Investigation of the factors influencing the molecular weight of porphyran and its associated antifungal activity

Bioactive polysaccharides from red seaweed as potent food supplements: a systematic review of their extraction, purification, and biological activities

Most marine macroalgae such as red seaweeds are potential alternative sources of useful bioactive compounds. Beside serving as food source, recent studies have shown that red seaweeds are rich sources of bioactive polysaccharides. Red seaweed polysaccharides (RSPs) have various physiological and biological activities, which allow them to be used as immunomodulators, anti-obesity agents, and prebiotic ingredients. Lack of summary information and human clinical trials on the various polysaccharides from red seaweeds, however limits industrial-scale utilization of RSPs in functional foods. This review summarizes recent information on the approaches used for RSPs extraction and purification, mechanistic investigations of their biological activities, and related molecular principles behind their purported ability to prevent diseases. The information here also provides a theoretical foundation for further research into the structure and mechanism of action of RSPs and their potential applications in functional foods.

Immunomodulatory effects of polysaccharides from marine algae for treating cancer, infectious disease, and inflammation

A significant rise in the occurrence and severity of adverse reactions to several synthetic drugs has fueled considerable interest in natural product-based therapeutics. In humans and animals, polysaccharides from marine microalgae and seaweeds have immunomodulatory effects. In addition, these polysaccharides may possess antiviral, anticancer, hypoglycemic, anticoagulant, and antioxidant properties. During inflammatory diseases, such as autoimmune diseases and sepsis, immunosuppressive molecules can serve as therapeutic agents. Similarly, molecules that participate in immune activation can induce immune responses against cancer and infectious diseases. We aim to discuss the chemical composition of the algal polysaccharides, namely alginate, fucoidan, ascophyllan, and porphyran. We also summarize their applications in the treatment of cancer, infectious disease, and inflammation. Recent applications of nanoparticles that are based on algal polysaccharides for the treatment of cancer and inflammatory diseases have also been addressed. In conclusion, these applications of marine algal polysaccharides could provide novel therapeutic alternatives for several diseases.

Plant/algal polysaccharides extracted by microwave: A review on hypoglycemic, hypolipidemic, prebiotic, and immune-stimulatory effect

Microwave-assisted extraction (MAE) is an emerging technology to obtain polysaccharides with an extensive spectrum of biological characteristics. In this study, the hypoglycemic, hypolipidemic, prebiotic, and immunomodulatory (e.g., antiinflammatory, anticoagulant, and phagocytic) effects of algal- and plant-derived polysaccharides rich in glucose, galactose, and mannose using MAE were comprehensively discussed. The in vitro and in vivo results showed that these bioactive macromolecules with the low digestibility rate could effectively alleviate the fatty acid-induced lipotoxicity, acute hemolysis, and dyslipidemia status. The optimally extracted glucomannan- and glucogalactan-containing polysaccharides revealed significant antidiabetic effects through inhibiting α-amylase and α-glucosidase, improving dynamic insulin sensitivity and secretion, and promoting pancreatic β-cell proliferation. These bioactive macromolecules as prebiotics not only improve the digestibility in gastrointestinal tract but also reduce the survival rate of pathogens and tumor cells by activating macrophages and producing pro-inflammatory biomarkers and cytokines. They can effectively prevent gastrointestinal disorders and microbial infections without any toxicity.

Strategies to Increase the Biological and Biotechnological Value of Polysaccharides from Agricultural Waste for Application in Healthy Nutrition

Nowadays, there is a growing interest in the extraction and identification of new high added-value compounds from the agro-food industry that will valorize the great amount of by-products generated. Many of these bioactive compounds have shown beneficial effects for humans in terms of disease prevention, but they are also of great interest in the food industry due to their effect of extending the shelf life of foods by their well-known antioxidant and antimicrobial activity. For this reason, an additional research objective is to establish the best conditions for obtaining these compounds from complex by-product structures without altering their activity or even increasing it. This review highlights recent work on the identification and characterization of bioactive compounds from vegetable by-products, their functional activity, new methodologies for the extraction of bioactive compounds from vegetables, possibly increasing their biological activity, and the future of the global functional food and nutraceuticals market.

Enhancement of the Antioxidant and Antimicrobial Activities of Porphyran through Chemical Modification with Tyrosine Derivatives

The chemical modification of porphyran hydrocolloid is attempted, with the objective of enhancing its antioxidant and antimicrobial activities. Sulfated galactan porphyran is obtained from commercial samples of the red algae Porphyra dioica using Soxhlet extraction with water at 100 °C and precipitation with isopropyl alcohol. The extracted porphyran is then treated with modified L-tyrosines in aqueous medium in the presence of NaOH, at ca. 70 °C. The modified tyrosines L1 and L2 are prepared through a Mannich reaction with either thymol or 2,4-di-tert-butylphenol, respectively. While the reaction with 2,4-di-tert-butylphenol yields the expected tyrosine derivative, a mixture of products is obtained with thymol. The resulting polysaccharides are structurally characterized and the respective antioxidant and antimicrobial activities are determined. Porphyran treated with the N-(2-hydroxy-3,5-di-tert-butyl-benzyl)-L-tyrosine derivative, POR-L2, presents a noticeable superior radical scavenging and antioxidant activity compared to native porphyran, POR. Furthermore, it exhibited some antimicrobial activity against S. aureus. The surface morphology of films prepared by casting with native and modified porphyrans is studied by SEM/EDS. Both POR and POR-L2 present potential applicability in the production of films and washable coatings for food packaging with improved protecting characteristics.

