Structural characterization and immunomodulatory activity of a new polysaccharide from jellyfish

Extraction, purification, structural characterization and pharmacological activities of polysaccharides from sea buckthorn (Hippophae rhamnoides L.): A review

ETHNOPHARMACOLOGICAL RELEVANCE

Sea buckthorn (Hippophae rhamnoides L.) is an edible fruit with a long history in China as a medicinal plant. The fruits of H. rhamnoides are rich in a variety of nutrients and pharmacological active compounds. As one of the most important active ingredients in sea buckthorn, polysaccharides have attracted the attention of researchers due to their antioxidant, anti-fatigue, and liver protective qualities.

AIM OF THE REVIEW

This review summarizes recent studies on extraction, purification, structural characterization and pharmacological activities of polysaccharides from sea buckthorn. In addition, the relationship between the structure and the activities of sea buckthorn polysaccharides (SBPS) were discussed. This review would provide important research bases and up-to-date information for the future in-depth development and application of sea buckthorn polysaccharides in the field of pharmaceuticals and functional foods.

MATERIALS AND METHODS

By inputting the search term "Sea buckthorn polysaccharides", relevant research information was obtained from databases such as Web of Science, Google Scholar, PubMed, China Knowledge Network (CNKI), China Master Theses Full-text Database, and China Doctoral Dissertations Full-text Database.

RESULTS

The main extraction methods of SBPS include hot water extraction (HWE), ultrasonic assisted extraction (UAE), microwave-assisted extraction (MAE), flash extraction (FE), and ethanol extraction. More than 20 polysaccharides have been isolated from sea buckthorn fruits. The chemical structures of sea buckthorn polysaccharides obtained by different extraction, isolation, and purification methods are diverse. Polysaccharides from sea buckthorn display a variety of pharmacological properties, including antioxidant, anti-fatigue, liver protection, anti-obesity, regulation of intestinal flora, immunoregulation, anti-tumor, anti-inflammatory, and hypoglycemic activities.

CONCLUSIONS

Sea buckthorn has a long medicinal history and characteristics of an ethnic medicine and food. Polysaccharides are one of the main active components of sea buckthorn, and they have received increasing attention from researchers. Sea buckthorn polysaccharides have remarkable pharmacological activities, health benefits, and broad application prospects. In addition, further exploration of the chemical structure of SBPS, in-depth study of their pharmacological activities, identification of their material basis, characterization of disease resistance mechanisms, and potential health functions are still directions of future research. With the accumulation of research on the extraction and purification processes, chemical structure, pharmacological effects, molecular mechanisms, and structure-activity relationships, sea buckthorn polysaccharides derived from natural resources will ultimately make significant contributions to human health.

Glucans from Armillaria luteo-virens: Structural Characterization and In Vivo Immunomodulatory Investigation under Different Administration Routes

Polysaccharides fromArmillaria luteo-virens (ALP) were investigated for structural characterization and immunomodulatory activities. Three fractions (ALP-1, ALP-2, and ALP-3) were obtained with the yield of 2.4, 3.7, and 3.0 wt %, respectively. ALP-1 was proposed as a β-(1 → 3)(1 → 6)-glucan with a triple-helix conformation; ALP-2 and ALP-3 were both identified as α-(1 → 4)(1 → 6)-glucan differing in their Mw and branching degree with a spherical conformation. The in vitro digestibility experiment and in vivo experiments using cyclophosphamide (CY)-treated mice demonstrated that intraperitoneal injection of α-glucan (1 mg·kg-1·day-1) and intragastric gavage of β-glucan (10 mg·kg-1·day-1) both effectively restored the decrease in body weight, immune organ indexes, immune cell activities, serum immune marker levels, colonic short-chain fatty acids (SCFA) levels, and Bacteroidetes/Firmicutes ratio in immunosuppression mice. This study provides novel insights into the immunomodulatory activity of α- and β-glucans under different administration routes, thereby promoting their application in both food and pharmaceutical areas.

Polysaccharide of Asparagus cochinchinensis (Lour.) Merr regulates macrophage immune response and epigenetic memory through TLR4-JNK/p38/ERK signaling pathway and histone modification

BACKGROUND

Innate immune memory of macrophages is closely linked to histone modifications. While various studies have demonstrated that the polysaccharide of Asparagus cochinchinensis (Lour.) Merr (ACMP), extracted through alcohol-alkali extraction, enhances macrophages' non-specific immune function; no literature currently addresses whether ACMP's regulatory effect is related to innate immune memory and histone modification.

PURPOSE

This study aims to investigate if ACMP induces innate immune memory emergence in macrophages via pattern recognition receptor (PRR).

STUDY DESIGN

After co-incubating different doses of ACMP with RAW264.7 cells and BMDM cells, we observed changes in signaling pathways related to PRR and assessed the presence of innate immune memory phenomenon in the cells.

METHODS

We observed the morphological characteristics of the ACMP using a scanning electron microscope, infrared spectrum, and HPLC pre-column derivatization method. We used q-PCR, Western blot, RNA-seq, and CUT&Tag-seq methods to examine ACMP's regulation of macrophage immune response and innate immune memory and explored its specific mechanism.

RESULTS

ACMP, primarily composed of Man, GlcN, Rha, Fuc, GalA, Xyl, Glc, Gal, Ara, and, exhibited a molar ratio of each monosaccharide (1.41: 0.35: 0.49: 0.18: 1.00: 97.12: 0.36: 3.58: 1.14). ACMP regulated immunological function in macrophages through the TLR4-MAPK-JNK/p38/ERK pathway. ACMP induced elevated levels of chromosomal H3K4me1, enhancing TNF-α, IL-1β, and other genes' responsiveness, allowing macrophages to develop innate immune memory to ACMP stimulation.

