الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Mankind have used both marine seaweeds and freshwater algae for more than 4000 years in order to obtain food. In recent years, algae have been used as a source to extract certain products which have a biological activity and widely used in medicine as drugs.
Marine organisms comprise over half a million species due to their usual living environment as compared with terrestrial organ isms. Marine organisms produce a variety of metabolic substances which often have various unpre-cedental chemical structures. In recent years, an increasing number of marine natural products have been reported to exhibit various biological activities such as antimicrobial, physiological and pharmacological ones. Some metabolites have also been noted by their significant toxi-cities. The effort to find out antitumor substances from marine organisms has been also under taken in recent years, and several novel compounds (eg. peptide, polyether, alkaloid prostanoid etc.) with antitumor activities, have been isolated from marine organisms such as sponges, octocorals, micro- and macro-algae, tunicates, nudibranches, bryozoans and others.’ ’