A fucoidan from Sargassum fusiforme was isolated and characterized.
Backbone was alternate 1,2-linked α-d-Manp and 1,4-linked β-d-GlcpA.
Branches contain fucose, xylose, galactose, glucuronic acid and sulfate group.
Fucoidan could significantly inhibit the tube formation.
Oligosaccharide fractions exhibited the anti-angiogenesis activities.