Sulfated Galactofucans: An Outstanding Class of Fucoidans with Promising Bioactivities

Abstract

Fucoidans encompass versatile and heterogeneous sulfated biopolysaccharides of marine origin, specifically brown algae and marine invertebrates. Their chemistry and bioactivities have been extensively investigated in the last few decades. The reported studies revealed diverse chemical skeletons in which l-fucose is the main sugar monomer. However, other sugars, i.e., galactose, mannose, etc., have been identified to be interspersed, forming several heteropolymers, including galactofucans/fucogalactans (G-fucoidans). Particularly, sulfated galactofucans are associated with rich chemistry contributing to more promising bioactivities than fucans and other marine polysaccharides. The previous reports in the last 20 years showed that G-fucoidans derived from Undaria pinnatifida were the most studied; 21 bioactivities were investigated, especially antitumor and antiviral activities, and seven unique biomedical applications compared to other marine polysaccharides were demonstrated. Hence, the current article specifically reviews the biogenic sources, chemistry, and outstanding bioactivities of G-fucoidans providing the opportunity to discover novel drug candidates.

Characterization and Cytotoxic Activity of Microwave-Assisted Extracted Crude Fucoidans from Different Brown Seaweeds

“…The high ratio of glucose in L. saccharina _MAE confirmed the high sugar content shown in Table 2 . Additionally, the absence of glucose in F. vesiculosus _MAE indicated its galactofucan nature and might propose a superior bioactivity compared with the other fucoidans of the current study [ 22 ].…”

“…Phenolic compounds are known to show specific activity against cancer and tumors [ 65 , 66 ]. Additionally, the monosaccharide composition indicated that the F. vesiculosus _MAE fucoidan belongs to the sulfated galactofucans which are characterized by their outstanding and potential bioactivities [ 22 ]. Hence, the bioactivity of phenolic residuals and sulfated galactofucan skeleton might explain the higher cytotoxic behavior against MCF7 and Caco-2 cell lines of F. vesiculosus _MAE compared with the other fucoidan fractions.…”

“…However, the recent studies found that the antioxidant activity is correlated potentially with the phenolic contents in crude fucoidan extracts [ 21 ]. Interestingly, fucoidans’ chemical and physico-chemical properties have been successfully related with their bioactivities in numerous structure-activity relationship studies such as sulfation degree and molecular weight, and monomeric composition [ 12 , 21 , 22 ]. Particularly, the antitumor activity of fucoidan fractions is typically attributed to low molecular weight and high sulfation degree [ 23 , 24 ].…”

Structural and functional characterization of the novel endo-α(1,4)-fucoidanase Mef1 from the marine bacterium Muricauda eckloniae

“…This type is found in the order Fucales, including, for example, Fucus evanescens, F. vesiculosus and F. serratus (Bilan et al, 2002;Ale & Meyer, 2013), whereas fucoidans from species of the order Laminariales, for example Saccharina latissima, have a backbone composed mainly of �(1!3)-linked l-fucosyl moieties (Bilan et al, 2010). A third type, known as sulfated galactofucans (Zayed et al, 2022), are found in various Fucales species prevalent in the Pacific, Western Pacific (South China Sea) and Indian Oceans, for example Turbinaria ornata, Sargassum mcclurei and S. oligocystum, and have a backbone containing both l-fucosyl and d-galactosyl residues (Zvyagintseva et al, 2021). In all types of fucoidans the l-fucosyl moieties may be substituted with sulfate (-SO À…”

Fucoidan from Marine Macroalgae: Biological Actions and Applications in Regenerative Medicine, Drug Delivery Systems and Food Industry

“…Recently, the pharmacological properties of secondary metabolites and other bioactive substances in marine macroalgae have been reviewed by Priyanka et al [ 8 ], emphasizing their antimicrobial, antitumor, anti-inflammatory, antidiabetic, antiprotozoal, antiviral, and antioxidant activities. Zayed et al [ 9 ] reviewed the biogenic sources and outstanding bioactivities of galactofucans/G-fucoidans, giving insights into the possibilities of novel drug discoveries. The current review focuses on the structure, chemical composition, extraction and purification of fucoidan from the marine brown macroalgae.…”