The anti-inflammatory activity of marine natural products--6-n-tridecylsalicylic acid, flexibilide and dendalone 3-hydroxybutyrate.

Three novel marine substances, 6-n-tridecylsalicylic acid, flexibilide and dendalone 3-hydroxybutyrate, isolated from a brown alga, a soft coral and a dictyoceratid sponge respectively, were active after oral administration in both acute and chronic animal models of inflammation. 6-n-Tridecylsalicylic acid has similar anti-inflammatory activity but less ulcerogenic activity on a molar basis than salicylic acid. The structure and activity of flexibilide did not resemble any known anti-inflammatory substance. Dendalone 3-hydroxybutyrate was a potent inhibitor of prostaglandin synthetase activity and platelet aggregation in vitro.