Yang Jing, Wang An-Qi, Li Xue-Jing, Fan Xue, Yin Shan-Shan, Lan Ke
Key laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.
Key laboratory of Drug Targeting and Drug Delivery System, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu 610041, China; State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China.
J Pharm Biomed Anal. 2016 May 10;123:147-54. doi: 10.1016/j.jpba.2016.02.017. Epub 2016 Feb 15.
Flavonoids analysis in herbal products is challenged by their vast chemical diversity. This work aimed to develop a chemical profiling strategy for the semi-quantification of flavonoids using extracts of Ginkgo biloba L. (EGB) as an example. The strategy was based on the principle that flavonoids in EGB have an almost equivalent molecular absorption coefficient at a fixed wavelength. As a result, the molecular-contents of flavonoids were able to be semi-quantitatively determined by the molecular-concentration calibration curves of common standards and recalculated as the mass-contents with the characterized molecular weight (MW). Twenty batches of EGB were subjected to HPLC-UV/DAD/MS fingerprinting analysis to test the feasibility and reliability of this strategy. The flavonoid peaks were distinguished from the other peaks with principle component analysis and Pearson correlation analysis of the normalized UV spectrometric dataset. Each flavonoid peak was subsequently tentatively identified by the MS data to ascertain their MW. It was highlighted that the flavonoids absorption at Band-II (240-280 nm) was more suitable for the semi-quantification purpose because of the less variation compared to that at Band-I (300-380 nm). The semi-quantification was therefore conducted at 254 nm. Beyond the qualitative comparison results acquired by common chemical profiling techniques, the semi-quantitative approach presented the detailed compositional information of flavonoids in EGB and demonstrated how the adulteration of one batch was achieved. The developed strategy was believed to be useful for the advanced analysis of herbal extracts with a high flavonoid content without laborious identification and isolation of individual components.
草药产品中的黄酮类化合物分析因其巨大的化学多样性而面临挑战。这项工作旨在以银杏叶提取物（EGB）为例，开发一种用于黄酮类化合物半定量的化学剖析策略。该策略基于这样一个原理：EGB中的黄酮类化合物在固定波长下具有几乎相等的分子吸收系数。因此，黄酮类化合物的分子含量能够通过常用标准品的分子浓度校准曲线进行半定量测定，并通过已表征的分子量（MW）重新计算为质量含量。对20批EGB进行HPLC-UV/DAD/MS指纹图谱分析，以测试该策略的可行性和可靠性。通过对归一化紫外光谱数据集进行主成分分析和Pearson相关分析，将黄酮类峰与其他峰区分开来。随后，通过质谱数据对每个黄酮类峰进行初步鉴定，以确定其分子量。需要强调的是，由于与I带（300-380nm）相比，II带（240-280nm）处黄酮类化合物的吸收变化较小，因此更适合用于半定量目的。因此，半定量在254nm处进行。除了通过常用化学剖析技术获得的定性比较结果外，这种半定量方法还展示了EGB中黄酮类化合物的详细组成信息，并揭示了一批产品是如何掺假的。人们认为，所开发的策略对于高黄酮含量草药提取物的高级分析很有用，无需费力地鉴定和分离单个成分。
