Immunomodulatory Activity In Vitro and In Vivo of a Sulfated Polysaccharide with Novel Structure from the Green Alga Ulvaconglobata Kjellman

Bioactive Compounds of Marine Algae and Their Potential Health and Nutraceutical Applications: A Review

Currently, marine algae are still an under-exploited natural bioresource of bioactive compounds. Seaweeds represent a sustainable source for obtaining bioactive compounds that can be useful for the fabrication of new active products with biomedical benefits and applications as biomedicinals and nutraceuticals. The objective of this review is to highlight scientific papers that identify biocompounds from marine macroalgae and emphasize their benefits. The method used was data analysis to systematize information to identify biocompounds and their various benefits in pharmaceuticals, cosmetics, and nutraceuticals. The research results demonstrate the multiple uses of seaweeds. As pharmaceuticals, seaweeds are rich sources of bioactive compounds like polysaccharides, protein compounds, pigments, and polyphenols, which have demonstrated various pharmacological activities such as antioxidant, antibacterial, anti-inflammatory, antiviral, anticoagulant, and potentially anticarcinogenic effects. Seaweed has gained recognition as a functional food and offers a unique set of compounds that promote body health, including vitamins, minerals, and antioxidants. In conclusion, the importance of this review is to expand the possibilities for utilizing natural resources by broadening the areas of research for human health and marine nutraceuticals.

Chlamydomonas reinhardtii polysaccharides retard rice starch retrogradation by weakening hydrogen bond strength within starch double helices

This study investigated the effects of Chlamydomonas reinhardtii polysaccharides (CRPs) on retarding the retrogradation of japonica rice starch (JS) and glutinous rice starch (GS). Structure characterization revealed that CRPs, with an average molecular weight of 505 kDa, mainly consisted of glucose, mannose, and galactose and featured a triple-helix structure. CRPs could reduce the storage modulus increment of JS during the cooling process by interacting with amylose, thereby inhibiting gel network formation. After long-term storage, CRPs decreased the hardness of JS and GS gels, limited the mobility of water molecules, and inhibited dehydration of gels. In addition, CRPs restricted starch recrystallization through interactions with amylopectin, resulting in reduced retrogradation enthalpy and relative crystallinity in JS and GS gels. Further investigation revealed that CRPs could weaken hydrogen bond strength within double helices in JS and GS after 14 days, with bond energies of 10.270 kJ for JS-0.4%CRPs and 10.241 kJ for GS-0.4%CRPs, which are lower than those of native starches (10.464 and 10.500 kJ). Moreover, the energy increments of hydrogen bonds within double helices in complexes were smaller than those of native rice starches during storage, which emerges as the essential reason behind the retardation of rice starch retrogradation by CRPs.

Sustainable and biocompatible hybrid materials-based sulfated polysaccharides for biomedical applications: a review

Sustainable biomaterials that are both efficient and environmentally friendly are the subject of research and development efforts among scientists and academics from a variety of contemporary scientific disciplines. Due to their significant involvement in several physiological and pathological processes, sulfated polysaccharides (SPs) have garnered growing interest across various application domains, including biomedicine. Nevertheless, mechanical and thermal stability are issues for unmodified polysaccharide materials. Interactions between polymers, such as the mixing of biopolymers with synthetic or biopolymers through chemical interaction or grafting into the main chain structure of raw materials to enhance their therapeutic effects, are essential to meet the high standards of biomedical features. Another way to improve the mechanical and thermal properties is to graft appropriate fillers onto the polysaccharide backbone. The characteristics of polysaccharide bio-nanocomposites in comparison to more traditional polymers have attracted a lot of interest. With an emphasis on anti-inflammatory, anticancer, antiviral, immunoregulatory, and anticoagulant properties, this review delves into the most recent biological uses of sulfated polysaccharides. As well as thoroughly outlining the factors that impact the biological properties, such as the extraction process, molecular weight (Mw), the degree of sulfation, distribution/position, modification procedures, and the filler size, etc., this review aims to: (1) provide a systematic and critical overview of the cutting-edge research on SPs and hybrid sulfated polysaccharide bio-nanocomposites; (2) identify the key factors, mechanisms, methods, and challenges impacting SPs bio-nanocomposites; (3) elucidate the current and potential biomedical applications, advantages, manufacturing challenges, and opportunities associated with SPs bio-nanocomposites; (4) offer insights into future research directions by suggesting improvements for bio-nanocomposites, including novel materials, and advanced processing techniques.

