CORDIS - EU research results

Chemistry of Marine Natural Products from the Mediterranean

Final Report Summary - CHIMICAMARINAANAPOLI (Chemistry of Marine Natural Products from the Mediterranean.)

Natural products are presently still the main source of bioactive compounds used both in the pharmaceutical industry and in traditional health care systems. Moreover, even newly developed pharmaceuticals are still predominantly mostly based on basic carbon skeletons first detected in natural products. If such natural products are found to interact with druggable targets but are prevented from direct use as active ingredients of pharmaceuticals, e.g. because their chemical properties are in conflict with one of Lipinski’s rules of five, semi-synthetic derivatives of these natural products are developed and used for the production of synthetic but natural product mimetic active ingredients of pharmaceutical drugs. One of the oldest and the most widely used representative of this group of substances is acetylsalicylic acid, the active ingredient of aspirin. In recent years, marine organisms have provided the most interesting new structures of natural products and also some of the most fascinating new bioactivities with potential relevance for human health. Apart from these anthropocentric investigations of marine natural products, which already have some tradition, studies focused on the ecological relevance of marine natural products are emerging scientific topics.
In the course of the CHIMICAMARINAAANAPOLI project natural products both from marine as well as from terrestrial sources have been isolated and their structures have been elucidated. Moreover, analytical systems to identify and quantify these compounds have been established. Finally, studies on the bioactivity and ecological relevance of these compounds have been performed. As a basis for these and future studies in natural products chemistry, additionally two reviews, one on the rare natural product isoetin, and one on metabolites from seagrasses as an important group of marine organisms, have been written within the project.
In detail, analytics, chemosystematics and bioactivities of isoetin (Biochemical Systematics and Ecology 2015, 61, 402-412) and secondary metabolites of seagrasses including their chemical diversity, bioactivity, and ecological function (Phytochemistry 2016, 124, 5-28) have been reviewed. Additionally, inspired by experiences made in the course of this project, a “viewpoint” encompassing suggestions for consistent characterisation and documentation of the source materials for studies in phytochemistry and phytopharmacology has been drafted (Phytochemistry, submitted 11.03.2016). Original manuscripts encompass one on stilbenoids from the Illyrian endemic Tragopogon tommasinii (Phytochemistry 2015, 117, 254-266) and one on monoterpenoids from Aruncus dioicus s.l. (Phytochemistry, submitted 26.02.2016). In the natural products chemistry of marine organisms, five studies were performed: I) one on secondary metabolites from the most important Mediterranean seagrass Posidonia oceanica. This study, however was terminated because another European group published their results in the very same area, while our studies were still under way (Grignon-Dubois and Rezzonico, 2015. Phenolic fingerprint of the seagrass Posidonia oceanica from four locations in the Mediterranean Sea: first evidence for the large predominance of chicoric acid. Botanica Marina 58, 379–391). II) The chemical investigation of a sponge sample from the Mediterranean coast of Egypt yielded metabolites already known from another marine source, the study has not yet been concluded because the taxonomic identification of the source material is still in progress. III) An extensive study on the chemical ecology of furanosesquiterpenes as aposematic olfactory signals has been finalised in the course of the project and is currently being drafted for submission in a high level journal (Proceedings of the National Academy of Science USA). IV) A comparative chemical analysis has been conducted on the polyene fraction from the lipophilic extract of different collections (from Spain, Italy, and Argentina) of Undaria pinnatifida, an invasive alga. Differences in the structure of the main components of distinct collections have been evidenced. The chemical characterization of some unprecedented polyenes will be completed shortly. V) Another publication worked on in the course of the project is the second edition of a book chapter on “HPLC in Chemosystematics” which will be part of the new edition of “High Performance Liquid Chromatography in Phytochemical Analysis”. Here, new aspects on marine organisms have been introduced and other parts of the chapter have been updated.
The direct socio-economic impact of the results which are all in the area of pure science will be (and was expected to be) negligible. However, the clearly defined prerequisites of meaningful studies in natural products chemistry, as stated in particular the viewpoint drafted in the course of the project, will have wider impact and will be of importance in making research in natural products chemistry a more focused, more reproducible, more reliable, and therefore also more successful branch of science. This in term could help in the discovery of new natural products with a real impact in the fields e.g. agriculture, human and veterinary medicine, and cosmetics.
Also the wider societal implications of the project are mostly indirect in nature. Proving, as we did in the course of this project, that obscure plant species and difficult to access species of marine organisms yield interesting new chemical compounds with wide ranges of potential bioactivities and practical applications, including economically interesting applications, make the protection of these species a less esoteric and therefore easier to defend part of the political agenda. Our results provide therefore one more (important) argument to make the conservation of natural resources including native species in their natural habitats a political priority.