CONCLUSION

This study first time demonstrates that ACMP regulates immunological function through the TLR4-MAPK-JNK/ERK/p38 signaling pathway, distinct from prior reports. ACMP induces innate immune memory in macrophages in response to its immune stimulation by promoting increased H3K4me1 on chromosomes. This mechanism may be crucial in how plant polysaccharides regulate macrophages and the body's immune function.

Structural characterization of solvent-based food preparation of jellyfish

Jellyfish as a potential sustainable food material has recently gained increasing interest. However, with their soft gel-like texture and easy spoilage, it remains challenging to achieve desirable edible structures from jellyfish. The culinary preparation of jellyfish is a complex process and extends beyond conventional cooking methods. In this study, we investigate the transformation of jellyfish into crispy-like structures by manipulating their microstructural and mechanical properties through a solvent-based preparation. The study focuses on the use of "poor solvents", namely ethanol and acetone, and employs rheology measurements and quantitative microscopy techniques to analyze the effects of these solvents on the mechanical properties and microstructure of jellyfish. Our findings reveal that both ethanol and acetone lead to a significant increase in jellyfish hardness and deswelling. Notably, a micro-scale network is formed within the jellyfish matrix, and this network is then mechanically reinforced before a crispy-like texture can be obtained. Our study points to solvent polarity as also being a crucial factor for creating these effects and determines an upper polarity limit in the range of 12.2-12.9 MPa1/2 for added solvents, corresponding to approximately 60% of added ethanol or 70% of added acetone. Our study highlights that solvent-based preparation serves as a "reverse cooking" technique, where mechanical modification rather than traditional softening mechanisms are employed to stabilize and strengthen the microstructures and fibers of jellyfish. By elucidating the underlying mechanisms of solvent-induced stabilization, our findings may facilitate the development of innovative and sustainable culinary practices, paving the way for broader applications of jellyfish and other soft edible materials in the gastronomic landscape.

In Vitro Anti-Inflammatory Activity and Structural Characteristics of Polysaccharides Extracted from Lobonema smithii Jellyfish

Crude polysaccharides were extracted from the white jellyfish (Lobonema smithii) using water extraction and fractionated using ion-exchange chromatography to obtain three different fractions (JF1, JF2, and JF3). The chemical characteristics of four polysaccharides were investigated, along with their anti-inflammatory effect in LPS-stimulated RAW264.7 cells. All samples mainly consisted of neutral sugars with minor contents of proteins and sulphates in various proportions. Glucose, galactose, and mannose were the main constituents of the monosaccharides. The molecular weights of the crude polysaccharides and the JF1, JF2, and JF3 fractions were 865.0, 477.6, 524.1, and 293.0 kDa, respectively. All polysaccharides were able to decrease NO production, especially JF3, which showed inhibitory activity. JF3 effectively suppressed iNOS, COX-2, IL-1β, IL-6, and TNF-α expression, while IL-10 expression was induced. JF3 could inhibit phosphorylated ERK, JNK, p38, and NF-κB p65. Furthermore, flow cytometry showed the impact of JF3 on inhibiting CD11b and CD40 expression. These results suggest that JF3 could inhibit NF-κB and MAPK-related inflammatory pathways. The structural characterisation revealed that (1→3)-linked glucopyranosyl, (1→3,6)-linked galactopyranosyl, and (1→3,6)-linked glucopyranosyl residues comprised the main backbone of JF3. Therefore, L. smithii polysaccharides exhibit good anti-inflammatory activity and could thus be applied as an alternative therapeutic agent against inflammation.

Assessment of the Effects of Structural Modification of Gastrodia elata Polysaccharide on Anti-Breast Cancer Activity Using Asymmetrical Flow Field-Flow Fractionation

Gastrodia elata ("Tian Ma" in Chinese) is used as a food and medical ingredient in traditional Chinese medicine. In this study, to enhance the anti-breast cancer activity of Gastrodia elata polysaccharide (GEP), GEPs were modified via sulfidation (SGEP) and acetylation (AcGEP). The physicochemical properties (such as solubility and substitution degree) and structural information (such as molecular weight M_w and radius of gyration R_g) of GEP derivatives were determined by Fourier transformed infrared (FTIR) spectroscopy and asymmetrical flow field-flow fractionation (AF4) coupled online with multiangle light scattering (MALS) and differential refractive index (dRI) detectors (AF4-MALS-dRI). The effects of the structural modification of GEP on the proliferation, apoptosis, and cell cycle of MCF-7 cell were studied systematically. The ability of MCF-7 cell for the uptake of GEP was studied by laser scanning confocal microscopy (LSCM). The results suggested that the solubility and anti-breast cancer activity of GEP were enhanced and the average R_g and M_w of GEP decreased after chemical modification. The AF4-MALS-dRI results showed that the chemical modification process simultaneously caused the degradation and aggregation of GEPs. The LSCM results revealed that more SGEP can enter the MCF-7 cell interior compared with AcGEP. The results indicated that the structure of AcGEP could play a dominating role in antitumor activity. The data obtained in this work can be used as a starting point for investigating the structure-bioactivity of GEPs.

Polygonatum cyrtonema Hua Polysaccharide Alleviates Fatigue by Modulating Osteocalcin-Mediated Crosstalk between Bones and Muscles

Osteocalcin was reported to regulate muscle energy metabolism, thus fighting fatigue during exercise. The current work aimed to investigate the anti-fatigue effect and the underlying mechanism of a homogeneous polysaccharide (PCPY-1) from Polgonatum cyrtonema after structure characterization. In the exhaustive swimming mouse model and the co-culture system of BMSCs/C2C12 cells, PCPY-1 significantly stimulated BMSC differentiation into osteoblasts as determined by ALP activity, matrix mineralization, and the protein expressions of osteogenic markers BMP-2, phosphor-Smad1, RUNX2, and osteocalcin. Meanwhile, PCPY-1 remarkably enhanced myoblast energy metabolism by upregulating osteocalcin release and GPRC6A protein expression; the phosphorylation levels of CREB and HSL; the mRNA levels of GLUT4, CD36, FATP1, and CPT1B; and ATP production in vitro and in vivo. Accordingly, PCPY-1 exhibited good anti-fatigue capacity in mice as confirmed by fatigue-related indicators. Our findings indicated PCPY-1 could enhance osteocalcin-mediated communication between bones and muscles, which was conducive to muscle energy metabolism and ATP generation, thus alleviating fatigue in exhausted swimming mice.

