Two New C21 Steroidal Glycosides from the Roots of Cynanchum paniculatum

Abstract

Cynanchum paniculatum (Bunge) Kitag is a vivacious herb broadly distributed in China, Japan and Korea, whose dried roots have been used as a Chinese herbal medicine for the treatment of rheumatic arthralgia, epigastric pain, toothache, lumbago, traumatic injuries, and eczema [ 1 , 2 , 3 ]. In the previous work, it has been confirmed that C. paniculatum contains C 21 steroidal glycosides [ 4 , 5 ]. Pregnanes and their glycosides have shown many aspect activities, such as antitumor, antifungal, antiviral and cytotoxic activities [ 6 , 7 ]. Our previous works found that pregnanes and their glycosides could inhibit tobacco mosaic virus through suppressing the expression of viral subgenomic RNA but without affecting the accumulation of viral genomic RNA [ 6 ]. Therefore, in order to find the structurally unique natural products in C. paniculatum and explore their biological activities, we investigated the dichloromethane extract of C. paniculatum , and two new steroidal glycosides paniculatumosides H ( 1 ) and I ( 2 ), together with four known ones glaucogenin C ( 3 ) [ 8 ], cynatratoside A ( 4 ) [ 8 ], cynapanoside A ( 5 ) [ 9 ] and neocynapanogenin F 3-O- β - d -oleandropyranoside ( 6 ) [ 10 ] were isolated. Furthermore, we tested the anti-TMV activities and cytotoxicity of these compounds (Fig. 1 ).