Abstract
Seven new monoterpene alkaloids (1 − 7), along with 16 known analogues, were isolated from an aqueous decoction of the hook-bearing stems of Uncaria rhynchophylla (Gou-teng). Their structures were determined by spectroscopic data analysis, single crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are stereoisomers belonging to a novel type of pseudoindoxyl monoterpene alkaloids, 3 is the first monoterpene furoindole alkaloid from nature, and 4 − 7 are derivatives of the known monoterpene alkaloids featuring different structures.
Acknowledgements
We dedicate this paper to Prof. Yu Dequan in commemoration of his life-time contribution to natural products researches.
Disclosure statement
No potential conflict of interest was reported by the authors.