SEASONAL VARIATIONS OF THE COMPOSITION, STRUCTURAL FEATURES, AND ANTITUMOR PROPERTIES OF POLYSACCHARIDES FROM Padina pavonica (LEBANON) AS A FUNCTION OF COMPOSITION

The variation of the polysaccharide composition of the brown alga Padina pavonica from the Mediterranean Sea was studied as a function of the collection season (April-July). It was shown that the principal polysaccharide (8.0-13.3% of dry alga weight) was alginic acid. Its content did not undergo significant changes from April to July. The content of water-soluble polysaccharides (laminarans and fucoidans) was low (<0.3% of dry alga weight). Water-soluble polysaccharides of the studied alga were practically pure fucoidan. The amount of laminarans was insignificant (<0.01% of dry alga weight). The content of fucoidans increased in alga samples from May through July. It was shown that P. pavonica is a promising source of alginic acids, which have a high capacity for gelation, and fucoidans, which exhibit antitumor action against RPMI-7951 human melanoma cells.