The succulent Euphorbias of Nigeria. II. aliphatic diterpene esters of the latices of E. poisonii Pax. and E. unispina N.E. Br.

Methanol-preserved latices of E. poisonii and E. unispina were examined for irritant principles. Six esters of the parent diterpene 12-deoxyphorbol were identified by spectroscopic and chemical methods. Three were the aliphatic esters 12-deoxyphorbol-13-(2-methyl-butyrate), 12-deoxyphorbol-13-angelate and 12-deoxyphorbol-13-isobutyrate, and a further three compounds were the 20-acetyl equivalents. Isobutyrate esters were absent from the latex of E. unispina, an observation of possible value in the identification of these two similar species.