Poultry Shelf-Life Enhancing Potential of Nanofibers and Nanoparticles Containing Porphyra dioica Extracts

Aqueous extracts of commercially available red macroalgae Porphyra dioica were integrated as inner coatings of food-grade polypropylene (PP) films through use of electrospinning and electrospraying technologies. Two coating formulations (A = 5 wt% P. dioica extract and 7.5 wt% polyvinyl alcohol (PVA); B = 1 wt% P. dioica extract, 1 wt% PVA, and 17% gelatine) were evaluated as to their capacity to delay spoilage of minced chicken breasts, through monitoring of microbial growth (total mesophile aerobic colony counts), colour stability, lipid oxidation (thiobarbituric acid reactive substances (TBARS)), and sensory analysis over a 4-day refrigerated storage. Scanning electron microscopy (SEM) imaging revealed an increased nanofiber and nanoparticle density on extract-enriched fibers, without compromise to their morphology or the homogeneity of the coatings. Total microbial counts on coating B samples was significantly (p < 0.001) reduced compared to uncoated plastic wraps. The coated samples also exhibited fewer colour degradation, though the coatings did not differ substantially from uncoated plastic wrap. Sensory analysis test subjects successfully distinguished the raw samples based on their treatment and gave a positive approval rating (66.7%) to the extract-enriched coatings when asked about edibility post storage.

In vitro antioxidant and antinociceptive properties of Porphyra vietnamensis

Background: Current investigation explores the anti-oxidant and antinociceptive potential of edible seaweed namely Porphyra vietnamensis.

Methods: Radical scavenging and antinociceptive potential of ethanolic (EE), aqueous (AE), acetone (ACE) and chloroform (CE) fractions were determined using various models and assays. Writhing, formalin, hot plate, acetic acid induce response models were performed to determine antinociceptive activity whereas different assays have been used to determine antioxidant potential.

Results: Among the various fractions, ACE showed maximum biological activity. In DPPH assay half maximal inhibitory concentration (IC50) was found to be 0.470 ug/ml (DPPH assay), 0.381 jug/m/ (H2O2 assay), 0.470 ug/ml (super oxide assay), 0.591ug/ml (lipid peroxidation) and 0.430 ug/ml (nitric oxide assay). However, comparatively the TPC was more in EE (977.0 mg GAE/gm DW).

Conclusion: It was concluded that acetone fraction of Porphyra showed marked antinociceptive and antioxidant activities, however pharmacological and chemical investigations are required to identify principle compounds responsible for activities and characterize their respective mechanism(s) for respective actions.

Effect of two seaweed polysaccharides on intestinal microbiota in mice evaluated by illumina PE250 sequencing

Effect of polysaccharides from two seaweeds, Porphyra haitanensis and Ulva prolifera, on intestinal microbiota in mice was evaluated by illumina PE250 sequencing. Analysis showed significant structural changes in fecal microbiota among the three sample groups. There were significant differences in the composition of fecal microbiota among the three groups at phylum and genus levels. At the phylum level, the most predominant phylum was Bacteroidetes contributing 58.76%, 73.39%, 75.38% and 64.40% of the fecal microbiota in K, Z, H and D groups respectively, followed by Firmicutes, contributing 37.61%, 23.99%, 21.87% and 30.82% respectively. Many genera were significantly higher in the Z and H group than in the K group, including Prevotellaceae UCG-001 (p<0.05) and Rikenellaceae RC9 (p<0.01). In conclusion, our results suggest that polysaccharide type and glycoside may contribute to shaping mice gut microbiota.

Effect of sulfated galactan from Porphyra haitanensis on H2O2-induced premature senescence in WI-38 cells

Porphyran sulfated galactan extracted from red algae Porphyra haitanensis is a sulfated polysaccharide, which possesses excellent activities. In the present study, WI-38 cells were treated with H₂O₂ to induce premature senescence and then the protection of porphyran against aging in vitro and associated molecular mechanisms were investigated. The protection occurred in a dose-dependent manner, offering an optimal efficacy starting at 10μg/mL. The proportion of SA-β-gal positive cells in porphyran group decreases from 53% to 23% in the cultures at 30 PDs. Porphyran has been detected specifically reducing SAHF-like foci formation in senescent cells. In addition, porphyran significantly affected the p53-p21 pathways in H₂O₂-treated WI-38 cells. Our data suggest the promising role of porphyran as an attractive and bio-safe agent with the potential to retard senescence and attenuate senescence-related diseases.