koumine and humantenine

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.

Topics: Alkaloids; Animals; Antineoplastic Agents, Phytogenic; Cyclic N-Oxides; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Gelsemium; Indole Alkaloids; Inhibitory Concentration 50; Lipopolysaccharides; Macrophages; Mice; Molecular Structure; Nitric Oxide; Nuclear Magnetic Resonance, Biomolecular; Plant Leaves; Plant Stems; Secologanin Tryptamine Alkaloids