Antitumour activities of alginate-derived oligosaccharides and their sulphated substitution derivatives

Alginate lyase, isolated from a marine culture of Vibrio sp. 510, was used to depolymerize alginate. Two alginate-derived oligosaccharides (ADOs) of different molecular weight were sulphated with the formamide-chlorosulphonic acid method. The antitumour activities of the two ADOs and their sulphated substitution derivatives that exhibited no direct cytotoxic effects on tsFT210 cells, were subsequently determined on Kunming mice. The best antitumour performer was Oligosaccharide A (molecular weight 3798 Da, sulphation degree 1.3), which exhibited 70.4 and 66.0% tumour inhibition against solid Sarcoma 180 at doses of 100 and 50 mg kg − 1, respectively. For ADOs and their sulphated derivatives, an indirect antitumour effect via modulation of the host-mediated immune defences is postulated.