The dermatitis-producing constituents of Euphorbia hermentiana latex.

Five ingenane derivatives, 3-O-n-(deca-2,4,6-trienoyl)-16-O-[(Z)-2-methyl-2-butenoyl]-16-hydroxyingenol (1), 3-O-[(Z)-2-methyl-2-butenoyl]-5,16,20-O-triacetyl-16-hydroxyingenol (2), 3-O-[(Z)-2-methyl-2-butenoyl]-16,20-O-diacetyl-16-hydroxyingenol (3), 3-O-[(Z)-2-methyl-2-butenoyl]-20-O-acetylingenol (4), and 3-O-[(Z)-2-methyl-2-butenoyl]-16-O-acetyl-20-deoxy-16-hydroxyingenol (5) were isolated with a new procedure that uses droplet counter-current chromatography, from a dermatitis-producing fraction of the latex of Euphorbia hermentiana Lem. The structures of the new compounds 2,3, and 5 were established by the interpretation of their spectroscopic data and those of their hydrolytic and acetylated derivatives.