Kite Geoffrey C, Howes Melanie-Jayne R, Simmonds Monique S J
Royal Botanic Gardens, Kew, Richmond TW9 3AB, UK.
Rapid Commun Mass Spectrom. 2004;18(23):2859-70. doi: 10.1002/rcm.1698.
Analysis of 50% aqueous methanolic extracts of bark of Quillaja saponaria Molina (quillaja) by liquid chromatography/mass spectrometry (LC/MS), using negative ion electrospray, revealed over 100 saponins. The majority could be assigned to known structures or generalised variations of these from the product ion spectra obtained by serial mass spectrometry in a quadrupole ion trap mass spectrometer. Ten saponins contained a fatty acid domain terminated with both a pentose and deoxyhexose unit, a feature thus far only reported in QS-III. Twenty saponins were based on a hydroxylated derivative of quillaic acid, whereas only six 22beta-hydroxyquillaic acid saponins have been described. The occurrence of pairs of saponins differing only by the presence of a rhamnose or xylose unit in the C-3-substituted saccharide was readily observed in two-dimensional mass maps, and these showed the presence of the unreported 'rhamnose partner' of QS-III. However, one sample labelled as Q. saponaria appeared to lack all saponins containing rhamnose in the C-3 saccharide. Methods to authenticate saponin extracts of quillaja by LC/MS are suggested based on the general metabolomic profile, the occurrence of specific major saponins covering known structural variations, or the presence of saponins containing the unusual fatty acid domain, revealed by neutral loss analysis.
采用负离子电喷雾液相色谱/质谱联用（LC/MS）技术，对皂树（皂树属莫利纳）树皮的50%甲醇水溶液提取物进行分析，结果显示有100多种皂苷。通过四极杆离子阱质谱仪进行串联质谱分析得到的产物离子光谱，大多数皂苷可归为已知结构或其一般变体。10种皂苷含有一个以戊糖和脱氧己糖单元结尾的脂肪酸结构域，这一特征迄今为止仅在QS-III中报道过。20种皂苷基于奎来酸的羟基化衍生物，而仅描述过6种22β-羟基奎来酸皂苷。在二维质谱图中很容易观察到仅在C-3取代糖中存在鼠李糖或木糖单元而不同的皂苷对，这些图谱显示了未报道的QS-III的“鼠李糖配对物”的存在。然而，一个标记为皂树的样品似乎在C-3糖中缺乏所有含鼠李糖的皂苷。基于一般代谢组学特征、涵盖已知结构变体的特定主要皂苷的存在，或通过中性丢失分析揭示的含有不寻常脂肪酸结构域的皂苷的存在，建议采用LC/MS技术对皂树皂苷提取物进行鉴定的方法。
