Koumine, Humantenine, and Yohimbane Alkaloids from Gelsemium elegans

Article abstract of DOI:10.1021/np5009619

Nine new alkaloids of the koumine (1-4), humantenine (5-7), and yohimbane (8, 9) types as well as 12 known analogues were isolated from the leaves and vine stems of Gelsemium elegans. Compound 1 is the first N-4-demethyl alkaloid of the koumine type, compound 7 is the first nor-humantenine alkaloid, and compounds 8 and 9 are the first N-1-oxide and the first seco-E-ring alkaloids, respectively, of the yohimbane type. Compounds 1 and 7 exhibited moderate cytotoxicity against five human tumor cell lines with IC₅₀ values in the range 4.6-9.3 μM. (Figure Presented)