP was 14.76: 12.31, with a molar ratio of 5.43:10.94 in TMP. Furthermore, the antioxidant activity of two polysaccharide components was evaluated. TAP and TMP could protect porcine jejunal epithelial (IPEC-J2) cells from oxidative damage by H₂ O₂ , but TAP exhibited stronger antioxidant effects. It was mainly reflected that TAP could increase the secretion level of intracellular antioxidant enzymes (superoxide dismutase and catalase) in IPEC-J2 cells, and had a significant effect on the total antioxidant capacity of cells. The reactive oxygen species and malondialdehyde had better scavenging ability at the concentration of 20 µg/ml. The difference between TAP and TMP may be due to the dissimilar structure. Its structure-activity relationship needs further study. PRACTICAL APPLICATION: The structure of TAP and TMP were different, and TAP had higher molecular weight. Besides, TAP and TMP can protect IPEC-J2 cells from oxidative stress, providing a theoretical basis for developing potential antioxidant drugs of practical significance.

Physicochemical properties, immunostimulatory and antioxidant activities of a novel polysaccharide isolated from Mirabilis himalaica (Edgew) Heim

Herbal medicines often contain bioactive polysaccharides. However, many medicinal herbs have not been explored for any active saccharides that may play key roles in their bioactivities. Herein, we extracted a novel polysaccharide from Mirabilis himalaica (Edgew) heim (denoted MHHP), a popular medicinal ingredient in traditional medicines. The structural and morphological characteristics of MHHP were measured and elucidated by high-performance gel permeation chromatography, gas chromatography connected with mass spectrometry, Fourier transform infrared and nuclear magnetic resonance spectroscopy as well as scanning electron microscopy. MHHP was homogeneous with a molecular weight of 16.1 kDa, M _w/M _n = 1.33, containing mainly α-d-glucan residues with (1→4)-linkage. The biological activities of MHHP upon proliferation of splenic lymphocyte, activation of related cytokine and production of nitric oxide (NO) in RAW264.7 cells were investigated in vitro. MHHP induced proliferation of mouse spleen lymphocytes and significantly promoted the secretion in TNF-α, IL-6 and NO production in RAW264.7 cells. Meanwhile, MHHP exhibited relatively low antioxidant abilities. Our data suggested that MHHP may have potential immunoregulatory and anti-inflammatory activity, with a moderate antioxidant activity.

Structure characterization and bioactivity of neutral polysaccharides from different sources of Polygonatum Mill

Polygonati rhizoma (PR), a traditional medical and edible product, is rich in polysaccharides and exhibits physiological activity, including antioxidant, hypoglycemic and hypolipidemic properties. Neutral polysaccharides have been reported to be one of the main active ingredients of Polygonatum, with many of these fractions being responsible for the biological activity. This behavior was shown to be closely connected to the chemical structure, monosaccharide composition, and glycosidic bond type. There are few reports on the chemical constituents of the neutral polysaccharides from different sources of PR. In this study, neutral polysaccharides of PR from four different regions of China (Chun'an (Zhejiang), Xixia (Henan), Danfeng (Shanxi), and Pan'an (Zhejiang)), named CAZJ, XXHN, DFSX, and PAZJ, respectively, were isolated by anion-exchange and gel-permeation chromatography. Structures of the four polysaccharides were investigated. The results showed that all of them were mainly glucose and mannose, while the monosaccharide composition and content of polysaccharides from different sources varied. The molecular weights of CAZJ, XXHN, DFSX, and PAZJ were 14.119, 22.352, 18.127, and 15.699 kDa, respectively. Infrared spectra illustrated the existence of α-glycosidic bond and β-glycosidic bond in the polysaccharides. CAZJ, XXHN, and DFSX possessed a pyranose ring structure, whereas PAZJ had a furanose ring structure. Congo red test indicated that XXHN, DFSX, and PAZJ had a triple-helix structure. X-ray diffraction showed that the polysaccharides consisted of crystalline and amorphous regions. All four polysaccharides exhibited different degrees of antioxidant and hypoglycemic activities with a dose-dependent manner in the 1.0-10.0 mg/mL concentration range. Correlation analysis revealed that the bioactivities of polysaccharides was significantly related to monosaccharide composition, uronic acid, and protein content. The results suggested that neutral polysaccharides could be used as potential natural antioxidants and hypoglycemic agents for functional and nutraceutical applications.

