Monoterpenoid Indole Alkaloids from the Leaves of Alstonia scholaris

chemical investigation on the ethanol extract from the leaves of Alstonia scholaris led to the isolation of two new monoterpenoid indole alkaloids, 17-formyl-10-demethoxyvincorine N(4)-oxide ( 1 ) and 10-methoxyalstiphyllanine H ( 2 ), along with one known alkaloid, 10-demethoxyvincorine N(4)-oxide ( 3 ). Their structures were established on the basis of extensive chromatographic properties and chemical and physicochemical methods.