Marine organisms biological activities

There are numerous examples of intramolecular Heck reactions,151 such as in Entries 10 to 14. Entry 11 is part of a synthesis of the antitumor agent camptothecin. The Heck reaction gives an 11 1 endocyclic-exocyclic mixture. Entries 12-14 are also steps in syntheses of biologically active substances. Entry 12 is part of a synthesis of maritidine, an alkaloid with cytotoxic properties the reaction in Entry 13 is on a route to galanthamine, a potential candidate for treatment of Alzheimer s disease and Entry 14 is a key step in the synthesis of a potent antitumor agent isolated from a marine organism. 

In this review, we use the terms, biologically active or bioactive for any substance which elicits some biological response in another organism. Early investigations on bioactive marine isonitriles focussed on compounds that might serve as chemical defense agents (cf. Sect. 5.1). As chemists began to resolve mixtures into individual components, other tests related to antiviral, antimicrobial, or antiparasitic activity, were reported. Often, bioassays were performed... 

A second approach is to focus on plants or marine organisms that are known to contain biologically active compounds. The hope is that such plants or marine organisms may yield new and different chemicals that may also be effective against certain types of disease. 

The study of marine natural products has great possibilities for new products. Thus, Paul Scheuer from Hawaii studied bioactive compounds from mollusks and other marine sources. Luigi Minale, Raffaele Riccio and Maria lorizzi from Italy, conducted a comprehensive research on marine steroidal glycosides. Joel Kashman from Tel-Aviv University investigated on the biologically active natural products from marine organisms. 

The majority of indolocarbazole alkaloids, isolated so far from nature, are derivatives of the indolo[2,3-fl]pyrrolo[3,4-c]carbazole ring system 292. They have been isolated from soil organisms, slime molds, and marine sources (3,7,8,252-255), and have shown a broad range of potent biological activities, such as antifungal, antimicrobial, antitumor, and antihypertensive activity (3,7,256-260,267-270). Their activity as potent inhibitors of protein kinase C (PKC) has received special attention, and was the focus of several investigations (8,257,258,271-280). The history of these natural products dates back about 30 years (Scheme 2.73). 

Baka, J.T. Wells, R.J. (1980) Biologically active substances from Australian marine organisms. In Natural Products as Medicinal Agents, Beal, J.L. Reinhard, E., eds., Hippokrates Valag, Stuttgart, pp. 281-318. 

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