Structural characteristics, anti-proliferative and immunomodulatory activities of a purified polysaccharide from Lactarius volemus Fr

Lactarius volemus Fr. is an edible mushroom widely consumed in China. Polysaccharide is an important nutritional component of L. volemus. This research aimed to isolate the polysaccharide from L. volemus and study its structure and bioactivities. A purified polysaccharide was identified and named as LVF-I whose primary structure was proposed considering the comprehensive results of monosaccharide composition, periodate oxidation-smith degradation, methylation analysis, FT-IR and 1D/2D NMR spectroscopy. Then the immunomodulation of LVF-I and its inhibition effect on H1299 and MCF-7 cells were investigated. Results showed that LVF-I (12,894 Da) contained fucose, mannose, glucose and galactose. It had a backbone consisting of →4)-α-D-Glcp-(1→, →6)-β-D-Manp-(1→, →6)-α-D-Galp-(1 → and →4)-β-D-Manp-(1→. And its side chains were branched at C2 of →4)-β-D-Manp-(1 → by →6)-α-D-Galp-(1→, α-D-Glcp-(1→, α-D-Galp-(1 → and α-L-Fucp-(1→. LVF-I (250-1000 μg/mL) could inhibit the proliferation of H1299 and MCF-7 cells, while enhance the proliferative response of splenocyte and the phagocytic ability of RAW264.7. Furthermore, LVF-I (250-1000 μg/mL) significantly induced the secretion of nitric oxide, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) by up-regulating their mRNA expression in macrophages. These results suggested that LVF-I had the potential to be developed as antitumor or immunomodulatory agents by inhibiting the proliferation of tumor cells and stimulating macrophages-mediated immune responses.

The chemical structure and immunomodulatory activity of an exopolysaccharide produced by Morchella esculenta under submerged fermentation

The extracellular polysaccharide of Morchella esculenta cultivated under submerged fermentation was extracted. A single polysaccharide was purified through DEAE-Cellulose 52 and Sephadex G 100, and named as MEP 2a. The molecular weight of MEP 2a was determined by HPGPC and it is about 1391.5 kDa. MEP 2a is composed of mannose and glucose as the monosaccharide unit with a molar ratio of 8.15 : 1.07. The main polysaccharide chemical structure was analyzed by 1D and 2D NMR. Methylation and NMR analysis revealed that the backbone of MEP 2a consists of 1,3,4-linked-Manp, 1,2-linked-Manp and 1,6-linked-Glcp. 1D and 2D NMR results indicated that the main chain is based on →1)-β-D-Glcp-(6→, →1)-α-D-Manp-(3,4→, →1)-α-D-Manp-(2→) and the branch chain is composed of α-D-Manp-(1→, →1)-β-D-Glcp-(6→ and α-D-Glcp-(1→). MEP 2a promoted the phagocytosis function and secretion of NO, IL-1β, IL-6 and TNF-α of macrophages. In the present study, the chemical structure and immunomodulatory ability of an extracellular polysaccharide of Morchella esculenta was investigated which guarantees further research studies and promising applications.

Modifications of polysaccharide-based biomaterials under structure-property relationship for biomedical applications

Polysaccharides are well accepted biomaterials that have attracted considerable attention. Compared with other materials under research, polysaccharides show unique advantages: they are available in nature and are normally easily acquired, those acquired from nature show favorable immunogenicity, and are biodegradable and bioavailable. The bioactivity and possible applications are based on their chemical structure; however, naturally acquired polysaccharides sometimes have unwanted flaws that limit further applications. For this reason, carefully summarizing the possible modifications of polysaccharides to improve them is crucial. Structural modifications can not only provide polysaccharides with additional functional groups but also change their physicochemical properties. This review based on the structure-property relation summarizes the common chemical modifications of polysaccharides, the related bioactivity changes, possible functionalization methods, and major possible biomedical applications based on modified polysaccharides.

Effect of steam explosion pretreatment on the structure and bioactivity of Ampelopsis grossedentata polysaccharides

Steam explosion (SE) was a friendly environmentally pretreatment method. In this study, the effect of steam explosion (SE) pretreatment on structure and α-glucosidase inhibitory activity of Ampelopsis grossedentata polysaccharides was evaluated. Two novel polysaccharides (AGP and AGP-SE) were extracted, isolated, purified and analyzed by NMR, FT-IR and methylation. The results indicated that AGP mainly consisted of Rha, Xyl, Glc, and Ara with a molecular weight of 2.74 × 10³ kDa and AGP-SE mainly consisted of Man, Ara, and Gal with a molecular weight of 2.14 × 10³ kDa. Furthermore, the backbone of AGP and AGP-SE were mainly composed of 5)-Araf-(1→, -Glcp-(1→, 6)-Glcp-(1→, 6)-Galp-(1→, 3,6)-Manp-(1→, and 2,3,6)-Glcp-(1→. Finally, we demonstrated that all polysaccharides exhibited obviously α-glucosidase inhibition activity and mixed type inhibition. AGP-SE had better α-glucosidase inhibition activity and the binding affinity KD on α-glucosidase by using Surface Plasmon Resonance (SPR) than AGP. Overall, SE pretreatment is an effective method for extracting polysaccharide and provides a new idea into the improvement of biological activity.

