Glycolipids from Sponges

In recent years, Porifera are showing to be one of the richest source of new glycolipids. Many glycolipids from marine sponges, even though belonging to the wide class of glycosphingolipids, have unusual structure, such as the immunostimulating alpha-galactosyl-glycosphingolipids from Agelas species or the immunosuppressive plakoside A (1) and B from Plakortis simplex. In addition, marine sponges contain a number of atypical glycolipids, without counterpart among glycolipids from other phyla. For example, simplexides (2) are glycoside of a very-long-chain secondary alcohol, whereas plaxyloside (3) possesses a linear polyisoprenoid aglycon and a carbohydrate chain composed of six linearly arranged xylopyranose units. The systematic study of glycolipids from porifera is far from being terminated, and many new compounds are currently under investigation. This communication will deal with our most recent results in this field.