[Quality standard study on Tibetan medicine Gentianae Urnulae Herba]

Gentianae Urnulae Herba, dried whole herb of Gentiana urnula,is a commonly used Tibetan medicine. However, only the character identification is used as quality control standard officially at present. As a part of project for the Chinese Pharmacopoeia (2015 edition), the quality standard of this species was established in this study. The tests of water content, total ash, acid-insoluble ash and ethanol-soluble extractives of the crude drugs were carried out following the methods recorded in appendix of Chinese Pharmacopeia (2010 edition, volume 1). The TLC identification method was established by using gentiournoside A as reference substance, and a mixture of ethyl acetate-methanol-water-formic acid(7:1. 5:1: 0. 2) as the developing solvent system on silica gel G TLC plate. The content of gentiournoside A was assayed by HPLC on an Agilent Zorbax SB-C18 (4.6 mm x 250 mm,5 μm) column, using acetonitrile-water (0.1% phosphoric acid) (26:74) as the mobile phase at a flow rate of 1.0 mL x min(-1). The column temperature is at 30 degrees C and the detection wavelength is at 240 nm. As a result, gentiournoside A and the other constituents were separated and presented the same fluorescence light comparing with the reference substance on TLC detected under the UV light(366 nm). The methodology validation for the assay of gentiournoside A showed that it was in a good linear correlation in the range of 0.009 95-0.398 g x L(-1) with the regression equation of Y = 1 467.1X +41.407(r = 0.999 9), and the average recovery was 98. 3% (RSD 2.2%). The mass fractions of gentiournoside A, water content, ethanol-soluble extractives of 15 batches samples were varied in the ranges of 0.175% -1.83%, 8.60% - 9.93% and 29.2% - 35.2%, respectively. Total ash and acid-insoluble ash were 10.2% - 17.2% and 5.26% - 10.8% detected from 10 batches samples. The recommended standards of quantitative indexes are that the mass fractions of gentiournoside A and extractives are not less than 0.80% and 26.0%, respectively; the water, total ash and acid-insoluble ash are not more than 12.0%, 15.0% and 8.0%, respectively.