Chemical structure and antioxidant activity of a polysaccharide from Siraitia grosvenorii

A novel polysaccharide from Siraitia grosvenorii residues (SGP, molecular weight 1.93 × 10³ KDa) was isolated and purified. SGP was composed of α-L-Arabinose, α-D-Mannose, α-d-Glucose, α-D-Galactose, Glucuronic acid, and Galacturonic acid with the ratio of 1: 1.92: 3.98: 7.63: 1.85: 7.34. The backbone of SGP was consist of galactoses and linked by α-(1,4)-glycosidic bond. The branch chains including α-1,6 linked glucose branch, α-1,6 linked mannose branch, α-1,3 linked galactose branch and arabinose branched (α-L-Ara(1→). The results of bioactivity experiments suggested that SGP had antioxidant in vitro, especially on scavenging DPPH radicals. Besides, SGP resulted in the decrease of ROS and the percentage of apoptotic and necrotic cells in a dose-dependent manner in H₂O₂ oxide injury PC12 cells. This research could help to develop the potential value and utilization of Siraitia grosvenorii.

Purification, structural elucidation and in vivo immunity-enhancing activity of polysaccharides from quinoa (Chenopodium quinoa Willd.) seeds

Quinoa crude polysaccharides (QPS) were extracted from Chenopodium quinoa Willd. The soluble non-starch polysaccharide fraction (QPS1) was subsequently purified by DEAE-52 cellulose and Sephadex G-50 gel chromatography, using QPS as raw materials. Its chemical structure was identified using FT-IR, NMR, AFM, SEM and Congo red staining. High performance gel permeation chromatography (HPGPC) was used to determine molecular weight, and composition by HPLC. QPS1, with a molecular weight of 34.0 kDa, was mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose at a molar ratio of 2.63:2.40:1.64:6.28:1.95:2.48:5.01. In addition, we evaluated the ameliorative effects of QPS1 on the improvement of anti-cyclophosphamide (CTX)-induced immunosuppression in ICR mice. The result exhibited significantly immune-enhancing activity: QPS1 successfully improved the content of IFN-γ, IL-6, IFN-ɑ, IgM and lysozyme (LYSO) in serum for three weeks, enhanced the phagocytic function of mononuclear macrophages and ameliorated delayed allergy in mice.

Characterization of polysaccharides isolated from Hericium erinaceus and their protective effects on the DON-induced oxidative stress

In this study, the structure characteristic of the Hericium erinaceus polysaccharide (HEP) was investigated using Fourier transformed infrared spectrometry (FT-IR), gas chromatography-mass spectrometry (GC-MS), gel permeation chromatography (GPC), methylation and nuclear magnetic resonance (NMR). The results showed that HEP, with a molecular weight of 43 KDa, was mainly composed of glucose and rhamnose. The linkages of the sugar residues of HEP were → 6) β-d-Glcp-(1 → and → 2) -α-l-Rhap-(1 → residue at the end of the branches. The Fusarium toxin deoxynivalenol (DON)-induced cellular injury model for IPEC-J2 cells was established and used to investigate the protective effects of HEP against the oxidative stress. The results suggest that HEP could significantly protect IPEC-J2 cells from DON-induced oxidative stress, inhibit DON-induced apoptosis and reduce the production of reactive oxygen species (ROS). Overall, this study suggested that HEP could be explored as potential antioxidant agents for DON-induced intestinal mucosa injury.

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

Lachnum polysaccharide suppresses S180 sarcoma by boosting anti-tumor immune responses and skewing tumor-associated macrophages toward M1 phenotype

Therapeutic strategies that targeting tumor-associated macrophages (TAMs) reprogramming play a crucial role in ameliorating the immunosuppressive tumor microenvironment and boosting anti-tumor immune responses. In this study, we demonstrated that Lachnum polysaccharide (LEP) could work as an immunomodulator to reset TAMs from pro-tumor M2 to anti-tumor M1 phenotype. Mechanistically, LEP promoted Th1 polarization and the secretion of IFN-γ, which played a key role in M1 phenotype polarization. In parallel, LEP might directly activate M1 macrophages via TLR4 mediated NF-κB signaling pathway. Moreover, LEP also resulted in the accumulation of anti-tumor immune cells and decreased the infiltration of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and Treg cells, thereby potentiating anti-tumor immunity. In summary, these results revealed a novel mechanism of the anti-tumor effect of LEP and provided a potential new avenue targeting TAMs and cancer immunotherapy.

