Proteins and Carbohydrates from Red Seaweeds: Evidence for Beneficial Effects on Gut Function and Microbiota

Abstract

Based on their composition, marine algae, and namely red seaweeds, are good potential functional foods. Intestinal mucosal barrier function refers to the capacity of the intestine to provide adequate containment of luminal microorganisms and molecules. Here, we will first outline the component of seaweeds and will summarize the effects of these on the regulation of mucosal barrier function. Special attention will be paid to unique components of red seaweeds: proteins and derived peptides (e.g., phycobiliproteins, glycoproteins that contain “cellulose binding domains”, phycolectins and the related mycosporine-like amino acids) together with polysaccharides (e.g., floridean starch and sulfated galactans, such as carrageenans, agarans and “dl-hybrid”) and minerals. These compounds have been shown to exert prebiotic effects, to regulate intestinal epithelial cell, macrophage and lymphocyte proliferation and differentiation and to modulate the immune response. Molecular mechanisms of action of peptides and polysaccharides are starting to be elucidated, and evidence indicating the involvement of epidermal growth factor receptor (EGFR), insulin-like growth factor receptor (IGFR), Toll-like receptors (TLR) and signal transduction pathways mediated by protein kinase B (PKB or AKT), nuclear factor-κB (NF-κB) and mitogen activated protein kinases (MAPK) will also be summarized. The need for further research is clear, but in vivo experiments point to an overall antiinflammatory effect of these algae, indicating that they can reinforce membrane barrier function.

Marine macroalgae as sources of protein and bioactive compounds in feed for monogastric animals

“…They also contain other plant components like lignin. Since dietary fiber is not digested in the small intestine, it reaches the large intestine or colon where it can be partially or fully fermented . The average total dietary fiber content can vary from 100 to 690 g kg −1 of DM.…”

“…Since dietary fiber is not digested in the small intestine, it reaches the large intestine or colon where it can be partially or fully fermented. 26,48 The average total dietary fiber content can vary from 100 to 690 g kg −1 of DM. In red and green macroalgae, the soluble fiber fraction ranges from 520 to 560 g kg −1 of total fiber, but the soluble fiber content of brown algae is usually higher.…”

Transcriptional response of Nautella italica R11 towards its macroalgal host uncovers new mechanisms of host–pathogen interaction

“…Additional genes involved in carbohydrate metabolism and differentially expressed in response to D. pulchra include those within a predicted galactose operon (Table 3), namely a-galactosidase and bgalactosidase. Galactose metabolism is of particular interest as the cell wall of red algae is comprised of sulphated galactans, a polysaccharide formed by monomers of a-galactose and b-galactose residues with a sulphate ester (Cian, Drago, de Medina, & Mart ınez-Augustin, 2015). Sulphated galactans constitute a crucial carbon source for a number of marine bacteria, which secrete glycoside hydrolases, such as galactosidases, to degrade polysaccharides (Guibet et al, 2007;Lee et al, 2014;Michel, Nyval-Collen, Barbeyron, Czjzek, & Helbert, 2006).…”

Screening of proteins based on macro-algae from West Java coast in Indonesian marine as a potential anti-aging agent

“…protein and derived peptides, phycolectins and polysaccharides [36]. Among the species under study, it was found that algae with good value of protein content were dominated by phylum Rhodophyta and Chlorophyta, while species from phylum Phaeophyta mostly possessed a lower amount of protein.…”