Effects of the polysaccharide SPS-3-1 purified from Spirulina on barrier integrity and proliferation of Caco-2 cells

Dietary Spirulina effects in Eimeria-challenged broiler chickens: growth performance, nutrient digestibility, intestinal morphology, serum biomarkers, and gene expression

This study investigated the growth performance, nutrient utilization, and intestinal health responses of Eimeria-challenged broiler chickens to dietary Spirulina (Arthrospira platensis). On day 1, birds were assigned to 2 diets supplemented with Spirulina (0 or 5 g/kg) in a randomized complete block design. The birds within each diet were divided into 2 Eimeria-challenge groups (challenge or no-challenge) and that resulted in a 2 × 2 factorial arrangement with 2 levels each of Spirulina and challenge on day 14. On day 15, the birds in the challenge or no-challenge groups were orally gavaged with a solution containing Eimeria oocysts or 1% PBS, respectively. Samples were collected on days 21 and 26 (6- and 11-d post-infection; dpi). Data collected from days 1 to 26 were analyzed using the MIXED procedure of SAS. Birds that were fed Spirulina-supplemented diets had increased (P < 0.05) BW gain, gain-to-feed ratio, and total tract retention nitrogen from days 14 to 21. The ileal villus perimeter and area, serum catalase, HMOX1 and SOD1 jejunal abundance were all increased (P < 0.05) in birds fed Spirulina-supplemented diets on day 21 (6 dpi). However, there was no effect on bone ash or oocyst count. From days 21 to 26, there was a tendency (P = 0.059) for a Spirulina × Challenge interaction on the BW gain of birds. Moreover, dietary Spirulina addition increased (P < 0.05) serum catalase, total antioxidant capacity, ileal villus perimeter, tibia bone ash, and the relative mRNA expression of HMOX1, SOD1, claudin 1, and TNFα in the jejunal mucosa of birds on day 26 (11 dpi). On both 6 and 11 dpi, the Eimeria challenge negatively (P < 0.05) impacted growth performance, gut morphology, and the relative mRNA expression of genes. Overall, assessing the impact of Spirulina in broilers revealed its positive antioxidant, immune-modulating, and health benefits. However, its dietary addition did not completely reverse the Eimeria-induced effects in these birds. Ultimately, this study outlines the positive properties of dietary Spirulina beyond its use in the diet of healthy broiler chickens.

Metabolomics reveals the effects of Lactiplantibacillus plantarum dy-1 fermentation on the lipid-lowering capacity of barley β-glucans in an in vitro model of gut-liver axis

Bioactive polysaccharides known as the biological response modifiers, can directly interact with intestinal epithelium cells (IEC) and regulate key metabolic processes such as lipid metabolism. Here, the coculture of Caco-2/HT29 monolayer (>400 Ω × cm2) and HepG2 cells was developed to mimic the gut-liver interactions. This system was used to investigate the effects of raw and fermented barley β-glucans (RBG and FBG) on lipid metabolism by directly interacting with IEC. Both RBG and FBG significantly and consistently reduced the lipid droplets and triacylglycerol levels in monoculture and coculture of HepG2 overloaded with oleic acid. Notably, FBG significantly and distinctly elevated PPARα (p < 0.05) and PPARα-responsive ACOX-1 (p < 0.01) gene expressions, promoting lipid degradation in cocultured HepG2. Moreover, the metabolomics analyses revealed that FBG had a unique impact on extracellular metabolites, among them, the differential metabolite thiomorpholine 3-carboxylate was significantly and strongly correlated with PPARα (r = -0.68, p < 0.01) and ACOX-1 (r = -0.76, p < 0.01) expression levels. Taken together, our findings suggest that FBG-mediated gut-liver interactions play a key role in its lipid-lowering effects that are superior to those of RBG. These results support the application of Lactiplantibacillus fermentation for improving hypolipidemic outcomes.

