The 6 years that have elapsed since the subject of biological activity in terpenoids and their derivatives was previously reviewed in this series [1] have witnessed many notable advances in our knowledge of the pharmacological, physiological and biochemical properties of this major group of compounds. For instance, a number of triterpene acids have recently been shown [2–6] to be potent uncoupling agents of oxidative phosphorylation, i.e. to inhibit the mitochondrial biosynthesis of adenosine-5′-triphosphate without inhibiting mitochondrial respiration — an action which is suggested [7] to be linked with their anti-inflammatory activity [8–13] and ability to heal gastric ulcers [14 to 19]. Again, it is now apparent that various lower terpenoids have a much greater physiological significance in insects and in plants than was realised at the time of the earlier survey and so the new approaches to insect control and weed control opened up by this knowledge can be expected to see intensive exploitation in the near future. In the case of insects, apart from the discoveries of further terpenoids as constituents of defensive secretions in various species, a number of mono- and sesqui-terpenoids have now been assigned their rightful place beside other relatively simple aliphatic compounds as pheromones and sex attractants of particular species [20–22].

Biological activity of the terpenoids and their derivatives--recent advances.

no protein or acetone; a few leukocytes and bacteria per high-power field. Other tests negative. Chest disclosed diffuse mottled densities in both lung fields, more marked on the right than the left (Fig. 1). These changes were deemed compatible with an extensive chemical inhalation pneumonitis. Capillary blood gas determinations revealed p02 78 and pC02 56 mm. Hg. The infant was immediately placed in a mist tent with oxygen, given intra-

R.A. Evans

Papers

Antitussive action of aerosolized terpenes in guinea pigs and humans