Rhopilema esculentum polysaccharides enhance epithelial cell barrier in vitro and alleviate chronic colitis in mice

The purposes of this study were to characterize polysaccharides from Rhopilema esculentum and to explore their impacts on gut barrier function and inflammation in vitro and in mice with chronic colitis triggered by long-term administration of dextran sulfate sodium (DSS). Two polysaccharides were isolated and purified from Rhopilema esculentum, named REP-1 and REP-2. REP-1 with a molecular weight of 8.21 kDa was composed of mannose, glucosamine, galactosamine, glucose, galactose, and arabinose with a molar ratio of 0.04:0.03:0.38:1:1.36:0.06, and REP-2 with a molecular weight of 10.11 kDa mainly consisted of mannose, glucuronic acid, galactosamine, glucose, galactose, and arabinose with a molar ratio of 0.04:0.12:0.41:1:1.2:0.06. Compared to REP-1, REP-2 displayed better ability to up-regulate the expression of genes related to tight junctions and mucus in LPS-stimulated Caco-2 cells and better immunomodulatory activities in RAW264.7 macrophages. Then mice experiments showed that REP-2 efficiently attenuated the symptoms of colitis, decreased the secretion of pro-inflammatory cytokines, and restored intestinal barrier function in mice with chronic colitis. These results demonstrate that REP-2 might be a promising agent for protecting intestinal and mucus barrier and mitigating inflammation-associated intestinal diseases such as ulcerative colitis.

Jellyfishes—Significant Marine Resources with Potential in the Wound-Healing Process: A Review

The wound-healing process is a significant area of interest in the medical field, and it is influenced by both external and patient-specific factors. The aim of this review paper is to highlight the proven wound-healing potential of the biocompounds found in jellyfish (such as polysaccharide compounds, collagen, collagen peptides and amino acids). There are aspects of the wound-healing process that can benefit from polysaccharides (JSPs) and collagen-based materials, as these materials have been shown to limit exposure to bacteria and promote tissue regeneration. A second demonstrated benefit of jellyfish-derived biocompounds is their immunostimulatory effects on growth factors such as (TNF-α), (IFN-γ) and (TGF), which are involved in wound healing. A third benefit of collagens and polysaccharides (JSP) is their antioxidant action. Aspects related to chronic wound care are specifically addressed, and within this general theme, molecular pathways related to tissue regeneration are explored in depth. Only distinct varieties of jellyfish that are specifically enriched in the biocompounds involved in these pathways and live in European marine habitats are presented. The advantages of jellyfish collagens over mammalian collagens are highlighted by the fact that jellyfish collagens are not considered transmitters of diseases (spongiform encephalopathy) or various allergic reactions. Jellyfish collagen extracts stimulate an immune response in vivo without inducing allergic complications. More studies are needed to explore more varieties of jellyfish that can be exploited for their biocomponents, which may be useful in wound healing.

Dendrobium huoshanense stem polysaccharide ameliorates alcohol-induced gastric ulcer in rats through Nrf2-mediated strengthening of gastric mucosal barrier

This study aimed to explore whether Dendrobium huoshanense stem polysaccharide (cDHPS) ameliorates alcohol-induced gastric ulcer (GU) through the strengthening effect of the gastric mucosal barrier in rats and its potential mechanism. In normal rats, the pretreatment of cDHPS effectively strengthened gastric mucosal barrier by increasing mucus secretion and tight junction protein expression. In GU rats, cDHPS supplementation effectively alleviated alcohol-induced gastric mucosal injury and nuclear factor κB (NF-κB)-driven inflammation by strengthening gastric mucosal barrier. Moreover, cDHPS significantly activated nuclear factor E2-related factor 2 (Nrf2) signaling and promoted antioxidant enzymes activities in both normal and GU rats. These results suggested that the pretreatment of cDHPS could strengthen gastric mucosal barrier to inhibit oxidative stress and NF-κB-driven inflammation induced gastric mucosal injury, which was likely related to the activation of Nrf2 signaling.

Inulin-type fructans obtained from Atractylodis Macrocephalae by water/alkali extraction and immunoregulatory evaluation

Two homogenous polysaccharides extracted from Atractylodes macrocephala Koidz. were investigated by water extraction (AMP-F_W) and alkali solution extraction (AMP-F_A) after purification by anion exchange column and size exclusion chromatography. The molecular weight of AMP-F_W and AMP-F_A were 2874 Da and 3438 Da, respectively, estimated by high performance gel permeation chromatography (HPGPC). The monosaccharide compositions of AMP-F_W and AMP-F_A were glucose and fructose at a molar ratio of 0.11:0.89 determined by high performance anion exchange chromatography (HPAEC). The functional groups, glycosidic linkages and the chemical structure were characterized by FT-IR, GC-MS and NMR, which comprehensively indicated a similar inulin-type fructan structure of the two polysaccharides from A. macrocephala. However, the scanning electron microscopy (SEM) results showed different microstructures that irregular lamellar shape for the AMP-F_W and spheroid shape for the AMP-F_A. The further studies on immunomodulation showed that AMP-F_W at 50 μg/mL could significantly (P < 0.05) stimulate RAW 264.7 cells by enhancing the mRNA expression of TNF-α and IL-1β, which had a relative high immunomodulatory potential when compared to AMP-F_A. Their activation on different toll-like receptors (TLR) also indicated their different roles in the immunoregulation. Overall, these findings reported here will serve as the basis for further structure-activity relationship studies.