Longan Polysaccharides with Covalent Selenylation Combat the Fumonisin B1-Induced Cell Toxicity and Barrier Disruption in Intestinal Epithelial (IEC-6) Cells

In this study, the soluble, but non-digestible, longan (Dimocarpus longan Lour.) polysaccharides (LP) were extracted from dried longan fruits and then chemically selenylated to produce two selenylated products, namely SeLP1 and SeLP2, with different selenylation extents. The aim was to investigate their protective effects on rat intestinal epithelial (IEC-6) cells exposed to the food toxin fumonisin B1 (FB1). LP only contained total Se content of less than 0.01 g/kg, while SeLP1 and SeLP2 were measured with respective total Se content of up to 1.46 and 4.79 g/kg. The cell viability results showed that these two selenylated products were more efficient than LP in the IEC-6 cells in alleviating FB1-induced cell toxicity, suppressing lactate dehydrogenase (LDH) release, and decreasing the generation of intracellular reactive oxygen species (ROS). These two selenylated products were also more effective than LP in combating FB1-induced barrier disruption via increasing the transepithelial electric resistance (TEER), reducing the paracellular permeability, decreasing the mitochondrial membrane potential (MMP) loss, and maintaining cell barrier integrity by upregulating the tight-junction-related genes and proteins. FB1 caused cell oxidative stress and barrier dysfunction by activating the MAPK and mitochondrial apoptosis signaling pathways, while SeLP1 and SeLP2 could regulate the tMAPK- and apoptosis-related proteins to suppress the FB1-mediated activation of the two pathways. Overall, SeLP2 was observed to be more active than SeLP1 in the IEC-6 cells. In conclusion, the chemical selenylation of LP caused an activity enhancement to ameliorate the FB1-induced cell cytotoxicity and intestinal barrier disruption. Meanwhile, the increased selenylation of LP would endow the selenylated product SeLP2 with more activity.

Preparation and Characterization of Intracellular and Exopolysaccharides during Cycle Cultivation of Spirulina platensis

The dried cell weight (DCW) of Spirulina platensis gradually decreased from 1.52 g/L to 1.18 g/L after five cultivation cycles. Intracellular polysaccharide (IPS) and exopolysaccharide (EPS) content both increased with increased cycle number and duration. IPS content was higher than EPS content. Maximum IPS yield (60.61 mg/g) using thermal high-pressure homogenization was achieved after three homogenization cycles at 60 MPa and an S/I ratio of 1:30. IPS showed a more fibrous, porous, and looser structure, and had a higher glucose content and Mw (272.85 kDa) compared with EPS, which may be indicative of IPS's higher viscosity and water holding capacity. Although both carbohydrates were acidic, EPS had stronger acidity and thermal stability than IPS; this was accompanied by differences in monosaccharide. IPS exhibited the highest DPPH (EC₅₀ = 1.77 mg/mL) and ABTS (EC₅₀ = 0.12 mg/mL) radical scavenging capacity, in line with IPS's higher total phenol content, while simultaneously showing the lowest HO^• scavenging and ferrous ion chelating capacities; thus characterizing IPS as a superior antioxidant and EPS as a stronger metal ion chelator.

The Analgesic and Anti-inflammatory Effects of Partially Purified Polysaccharide Fractions of Cell-free Medium and Biomass of Spirulina platensis PCST5

Background

Spirulina is a cyanobacteria species containing various bioactive compounds. Spirulina is a known source of nutrients in some traditional diets. Different activities have been reported for various extracts of S. platensis.

Objectives

In this study, the polysaccharide content of culture media and biomass extract of one species of Spirulina was partially purified, and its analgesic and anti-inflammatory effects were evaluated.

Methods

Spirulina platensis PCST5 was cultured in a sterile Zarouk medium at 27°C and 16/8h of light/ dark exposure cycle for 25 days. Then, the polysaccharide content of biomass and cell-free culture medium samples (BPSs and CFPSs, respectively) was partially purified. The analgesic and anti-inflammatory effects were evaluated using animal models.

Results

16S rRNA gene analysis confirmed that the organism was genetically similar to Spirulina platensis. The CFPSs (30 and 100 mg/kg) and BPSs (30 mg/kg) significantly reduced pain-related behaviors in rats. Similarly, all samples could significantly reduce carrageenan-induced paw inflammation volume compared with the control group. Our results suggest Spirulina's polysaccharide fractions (CFPSs and BPSs) had significant analgesic and anti-inflammatory effects.

