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

Viola yedoensis Makino alleviates lipopolysaccharide-induced intestinal oxidative stress and inflammatory response by regulating the gut microbiota and NF-κB-NLRP3/ Nrf2-MAPK signaling pathway in broiler

Viola yedoensis Makino (Vy) is a well-known traditional Chinese medicine widely used to treat inflammatory diseases. However, the regulatory effects of dietary Vy supplementation on lipopolysaccharide (LPS)-induced intestinal damage in broilers and the underlying molecular mechanisms remain unclear. In this study, broilers were intraperitoneally injected with 1 mg/kg LPS on days 17, 19 and 21 to induce intestinal damage. Vy supplementation at 0.5, 1.5 and 4.5 % in the diet was administered separately for 21 days to investigate the potential protective effects of Vy supplementation against LPS-induced intestinal impairment in broilers. Vy supplementation improved intestinal morphology and restored growth performance. Vy supplementation attenuated intestinal inflammation by regulating the nuclear factor kappa B (NF-κB) / NLR family pyrin domain-containing 3 (NLRP3) signaling pathway and inhibited its downstream pro-inflammatory factor levels. In addition, Vy supplementation relieved intestinal oxidative impairment by regulating the nuclear factor erythroid-2 related factor 2 (Nrf2) / mitogen-activated protein kinase (MAPK) signaling pathway and downstream antioxidant enzyme activity. Vy supplementation reduced LPS-induced mitochondrial damage and apoptosis. Furthermore, Vy supplementation alleviated LPS-induced intestinal inflammation and oxidative damage in chickens by increasing the abundance of protective bacteria (Lactobacillus and Romboutsia) and reducing the number of pathogenic bacteria (unclassified_f_Ruminococcaceae, unclassified_f_Oscillospiraceae and norank_f_norank_o_Clostridia_vadinBB60_group). Overall, Vy supplementation effectively ameliorated LPS-induced intestinal damage by regulating the NF-κB-NLRP3/Nrf2-MAPK signaling pathway and maintaining intestinal microbiota balance. Vy supplementation can be used as a dietary supplement to protect broilers against intestinal inflammation and oxidative damage.

Effect of subcritical water temperature on the structure, antioxidant activity and immune activity of polysaccharides from Glycyrrhiza inflata Batalin

In this study, the polysaccharide from Glycyrrhiza inflata Batalin extracted by hot water (HW-GP) was further physically modified with subcritical water to obtain novel polysaccharides (SW-GP). Comparative analysis was conducted to examine the disparities in conformation and bioactivity between HW-GP and SW-GP, aiming to precisely regulate the structure of the polysaccharides and enhance their bioactivity by controlling subcritical water temperature. The results showed that, compared with HW-GP, subcritical water modification (100-160 °C) not only significantly reduced the molecular weight of polysaccharides (from 5.586 × 105 g/mol to 1.484 × 105 g/mol), but also modulated the intermolecular interaction forces, which maintain the conformation of the polysaccharides, including electrostatic and hydrophobic interactions, thereby dynamically transforming the polysaccharide chain conformation from triple helix to random coil, and the strength of the chain conformation shifted from rigid to flexible. In addition, the modification of the SW-GP structure by subcritical water also enhanced its biological activity. SW-GP (140 °C) with low molecular weight and semi-rigid triple helix conformation showed the best scavenging effect on the DPPH, ABTS, and hydroxyl radicals, and exhibited excellent antioxidant activity. SW-GP (130 °C) with medium molecular weight and semi-rigid triple helix conformation significantly promoted the proliferation and phagocytosis of RAW264.7 cells, as well as increased the release levels of NO, TNF-α, IL-6, and IL-1β, and the immunomodulatory activity was much higher than that of other polysaccharides. These findings confirmed the feasibility of using subcritical water temperature as a regulatory feature for the structure and bioactivity of glycyrrhiza polysaccharides, which may have reference significance for the modification of polysaccharides with heightened bioactivity.