Gut microbiota mediates the anti-colitis effects of polysaccharides derived from Rhopilema esculentum Kishinouye in mice

Ulcerative colitis (UC) is closely associated with the disturbance of gut microbiota. Crude polysaccharide-rich extract from Rhopilema esculentum Kishinouye has been proven to alleviate dextran sulfate sodium (DSS)-triggered colitis. However, it remains unclear whether the polysaccharides from Rhopilema esculentum (REP) in the extract play a predominant role in ameliorating colitis and whether gut microbiota mediates the beneficial effect of REP. Herein, we aimed to investigate the anti-colitis effects of REP and its mechanisms and to explore the role of REP-modulated gut microbiota in alleviating colitis in mice. Oral REP supplementation ameliorated the symptoms, inflammatory responses, colonic damage and gut microbial dysbiosis in colitic mice. REP significantly enriched SCFA-producing bacteria such as Roseburia and probiotics such as Bifidobacterium and restored the level of SCFAs especially butyric acid and propionic acid. Next, we found that transplantation of microbiota from REP-treated mice alleviated DSS-induced acute colitis, evidenced by improved gut barrier integrity and lower inflammation compared with mice receiving microbiota from control mice. Notably, dramatically enriched Bifidobacterium, Faecalibaculum and SCFA-producing bacteria including Butyricicoccus and Roseburia were found in mice receiving microbiota from the REP-treated donor mice. Lastly, the protective effect of REP supplementation on colitis was abolished in the antibiotic-treated mice. Overall, our findings suggest that REP could alleviate DSS-induced colitis in mice by regulating the imbalance of the microbiome. The polysaccharides of Rhopilema esculentum Kishinouye have the potential to be developed into promising prebiotic agents for rectifying dysbiosis of gut microbiota and preventing UC.

Chemical Characterization and Immunomodulatory Activity of Fucoidan from Sargassum hemiphyllum

Fucoidan is a sulfated algal polyanionic polysaccharide that possesses many biological activities. In this paper, a fucoidan (SHF) polysaccharide was extracted from Sargassum hemiphyllum collected in the South China Sea. The SHF, with a molecular weight of 1166.48 kDa (44.06%, w/w), consisted of glucose (32.68%, w/w), galactose (24.81%, w/w), fucose (20.75%, w/w), xylose (6.98%, w/w), mannose (2.76%, w/w), other neutral monosaccharides, and three uronic acids, including glucuronic acid (5.39%, w/w), mannuronic acid (1.76%, w/w), and guronuronic acid (1.76%, w/w). The SHF exhibited excellent immunostimulatory activity. An immunostimulating assay showed that SHF could significantly increase NO secretion in macrophage RAW 264.7 cells via upregulation of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels based on both gene expression and protein abundance. These results suggest that SHF isolated from Sargassum hemiphyllum has great potential to act as a health-boosting ingredient in the pharmaceutical and functional-food fields.

Jellyfish Polysaccharides for Wound Healing Applications

Jellyfishes are considered a new potential resource in food, pharmaceutical and biomedical industries. In these latter cases, they are studied as source of active principles but are also exploited to produce marine collagen. In the present work, jellyfish skin polysaccharides (JSP) with glycosaminoglycan (GAG) features were extracted from Rhizostoma pulmo, a main blooming species of Mediterranean Sea, massively augmented by climate leaded “jellyfishication” of the sea. Two main fractions of R. pulmo JSP (RP-JSPs) were isolated and characterized, namely a neutral fraction (RP-JSP1) and a sulphate rich, negatively charged fraction (RP-JSP2). The two fractions have average molecular weights of 121 kDa and 590 kDa, respectively. Their sugar composition was evaluated through LC-MS analysis and the result confirmed the presence of typical GAG saccharides, such as glucose, galactose, glucosamine and galactosamine. Their use as promoters of wound healing was evaluated through in vitro scratch assay on murine fibroblast cell line (BALB/3T3 clone A31) and human keratinocytes (HaCaT). Both RP-JSPs demonstrated an effective confluency rate activity leading to 80% of scratch repair in two days, promoting both cell migration and proliferation. Additionally, RP-JSPs exerted a substantial protection from oxidative stress, resulting in improved viability of treated fibroblasts exposed to H₂O₂. The isolated GAG-like polysaccharides appear promising as functional component for biomedical skin treatments, as well as for future exploitation as pharmaceutical excipients.

Structure elucidation and antitumor activity of a water soluble polysaccharide from Hemicentrotus pulcherrimus

Sea urchin nowadays serves as a delicacy around the world, and its gonads accumulate abundant polysaccharides before gametogenesis. However, the structure and bioactivity of these polysaccharides remain less well understood. Herein, a water soluble polysaccharide (HPP-1S) with a molecular weight of 2.996 × 10⁷ Da was purified from the gonads of Hemicentrotus pulcherrimus. Chemical, spectroscopic and oligosaccharide sequencing analyses revealed that HPP-1S was a highly homogeneous polysaccharide featuring a linear backbone of 1,4-linked α-d-glucose with 1,6-α-d-glucose and 1,6-α-D-glucuronic acid side chains grafted on the backbone in an alternating pattern. In vitro, HPP-1S can arrest the cell cycle at G2/M and sub-G1 phases, and induce apoptosis in Hela cells potentially by increasing expression ratio of Bax/Bcl-2. In vivo, HPP-1S exhibited obvious antitumor efficacy in Hela xenograft-bearing nude mice with low toxicity. These findings indicated that HPP-1S might serve as a potential low toxic antitumor agent.