A critical review on pharmacological properties of sulfated polysaccharides from marine macroalgae

The marine ecosystem contains an assorted range of organisms, among which macroalgae stands out marine resources as an invaluable reservoir of structurally diverse bioactive compounds. Marine macroalgae are considered as primary consumers have gained more attention for their bioactive components. Sulfated polysaccharides (SPs) are complex polymers found in macroalgae that play a crucial role in their cell wall composition. This review consolidates high-tech methodologies employed in the extraction of macroalgal SPs, offering a valuable resource for researchers focuses in the pharmacological relevance of marine macromolecules. The pharmacological activities of SPs, focusing on their therapeutic action by encompassing diverse study models are summarized. Furthermore, in silico docking studies facilitates a comprehensive understanding of SPs interactions with their binding sites providing a valuable insight for future endeavors. The biological properties of algal SPs, along with a brief reference to mode of action based on different targets are presented. This review utilizes up-to-date research discoveries across various study models to elucidate the biological functions of SPs, focusing on their molecular-level mechanisms and offering insights for prospective investigations. Besides, the significance of SPs from seaweeds is highlighted, showcasing their potential beneficial applications in promoting human health. With promising biomedical prospects, this review explores the extensive uses and experimental evidence supporting the important roles of SPs in various fields.

Supercritical CO2 extracts of propolis inhibits tumor proliferation and Enhances the immunomodulatory activity via activating the TLR4-MAPK/NF-κB signaling pathway

Propolis is a natural immunomodulator with anticancer activity. This study investigated the immunomodulatory mechanism and anti-tumor activity of supercritical CO2 extracts of propolis (SEP) in tumor-bearing immunosuppression mice. We used cyclophosphamide (CTX) to construct the immunosuppressive mice model and then inoculated them with CT26 cells to build the CT26 tumor-bearing immunosuppression mice model. Upon treatment with SEP, tumor proliferation in mice was markedly suppressed, with tumor volumes decreasing from 1881.43 mm3 to 1049.95 mm3 and weights reducing from 2.07 g to 1.13 g. Concurrently, the immune system recovered well, and the spleen and thymus indexes increased significantly. The total T lymphocyte (CD3+ T cell) contents in the spleen and blood recovered from 11.88 % to 21.19 % and 15.32 % to 22.19 %, respectively. In addition, the CD4+ /CD8+ ratio has returned to a healthy level, 3.12 in the spleen and 5.42 in the blood. The levels of IL-1β, IL-6, and TNF-α were increased by 2.17, 2.76, and 7.15 times in the spleen, 2.76, 1.92, and 3.02 times in the serum. Moreover, the western blot results showed that SEP treatment increased the expression of toll-like receptor 4 (TLR4) and the phosphorylation of p38, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p65. These results indicated that SEP activated the immune activity of RAW 264.7 macrophages through the TLR4-mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) signaling pathway to exert immunomodulatory function and inhibit tumor proliferation. This study facilitated the further application of SEP as a potential immunomodulatory and anti-tumor functional food.

Preparation and characterization of kelp polysaccharide and its research on anti-influenza a virus activity

The beneficial effects of kelp polysaccharide (KPS) have recently attracted attention. In this study, KPS was extracted from kelp using the enzyme hydrolysis combined with freeze-drying, namely, KPS-EF. The structural characterization showed that KPS-EF was a highly sulfated macromolecule with the Mw of 764.2 kDa and the sulfate content of 23.49 %. The antiviral activity of KPS-EF in vitro was verified, and the IC50 value of KPS against the PR8 virus was 0.58 mg/mL. Intranasal administration of KPS-EF significantly inhibited death and weight loss in IAV-infected mice and alleviated virus-induced pneumonia symptoms, meanwhile, KPS-EF (10 mg/kg/day) significantly decreased the production levels of chemokines (CXCL1, RANTES) and inflammatory cytokines (IL-6, TNF-α) in lungs (p < 0.05). KPS-EF could downregulate the activity of viral neuraminidase (NA) primarily in the late stage of viral adsorption with an IC50 value of 0.29 mg/mL. This study provides a theoretical basis for the using KPS as a supplement to NA inhibitors or anti-influenza drugs.