The potential, challenges, and prospects of the genus Spirulina polysaccharides as future multipurpose biomacromolecules

Spirulina has been widely used worldwide as a food and medicinal ingredient for centuries. Polysaccharides are major bioactive constituents of Spirulina and are of interest because of their functional properties and unlimited application potential. However, the clinical translation and market industrialization of the polysaccharides from genus Spirulina (PGS) are retarded due to the lack of a further understanding of their isolation, bioactivities, structure-activity relationships (SARs), toxicity, and, most importantly, versatile applications. Herein, we provide an overview of the extraction, purification, and structural features of PGS; meanwhile, the advances in bioactivities, SARs, mechanisms of effects, and toxicity are discussed and summarized. Furthermore, the applications, potential developments, and future research directions are scrutinized and highlighted. This review may help fill the knowledge gap between theoretical insights and practical applications and guide future research and industrial application of PGS.

Restoration of mitochondrial function by Spirulina polysaccharide via upregulated SOD2 in aging fibroblasts

Reactive oxygen species (ROS), such as superoxide, are crucial factors involved in the stimulation of cellular aging. Mitochondria, which are important organelles responsible for various metabolic processes in cells, produce ROS. These ROS impair mitochondrial function, thereby accelerating aging-related cellular dysfunction. Herein, we demonstrated that the Spirulina polysaccharide complex (SPC) restores mitochondrial function and collagen production by scavenging superoxide via the upregulation of superoxide dismutase 2 (SOD2) in aging fibroblasts. We observed that SOD2 expression was linked to inflammatory pathways; however, SPC did not upregulate the expression of most inflammatory cytokines produced as a result of induction of LPS in aging fibroblasts, indicating that SPC induces SOD2 without activation of inflammatory pathways. Furthermore, SPC stimulated endoplasmic reticulum (ER) protein folding by upregulating ER chaperones expression. Thus, SPC is proposed to be an antiaging material that rejuvenates aging fibroblasts by increasing their antioxidant potential via the upregulation of SOD2.

Study on the preparation and biological activities of low molecular weight squid ink polysaccharide from Sepiella maindroni

Sepiella maindroni ink polysaccharide (SIP) from the ink of cuttlefish Sepiella maindroni and its sulfated derivative (SIP-SII) have been demonstrated to possess diverse biological activities. But little is known about low molecular weight squid ink polysaccharides (LMWSIPs). In this study, LMWSIPs were prepared by acidolysis, and the fragments with molecular weight (M_w) distribution in the ranges of 7 kDa to 9 kDa, 5 kDa to 7 kDa and 3 kDa to 5 kDa were grouped and named as LMWSIP-1, LMWSIP-2 and LMWSIP-3, respectively. The structural features of LMWSIPs were elucidated, and their anti-tumor, antioxidant and immunomodulatory activities were also studied. The results showed that with the exception of LMWSIP-3, the main structures of LMWSIP-1 and LMWSIP-2 did not change compared with SIP. Though there were no significant differences in the antioxidant capacity between LMWSIPs and SIP, the anti-tumor and immunomodulatory activities of SIP were enhanced to a certain extent after degradation. It is particularly noteworthy that the activities of LMWSIP-2 in anti-proliferation, promoting apoptosis and inhibiting migration of tumor cells as well as promoting the proliferation of spleen lymphocytes were significantly higher than those of SIP and the other degradation products, which is promising in the anti-tumor pharmaceutical field.

Polysaccharides from Spirulina platensis: Extraction methods, structural features and bioactivities diversity

Spirulina platensis, a well-known blue-green microalga cultivated and consumed in China and United States, is traditionally used as a food supplement and medical ingredient. Increasing evidence has confirmed that the Spirulina platensis polysaccharides (SPPs) are vital and representative pharmacologically active biomacromolecules and exhibit multiple health-promoting activities both in vivo and in vitro, such as those of anti-cancer, anti-oxidant, immunomodulatory, hypolipidemic and hypoglycemic, anti-thrombotic, anti-viral, regulation of the gut microbiota properties and other biological activity. The purpose of this review aims to comprehensively and systematically outline the extraction and purification methods, structural features, biological activities, underlying mechanisms, and toxicities of SPPs to support their potential utilization value in pharmaceuticals fields and functional foods. The structural and activities relationship of SPPs is also discussed. Besides, new valuable insights for future research with SPPs have also been proposed in the important areas of structural characterization and pharmacological activities.

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.