Conclusions

Since Spirulina is a readily available source of bioactive compounds, finding such potent anti-inflammatory and anti-nociceptive compounds can provide promising leads for novel drug development.

Pterostilbene attenuates intestinal epithelial barrier loss induced by high loading intensity of exercise

Mounting evidence suggested that high loading intensity of exercise might be detrimental to human health, especially the gastrointestinal tract. Pterostilbene (PTE), derived from grapes and blueberries, might reach a high concentration of intestinal contents. Our study aimed to evaluate PTE’s ability to prevent the loss of intestinal epithelial barrier in high loading intensity of exercise. The exercise model was established by the forced running of mice. An effective HPLC-UV method was developed to quantify PTE concentration in intestinal content. The mRNA changes were detected by quantitative polymerase chain reaction (qPCR). The structure of intestinal flora was analyzed by 16S rRNA sequencing. The PTE (100 mg/kg/d) could significantly attenuate exercise-induced intestinal epithelial barrier loss. Moreover, the HPLC-UV assay showed that the PTE concentration of intestinal content could last 12 h. Furthermore, the exercise increased the abundance of Alistipes, which was related to lipopolysaccharide (LPS) production but could not be reversed by PTE intervention. Besides, cell experiments showed that PTE could promote the expression of intestinal epithelial tight junction (TJ) molecules in vitro. In conclusion, PTE has a significant interest in preventing exercise-induced intestinal damage.

Novel Compound Polysaccharides from Chinese Herbal Medicines: Purification, Characterization, and Antioxidant Activities

The present study investigated physicochemical properties and antioxidant activities in vivo and in vitro of purified compound polysaccharides (CPs-1) from Chinese herbal medicines, composed of lotus leaf, hawthorn, Fagopyrum tataricum, Lycium barbarum, Semen cassiae, and Poria cocos with the mass ratio of 2 : 4 : 2 : 1 : 1.5 : 1. The HPGPC profile and FT-IR spectra indicated that the average molecular weight of CPs-1 was 38.7 kDa and possessed the α- and β-D-pyranose, respectively. The methylation analysis and NMR spectrum demonstrated that CPs-1 had a →6)-β-D-Glcp-(1→6)-β-D-Glcp(1→ backbone. Furthermore, the antioxidant assays in vitro revealed that CPs-1 displayed high scavenging abilities for DPPH, hydroxyl, and reducing power, as well as ABTS and superoxide scavenging capacity. The antioxidant experiments in vivo revealed that CPs-1 could significantly enhance CAT, SOD, and GSH-Px activities and dramatically reduce MDA levels in liver and serum of high-fat mice. Therefore, CPs-1 could be potentially incorporated into pharmaceutical products or functional foods as a natural antioxidant.

Applications of algae to obtain healthier meat products: A critical review on nutrients, acceptability and quality

Meat constitutes one the main protein sources worldwide. However, ethical and health concerns have limited its consumption over the last years. To overcome this negative impact, new ingredients from natural sources are being applied to meat products to obtain healthier proteinaceous meat products. Algae is a good source of unsaturated fatty acids, proteins, essential amino acids, and vitamins, which can nutritionally enrich several foods. On this basis, algae have been applied to meat products as a functional ingredient to obtain healthier meat-based products. This paper mainly reviews the bioactive compounds in algae and their application in meat products. The bioactive ingredients present in algae can give meat products functional properties such as antioxidant, neuroprotective, antigenotoxic, resulting in healthier foods. At the same time, algae addition to foods can also contribute to delay microbial spoilage extending shelf-life. Additionally, other algae-based applications such as for packaging materials for meat products are being explored. However, consumers' acceptance for new products (particularly in Western countries), namely those containing algae, not only depends on their knowledge, but also on their eating habits. Therefore, it is necessary to further explore the nutritional properties of algae-containing meat products to overcome the gap between new meat products and traditional products, so that healthier algae-containing meat can occupy a significant place in the market.

