Structures and bioactivity of alkaloids from Stemona

The roots of Stemona species (Stemonaceae) have been used as antitussive agent and insecticide for thousands of years in Traditional Chinese Medicine. Alkaloids, present as the main components in the roots of this plant, are believed to be responsible for its bioactivities. In our systematical investigation on the five main Stemona species in China, more than 60 alkaloids were isolated and structure identified. Those alkaloids, according to their structural characteristics, could be classified into seven subtypes, namely stemofoline-type, protostemonine-type, maistemonine-type, tuberostemonine-type, croomine-type, stemoninine-type and parvistemonine-type.

On the basis of the clue of traditional applications, most of the isolated compounds were screened for two bioactivity indications. One is the in vivo screening against agricultural relevant insect pests; the other is the guinea pig cough model. The results indicated that some stemofoline-type alkaloids showed good insecticidal activities, while some stemoninine-type alkaloids exhibited significant antitussive activities.

Through our investigation, antitussive and insecticidal activities of this traditional medicine have been well demonstrated by relevant distinct bioactive alkaloids in certain species. The phytochemical and pharmaceutical investigations of these Stemona species offered the substantial basis to disclose the relationships between certain Stemona species, the alkaloids of different types and the corresponding bioactivities.

References: [1] Li-Gen Lin et al. (2006), J. Nat. Prod., 69: 1051–4. [2] Chang-qiang Ke et al. (2003), Chinese Chem. Lett., 14: 173–5. [3] Yang Ye et al. (2003), Tetrahedron Lett., 44: 7171–3. [4] Yang Ye et al. (1994), Phytochemistry, 37: 1205–8.