The role of Cnidaria in drug discovery.

A lot of organisms, including microbes, algae, plants and animals, are known to produce substances of pharmacological concern provided with different biological activity. At present, several bioactive natural substances have application as drugs, pigments, biocides or have been utilized to synthesize biologically active molecules. Oceans are inhabited by an enormous amount of species. For this reason the marine environment is thought to be the richest and the most complex ecosystem. Nevertheless, despite the 50-year-long research activity and interest in this subject, natural compounds from marine organisms have been considered slightly in pharmacology and have had limited therapeutical application. Cnidarians are gelatinous invertebrates, in large part inhabiting seawaters, which play an important role among venom-producing organisms and are viewed with particular concern owing to the implications of their stings on human health and on economy. Cnidarian tentacles and/or oral arms, and at times the whole body, are armed with nematocysts, specialized venom-containing structures provided with a tightly wrapped and spiralized thread used to inject the venom. Taking into account that during the last decades a lot of interesting bioactive substances have been isolated from Cnidaria and demonstrated cytotoxic, hemolytic, anti-infl ammatory, antitumoral, anti-infective, anti-parasite, as well as other interesting properties, this chapter aims to review the recent data about cnidarian extracts that could be of concern for drug discovery as potential sources for pharmaceuticals.