C21 Steroidal Glycosides from the Root of Cynanchum paniculatum

摘要

Cynanchum paniculatum (Bunge) Kitag. (Asclepiadaceae) grows in areas of Asia, such as China and Korea, and has been used in Chinese traditional medicine for treating snake bites and chronic bronchitis. The root of this plant has been used as a diuretic in Korean folk medicine. Steroidal glycosides and phenolic compounds were reported in C. paniculatum and showed neuroprotective activity and analgesic effect. The EtOH extract of C paniculatum shows protective activity for treating herpes simplex encephalitis.8 In our continuing efforts to study the secondary metabolites of natural plant sources, the MeOH extract of C. paniculatum was investigated, and two new steroidal glycosides (1 and 2) and five known ones (3-7) (Figure 1) were isolated. The structures of the new isolated compounds were determined based on spectroscopic analyses (~1H- and ~(13)C-NMR, DEFT, ~1H-~1H COSY, HMQC, HMBC, and ROESY).