Basic information of seaweed polysaccharide

There are two kinds of bioactive substances in seaweed. One kind is substances with low molecular weight, which can directly or indirectly affect metabolism in vivo after absorption, mainly including halogen compounds, terpenoids, bromophenols, hydroquinone, seaweed tannin, laminin and so on. The other is intercellular viscous polysaccharide, which is difficult to digest and absorb, and mainly includes alginic acid, fucoidan, sulfated polysaccharide, agar and carrageenan in red algae. Polysaccharide is an important component of all living organisms, which plays an important role in controlling cell division, regulating cell growth and maintaining normal metabolism of living organisms.

Algal polysaccharide mainly comes from kelp, Sargassum fusiforme (Sargassum), macroalgae, submerged algae, fucoidan and other algae. Algae polysaccharide mainly includes fucoidan, fucoidan and fucoidan starch. The crude products of fucoidan, fucoidan and fucoidan separated from kelp are all white and yellowish powders. The purified sodium alginate is white silk; Fucoidan is milky white powder; Both of them are soluble in water and insoluble in organic solvents such as ethanol, acetone and chloroform.

Fucoidan sulfate was extracted from brown algae by Bilanmi, and the structural composition of some fragments was determined. The molar ratio of L- fucose, sulfate and acetate is 1: 2.22: 0.08, and the sugar chain structure is composed of typical disaccharide units. The disaccharide unit structure (see figure 1) shows that the sulfate content is relatively high. Algal polysaccharides can be divided into four categories: brown algae polysaccharides, red algae polysaccharides, green algae polysaccharides and cyanobacteria polysaccharides, among which the first two categories are studied more.

1 red algae polysaccharide Red algae polysaccharide mainly includes agar, carrageenan and agar-carrageenan intermediate polysaccharide, all of which are galactans combined with galactose.

2 Fucoidan Fucoidan mainly comes from kelp, kelp, fucoidan and fucoidan, including fucoidan, fucoidan and laminarin.

3 green algae polysaccharide green algae polysaccharide is xylan and/or mannan that constitutes its cell wall filler, and there is a small amount of glucan in the cytoplasm.

At present, there is little research on cyanobacteria polysaccharide, mainly represented by spirulina polysaccharide.