Abstract
Bioactivity-directed fractionation of the crude extract of Stemona tuberosa led to the isolation and characterization of four new stenine-type Stemona alkaloids, namely tuberostemonine J (2), tuberostemonine H (3), epi-bisdehydrotuberostemonine J (4) and neostenine (5), together with the known neotuberostemonine (1). These five isolated alkaloids were examined for antitussive activity in guinea pig after cough induction by citric acid aerosol stimulation. In this report, we demonstrated, for the first time, that compounds 1 and 5 showed significant antitussive activities. Further study of the structure-activity relationship on these isolated alkaloids and two synthetic analogues revealed that the saturated tricyclic pyrrolo[3,2,1-jk][1]benzazepine nucleus is the primary key structure contributing to the antitussive activity and all cis configurations at the three ring junctions are the optimal structure for the antitussive activity of stenine-type Stemona alkaloids.
Key words
Stenine-type alkaloids - antitussive activity -
Stemona tuberosa Lour. -
Stemonaceae
References
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1
Pilli R A, Ferreira de O liveira, MdC.
Recent progress in the chemistry of the Stemona alkaloids.
Nat Prod Rep.
2000;
17
117-27
Prof. Dr. Ge Lin
Department of Pharmacology
Faculty of Medicine
The Chinese University of Hong Kong
Shatin, N. T.
Hong Kong SAR
Phone: +852-2609-6824
Fax: +852-2603-5139
Email: linge@cuhk.edu.hk