Effect of Ultrasonic Irradiation on the Physicochemical and Structural Properties of Laminaria japonica Polysaccharides and Their Performance in Biological Activities

Due to the large molecular weight and complex structure of Laminaria japonica polysaccharides (LJP), which limit their absorption and utilization by the body, methods to effectively degrade polysaccharides had received more and more attention. In the present research, hot water extraction coupled with three-phase partitioning (TPP) was developed to extract and isolate LJP. Ultrasonic L. japonica polysaccharides (ULJP) were obtained by ultrasonic degradation. In addition, their physicochemical characteristics and in vitro biological activities were investigated. Results indicated that ULJP had lower weight-average molecular weight (153 kDa) and looser surface morphology than the LJP. The primary structures of LJP and ULJP were basically unchanged, both contained α-hexo-pyranoses and were mainly connected by 1,4-glycosidic bonds. Compared with LJP, ULJP had stronger antioxidant activity, α-amylase inhibitory effect and anti-inflammatory effect on RAW264.7 macrophages. The scavenging rate of DPPH free radicals by ULJP is 35.85%. Therefore, ultrasonic degradation could effectively degrade LJP and significantly improve the biological activity of LJP, which provided a theoretical basis for the in-depth utilization and research and development of L. japonica in the fields of medicine and food.

Combination of Spirulina platensis, Ganoderma lucidum and Moringa oleifera Improves Cardiac Functions and Reduces Pro-Inflammatory Biomarkers in Preclinical Models of Short-Term Doxorubicin-Mediated Cardiotoxicity: New Frontiers in Cardioncology?

Anthracyclines are essential adjuvant therapies for a variety of cancers, particularly breast, gastric and esophageal cancers. Whilst prolonging cancer-related survival, these agents can induce drug-related cardiotoxicity. Spirulina, Reishi (Ganoderma lucidum) and Moringa are three nutraceuticals with anti-inflammatory effects that are currently used in cancer patients as complementary and alternative medicines to improve quality of life and fatigue. We hypothesize that the nutraceutical combination of Spirulina, Reishi and Moringa (Singo) could reduce inflammation and cardiotoxicity induced by anthracyclines. Female C57Bl/6 mice were untreated (Sham, n = 6) or treated for 7 days with short-term doxorubicin (DOXO, n = 6) or Singo (Singo, n = 6), or pre-treated with Singo for 3 days and associated with DOXO for remaining 7 days (DOXO−Singo, n = 6). The ejection fraction and radial and longitudinal strain were analyzed through transthoracic echocardiography (Vevo 2100, Fujifilm, Tokyo, Japan). The myocardial expressions of NLRP3, DAMPs (galectin-3 and calgranulin S100) and 13 cytokines were quantified through selective mouse ELISA methods. Myocardial fibrosis, necrosis and hypertrophy were analyzed through immunohistochemistry (IHC). Human cardiomyocytes were exposed to DOXO (200 nM) alone or in combination with Singo (at 10, 25 and 50 µg/mL) for 24 and 48 h. Cell viability and inflammation studies were also performed. In preclinical models, Singo significantly improved ejection fraction and fractional shortening. Reduced expressions of myocardial NLRP3 and NF-kB levels in cardiac tissues were seen in DOXO−Singo mice vs. DOXO (p < 0.05). The myocardial levels of calgranulin S100 and galectin-3 were strongly reduced in DOXO−Singo mice vs. DOXO (p < 0.05). Immunohistochemistry analysis indicates that Singo reduces fibrosis and hypertrophy in the myocardial tissues of mice during exposure to DOXO. In conclusion, in the preclinical model of DOXO-induced cardiotoxicity, Singo is able to improve cardiac function and reduce biomarkers involved in heart failure and fibrosis.

Guava (Psidium guajava L.) seed: A low-volume, high-value byproduct for human health and the food industry

Guava processing industries generate peel and seeds as primary waste fractions. Guava seeds obtained after fruit processing possess untapped potential in the field of food science due to the presence of a diversity of nutritional and bioactive compounds. Along with offering a detailed understanding of the nutritional attributes of guava seeds, the present review comprehensively elaborates on the therapeutic activities of their bioactive compounds, their techno-functional properties, and their other edible and nonedible applications. The limited molecular and biochemical mechanistic studies outlining the antioxidant, immunomodulatory, anticancer, antimicrobial, neuroprotective and antidiabetic activities of guava seeds available in the literature are also extensively discussed in this review. The use of guava seed constituents as food additives and food functional and structural modulators, primarily as fat reducers, emulsifiers, water and oil holding agents, is also conceptually explained. Additional human intervention and molecular mechanistic studies deciphering the effects of guava seeds on various diseases and human health are warranted.

