Pure Appl. Chem., Vol. 75, Nos. 2–3, pp. 343–352, 2003. © 2003 IUPAC 343 Detection of pharmacologically active natural products using ecology. Selected examples from Indopacific marine invertebrates and sponge-derived fungi* ,† P. Proksch 1,‡ , R. Ebel 1 , R. A. Edrada 1 , P. Schupp 2 , W. H. Lin 3 , Sudarsono 4 , V. Wray 5 , and K. Steube 6 1 Institut für Pharmazeutische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1 Geb. 26.23, D-40225 Düsseldorf, Germany; 2 Centre for Marine Biofouling and Bio-Innovation, University of New South Wales, Sydney, 2052 Australia; 3 National Research Laboratories of Natural and Biomimetic Drugs, Peking University, No.8 Xueyang Road, 100083 Beijing, PR China; 4 Centre for Traditional Medicine, Gadjah Mada University, Yogyakarta 55281, Indonesia; 5 Gesellschaft für Biotechnologische Forschung mbH, Mascheroder Weg 1, D-38124 Braunschweig, Germany; 6 DSMZ, Mascheroder Weg 1b, D-38124 Braunschweig, Germany Abstract: This review article presents our group’s recent research findings with regard to bioactive natural products from marine sponges and tunicates, as well as from sponge- derived fungi. The organisms discussed originate in the Indopacific region, which has an exceptionally rich marine biodiversity. Major topics that are covered in our review include the chemical ecology of sponges, focusing on defense against fishes, as well as the isolation and identification of new bioactive constituents from sponges and tunicates. Sponge-derived fungi are introduced as an emerging source for new bioactive metabolites, reflecting the cur- rently growing interest in natural products from marine microorganisms. INTRODUCTION Nature has continuously provided mankind with a broad and structurally diverse array of pharmaco- logically active compounds that have proved to be indispensable for the cure of deadly diseases or as lead structures for novel pharmaceuticals [1]. At least until the arrival of antibiotics such as penicillin, streptomycin, and others, higher terrestrial plants had certainly the strongest impact on drug discovery from natural sources. Oddly enough, even though the oceans cover over 70 % of the earth’s surface, they have only comparatively recently attracted the serious attention of drug prospectors, which is in sharp contrast to the important and long-standing impact of the sea on human nutrition. Marine natural products chemistry began to focus on the discovery of new potential drugs in 1951 when Bergmann and Feeney [2] reported on the isolation of the unusual nucleosides spongouridin and spongothymidin from the sponge Cryptotethya crypta, which served as lead structures for antiviral drugs such as Ara-A. More than a decade later, the discovery of prostaglandins in the Caribbean gorgonian Plexaura homomalla * Pure Appl. Chem. 75, 141–419 (2003). An issue of reviews and research papers based on lectures presented at the 23 rd IUPAC International Symposium on the Chemistry of Natural Products, Florence, Italy, 28 July–2 August 2002 on the theme of natural products. † Dedicated to the memory of our late coworker Ms. Cho Cho Minh from Myanmar. ‡ Corresponding author: Tel.: 0049-211-8114163; Fax: 0049-211-8111923; E-mail: proksch@uni-duesseldorf.de