四川九节龙中新五糖三萜皂苷结构的NMR研究

从四川九节龙(Ardisia pusilla A.DC)的正丁醇提取物中分得一个三萜皂苷.经过测定,它为:3-O-β-D-吡喃木糖(1→2)-β-D吡喃葡萄糖(1→4)] β-D-吡喃葡萄糖(1→2)-β-D-吡喃葡萄糖(1→2)]-α-L-吡喃阿拉伯糖仙客来亭A,为一新五糖皂苷(1).糖体间和糖体与苷元间的连接顺序和连接位置采用一维SEMDY和旋转坐标系NOE差谱核磁共振新技术相结合的方法进行了研究.结果表明,这一方法用于测定寡糖链结构具有准确、简便、快速等特点,对化合物不需要进行化学降解或衍生化,糖基的重叠¹H NMR信号可以分辨和正确指定.

NMR STUDY ON A NEW TRITERPENOID GLYCOSIDE OF ARDISIA PUSILLA

A new triterpenoid saponin was isolated from Ardisia pusilla A. DC.which has improved immunological and antitumor and its structure established as 3-O-β-D-xylopyranosyl (1→2) -β -D-glucopyranosyl(1→4)] β -D-glucopyranosyl(1→2) -β-D-glucopyranosyl(1→2)]-α -L-arabinopyranosyl cyclamiretin A.The results showed that the chemical structure of oligosaccharide chains of the saponin could be elucidated by the combination of 1D-SEMDY and NOE difference spectroscopy in rotating frame techniques, without having recourse to chemical degration or modification. Complete assignments of severely overlapping proton resonance of the sugar residues were obtained.