Novel Indole Alkaloids from the Leaves of Rauwolfia sumatrana JACK. in Thailand.

Chemical investigation of the leaves of Rauwolfia sumatrana JACK. collected in Thailand resulted in the isolation of three new indole alkaloids, 11-methoxystrictamine (1), rausutrine (4) and rausutranine (7), along with ten known bases, harman, tetraphyllicine, flexicorine, lanceomigine, perakine, β-carboline, peraksine, 10-hydroxystrictamine, cabufiline and compactinervine. Rausutrine (4) and rausutranine (7) are novel bis-indole alkaloids composed of an akuammilane unit and a vincorane unit, the latter of which has a unique iminoquinone function.