Assay of amino acids in leaves of Eucommia ulmoides under arbor forest mode and leaf-oriented cultivation mode by pre-column derivatization HPLC / 中国中药杂志

This study aims to develop the pre-column derivatization high performance liquid chromatography(HPLC) method for the determination of 16 kinds of amino acids in Eucommia ulmoides leaves, and compare the content of amino acids in the leaves harvested at different time and under leaf-oriented cultivation mode(LCM) and arbor forest mode(AFM). The HPLC conditions are as below: phenyl isothiocyanate(PITC) as pre-column derivatization agent, Agilent ZORBAX C_(18 )column(4.6 mm×250 mm, 5 μm), mobile phase A of acetonitrile-water(80∶20), mobile phase B of 0.1 mol·L~(-1) sodium acetate solution-acetonitrile(94∶6), gradient elution, flow rate of 1.0 mL·min~(-1), injection volume of 5 μL, column temperature of 40 ℃, and detection wavelength of 254 nm. The HPLC profile indicated well separation of 16 kinds of amino acids and the amino acid content in E. ulmoides leaves was up to 16.26%. In addition, the amino acid content in leaves of E. ulmoides under LCM was higher than under AFM. The amino acid content varied with the harvesting time. Through orthogonal partial least squares discriminant analysis, the amino acids of E. ulmoides under LCM and AFM were compared, which can distinguish the leaves under LCM from those under AFM. Principal component analysis was applied to comprehensively score the amino acids of E. ulmoides leaves. The results showed that the score of leaves under LCM was higher than that under AFM. Nutritional evaluation results indicated that the proteins in E. ulmoides leaves belonged to high-quality vegetable proteins. The established method for the determination of amino acid content is reliable. With the amino acid content as index, the leaf quality of E. ulmoides under LCM is better than that under AFM. This study lays a theoretical basis for the promotion of LCM for E. ulmoides and the development of medicinal and edible products from E. ulmoides leaves.

Analysis and Identification of Flavonoids in Citri Reticulatae Pericarpium with Different Aging Time by UPLC-Q-Orbitrap HRMS / 中国实验方剂学杂志

Objective:To analyze and identify the flavonoids of Citri Reticulatae Pericarpium with different aging time by an ultra-performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry （UPLC-Q-Orbitrap HRMS）. Method:Compounds were separated on Agilent Extend-C₁₈ column （3.0 mm×100 mm， 1.8 μm）， mobile phase was 0.1% acetic acid aqueous solution （A）-0.1% acetic acid methanol solution （B） for gradient elution （0-25 min， 5%-95%B； 25-30 min， 95%B； 30-30.1 min， 95%-5%B； 30.1-35 min， 5%B）， the flow rate was 0.4 mL·min^-1， and the column temperature was set at 30 ℃. High resolution mass spectrometry was performed with electrospray ionization （ESI）， and scanned in positive and negative ion modes by means of full scan/data dependent secondary scan （Full MS/dd-MS²）. The multistage ion fragment information combined with mzCloud network database， local high resolution mass spectrometry database of traditional Chinese medicine components （OTCML）， literature information and relevant reference materials were used for accurate qualitative analysis. Result:Totally 43 flavonoids in Citri Reticulatae Pericarpium were identified， including 24 flavones， 5 flavonols， 13 dihydroflavones and 1 chalcone. The flavonoids in samples with different aging time were basically consistent in material types， but the peak area was different. According to the comparison of relative content in the peak area， it was found that the relative contents of 30 flavonoids showed an overall increasing trend with the increase of aging time. Among them， the relative contents of 24 flavonoids （such as hesperidin， diosmin， 6-demethoxytangeretin， nobiletin and tangeretin） increased significantly. There was no significant change in the relative contents of the other 13 flavonoids （such as naringenin and neohesperidin）. Conclusion:An efficient method is established in this paper to identify flavonoids in Citri Reticulatae Pericarpium with different aging time and their relative content changes rapidly and accurately. The findings provide a methodological reference for the study on pharmacodynamic material base and quality control of Citri Reticulatae Pericarpium， and it provides experimental basis that drugs processed long time ago have better effect of Citri Reticulatae Pericarpium.