Potentials of Ulva spp.-derived sulfated polysaccharides as gelling agents with promising therapeutic effects

Ulvan, a sulfated polysaccharide extracted from Ulva spp., has garnered significant attention in the food and pharmaceutical industries due to its potential health benefits. These include immunomodulation, antiviral, anti-inflammatory, anti-hyperlipidemic, and anti-cancer effects. Nonetheless, practical applications in these fields remain limited due to an incomplete understanding of its gelation mechanisms. Additionally, the underlying mechanisms of its gelation have not been completely understood and thoroughly reviewed. The primary objective is to provide current insights into ulvan's gelling mechanisms and potential health impacts. This review also delves into the existing applications of ulvan polysaccharides. By unraveling these aspects, the information provided in this work is expected to deepen our understanding of ulvan's gelation mechanisms and its prospective role in enhancing health, holding promise for advancements in the fields of food science and disease prevention. This work's theoretical insights contribute significantly to a deeper understanding of these aspects, which holds paramount importance in unleashing the full potential of ulvan and elevating its scientific significance.

The Ocean's Pharmacy: Health Discoveries in Marine Algae

Non-communicable diseases (NCDs) represent a global health challenge, constituting a major cause of mortality and disease burden in the 21st century. Addressing the prevention and management of NCDs is crucial for improving global public health, emphasizing the need for comprehensive strategies, early interventions, and innovative therapeutic approaches to mitigate their far-reaching consequences. Marine organisms, mainly algae, produce diverse marine natural products with significant therapeutic potential. Harnessing the largely untapped potential of algae could revolutionize drug development and contribute to combating NCDs, marking a crucial step toward natural and targeted therapeutic approaches. This review examines bioactive extracts, compounds, and commercial products derived from macro- and microalgae, exploring their protective properties against oxidative stress, inflammation, cardiovascular, gastrointestinal, metabolic diseases, and cancer across in vitro, cell-based, in vivo, and clinical studies. Most research focuses on macroalgae, demonstrating antioxidant, anti-inflammatory, cardioprotective, gut health modulation, metabolic health promotion, and anti-cancer effects. Microalgae products also exhibit anti-inflammatory, cardioprotective, and anti-cancer properties. Although studies mainly investigated extracts and fractions, isolated compounds from algae have also been explored. Notably, polysaccharides, phlorotannins, carotenoids, and terpenes emerge as prominent compounds, collectively representing 42.4% of the investigated compounds.

Synergistic Antitumor Effect of Grifola frondose Polysaccharide—Protein Complex in Combination with Cyclophosphamide in H22 Tumor-Bearing Mice

Hepatocellular carcinoma (HCC) is the most common type of liver malignancy and remains a global health threat. The objective of the current study was to determine whether the combination of a cold-water extracted polysaccharide-protein complex from Grifolia frondosa (GFG) and cyclophosphamide (CTX) could inhibit tumor growth by suppressing the expression of angiogenesis-related proteins in H22 tumor-bearing mice. The results showed that the inhibition rate of GFG combined with CTX on H22 tumors was 65.29%, which was significantly higher than that of GFG treatment alone (24.82%). GFG combined with CTX significantly increased the expression levels of vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinase 2, and matrix metalloproteinase 9. Additionally, thymus index, spleen index, natural killer (NK) cell activity, interferon-γ (IFN-γ), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) levels increased significantly after GFG treatment, especially after high-doses of GFG combined with CTX treatment (p < 0.05). The thymus index, spleen index, NK cell activity, IFN-γ, IL-1β, TNF-α, and IL-2 levels were 1.90, 1.46, 1.30, 2.13, 1.64, 2.03, and 1.24 times of those treated with CTX alone. Thus, we proposed that GFG can alleviate the side effects of CTX by relieving the immunosuppressive effect, liver/renal injury, and oxidative stress. In conclusion, the combination of GFG and CTX for cancer treatment may be a promising strategy, and GFG is expected to be a potential adjuvant alternative for the treatment of HCC.

Global seaweed farming and processing in the past 20 years

Seaweed has emerged as one of the most promising resources due to its remarkable adaptability, short development period, and resource sustainability. It is an effective breakthrough to alleviate future resource crises. Algal resources have reached a high stage of growth in the past years due to the increased output and demand for seaweed worldwide. Several aspects global seaweed farming production and processing over the last 20 years are reviewed, such as the latest situation and approaches of seaweed farming. Research progress and production trend of various seaweed application are discussed. Besides, the challenges faced by seaweed farming and processing are also analyzed, and the related countermeasures are proposed, which can provide advice for seaweed farming and processing. The primary products, extraction and application, or waste utilization of seaweed would bring greater benefits with the continuous development and improvement of applications in various fields.

Graphical Abstract