Biological properties and potential of compounds extracted from red seaweeds

Abstract

Macroalgae have been recently used for different applications in the food, cosmetic and pharmaceutical industry since they do not compete for land and freshwater against other resources. Moreover, they have been highlighted as a potential source of bioactive compounds. Red algae (Rhodophyta) are the largest group of seaweeds, including around 6000 different species, thus it can be hypothesized that they are a potential source of bioactive compounds. Sulfated polysaccharides, mainly agar and carrageenans, are the most relevant and exploited compounds of red algae. Other potential molecules are essential fatty acids, phycobiliproteins, vitamins, minerals, and other secondary metabolites. All these compounds have been demonstrated to exert several biological activities, among which antioxidant, anti-inflammatory, antitumor, and antimicrobial properties can be highlighted. Nevertheless, these properties need to be further tested on in vivo experiments and go in-depth in the study of the mechanism of action of the specific molecules and the understanding of the structure–activity relation. At last, the extraction technologies are essential for the correct isolation of the molecules, in a cost-effective way, to facilitate the scale-up of the processes and their further application by the industry. This manuscript is aimed at describing the fundamental composition of red algae and their most studied biological properties to pave the way to the utilization of this underused resource.

Global seaweed farming and processing in the past 20 years

“…Polysaccharide is the most developed molecule in the cell wall of seaweed, accounting for 40-50 percent of its dry matter. It is worth noting that carrageenan and agar are the most relevant and developed compounds in red seaweed (Carpena et al 2022). Carrageenan, the primary algal group of red seaweed, has been extensively studied for its wide range of biological activities, including its antitumor, antiproliferation, antiviral and anticoagulant activities (Guo et al 2019;Cotas et al 2020aCotas et al , 2020bCotas et al , 2020cJazzara et al 2016;Gomaa & Elshoubaky et al 2016;Carlucci et al 1997).…”

Antioxidant Activity and Inhibition of Liver Cancer Cells’ Growth of Extracts from 14 Marine Macroalgae Species of the Mediterranean Sea

“…Specifically, the most important macroalgae’s metabolites accounting for their antioxidant activity are phenols (e.g., phlorotannins, flavonoids, phenolic acids, and bromophenols), polysaccharides (e.g., carrageenans, sulfated polysaccharides, agar, fucoidan), fatty acids, phytosterols, proteins (e.g., phycobiliproteins), terpenoids (e.g., carotenoids, zeaxanthin), pigments (e.g., chlorophylls), and iodine [ 87 ]. For instance, sulfated polysaccharides (e.g., fucoidan and alginate) from C. sinuosa , C. barbata , and U. rigida exhibited antioxidant activity [ 82 , 88 , 89 , 90 , 91 , 92 ]. Red macroalgae such as Gigartina and Gracilaria species are also rich in carrageenans and sulfated polysaccharides, demonstrating antioxidant properties [ 93 ].…”

“…Macroalgae extracts have been reported to possess anticancer activity [ 88 ]. Macroalgae’s main group of metabolites exhibiting anticancer properties are polysaccharides (e.g., sulfated polysaccharides and carrageenans), halogenated metabolites, phenols (e.g., bromophenols, polyphenols, and phlorotannins), pigments (e.g., pheophorbide A), iodine, lipids (e.g., sulfolipids), proteins (e.g., lectins), and terpenes (e.g., brominated terpenes and elatol) [ 88 ]. Thus, macroalgae extracts, apart from their antioxidant capacities, inhibited growth of liver HepG2 cancer cells ( Figure 6 ).…”

Edible Seaweeds Extracts: Characterization and Functional Properties for Health Conditions

“…Porphyra tenera , known as Nori, is a red seaweed considered the most valuable maricultured seaweed in the world, as it is one of the most popular edible seaweeds used in sushi and soups [ 32 , 33 ]. It is known to have major bioactive compounds phenolic compounds, sulfated polysaccharides, and peptides [ 34 , 35 ]. It is also a source of dietary fiber, essential fatty acids, vitamins, and minerals [ 36 ].…”

“…Three of the most consumed edible seaweeds, Aramé, Fucus, and Nori, were matched for the composition and biological activities associated to the aqueous extracts of the seaweeds. Though there are various reports about Aramé [ 13 , 14 ], Fucus [ 22 , 23 , 24 ], and Nori [ 34 , 35 ], individually there are no studies comparing their composition and beneficial health effects.…”