Prospectus and suggestions for further research

Abstract

There is a search for natural bioactive terpenoids by scientists of several disciplines. Biologists seek for bioactive essential oils and other plant-derived terpenoids, biochemists try to elucidate biosynthetic routes and to reveal the structure and function of the corresponding enzymes, gene technologists trace the responsive genes. Biologists and pharmacologists organize expeditions to rain forests and other regions of the world in search for new compounds. Not everyone has to go a long way: Indian scientific journals regularly report the isolation of bioactive terpenoids not seen before. Many novel terpenoids are discovered by marine biologists. In chapter 4.1 and section 7.1.8 terpenoids with anti-tumour functions have been reported to originate from marine biology. Once their modes of action have been elucidated they can be tested for different purposes. The marine pulmonates Trimusculus reticulatus and T. conica (Trimusculidae) have a unique lifestyle. The adults are essentially sessile and feed by filtering a mucous net produced by subepithelial glands on the mantle and sides of the foot. Being sessile they cannot escape from predators such as seastars, and their way of collecting and ingesting food (mostly microalgae) makes that they have to cope with intruders of their habitat. There is little space in the intertidal zone and much competition. Manker and Faulkner (1996) investigated the distribution and function of secondary metabolites from trimusculid limpets and found two diterpenes highly concentrated in the mantle, foot and mucus of T. reticulatus (Fig. 8.1).