Determination of markers from characteristic HPLC chromatogram of phenols in three official origins of Ephedrae Herba and quantitative analysis of four phenols / 中国中药杂志

ABSTRACT

This study is to establish the characteristic HPLC chromatogram of phenols in Ephedrae Herba, from which to pick out the marker peaks, followed by the analysis of the regularity of their distribution and content in the herbaceous stems of Ephedra sinica, E. intermedia and E. equisetina. The HPLC-DAD method for the characteristic chromatogram as well as quantitative analysis was established. The separation was carried out on a YMC-Pack ODS-A column (4.6 mm x 250 mm, 5 µm), eluted with the mobile phases as 0.01% formic acid aqueous solution (A) and acetonitrile (B) in a linear gradient (0-10 min, 17% B; 10-25 min, 17%-19% B; 25- 33 min, 19%-48% B; 33-35 min, 48%-51% B; 35-44 min, 51% B). The flow rate was kept at 1.0 mL · min⁻¹. The column tem- perature was 40 °C, and the detection wavelength was set at 350 nm (0-16 min) and 330 nm (16-44 min). Forty-six batches of collected samples from three official origins of Ephedrae Herba were detected, whose liquid chromatograms proven to be helpful to the differentiation of different origins. With principal component analysis and the analysis of distribution of peak area, twelve key peaks from the chromatogram were discussed in details on their contributions to the characteristics and differences of three official origins of the herb peak area of peak 10, 11, 12 were found out to be significantly higher in E. equisetina than in other two origins, whose sum (higher than 146 mAU in E. equisetina) was useful for the discrimination between E. equisetina and the other two origins; peak area of 1 and 4 were respectively higher in E. sinica and E. intermedia than in other official origins, indicating their important effect on the differen- tiation of corresponding origins; peak 8 and 9 were picked out as two characteristic common peaks in three official origins of the herb, whose peak area showed little difference among different origins; further, peak area of other key peaks in the chromatogram also showed some difference among three origins, which make contributions to the differentiation of origins as well. Then, four phenols as 2"-O-α- L-rhamnosyl-isovitexin (1), vitexin (2), pollenitin B (5) and herbacetin-7-O-β-D-glucoside (6) were quantitative analyzed with the above-mentioned method, with good linear relationship and accuracy (recoveries in a range of 97.8%-102.5%). The content of the four phenols were firstly reported in Ephedrae Herba from official origins, which were respectively trace-1.55 (1), trace-0.160 (2), trace-0.284 (5) and trace-0.620 (6) mg · g⁻¹ in all of the tested samples. In addition, the content of these phenols showed differences in three official origins, especially 1, whose content in E. sinica [(0.670 ± 0.88) mg ± g⁻¹] were significantly higher than in other two origins (lower than 0.16 mg ± g⁻¹ besides sample Ei-060630-2-2), and 6, whose average content in E. equisetina [(0.260 ± 0.039 2) mg · g⁻¹] were twice as high as in E. sinica [(0.120 ± 0.270) mg · g⁻¹] and E. intermedia [(0.136 ± 0.485) mg g⁻¹], indicating the important effects of the two constituents on the differentiation among three official origins of the herb. The method established for the characteristic HPLC chromatogram and quantitative analysis of phenols was simple and accurate, and the marker constituents selected may provide new guides for the discrimination of official origins as well as the improvement of quality criteria of EphedraeHerba.