Chapter 8 Steroid Alkaloids: Alkaloids of Apocynaceae and Buxaceae

Abstract

Publisher Summary This chapter discusses studies focusing on steroid alkaloids of Apocynaceae and Buxaceae. The study of Holarrhena alkaloids resulted in structure elucidation of numerous alkaloids, which were either newly isolated or subjected to reinvestigation. The structure of conkurchine and related bases was established. In newly isolated alkaloids new findings are restricted chiefly to broadening of the knowledge of the character of skeletal substitution, for example, isolation of mononitrogen bases, alkaloids substituted by the 3α-amino group, pregnane derivatives lacking the substituent in position 18, and α-amino alcohols. A more significant finding was the isolation of kurcholessine, which is substituted by a methyl group in position 4, thus resembling Buxus alkaloids in this particular structural feature. Steroid alkaloids were also found in Funtumia and Malouetia. The genus Funtumia comprises tropical trees indigenous to equatorial and West Afrika. The genus Malouetia occurs in both Africa and South America. It is distinguished by the same types of alkaloids as Funtumia and Holarrhena. Of particular interest is the isolation of the quaternary alkaloid malouetine with curarizing effect in the African Malouetia bequaertiana Woods.