College of the First Clinical Medical, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, China.
First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510405, China.
Rapid Commun Mass Spectrom. 2021 Mar 30;35(6):e9012. doi: 10.1002/rcm.9012.
Flavones are significant indicators of quality in traditional Chinese medicines (TCMs) and thus play a significant role in the quality control of TCMs in the pharmaceutical industry. Most flavones in Dendrobium nobile Lindl, a TCM with a long cultivation history and rich sources, have not been identified. This study was aimed at identifying the flavones in D. nobile from various habitats.
High-performance liquid chromatography (HPLC) coupled with diode-array detection and HPLC multiple-stage tandem mass spectrometry was used to identify the chemical constituents of D. nobile from various habitats, and a method was established to determine the content of vicenin II, violanthin and isoviolanthin. Hierarchical cluster analysis, principal component analysis and orthogonal partial least-squares discriminant analysis were used to analyze the variations among 26 batches from different habitats.
A total of 33 flavones were tentatively identified. Twenty-five flavones, previously undescribed in D. nobile, were acylated by p-coumaroyl, feruloyl, sinapoyl or 3-hydroxy-3-methylglutaryl. The D. nobile habitats were distinguished by significant differences in their flavone content. The C-glycosyl flavones were demonstrated to be characteristic compounds for evaluating D. nobile from various habitats. In particular, flavones acylated with 3-hydroxy-3-methylglutaryl were specific compounds that were only detected in samples from Yunnan.
The results of this study could be used to improve the quality control of D. nobile and could provide references for the identification of acylated C-glycosyl flavones in other natural products.
类黄酮是中药（TCM）质量的重要指标，因此在制药行业的 TCM 质量控制中起着重要作用。历史悠久、资源丰富的铁皮石斛中的大多数类黄酮尚未被鉴定。本研究旨在鉴定来自不同栖息地的铁皮石斛中的类黄酮。
采用高效液相色谱（HPLC）-二极管阵列检测和 HPLC 多级串联质谱联用技术鉴定来自不同栖息地的铁皮石斛的化学成分，并建立了测定次野鸢尾黄素、芫花素和异芫花素含量的方法。采用层次聚类分析、主成分分析和正交偏最小二乘判别分析对来自不同栖息地的 26 批样品进行分析。
共鉴定出 33 种类黄酮。25 种类黄酮在铁皮石斛中以前没有被描述过，它们被对香豆酰基、阿魏酰基、肉桂酰基或 3-羟基-3-甲基戊二酰基酰化。铁皮石斛的栖息地因其类黄酮含量的显著差异而不同。C-糖苷类黄酮被证明是评价不同产地铁皮石斛的特征化合物。特别是，只有在来自云南的样品中才检测到 3-羟基-3-甲基戊二酰基酰化的类黄酮。
本研究结果可用于提高铁皮石斛的质量控制，并可为其他天然产物中酰化 C-糖苷类黄酮的鉴定提供参考。
