Chapter 1 Alkaloids of Strychnos and Gardneria Species

Publisher Summary This chapter provides an overview of the Slrvcknos alkaloids, Gardneria alkaloids, and pharmacology of Gardneria alkaloids. Five species in Japan and Taiwan have been collected, and their alkaloids have been chemically studied. All of the species are lianas, and they seem to be divided into two groups, based on morphological similarities of the inflorescences—the first group consists of two species, Gardneria nutans Sieb. et Zucc. and G . insularis Nakai, having only one to three flowers in an inflorescence, while the second group, including G. multiflora Makino, G. Shimudui Hayata (restricted to Taiwan), and G. liukiuensis Hatsushima, has 3 to 10 flowers in a congested inflorescence. Plants of the G. nutans group (Japanese name Horai-kazura) contain gardnerine and gardneramine as the main bases, and gardnutine, hydroxygardnutine, and 18-hydroxygardnerine as minor constituents. The features of the structure of gardneramine are the presence of an iminoether group, which can be regarded as a masked oxindole, and Z orientation of the side chain double bond. Plants of the G. multifloru group do not contain gardnerine or its derivatives, which are characterized by their typical indole chromophore.