Quality standard study on Vigna radiata

Abstract

In order to control the quality of Vigna radiata, the quality control method and standard were established in this study. The tests of water content, ash and ethanol-soluble extractives of V. radiata were carried out according to the methods recoded in appendix of Chinese Pharmacopeia (2010 edition, volume 1). The TLC method was established by using vitexin and isovitexin as references, and a mixture of acetate-method-water (10: 1.7 : 1.3) as the developing solvent system on GF254 thin layer plate. The contents of vitexin and isovitexin were determined by HPLC on a Prevail C18 (4.6 mm x 250 mm, 5 microm) column, using acetonitrile: water (23 : 77) as mobile phase at a flow rate of 1.0 mL x min(-1). The column temperature is 30 degrees C and the detection wavelength is 337 nm. As a result, vitexin, isovitexin and the other constituents were well separated on TLC detected under the UV light (254 nm). The methodology validation for the assay of vitexin and isovitexin presented that they were in good linear correlation in the ranges of 6.12-98 mg x L(-1) and 6.85-109.6 mg x L(-1), with the regression equations of Y = 46.213X - 7.100 (r = 1.000) and Y = 54.515X + 6.829 (r = 1.000), and the average recoveries were 98.2% (RSD 1.9%) and 97.2% (RSD 0.79%), respectively. The content ranges of vitexin and isovitexin from 25 different batches of V. radiata were 1.076-2.062 mg x g(1) and 1.127-2.303 mg x g(-1), respectively. suggesting that the qualities of V. radiata are relatively stable. The ethanol-soluble extractives, water content and total ash of 25 samples varied in the ranges of 13.27% - 18.46%, 9.59% - 12.43% and 2.63% - 3.53%, respectively. All of the above data proved that the established quality of control method V. radiata is specific and accurate, which can be used for the quality control of this drug.