Extraction, Structural Characterization, and Immunomodulatory Activity of a High Molecular Weight Polysaccharide From Ganoderma lucidum

Ganoderma lucidum polysaccharides (GLP) exhibited excellent immunomodulatory activity. Unfortunately, the structure and immunomodulatory activity of GLP are still unclear. GLP was separated into two fractions [high Mw Restriction Fragment Length Polymorphism (RGLP) and low Mw EGLP] using 10 kDa cut-off ultrafiltration membrane. Although the RGLP content was low in GLP, the immunomodulatory activity in RGLP was significantly higher than that of EGLP. Moreover, RGLP was further separated via the Sephacryl column to obtain RGLP-1 showed the best immunomodulatory activity in the macrophage RAW264.7 model. Structural analysis revealed that RGLP-1 was 3,978 kDa and mainly consisted of glucose. Periodate oxidation, Smith degradation, and methylation results indicated that RGLP-1 is a β-pyran polysaccharide mainly with 1→3, 1→4, 1→6, and 1→3, 6 glycosyl bonds at a molar ratio of 40.08: 8.11: 5.62: 17.81. Scanning electron microscopy, atomic force microscopy, and Congo red experiments revealed that RGLP-1 intertwined with each other to form circular aggregates and might possess a globular structure with triple-helix conformation in water. Overall, these results provide RGLP-1 as a potential functional food ingredient or pharmaceutical for immunomodulatory.

Hydroxytyrosol Alleviates Dextran Sulfate Sodium-Induced Colitis by Modulating Inflammatory Responses, Intestinal Barrier, and Microbiome

Hydroxytyrosol (HT), a polyphenol derived from olive oil, was examined against dextran sulfate sodium (DSS)-induced colitis to study its potential in preventing colitis and the underlying mechanisms involved. The low dose and high dose of HT used in mice were 10 and 50 mg/kg, respectively. Research findings have shown that HT is effective in preventing colitis by alleviating the signs of colitis. HT intervention significantly reduces colitis markers such as myeloperoxidase (MPO) and proinflammatory cytokine (IL-6, IL-1β, and TNF-α). Also, mice treated with a high dose of HT showed increased secretion of antioxidant enzymes (heme oxygenase-1 (HO) and anti-inflammatory cytokine (IL-10) by 2.32- and 2.28-fold, respectively, in comparison to the DSS-treated group. Modulation effects of HT on the antioxidant signal pathway (NRF2) and the inflammatory pathway (NF-κB) were confirmed. Meanwhile, HT promoted the regeneration of the intestinal barrier and maintained intestinal functional homeostasis by boosting the regeneration of goblet cells and the expression of mucin protein (Muc2) and tight junction (TJ) proteins (claudin-1, occludin, and Zonula Occludens-1). Moreover, HT intervention obviously transformed the gut microbiota, leading to a lower abundance of inflammation-related microbes (e.g., Bacteroidaceae and Desulfovibrionaceae) and a higher level of short-chain fatty acids (SCFAs) producing bacteria (e.g., Lachnospiraceae, Muribaculaceae, ASF356, and Colidextribacter). Scientific evidence for the beneficial effect of the "Mediterranean diet" (MD) on intestinal health was achieved by elucidating the alleviation mechanism of hydroxytyrosol on colitis.

Protective Effects of Natural Polysaccharides on Intestinal Barrier Injury: A Review

Owing to their minimal side effects and effective protection from oxidative stress, inflammation, and malignant growth, natural polysaccharides (NPs) are a potential adjuvant therapy for several diseases caused by intestinal barrier injury (IBI). More studies are accumulating on the protective effects of NPs with respect to IBI, but the underlying mechanisms remain unclear. Thus, this review aims to represent current studies that investigate the protective effects of NPs on IBI by directly maintaining intestinal epithelial barrier integrity (inhibiting oxidative stress, regulating inflammatory cytokine expression, and increasing tight junction protein expression) and indirectly regulating intestinal immunity and microbiota. Furthermore, the mechanisms underlying IBI development are briefly introduced, and the structure-activity relationships of polysaccharides with intestinal barrier protection effects are discussed. Potential developments and challenges associated with NPs exhibiting protective effects against IBI have also been highlighted to guide the application of NPs in the treatment of intestinal diseases caused by IBI.

