C21 steroids from the stems of Marsdenia tenacissima

To study the C_(21) steroids of the stems of Marsdenia tenacissima(Roxb.) Wight et Arn,various chromatography methods were used for the isolation of the constituents and their structures were identified by spectral analysis.Eight C_(21) steroids were isolated from the CHCl_3 extract,which were identified as 11α-O-tigloyl-17βtenacigenin B(1),17β-tenacigenin B(2),tenacigenoside A(3),11α-O-2-methylbutyryl-12β-O-acetyl tenacigenin B(4),tenacissoside H(5),marsdenoside A(6),tenacissoside G(7),and tenacissoside I(8).Among them,compound 1 is a new compound.