INDOLE ALKALOIDS AND TERPENOIDS FROM TABERNAEMONTANA-MARKGRAFIANA

The bark of Tabernaemontana markgrafiana yielded five acetylated penta cyclic triterpenes and 24 monoterpene indole alkaloids. The major trit erpene was baurenyl acetate, which constituted ca 6% of the crude petr ol extract. An X-ray study of iso-ursenyl acetate was carried out for the first time. The indole alkaloids were primarily of the iboga-type and constituted ca 3% of the dried bark and 20% of the total extracts. The major alkaloids were coronaridine, (19S)-heyneanine, voacangine a nd ibogamine. Among the minor components, four new alkaloids were iden tified: 5,6-dehydro-coronaridine, 3R-methoxy-coronaridine, 3R-methoxyv oacangine and the 10,11-demethoxy chippiine.