Abstract: From the stem of Marsdenia tenacissima(Roxb)Wight et Arn.,four new steroidal glycosides desgnated tenacissoside F(3),G(4),H(5) and I(6)possessing the same sugar chain:6-deoxy-3-O-methyl-β-D-allopyanosyl-(1→4)-β-D-oleandropyranosose,along with two known tenacissoside A(1),and B(2),were isolated and characterized by means of spectroscopic and chemical evidence.Furthermore ,diester groups at C-11 and C-12 of aglycone of these glycosides had been assigned by COLOC and 2D NMR techniques.

Key words: Asclepiadaceae, Marsdenia Tenacissima, C21 steroidal glycosides, Tenacissosides F, G, H and I

摘要： 从通光藤(Marsdenia tenacissima)的茎中分离得到4个新的C21甾体甙-通光藤甙F(3)，G(4)，H(5)和I(6)，以及2个已知化合物通光藤甙A(1)和B(2)。根据光谱数据和化学方法推定了其结构。同时，通过COLOC谱和二维核磁共振谱指定了这些化合物中甙元上11和12位的酯基确切连接位置。

关键词: 萝摩科, 通光藤, C21甾体甙, 通光藤甙F, G, H和I