Jellyfish as Food: A Narrative Review

Studies toward a sustainable future conducted by international organizations uniformly agree about having to change some of our present consumer behaviors. Regarding food, suggestions include eating locally farmed, less industrialized and renewable food to promote health and circularity, and limiting waste. Jellyfish are frequently sorted and discarded after being caught with fish in fishing nets and gear. In contrast, we propose utilizing this by-catch as food. This review discusses the economic value and sustainability of jellyfish, the technologies used to prepare them for human consumption, their nutritional profile and health impacts and, finally, consumer acceptability and sensory evaluation of jellyfish food products. This discussion is critical for promoting jellyfish as an important aquatic resource to support blue and circular economies.

A new polysaccharide platform constructs self-adjuvant nanovaccines to enhance immune responses

Background

Nanovaccines have shown the promising potential in controlling and eradicating the threat of infectious diseases worldwide. There has been a great need in developing a versatile strategy to conveniently construct diverse types of nanovaccines and induce potent immune responses. To that end, it is critical for obtaining a potent self-adjuvant platform to assemble with different types of antigens into nanovaccines.

Results

In this study, we identified a new natural polysaccharide from the rhizomes of Bletilla striata (PRBS), and used this polysaccharide as a platform to construct diverse types of nanovaccines with potent self-adjuvant property. In the construction process of SARS-CoV-2 nanovaccine, PRBS molecules and RBD protein antigens were assembled into ~ 300 nm nanoparticles by hydrogen bond. For HIV nanovaccine, hydrophobic effect dominantly drove the co-assembly between PRBS molecules and Env expression plasmid into ~ 350 nm nanospheres. Importantly, PRBS can potently activate the behaviors and functions of multiple immune cells such as macrophages, B cells and dendritic cells. Depending on PRBS-mediated immune activation, these self-adjuvant nanovaccines can elicit significantly stronger antigen-specific antibody and cellular responses in vivo, in comparison with their corresponding traditional vaccine forms. Moreover, we also revealed the construction models of PRBS-based nanovaccines by analyzing multiple assembly parameters such as bond energy, bond length and interaction sites.

Conclusions

PRBS, a newly-identified natural polysaccharide which can co-assemble with different types of antigens and activate multiple critical immune cells, has presented a great potential as a versatile platform to develop potent self-adjuvant nanovaccines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01533-3.

Protective effects of three flavonoids from Dendrobium huoshanense flowers on alcohol-induced hepatocyte injury via activating Nrf2 and inhibiting NF-κB pathways

Dendrobium huoshanense flowers have been widely used for liver protection in China. This work was aimed to discover the natural products with activity of mitigating alcoholic hepatocyte injury from Dendrobium huoshanense flowers via bioactivity-guided isolation, and to clarify the underlying mechanisms of these natural products. As a result, three flavonoids, 3'-O-methylquercetin-3-O- β -D-galactopyranoside ( 1 ), 3'-O-methylquercetin-3-O- β -D-glucopyranoside ( 2 ) and quercetin-3-O- β -D-glucopyranoside ( 3 ), were firstly isolated from D. huoshanense flowers. Results exhibited that flavonoids 1-3 could enhance the cell viability, decrease the expression of ALT and AST, inhibit the cell apoptosis, alleviate the oxidative stress, and mitigate the inflammatory response of alcohol-induced L02 cells. Mechanism study exhibited that flavonoids 1 - 3 could increase the expression of Nrf2 as well as its downstream antioxidation genes of alcohol-induced L02 cells, while ML-385 (Nrf2 inhibitor) could abolish the inhibitory effects of 1 - 3 on alcohol-induced hepatocyte injury. Flavonoids 1 - 3 could also reduce the phosphorylation levels of I κ B α and NF- κ B p65 of alcohol-induced L02 cells, while SC75741 (NF- κ B inhibitor) could not enhance the inhibitory effects of 1 - 3 on alcohol-induced L02 cells injury. The data above indicated that flavonoids 1 - 3 could inhibit alcohol-induced hepatocyte injury, which might be attributed to alleviating oxidative stress and mitigating inflammatory response by activating Nrf2 and inhibiting NF- κ B pathways.

Structural characterization and immunoregulatory activity of a novel acidic polysaccharide from Scapharca subcrenata

A novel acidic polysaccharide named SSPA50-1 was isolated from Scapharca subcrenata using a simulated gastric fluid extraction method. SSPA50-1 is a heteropolysaccharide with an average molecular weight of 44.7 kDa that is composed of galacturonic acid, glucose, galactose, mannose, ribose, rhamnose, fucose, xylose and arabinose at a molar ratio of 1.00:5.40:9.04:3.10:1.59:4.01:2.10:2.21:2.28. The structural characterization based on the methylation and 1D/2D NMR analyses indicated that SSPA50-1 is composed of →3)-β-L-Rhap-(1→, →3)-β-L-2-O-Me-Fucp-(1→, →2)-α-D-Xylp-(1→, →5)-α-L-Araf-(1→, →3)-β-D-Galp-(1→, →6)-α-D-Glcp-(1→, →3,4)-β-D-Manp-(1→, →3,4)-β-D-Galp-(1→, β-D-Ribf-(1→, α-D-Glcp-(1→, and α-D-GalAp6Me-(1→. Furthermore, SSPA50-1 possessed potent immunoregulatory activity by enhancing the phagocytosis and NO, iNOS, TNF-α and IL-6 secretion capacity of RAW264.7 cells. Otherwise, SSPA50-1 significantly promoted the proliferation of splenic lymphocytes and RAW264.7 macrophages. These results indicated that SSPA50-1 could be developed as a potential ingredient for immunostimulatory agents.

