Simultaneous qualitative and quantitative analysis of 10 bioactive flavonoids in Aurantii Fructus Immaturus (Zhishi) by ultrahigh-performance liquid chromatography and high-resolution tandem mass spectrometry combined with chemometric methods.

Introduction: Aurantii Fructus Immaturus (Zhishi in Chinese) is the dried young fruit of Citrus aurantium L. (CA) and its cultivated varieties or Citrus sinensis Osbeck (CS). The content of flavonoids in different varieties of Zhishi may be significantly different. However, there is confusion about the botanical origin of Zhishi, and there is no reliable and systematic method to control Zhishi quality.

Objectives: We aimed to establish an ultrahigh-performance liquid chromatography method coupled with diode-array detection and high-resolution tandem mass spectrometry (UPLC-DAD-HRMS/MS) for the quantitative analysis of 10 flavonoids in Zhishi that could be used for quality control and botanical origin identification.

Methodology: A UPLC-DAD-HRMS/MS method was established for simultaneous identification and quantification of 10 flavonoids. Separation was performed on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 μm) with 0.1% formic acid and acetonitrile as mobile phase under gradient elution. MS was performed in positive and negative ionisation modes. The flavonoids in 41 batches were isolated and quantified. Zhishi of different botanical origins were identified by chemometrics.

Results: The results showed that the established method for the determination of 10 components was reliable and accurate. Chemometrics could be used to distinguish Zhishi of different botanical origins. There were significant differences in the contents of 10 flavonoids in samples of different botanical origins.

Conclusions: The quantitative analysis method in this study can be used to accurately determine the content of 10 flavonoids and provide a chemical basis for quality control and botanical origin identification of Zhishi.