U. callophylla

Uncaria callophylla provided three bisindole alkaloids, callophylline (278), callophylline A (279), and callophylline B (280), constituted from union of heteroyohimbine and yohimbine moieties (183). Gambirine (281), a tetracyclic heteroyohimbine unique to U. callophylla (as is callophylline) (183,184), was the common unit present in all three bisindoles. The structures of these alkaloids were established based on their spectral data. Callophylline has been previously reported by Goh (185,186), and is identical to uncaramine, for which a detailed NMR study has also firmly established its structure (187). A novel bisindole strychnofuranine (282) was isolated from S. matopensis. The structure was determined based on the spectral data, which revealed its constitution from the union of two geissoschizal units, with C(16) and C(17) condensed into a furan ring (188). 

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