Koumine, Humantenine, and Yohimbane Alkaloids from Gelsemium elegans

Abstract

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.

Natural Products Research in China From 2015 to 2016

“…Leaves and vine stems of Gelsemium elegans (Xishuangbanna, Yunnan, China) afforded nine new koumine-, humantenine-, and yohimbine- type alkaloids as well as 12 known analogs. Compound 601 was the first example of N -4-demethyl koumine type alkaloid, orhumantenine A ( 602 ) was the first norhumantenine alkaloid, and compounds 603 and 604 were the first N -1-oxide and seco-E-ring yohimbane type alkaloids, respectively (Xu et al, 2015d ).…”

Nucleophile-intercepted Beckmann fragmentation reactions

“…Herein, we report the rst instance of nucleophile-intercepted Beckmann fragmentations of indolinyl oximes using a diverse set of nucleophiles to generate cyclohexa [b]indolines featuring four contiguous stereocenters (eqn (1)). We anticipate that rapid and efficient access to these compounds may be useful in the synthesis of members of the akuammiline [10][11][12] and koumine [13][14][15][16] families of natural products (Fig. 2).…”

“…Furthermore, the aromatic nucleus of the indoline may be substituted with various halides, methyl, or the electron-rich methoxy group (entries 2, 6-10 and 12). Reactions involving both tryptamineand tryptophol-derived oximes 6k-o also proceeded smoothly to provide the desired products (entries [11][12][13][14][15]. The use of oximes with a free N-H indoline nitrogen resulted in decomposition.…”

The Difference in Cytotoxic Activity between Two Optical Isomers of Gelsemine from Gelsemium elegans Benth. on PC12 Cells

“…( G. elegans ), referred to as “Gou-Wen” and “Duan-Chang-Cao” in China, belongs to Loganiaceae family and is a famous toxic plant that is widely distributed in Southeast Asia and southern China [1]. This plant has been used as a traditional medicine for the treatment of pain, spasticity, skin ulcers, migraines, neuralgia, sciatica, cancer, and various types of sores [2,3,4,5,6,7,8]. The Gelsemium genus includes three species, all of which have a large number of alkaloids, including indole, bisindole, and monoterpenoid alkaloids [7,9,10,11].…”