Studies On The Chemical Constituents Of The Stems Of Marsdenia Tenacissima

The stem of Marsdenia tenacissima(Asclepiadaceae)was firstly recorded as an herbal medicine in "Materia Medica of Southern Yun Nan"(Dian Nan Ben Cao)with the name of Tongguangteng.Its nature and flavor is bitter and sub-cold.It can clear away the heat-evil,expel superficial evil,eliminate inflammation,clear away heat-toxin,relieve cough and asthma and relieve pain by removing obstruction.It was used to treat bronchitis,bronchial asthma,cancer,neoplasia and long-standing toxin. It is known as a rich source of secondary metabolites such as C₂₁steroids,triterpenes, saccharides,cyclitols etc.The chemical constituents of the 70%EtOH extract from the stems of Marsdenia tenacissima(Roxb.)Wight et Arn.were studied systematically.Twenty-three compounds were isolated by repeated silica gel,Sephadex LH-20 column chromatography and prep.HPLC.On the basis of spectral data and measurement of physico-chemical characters,the structures of these compounds were identified as tenacigenin B(1),17β-tenacigenin B(2),11α-O-tigloyl-17β-tenacigenin B(3), 11α-O-2-methylbutyryl-12β-O-acetyl tenacigenin B(4),11α-O-2-methylbutyryl -12β-O-benzoyl tenacigenin B(5),11α-O-2-methylbutyryl-12β-O-tigloyl tenacigenin B(6),tenacigenoside A(7),tenacissoside G(8),17β-tenacissoside G(9), tenacissoside H(10),tenacissosideâ… (11),marsdenoside A(12),marsdenoside F(13), tenacissoside B(14),tenacissoside O(15),17β-tenacissoside O(16),α-methyl -pachybioside(17),sucrose(18),conduritol A(19),dihydroconduritol(20),vanillic acid(21),β-sitosterol(22)and daucosterol(23).Among them,compounds 3,9,15 and 16 are four new compounds,and compounds 17 and 21 were obtained for the first time from Marsdenia genus.