Two new pregnane glycosides from the root of Cynanchum auriculatum

Abstract

Two new pregnane glycosides (1 and 2), together with four known ones (3– 6), were isolated from the roots of Cynanchum auriculatum Royle ex Wight (Asclepiadaceae). On the basis of detailed spectroscopic analysis and chemical method, the structures of new compounds were characterized to be metaplexigenin 3-O-β-D-cymaropyranosyl- (1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (1), metaplexigenin 3-O-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside (2). All the isolated compounds (1–6) were tested for their in vitro inhibitory activity against the growth of human colon cancer cell lines HCT-116. Compounds 5 and 6 showed significant cytoxicities with IC₅₀ values of 43.58 µM and 52.21 µM.

Keywords:

• Asclepiadaceae
• Cynanchum auriculatum
• pregnane glycosides
• cytotoxic activity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Figure 1. Structures of compounds 1 and 2..

Figure 2. Key HMBC and ¹H-¹H COSY correlations of compounds 1 and 2.

Additional information

Funding

This research work was financially supported by the grant (2020A1515010389) of Natural Science Foundation Committee of Guangdong Province, and the National Key R&D Program of China (No.2017YFC1703800).