ABSTRACT
Esters of ingenol and other ingenane polyols probably account for the greatest proportion of the skin irritant compounds found in the plant family Euphorbiaceae. As a class of compounds, they are comparatively more homogeneous than the tiglianes and the daphnanes, their parent polyols differing from one another only in the number and position of hydroxyl groups. Ingenane polyol esters, in common with tigliane and daphnane polyol esters, are also known to exhibit piscicidal activity, this property being exploited in some laboratories to monitor fractionation of extracts thought to contain such compounds. In contrast to the structure elucidation of phorbol, partial and proposed structures for which were a feature of the chemical literature for a number of years prior to the final surrender of phorbol to X-ray crystallography, the structure elucidation of ingenol, as its 3,5,20-triacetate, was achieved. electron-impact mass spectrometry (EIMS) of 16-hydroxyingenol-3,5,16-20-tetraacetate is typical of ingenane polyol esters.