Synergistic Hypolipidemic and Immunomodulatory Activity of Lactobacillus and Spirulina platensis

Hyperlipidemia is a significant risk factor for atherosclerosis and coronary heart disease (CHD). The aim of this study was to investigate hypolipidemic effects of Lactobacillus, Spirulina and their combination on Swiss albino mice fed a regular or high-cholesterol diet. Rosuvastatin was used as a reference drug The highest body weight, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol LDL-C and the lowest high-density lipoprotein cholesterol were recorded in a positive control group (G5). Treatment with Lactobacillus or Spirulina or by their combination resulted in a significant decrease in body weight, TC, TG, LDL-C and significant increase in HDL-C (p < 0.05) in both mice fed a regular diet or high-cholesterol diet. The treatments induced a significant increase in Hb, MCHC and HCT levels in mice fed a regular diet (p < 0.05). They did not induce a significant effect on these parameters in mice fed a high-cholesterol diet, while treatment with standard rosuvastatin induced a significant decrease in these parameters (p < 0.05). The treatments induced a significant increase in the platelet count and WBC number in mice fed a regular diet p < 0.05), while they induced significant decrease in these parameters in mice fed a high-cholesterol diet p < 0.05. They also stimulated the innate immunity represented by both monocyte and neutrophil cells in mice fed a regular diet, while this immunity was reduced in mice fed a high-cholesterol diet. It also caused a marked reduction in inflammation and an improvement in the congestion of cardiac tissues, the aorta, and the spleen. The treatment of hyperlipidemic mice with combination of Lactobacillus and Spirulina gave similar results to those obtained with treatment by rosuvastatin.

Subacute cadmium exposure modulates Th1 polarization to trigger ER stress-induced porcine hepatocyte apoptosis via regulation of miR-369-TNFα axis

Cadmium (Cd), as a common environmental pollutant, has been reported to cause T lymphocyte dysfunction and cell apoptosis in multiple organs. However, whether subacute Cd exposure can induce apoptosis of hepatocytes and the relationship with Th1/Th2 imbalance were still unclear. In this study, ten 6-week-old piglets were selected and randomly assigned into two groups, the control group and the Cd group. The control group was fed with the standard diet, and for the Cd group, the standard diet was supplemented with 20 mg/kg CdCl2; liver tissue was collected on the 40th day of the experiment. Immunofluorescence, qRT-PCR, and western blot were performed to detect the expression of miR-369, Th1/Th2 biomarkers, endoplasmic reticulum (ER) stress-related genes, and apoptotic genes. TUNEL assay was applied to stain apoptotic hepatocytes. In the Cd group, the apoptosis of hepatocytes was significantly increased, and associated with the declined expression of miR-369, Th1 polarization, the elevated expression of ER stress pathway genes and their downstream pro-apoptosis genes, and downregulated expression of anti-apoptotic genes. These results manifest that subacute Cd exposure mediates Th1 polarization to promote ER stress-induced porcine hepatocyte apoptosis via regulating miR-369-TNFα. These results not only provide a basis for the enrichment of Cd toxicology but also support a theoretical foundation for the prevention and therapy of Cd poisoning. Schematic diagram illustrating the proposed mechanism of subacute cadmium exposure modulates Th1 polarization to trigger ER stress-induced porcine hepatocyte apoptosis via regulation of miR-369-TNFα axis.

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.

