Gardneria

G. Sarpagine type alkaloids (including gardneria bases).135... 

Gardmultine (C45H54N4O10) a bisindole alkaloid isolated from Gardneria multiflora Makino, comprises gardneramine and chitosenine linked by a spiro five-membered ring. The structure proposed from chemical and spectroscopic properties (50) was confirmed by the crystal-structure analysis (51). The structural formula and the stereodrawing, shown in Fig. 25, illustrate the spiro junction at atom C-16 between the two component alkaloids of gardmultine. 

Details of the structure elucidation of gardneramine and 18-demethyl-gardneramine have now been published these and other Gardneria alkaloids figure prominently in an account of Sakai s own investigations on indole alkaloids of Japanese plants. 

Hara et al. demonstrated a systematic approach to solvent system optimization with the separation of a series of uncaria and Gardneria alkaloids. 

RSP,yOh,Uncaria and Gardneria alkaloids Solvent system optimization procedure Spherosil X0A-600, 5 ym or Wakogel LCH-10, 10ym 100x0.5 n-hexane-THF, CH.Cl.-DEA, CHCl.-MeOH, THF-MeOH in varibus ratios J Stepgradient CH,Cl,-Me0H-DEA(100 0.1 0.01) to (100 110.6l) 42 ... 

Scheme I. Gardneria alkaloids isolated from Gardneria nutans Sieb. et Zucc.

Plants of the G. multiflora group do not contain gardnerine (1) or its derivatives, which are characterized by their typical indole chromophore. The main constituent, gardneramine (4), and various accompanying alkaloids are all at the oxidation level of oxindole. As shown in Table HI, thirteen monomeric and two dimeric Gardneria alkaloids have been isolated, and most of the structures were elucidated through chemical correlation with the established structure of 4 165,166,169,172). 

The structure of gardfloramine has recently been established as formula 27 by the use of X-ray crystallography. It is interesting to note that 27 has a pattern of oxidation on the aromatic ring different from that of gardneramine (4) and all other trimethoxylated Gardneria alkaloids (177). 

Gardneramine (4) exhibits a mild central depressive effect, while the comparable effect of gardnerine (1) is much weaker. A medium grade of acute toxicity was found for Gardneria alkaloids. Low toxicity was observed for hydroxygardnutine (3), which should be compared with that of gardnutine (2) (176) (Table IV). 

Other alkaloids of this structural type have been isolated from Gardneria nutans. Gardnutine " (77b), which is a 6-methoxyindole derivative and lacks... 

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