C₂₁ steroids from the stems of Marsdenia tenacissima

To study the C₂₁ 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 C₂₁ steroids were isolated from the CHCl₃ extract, which were identified as 11α-O-tigloyl-17β-tenacigenin 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.