Structural characterization, and in vitro immunostimulatory and antitumor activity of an acid polysaccharide from Spirulina platensis

In this study, a novel heteropolysaccharide named SP90-1 with immunostimulatory and antitumor activity was purified and characterized from Spirulina platensis. SP90-1 has a molecular weight of 63.92 kDa and mainly consists of rhamnose (Rha), glucose (Glc), galactose (Gal) and glucuronic acid (GlcA), followed by the minor components Fuc and Xyl. The backbone of SP90-1 was determined to be →2)-α-d-Rhap-(1 → 2,3)-α-d-Rhap-(1 → 4)-β-d-Glcp-(1 → [3)-β-d-Rhap-(1→]₃, with branches at the O-3 of Rha, consisting of the side chains 4-Galp and 4-GlcpA. SP90-1 was found to significantly enhance phagocytic capacity, promote the secretion of nitric oxide (NO), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in RAW264.7 cells, and remarkably inhibit the growth of A549 lung cancer cells. These findings demonstrate that SP90-1 could potentially be further explored for immunomodulatory biomedical applications.

WSG, a glucose-enriched polysaccharide from Ganoderma lucidum, suppresses tongue cancer cells via inhibition of EGFR-mediated signaling and potentiates cisplatin-induced apoptosis

Tongue cancer, a kind of oral cancer, is common in Southeast Asian countries because of dietary habits. However, there is no specific targeted drug that could effectively inhibit oral cancer. WSG, as a water soluble glucose-enriched polysaccharide from Ganoderma lucidum, exerts excellent pharmacological efficacy of anti-lung cancer. However, its anticancer functions and mechanisms in human tongue cancer need to be further explored. Herein, we showed that WSG dramatically reduced cell viability and colony formation of tongue cancer cells. WSG increased subG1 and G2/M populations as well as induced apoptotic responses. In parallel, WSG enhanced apoptosis-related Bax/Bcl2 ratio. Mechanistic studies showed that WSG reduced phosphorylation of EGFR and AKT. In addition, we found a synergistic effect of WSG with cisplatin in inhibition of cell viability and induction of apoptosis. WSG significantly reduced the inhibition concentration 50% (IC₅₀) of cisplatin. More importantly, WSG ameliorated cisplatin-induced cytotoxicity in normal human oral epithelial SG cells. In conclusion, our findings provided important insights into the anti-tongue cancer effects of WSG via inhibition of EGFR/AKT axis and induction of apoptosis, which indicated that WSG could be a promising supplement for tongue cancer treatment.

Extraction kinetics, physicochemical properties and immunomodulatory activity of the novel continuous phase transition extraction of polysaccharides from Ganoderma lucidum

Ganoderma lucidum polysaccharides (GLP) possess remarkable bioactivity and have been studied widely. However, the application of new technologies in the polysaccharide extraction has not been investigated. Herein, a novel continuous phase transition extraction (CPTE) technology was applied for the extraction of polysaccharides from Ganoderma lucidum. The extraction kinetics, physicochemical properties and immunomodulatory activity of GLP were evaluated. The kinetics results showed that the extraction process could be fitted to a two-site kinetic model due to the high R² values in the range of 0.9939-0.9999. Polysaccharides extracted by different technologies showed that GLP yield by CPTE could be significantly improved, which was 3.34 times and 2.68 times that of hot water and ultrasonic-assisted extraction, respectively. Molecular weight distribution analysis indicated that high molecular mass polysaccharide proportion by CPTE was the highest among the three extraction methods, which was 2.03 times and 3.41 times as much as that of the hot water and ultrasonic-assisted extraction. Morphology analysis showed that CPTE treatment caused disruption of most of the cells and effective release of intracellular components, implying that CPTE was beneficial to extract polysaccharides. Furthermore, the immunomodulatory assays demonstrated that GLP significantly enhanced the proliferation and production of NO, TNF-α and IL-6 in macrophages. Therefore, CPTE was more effective for extracting polysaccharides from Ganoderma lucidum than the common extraction.