Abstract

The present study has tentatively elucidated the structure of two acylated polyoxypregnane glycosides from Caralluma quadrangula (Forssk.) N.E.Br. (CQ). The analyses were performed using an electrospray-ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer in positive ionization modes to explore fragmentation pathways. The used ionization mode provided consistent and/or complementary information for most of the pregnane glycosides, their fragmentation sequences, and their aglycones. Presumably, this is due to higher efficiency, sensitivity, and better selectivity of the mass spectrometry-based method. The present experimental and theoretical report deals with the characteristic fragmentation behaviors of two acylated polyoxypregnane glycosides CQ1 and CQ2 from the aerial parts of C. quadrangular. A DFT Study was performed to elucidate the position of ikemoyl, and benzoyl residues in compounds CQ1 and CQ2, respectively.

摘要

本研究初步阐明了Caralluma quadrangula (Forssk.) NEBr 中两种酰化聚氧孕烷糖苷的结构。( CQ). 使用电喷雾电离四极飞行时间 (ESI-Q-TOF) 质谱仪在正电离模式下进行分析，以探索碎裂途径。所使用的电离模式为大多数孕烷糖苷、它们的碎片序列和糖苷配基提供了一致和/或互补的信息。据推测，这是由于基于质谱的方法具有更高的效率、灵敏度和更好的选择性。本实验和理论报告涉及 C. quadrangular 地上部分的两种酰化聚氧孕烷糖苷 CQ1 和 CQ2 的特征性碎裂行为。进行 DFT 研究以分别阐明化合物 CQ1 和 CQ2 中的 ikemoyl 和苯甲酰基残基的位置。