Immunomodulating effects of extracts from Icelandic marine invertebrates

Iceland has a unique position in the North Atlantic, with marine biodiversity largely unexplored with respect to chemical constituents. In particular, the confluence of cold-water currents from Atlantic gyres and warm-water geothermal activity accounts for a unique marine biogeography that has never been evaluated for the potential of marine natural product diversity. The aim of this project is to investigate the immunomodulating effects of extracts and fractions obtained from marine invertebrates collected around Iceland. As dendritic cells play an important role as a bridge between the innate and adaptive immune response the effects of extracts from marine organisms were tested by analysing the cytokine secretion and expression of surface molecules on human monocyte-derived dendritic cells. Sixty extracts were prepared by solvent extraction [dichloromethane/methanol (1:1)] and screened for immunomodulating effects. Four extracts at the concentration 100µg/mL were shown to be cytotoxic and seven reduced both IL-12p40 and IL-10 secretion and CD86 expression. An active extract of the sponge, Isodictya palmata, was further fractionized using modified Kupchan partition and the chloroform and hexane fractions were shown to be active in the dendritic cell model. Further fractionation and characterization is in progress.