Biological Activity of Polycyclic Compounds

Abstract

A review is made for the recent findings on biological activities (antimicrobial, plant-hormonal, herbicidal, insecticidal, pheromone, medicinal, and toxicological) of natural as well as synthetic aliphatic bridged and condensed polycyclic compounds (alkaloids, steroids, prostaglandins, adamantane and heteroadamantane compounds, and dicyclopentadiene derivatives being excluded). Polycyclic skeletons so far used are mainly bicyclic norborn (en) yl, isobornyl, bicyclo [2. 2. 2] octyl, bicyclo [3. 3. 1] nonyl and their oxygen and nitrogen analogs, and more complex tri- and polycyclic ones are found less utilities, probably because of the difficulties involved in their acquisitions. In the field of medicine synthesis, most of the efforts are devoted to modify the established drugs with polycyclic residues in the hope of enhancement of the activities with the high lipophilicity and reluctant decomposition delivered by these three-dimensional, densely packed, bulky skeletons, rather than to discover new polycyclic structures with unexpected pharmacological actions. The latter purpose seems to have been achieved mostly by the physiological studies of natural products which, also hereafter, would remain to be one of the most fruitful methodology for this objective.