Bioactive alkylpyridinium compounds from marine sponges

Marine sponges are a rich source of structurally novel and biologically act ive molecules. Among them is a class of alkylpyridinium compounds commonly found in sponges belonging to the order Haplosclerida. Alkylpyridinium comp ounds exert several biological activities and are therefore interesting as potential therapeutics. This review presents most alkylpyridinium and some other pyridinium compounds that have been isolated from marine sponges so f ar. The compounds are listed according to their basic structural types with indications of their biological properties and their possible significance in sponge taxonomy.