title: Skin irritants of Euphorbia fortissima.
abstract: By means of a combination of partition and chromatographic methods six irritant constituents were isolated from the fresh latex of Euphorbia fortissima. Compounds A-D were di-esters of the common parent diterpene 12-deoxyphorbol, and compounds E and F were mono-esters of the same diterpene. The fresh latex had an irritant dose 50% (ID50) on mice of 0-64 mug mul- minus 1. Compounds A-D are short-acting irritants reaching a maximum activity within 4 h of application to the skin, whilst the monoesters maintained potent irritant effects for up to 24 h. Selective hydrolysis of the di-esters at the C-20 primary ester group also produced mono-esters of greater potency after 24 h. An increase in the length of the fatty acid located at C-13 produced greater biological activity in both the mono- and di-ester groups.
mesh_terms: D000818:Animals; D006868:Hydrolysis; D007509:Irritants / Q000032:analysis / Q000302:isolation & purification* / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D051379:Mice; D010703:Phorbol Esters / Q000032:analysis / Q000302:isolation & purification*; D010704:Phorbols / Q000302:isolation & purification*; D010944:Plants / Q000032:analysis*; D012408:Rubber / Q000032:analysis
chemical_list: D007509:Irritants; D010703:Phorbol Esters; D010704:Phorbols; D012408:Rubber