Novel acylated saponins from montbretia (Crocosmia crocosmiiflora). II. The structures of crocosmiosides C, D, E, F, G and I.
作者:Yoshihisa ASADA、Takehito UEOKA、Tsutomu FURUYA
DOI:10.1248/cpb.38.142
日期:——
Six novel triterpenoid saponins, named crocosmiodsides C, D, E, F, G, and I, were isolated from the corms of montbretia (Crocosmia crocosmiiflora N.E.Br., Iridaceae). The structures of these saponins were determined on the basis of spectral and chemical evidence. They are 3, 28-di-O-glycosides of polygalacic acid, carrying hydroxylated palmitic acid derivatives at the C-4 position of the β-D-fucopyranosyl moiety. Namely, crocosmiosides C (1), D (2), E (3), F (4), and G (5) bear 3-O-[α-L-arabinopyranosyl-(1→ 6)-β-D-glucopyranosyl]-28-O-2-O-[β-D-apio-D-furanosyl-(1→4)-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl]-3-O-(β-D-glucopyranosyl)-β-D-fucopyranosyl}-polygalacic acid as as common structural unit of the desacylsaponin moiety, while the structures of the acyl moiety of crocosmiosides C (1), D (2), E (3), F (4), and G (5) are 9-oxo-16-hydroxy-2-β-D-xylopyranosyloxyhexadecanoic acid, 9, 16-dihydroxy-2-β-D-xylopyranosyloxyhexadecanoic acid, 2, 9, 16-trihydroxyhexadecanoic acid, 2, 9-dihydroxy-16-α-L-rhamnopyranosyloxyhexadecanoic acid, and 9-oxo-16-α-L-rhamnopyranosyloxy-2-β-D-xylopyranosyloxyhexadecanoic acid, respectively. In addition, the structure of crocosmioside I (6) which has a different desacylsaponin moiety was elucidated as 3-O-[α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]-28-O-2-O-[β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl]-3-O-(β-D-glucopyranosyl)-4-O-(2, 9-dihydroxy-16-α-L-rhamnopyranosyloxyhexadecanoyl)-β-D-fucopyranosyl}-polygalacic acid.
从 montbretia(Crocosmia crocosmiiflora N.E.Br.,鸢尾科)的球茎中分离出六种新型三萜皂苷,命名为 crocosmiodsides C、D、E、F、G 和 I。这些皂苷的结构是根据光谱和化学证据确定的。它们是聚半乳糖酸的 3, 28-二-O-糖苷,在 β-D-吡喃岩藻糖基部分的 C-4 位上带有羟基化棕榈酸衍生物。即,番红花苷 C (1)、D (2)、E (3)、F (4) 和 G (5) 带有 3-O-[α-L-阿拉伯吡喃糖基-(1→ 6)-β-D-吡喃葡萄糖基]-28-O-2-O-[β-D-apio-D-呋喃糖基-(1→4)-β-D-吡喃木糖基-(1→4)-α-L-吡喃鼠李糖基]-3- O-(β-D-吡喃葡萄糖基)-β-D-吡喃岩藻糖基}-聚半乳酸作为去酰基皂苷部分的共同结构单元,而番红花苷C(1)、D(2)、E( 3)、F(4)和G(5)为9-氧代-16-羟基-2-β-D-木吡喃糖氧基十六烷酸、9、16-二羟基-2-β-D-木吡喃糖氧基十六烷酸、2、9、分别为16-三羟基十六烷酸、2, 9-二羟基-16-α-L-吡喃糖氧基十六烷酸和9-氧代-16-α-L-吡喃鼠李氧基-2-β-D-木吡喃糖氧基十六烷酸。此外,具有不同脱酰基皂苷部分的crocosmioside I (6)的结构被阐明为3-O-[α-L-阿拉伯吡喃糖基-(1→6)-β-D-吡喃葡萄糖基]-28-O-2 -O-[β-D-吡喃木糖基-(1→4)-α-L-吡喃鼠李糖基]-3-O-(β-D-吡喃葡萄糖基)-4-O-(2, 9-二羟基-16-α- L-吡喃糖基氧基十六酰基)-β-D-吡喃岩藻糖基}-聚半乳糖酸。