Immunomodulatory activity of Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatwr seed polysaccharide fraction through the activation of the MAPK signaling pathway in RAW264.7 macrophages

Senegalia macrostachya (Reichenb. ex DC.) Kyal. & Boatwr seed (SMS) is a wild legume used as food and medicine in many African countries. In the current study, a novel polysaccharide (SMSP2) was extracted from SMS using hot water and purified with DEAE-52 cellulose. Its structure was characterized, and the immunomodulatory activity and possible molecular mechanism in murine macrophage RAW264.7 were explored. The results revealed that SMSP2 was a uronic acid-rich polysaccharide (51.6%, w/w) with a molecular weight of 52.07 kDa. The neutral sugars were mainly arabinose, xylose, mannose, and galactose at a molar ratio of 1.00 : 0.84 : 0.90 : 0.07. Interestingly, SMSP2 treatment markedly promoted macrophage proliferation and phagocytosis and induced the expression of inflammatory mediators, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-10. SMSP2-induced macrophage stimulation occurs through the activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Moreover, macrophage surface complement receptor 3 (CR3) might play an important role in SMSP2-induced macrophage activation. This study revealed that SMSP2 is a potent immunomodulator, which could be used as a functional food and a pharmaceutical adjuvant in treating immune-compromising diseases.

Structural characterization and tumor microvascular inhibition activity of total polysaccharide from Trametes sanguinea Lloyd

Trametes sanguinea Lloyd total polysaccharide (TsLTP), was obtained by water extraction and ethanol precipitation from T. sanguinea . The structural characterization of TsLTP was elucidated mutually by TsL1 and TsL2, whose mass ratio is 1 : 4. TsL1 is mainly composed of mannose, glucose, galactose, and fucose, and consist of T-Linked-Fuc p , T-Linked-Man p , T-Linked-Gal p , 1,4-Linked-Man p , 1,4-Linked-Glc p , 1,6-Linked-Man p , 1,6-Linked-Gal p , 1,3,4-Linked-Glc p , 1,4,6-Linked-Glc p and 1,3,6- Linked-Glc p , with a molar ratio of 2.1 : 1.7 : 1.4 : 1.0 : 3.6 : 2.0 : 8.6 : 1.3: 2.2: 1.2, while TsL2 mainly comprise of glucose and consist of T-Linked-Glc p , 1,3-Linked-Glc p , 1,4-Linked-Glc p and 1,4,6-Linked-Glc p , with a molar ratio of 1.0 : 2.1 : 7.6 : 1.4. TsLTP exhibited strong inhibitory effects on the migration, invasion, and tube formation of human umbilical vein endothelial cells (iHUVECs) and chick embryo chorioallantoic membrane (CAM) angiogenesis, whereas no inhibitory activity on human TNBC cell lines. Taken together, our study suggests that TsLTP possesses a significant inhibition of tumor microvascular activity both in vitro and in vivo . The study of TsLTP with novel monosaccharide composition and tumor microvascular inhibitory activity might be a beneficial attempt for application of polysaccharide from the genus Trametes in tumor therapy.

Anti-gastric cancer activity of cultivated Dendrobium huoshanense stem polysaccharide in tumor-bearing mice: Effects of molecular weight and O-acetyl group

The present study aimed at assuring whether homogeneous cultivated Dendrobium huoshanense stem polysaccharide (cDHPS) could inhibit gastric cancer in vivo, and whether its anti-gastric cancer activity could be affected by its molecular weight and O-acetyl group. Three different fractions (cDHPS-I, cDHPS-II and cDHPS-III) with decreased molecular weights and one fraction (cDHPS-IV) without O-acetyl group were prepared from cDHPS. Their structures were identified systematically. The backbone of cDHPS-I-III was the same as that of cDHPS, while their relative molecular weights displayed a decreasing order as follows: cDHPS > cDHPS-I > cDHPS-II > cDHPS-III. The backbone of cDHPS-IV was similar to those of cDHPS and cDHPS-I-III, but with the absence of O-acetyl groups. Animal experiments exhibited that cDHPS and cDHPS-I-IV could significantly inhibit tumor growth, induce tumor cell apoptosis, suppress tumor angiogenesis and enhance T cell immune response of murine forestomach carcinoma (MFC) tumor-bearing mice. Moreover, all the above effects of cDHPS and cDHPS-I-IV on MFC tumor-bearing mice exhibited a decreasing order as follows: cDHPS > cDHPS-I > cDHPS-II > cDHPS-III > cDHPS-IV. The results suggest that cDHPS could inhibit gastric cancer in vivo, and its anti-gastric cancer activity was closely linked with its molecular weight and O-acetyl group.

Structure features, selenylation modification, and improved anti-tumor activity of a polysaccharide from Eriobotrya japonica

A homogeneous polysaccharide, EJP90-1, was isolated from the leaves of E. japonica by hot water extraction in this study. EJP90-1 (7702 Da) was a heteropolysaccharide mainly consisting of →5)-linked-α-L-Araf-(1→, →4)-linked-β-D-Manp-(1→, →2,4)-linked-α-L-Rhap-(1→, →4)-linked-α-D-Xylp-(1→, →4)-linked-β-D-Galp-(1→, →2)-linked-β-D-Galp-(1→, →6)-linked-β-D-Glcp-(1→, α-D-Glcp-(4→, and t-linked-α-L-Araf. EJP90-1 was found to show moderate anti-tumor activity at the cellular level. In order to improve the anti-tumor activity and the potential applications of EJP90-1, a typical sodium selenite-nitric acid (Na₂SeO₃-HNO₃) modification on EJP90-1 was carried out. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometer (EDS) analysis confirmed that Se was successfully introduced into the polymer chain of EJP90-1. The subsequent in vitro cytotoxicity evaluation showed the selenylation modification derivative (EJP90-1-Se) possessed significant antiproliferative activity against cancer cells (HepG2 and A549 cells) through inducing cell apoptosis. The anti-tumor activity of EJP90-1-Se was further confirmed by zebrafish models, which inhibited the proliferation and migration of HepG2 cells and the angiogenesis.

