Water-soluble polysaccharides of some brown algae of the Russian Far-East. Structure and biological action of low-molecular mass polyuronans

The contents and structural characteristics of water-soluble polysaccharides such as polyuronans, fucoidans and laminarans dependent on species, age of algae and the year of collection were studied for four species of brown algae— Alaria fistulosa, A. marginata, Fucus evanescens and Laminaria cichorioides, widespread on the Russian Far-East. The mature L. cichorioides was shown to be the richest source of both laminarans and fucoidans, F. evanescens—fucoidans. However, the Alaria species and young age algae F. evanescens contained practically polyuronans only. Alaria marginata and A. fistulosa were revealed to have a little of fucoidan and negligible quantity of laminaran (less than 1%). Contents of water-soluble polyuronans in A. fistulosa were approximately 2 times more, than in A. marginata. Water-soluble polyuronans of these seaweeds are represented by polymannuronans (Mm about 40 kDa). It was shown, that the young age algae F. evanescens contains the water-soluble low-molecular mass mannuronans along with the high-molecular mass laminarans. Stimulating action of polyuronans on the sea urchin developing embryos was revealed.