Ebuman-type alkaloid

The great number of different alkaloids found in Tabemaemontana precludes a discussion of the structure elucidation and chemistry of all of them. To keep the treatment concise, a major compromise was necessary. The alkaloids that have been reported in previous volumes of this treatise (as indicated in Table I) and their trivial modification will not be mentioned here. This compromise eliminates from the discussion well-established and long-known alkaloids that were isolated not only from Tabemaemontana but also from other genera. Moreover, the plumeran alkaloids isolated up to 1976 and ebuman-type and bisindole alkaloids isolated up to 1979 are covered in Volumes XVII and XX. The main efforts of this chapter will be focused on more recently isolated compounds, some of which are structurally and biogenetically relevant and have been found only in plants of the genus Tabemaemontana. 

LeuconoUne (141) (Figure 22), the first example of ebuman—vobasine-type bisindole alkaloids, was isolated from the stem bark of Malayan... 

Two new indole alkaloids, bisnicalaterine D (1), consisting of an ebumane and a corynanthe type of skeletons, and nicalaterine A (2) were isolated from the bark of Hunteria zeylanica. Their structures were elucidated by various spectroscopic data such as NMR and CD spectra. A series of bisnicalaterines and nicalaterine A showed potent anti-plasmodial activity against P. falciparum 3D7 [28]. 

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