Alkaloids isolated from indigenous South African Amaryllidaceae: Crinum buphanoides (Welw. ex Baker), Crinum graminicola (I. Verd.), Cyrtanthus mackenii (Hook. f) and Brunsvigia grandiflora (Lindl)

Screening for alkaloids produced in four indigenous South African Amaryllidaceae plants, namely, Crinum buphanoides Welw. ex Baker, Crinum graminicola I. Verd., Cyrtanthus mackenii Hook. f and Brunsvigia grandiflora Lindl, leads to the isolation of lycorine as the one metabolite produced by all the species studied. C. graminicola produced lycorine in the best yield (2.1 g/kg). Moreover, 1-O-acetyl- and 2-O-acetyl-lycorine, pratorimine, hippadine and tazettine were isolated from C. buphanoides. Haemanthidine, haemanthamine and criwelline were isolated from C. graminicola, while tazettine and 11-hydroxyvittatine were produced by C. mackenii. Finally, crinamine and 11-hydroxyvittatine were isolated from B. grandiflora. This is the very first report on the isolation of these alkaloids from the four South African Amaryllidaceae. Furthermore, some interesting chemosystematic evaluations are reported.