Jellyfish skin polysaccharides enhance intestinal barrier function and modulate the gut microbiota in mice with DSS-induced colitis

Jellyfish skin polysaccharides (JSP) were isolated from Rhopilema esculentum Kishinouye and contained 55.11% polysaccharides and 2.26% uronic acid. To examine the anti-inflammatory, antioxidant and immunomodulatory activities of JSP in vivo, C57BL/6 mice were induced to develop ulcerative colitis by dextran sulfate sodium (DSS) and the roles of dietary JSP supplementation in modulating colitis were explored. JSP supplementation reduced the symptoms of colitis in mice, increased colon length, protected goblet cells, and improved intestinal epithelial integrity and permeability. JSP modulated oxidative stress and inflammatory responses, which was demonstrated by reduced MPO activity, NO level, and levels of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6 in mice. JSP suppressed NF-κB signaling pathways as evidenced by lower levels of phosphorylated p65 and IKB. Moreover, JSP supplementation enhanced the expression of tight junction proteins and mucins, and modulated the composition of the gut microbiota and the production of short-chain fatty acids. Taken together, these results reveal the anti-inflammatory effect of dietary JSP in vivo, suggesting the potential of JSP as a nutritional supplement or adjunct strategy in preventing or ameliorating colitis.

Biochemical Characterization of Cassiopea andromeda (Forsskål, 1775), Another Red Sea Jellyfish in the Western Mediterranean Sea

Increasing frequency of native jellyfish proliferations and massive appearance of non-indigenous jellyfish species recently concur to impact Mediterranean coastal ecosystems and human activities at sea. Nonetheless, jellyfish biomass may represent an exploitable novel resource to coastal communities, with reference to its potential use in the pharmaceutical, nutritional, and nutraceutical Blue Growth sectors. The zooxanthellate jellyfish Cassiopea andromeda, Forsskål, 1775 (Cnidaria, Rhizostomeae) entered the Levant Sea through the Suez Canal and spread towards the Western Mediterranean to reach Malta, Tunisia, and recently also the Italian coasts. Here we report on the biochemical characterization and antioxidant activity of C. andromeda specimens with a discussion on their relative biological activities. The biochemical characterization of the aqueous (PBS) and hydroalcoholic (80% ethanol) soluble components of C. andromeda were performed for whole jellyfish, as well as separately for umbrella and oral arms. The insoluble components were hydrolyzed by sequential enzymatic digestion with pepsin and collagenase. The composition and antioxidant activity of the insoluble and enzymatically digestible fractions were not affected by the pre-extraction types, resulting into collagen- and non-collagen-derived peptides with antioxidant activity. Both soluble compounds and hydrolyzed fractions were characterized for the content of proteins, phenolic compounds, and lipids. The presence of compounds coming from the endosymbiont zooxanthellae was also detected. The notable yield and the considerable antioxidant activity detected make this species worthy of further study for its potential biotechnological sustainable exploitation.

Structural characteristics and immunostimulatory activities of a new polysaccharide from Dendrobium fimbriatum Hook

A new polysaccharide (cDFP-W1) with high immunostimulatory activities was isolated from the stems of Dendrobium fimbriatum Hook. The analysis of the physicochemical properties showed that cDFP-W1 consisted of mannose and glucose in a molar ratio of 1 : 3.84, and its relative molecular weight was 4.0 × 10⁴ Da. Structural analysis implied that the linear backbone of cDFP-W1 was composed of α-1,4-d-Glcp, β-1,4-d-Manp, 3-O-acetyl-α-1,4-d-Glcp and α-1,4,6-d-Glcp, and its branches were the terminal β-d-Manp that was attached to the C-6 position of α-1,4,6-d-Glcp. An in vivo immunostimulatory assay exhibited that cDFP-W1 at 200 mg kg^-1 could significantly increase the proportions of CD4⁺ T-cell subpopulations, B cells, natural killer cells and dendritic cells, decrease the proportion of CD8⁺ T-cell subpopulations, and upregulate the percentage of activated macrophages (p < 0.01) in the spleen of mice. An in vitro immunostimulatory assay revealed that cDFP-W1 could effectively promote the proliferation of spleen lymphocytes, enhance the proliferation and phagocytosis of macrophage RAW264.7 cells, and stimulate the mRNA expression and extracellular release of NO, TNF-α and IL-1β of RAW264.7 cells. The western blot experiment suggested that the immunostimulatory activities of cDFP-W1 were closely related to the activation of MAPKs, NF-κB and PI3K/Akt signaling pathways.

Structure elucidation of arabinogalactoglucan isolated from Sedum sarmentosum Bunge and its inhibition on hepatocellular carcinoma cells in vitro

Sedum sarmentosum Bunge (SS) is clinically used as Chinese medicine for hepatitis related diseases treatment. The purpose of this study was to explore the chemical structures of polysaccharides from this plant. A neutral polysaccharide (SSWP) was isolated and purified by ion-exchange chromatography and Superdex-75 column. The obtained SSWP was a homogenous one with a molecular weight of 21.5 kDa according to the high-performance gel permeation chromatography. The major monosaccharide composition of SSWP was arabinose, glucose and galactose in a molar ratio of 2.4:1:1.8. The methylation analysis showed that SSWP consists mainly of Araf-(1→, →5)-Araf-(1→, →3,5)-Araf-(1→, →4)-Galp-(1→, →4)-Glcp-(1→. The NMR result and enzymatic digestion data comprehensively indicated that SSWP was a novel arabinogalactoglucan-type structure. The anticancer assay in vitro exhibited that SSWP could effectively inhibit 48.9% of Huh-7 cells growth at 50 μg/mL and arrest cells at S-phase, and induce tumor cells apoptosis. Together, polysaccharide from S. sarmentosum Bunge could be a potential natural antitumor agent.