An alcohol-soluble polysaccharide from Atractylodes macrocephala Koidz induces apoptosis of Eca-109 cells

In this study, polysaccharides from Atractylodes macrocephala Koidz (APA) which were soluble in alcohol were prepared, purified, analyzed the structure and investigated the antitumor activity in vitro cell experiment. Results of high-performance gel permeation chromatography (HPGPC), fourier-transform infrared spectroscopy (FT-IR), and gas chromatography (GC) showed that APA was a 2.1KDa neutral hetero polysaccharide composed of arabinose and glucose (molar ratio, 1.00:4.57) with pyranose rings and α-type and β-type glycosidic linkages. Results by MTT experiments showed that the proliferation inhibition was 74.63% in Eca109 cells treated with 2 mg/mL dose of APA. Annexin V/PI assay, Hoechst 33,258 staining, cell cycle distribution, rhodamine 123 dye assay and western blot assay clarified that APA could accelerate the apoptosis of Eca109 cells by mitochondrial pathway and stocked cells at S phase. These data indicated that APA is a promising potential candidate for therapeutic treatment of esophageal cancer.

A novel polysaccharide obtained from Craterellus cornucopioides enhances immunomodulatory activity in immunosuppressive mice models via regulation of the TLR4-NF-κB pathway

The immunoregulatory effect of a novel Craterellus cornucopioides polysaccharide (CCP) with a triple-helix structure on immunosuppressive BALB/c mice models was investigated; moreover, the immune response of BALB/c mice models in the preventive and therapeutic treatment groups treated with CCP was explored, and its molecular mechanism was elucidated. It was found that the BALB/c mice models in the preventive groups treated with CCP (120 and 240 mg kg^-1 d^-1) had better immunoregulatory activity. The spleen and thymus weight indices of the BALB/c mice models were significantly increased, and the histopathological analysis indicated a protective function of CCP against the immunosuppression induced by cyclophosphamide (CTX). Moreover, CCP displayed definite and clear synergistic effects on the T- or B-lymphocyte proliferation induced by ConA or LPS, respectively, promoted the natural killer (NK) cell activity and significantly increased phagocytic activity to activate peritoneal macrophages in immunosuppressive mice. The western blot and quantitative real-time polymerase chain reaction (qRT-PCR) results provided comprehensive evidence that CCP could upregulate the protein expression of the G-protein-coupled cell membrane receptor TLR4 and the production of its downstream protein kinases (TRAF6, TK1, p-IKKα/β and NF-κB p50); this, in turn, enhanced the production of cytokines (IL-2, IL-6, TNF-α and IFN-α) through both preventive and therapeutic treatments via regulation of the TLR4-NFκB pathway in the peritoneal macrophage of immunosuppressive mice.

Deep in the Jelly: Histochemical and Functional Aspects of Mucilage-Secreting Floral Colleters in the Orchids Elleanthus brasiliensis and E. crinipes

Colleters are trichomes or emergencies that produce a sticky exudate consisting of a mixture of mucilage, lipids, terpenes, and phenolic compounds. Colleters occur in at least 60 families of angiosperms; however, reports of them are scarce for the Orchidaceae. Elleanthus brasiliensis is distinguished by the presence of an abundant gelatinous secretion that covers almost all of its inflorescences. We aimed to describe the histology of colleters in inflorescences of E. brasiliensis and Elleanthus crinipes, and to analyze the chemical composition of their secretion to better understand the functions of these secretory structures. Due to the low frequency of colleters and lack of visible secretion in E. crinipes, histochemical tests and chemical analyses were not performed for this species. Colleters are of a brush type and their secretion has, at the same time, hydrophilic and lipophilic components. Histochemical tests further revealed the presence of pectin, mucilage, lipids, terpenes, phenolic compounds, and proteins. The GC-MS analysis confirmed the presence of γ-sitosterol and palmitic, linoleic, and stearic acids in the secretion of E. brasiliensis. Infrared analysis indicated the possible presence of polysaccharides in the secretion. The occurrence of colleters in both species studied and in other orchids described in the literature suggests that these structures are common in the inflorescences of tropical orchids. In these environments, the hydrated polysaccharides in the secretion form a dense matrix that can act as a physical barrier, and terpenes may help to protect against herbivores and pathogenic microorganisms. This information broadens our knowledge of the morphological and chemical diversity of the secretions produced by orchid colleters.