Separation, Purification, Structure Analysis, In Vitro Antioxidant Activity and circRNA-miRNA-mRNA Regulatory Network on PRV-Infected RAW264.7 Cells of a Polysaccharide Derived from Arthrospira platensis

To investigate the structure of Arthrospira platensis polysaccharide (PAP) (intracellular polysaccharide) and the antioxidant activity of the first component of PAP (PAP-1) on pseudorabies virus (PRV) -infected RAW264.7 cells. The PAP was separated and purified by the Cellulose DE-52 chromatography column and Sephacryl S-200 high-resolution gel column to obtain PAP-1. The antioxidant activity and regulation of PAP-1 on PRV-infected RAW264.7 cells of circRNA-miRNA-mRNA network were investigated by chemical kit, Q-PCR, and ce-RNA seq. The results indicated that the molecular weight (Mw) of PAP-1, which was mainly composed of glucose and eight other monosaccharides, was 1.48 × 106 Da. The main glycosidic bond structure of PAP-1 was →4)-α-D-Glcp-(1→. PAP-1 may be increased the antioxidant capacity by regulating the circRNA-miRNA-mRNA network in PRV-infected RAW264.7 cells. This study provided a scientific foundation for further exploring the antioxidant activity of PAP-1 based on its structure.

Optimization of the composite enzyme extraction of polysaccharide from Erythronium sibiricum bulb and its immunoregulatory activities

An efficient compound enzyme extraction process was developed and optimized to extract the polysaccharide from Erythronium sibiricum bulb via response surface methodology. The polysaccharide E2P was obtained. Then, the preliminary characteristics of E2P were determined via colorimetry and chromatography. Additionally, the immunoregulatory activities of E2P and another polysaccharide (ESBP, extracted using the hot water method) were compared. The optimized extraction results were as follows: temperature (54.56 °C), time (2.52 h), pH (6.53), and enzyme concentration ratio (0.5% cellulase:1.5% amylase). The yield (64.18% ± 2.91%) obtained under the aforementioned conditions was considerably higher than the yield of ESBP (37.25% ± 0.17%). The total sugar, uronic acid, starch, and protein contents of E2P were 81.77% ± 2.84%, 3.31% ± 0.45%, 3.29% ± 0.01%, and 0.24% ± 0.02%, respectively. The HPLC result suggested that the predominant monosaccharides of E2P included glucose, galactose, and arabinose, with a molar ratio of 543.2:1:1.8. The in vitro tests in RAW264.7 cells indicated that ESBP exhibited better immunomodulatory activities than E2P. In particular, ESBP can promote the proliferation, phagocytosis, and cytokine secretion abilities of cytokines, such as nitric oxide, tumor necrosis factor-α, and interleukin (IL)-1β of RAW264.6 cells. By contrast, E2P can only promote phagocytosis ability and the secretion of IL-1β.

Effect of Arthrospira powders from different producers on the formation of endothelial cell monolayers

Arthrospira platensis (AP) and some of its derived products have well-established biological activities as antioxidants or as agents to reduce cardiovascular disease risk factors. Furthermore, AP products have gained increasing importance as potential anti-cancer agents. However, the ingredients of the available products vary greatly with the origin, the type of production and processing, which could have significant consequences for their biological effects. Therefore, the composition and biological influence of five distinct AP powders, which were acquired commercially or produced at a public biotechnology institute, were investigated in regard to their endothelialization capacity using a cell impedance- (CI) based measurement method. The study revealed that the AP composition and especially the influence on HUVEC proliferation differed significantly between the five AP powders up to 109%.Thus, it could be shown that the method used allows the reliable detection of quantitative differences in biological effects of different AP preparations.

Characterization of a neutral polysaccharide from pumpkin (Cucurbita moschata Duch) with potential immunomodulatory activity

A neutral polysaccharide designated as CMDP-1a (molecular mass 9.263 kDa) was isolated from Cucurbita moschata Duch through hot water extraction, ethanol precipitation, and column chromatography. On the basis of methylation, fourier-transform infrared, monosaccharide composition, and one- and two-dimensional nuclear magnetic resonance spectroscopy analyses, the structure of CMDP-1a was determined to be a backbone composed of α-1,4 linked glucopyranosyl residues with α-Glcp residue linkage at backbone C-6. Atomic force microscopy and scanning electron microscopy analyses revealed that CMDP-1a had a spherical conformation in solution. In immunostimulation assays, CMDP-1a promoted the proliferation of RAW 264.7 macrophages and significantly enhanced their pinocytic and phagocytic capacity. Furthermore, CMDP-1a induced the M1 polarization of original macrophages and the conversion of macrophages from M2 to M1, thereby modulating the balance of M1/M2 macrophages. These results indicated that CMDP-1a might be a potential immunomodulator for food purposes.