Alkaloids of catha edulis(khat). Part 1. Isolation and characterisation of eleven new alkaloids with sesquiterpene cores (cathedulins); identification of the quinone–methide root pigments
Extraction of fresh and dried specimens of Catha edulis(khat) originating from Ethiopia, Kenya, and the Yemen, has led to the isolation of eleven new celastraceous alkaloids having molecular weight of ca. 600—ca. 1 200 and a sesquiterpene core. They fall into three groups: (a) cathedulins E2 and E1, esters of a pentahydroxydihydroagarofuran; (b) cathedulins K1 (Y1), K2, K6, and K15, esters of euonyminol a nonahydroxyagarofuran, containing one dilactone bridge; and (c) cathedulins E3(K11), E4, E5, E6, and K12, more complex esters of euonyminol containing two dilactone bridges. Apart from norpseudoephedrine (cathine) and the corresponding ketone (cathinone) and a related pyrazine, khat contains steroids and triterpenes including, in the root-bark, a range of triterpenoid quinonemethides characteristic of the Celastraceae.