Structural elucidation of three novel oligosaccharides from Kunlun Chrysanthemum flower tea and their bioactivities

Coreopsis tinctoria is commonly called Kunlun Chrysanthemum and a plateau plant with tremendous commercial value in functional tea and medicinal applications. In folk medicine, Kunlun Chrysanthemum flower is often used as an adjunctive therapy for diabetes and Alzheimer's disease. To further explore the chemicals responsible for the health benefits of Kunlun Chrysanthemum flowers, three homogeneous oligosaccharides, CT70-1A, CT70-1B and CT70-2 were isolated, and their detailed structures were determined from chemical and spectral analyses. The three oligosaccharides were composed of glucose, mannose, galactose, and arabinose in different ratios. They showed dose-dependent α-amylase and α-glucosidase inhibitory effects. In addition, they showed NO production inhibitory activities in BV2 cells, with IC₅₀ values of 0.23, 0.24 and 0.27 mM, respectively. Taken together, these results suggested that Kunlun Chrysanthemum oligosaccharides might ameliorate hyperglycemia and neuroinflammation, which could prevent the development of diseases such as type 2 diabetes and Alzheimer's disease. This study provides chemical and bioactive perspectives that support the consumption of Kunlun Chrysanthemum flower tea for health benefits.

Jellyfish venom proteins and their pharmacological potentials: A review

Several research in the organisms of marine invertebrates to assess the medicinal ability of its bio-active molecules have yielded very positive results in recent times. Jellyfish secreted venoms are rich sources of toxins intended to catch prey or deter predators among invertebrate species, but they may also have harmful effects on humans. The nematocyst, a complex intracellular system that injects a venomous mixture into prey or predators that come into contact with the tentacles or other parts of the body of cnidarians, determines the venomous existence of cnidarians. Nematocyst venoms are mixtures of peptides, proteins and other components that in laboratory animals can induce cytotoxicity, blockade of ion channels, membrane pore formation, in vivo cardiovascular failure and lethal effects. There are also valuable pharmacological and biological aspects of jellyfish venoms. In the present review, overviews of the variety of possible toxin families in cnidarian venoms are addressed in this analysis and these potential toxins are surveyed with those from other cnidarians that offer insight into their potential functions such as anti-oxidant, anti-cancer activity and much more. This research review will provide awareness of the growing repertoire of jellyfish venom proteins and will help to further isolate and classify particular proteins to understand its structure and functional relationship.

Immunomodulatory Activity in vitro and in vivo of Polysaccharides from Kabuli Chickpea (Cicer arietinum L.) Hull

Research background

Polysaccharides isolated from plants, fungi and bacteria are associated with immunomodulatory effects. Chickpea hull, which is regarded as food industrial waste, contains considerable amount of antioxidants and bioactive compounds.

Experimental approach

In the present study, we investigated the immunomodulatory activity of polysaccharides from kabuli chickpea (Cicer arietinum L.) hull (CHPS). In vitro study was conducted with RAW264.7 cell line while in vivo study was carried out using specific pathogen-free BALB/c mouse animal model.

Results and discussion

In in vitro test with RAW264.7 murine macrophage cells, the three purified fractions of chickpea hull polysaccharides showed potent immunomodulatory activity. Sample CHPS-3 showed stronger effect on cell viability, promoted the phagocytosis index to a greater extent and had the best effect on acid phosphatase activity. Moreover, it was found that CHPS-3 significantly (p<0.05) enhanced the secretion of nitrogen monoxide and cytokine (interleukins IL-6, IL-1β and tumor necrosis factor-alpha (TNF-α)) levels. In in vivo study, CHPS-3 improved thymus and spleen indices in cyclophosphamide-induced immunodeficient mice. Increased activities of lysozyme, catalase, superoxide dismutase and glutathione peroxidase, serum haemolysin content and total antioxidant capacity were observed, while the amount of malondialdehyde in the liver decreased.

Novelty and scientific contribution

The results suggest that chickpea hull polysaccharides enhanced the immune activity and could be developed as the ingredient of functional foods.

Immunostimulatory Effects of Polysaccharides from Spirulina platensis In Vivo and Vitro and Their Activation Mechanism on RAW246.7 Macrophages

In this study, Spirulina platensis (S.p.) polysaccharide (PSP) was obtained by ultrasonic-microwave-assisted extraction (UMAE) and purified by an aqueous two-phase system (ATPS). Two different methods were applied to purified Spirulina platensis (S.p.) polysaccharide (PSP), respectively, due to PSP as a complex multi-component system. Three polysaccharide fractions (PSP-1, PSP-2, and PSP-3) with different acidic groups were obtained after PSP was fractionated by the diethyl aminoethyl (DEAE)-52 cellulose chromatography, and two polysaccharide fractions (PSP-L and PSP-H) with different molecular weight were obtained by ultrafiltration centrifugation. The chemoprotective effects of PSP in cyclophosphamide (Cy) treated mice were investigated. The results showed that PSP could significantly increase spleen and thymus index, peripheral white blood cells (PWBC), and peripheral blood lymphocytes (PBL). The in vivo immunostimulatory assays demonstrated that PSP could in dose-dependent increase of TNF-α, IL-10, and IFN-γ production in sera. The in vitro immunostimulatory assays showed that PSP and its fractions (PSPs) could evidently enhance the proliferation of splenocytes and RAW 264.7 cells and increase the productions of nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6). PSPs could also enhance phagocytic activity of RAW 264.7 cells. The acidic polysaccharide fractions of PSP-2, PSP-3, and PSP-L with small molecular weight had the higher immunostimulatory activity. Signaling pathway research results indicated that PSP-L activated RAW264.7 cells through MAPKs, NF-κB signaling pathways via TLR4 receptor.