Alginate oligosaccharides and derivatives thereof, as well as manufacture and use thereof

Alginate oligosaccharide derivatives according to the following formula (II), or pharmaceutically acceptable salts thereof, in which the alginate oligosaccharide is composed of β-D-mannuronic acid linked by α-1,4-glucosidic bonds: * * Formula ** in which n represents 0 or an integer from 1 to 19.