From the latex of Synadenium grantii Hook F. (Euphorbiaceae) were isolated by chromatographic methods five diterpene 12,13-diesters of the tigliane-type parent alcohols 4-deoxyphorbol (la), 4,20-dideoxy-5u-hydroxyphorbol (2a) and 20-.deoxy-5u-hydroxyphorbol (3a) with isobutyric, tiglic and phenylacetic acid. Of these, 4-deoxyphorbol-13-(phenylacetate)-12-tiglate (if) turned out to be highly irritant on the mouse ear while the rest of the esters had rather low or no irritant activity; if was also assayed for tumor-promoting activity and proved to be almost inactive.
TLCSpots were detected under UV light (254 mm) and made visible with vanillin/sulfuric acid (13).Downloaded by: NYU. Copyrighted material.