A new triterpenoid saponin containing five sugars was isolated from the ethanolic root extract of Dipsacus japonicus Miq., and its structure was established as 3-O-［β-D-glucopyranosyl(1→4)］［α-L-rhamnopyranosyl(1→3)］-β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl-oleanoic acid. The sites of glycosylation and the sequence of sugars in the glycoside can be determined unambiguously and total assignment of severely overlapping proton resonance of sugar residues were achieved by a combined use of the 1D-SEMDY and NOE difference spectroscopy in rotating frame techniques, without having recourse to chemical degration or modification. The results showed that these new NMR techniques are very effective and convenient for the structure determination and spectral assignment of this class of compounds.
日本续断中新五糖皂甙的结构及其核磁共振光谱
缪振春1* 冯锐1 周永新1 魏锋2
（1. 军事医学科学院毒物药物研究所，国家生物医学分析中心，北京100850；2. 北京医科大学药学院，北京100083）
摘要：从日本续断 (Dipsacusjaponicus Miq .)根的乙醇提取物中分得一个新的三萜皂甙 ,其结构被鉴定为 3_O_[β_D_吡喃葡萄糖 (1→ 4) ][α_L_吡喃鼠李糖 (1→ 3) ]_β_D_吡喃葡萄糖 (1→ 3)_α_L_吡喃鼠李糖 (1→ 2 )_α_L_吡喃阿拉伯糖 齐墩果酸。采用一维SEMDY谱和旋转坐标NOE差谱核磁共振新技术相结合的方法 ,对糖体间和糖体与甙元间的连接顺序和连接位置进行了研究。该方法的测定结果可靠 ,使用方便 ,不需要对化合物进行化学降解和衍生化 ,糖基上重叠的1H_NMR信号可以分辨和明确归属。
关键词： 日本续断；五糖皂甙；旋转坐标NOE差谱；一维SEMDY谱；糖体的1H-NMR谱
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