Major ity of the marine natural products have been isolated from sponges, coelenterates (sea whips, sea fans and soft corals), tuni cates, opisthobranch molluscs (nudi branchs, sea hares, etc.), echinoderms (starfish, sea cucumbers, etc.) and bryo zoans (moss animals) and a wide variety of marine microorganisms in their tis sues2.