A simple method for preparing herbal reference standards based on salting-out solvent extraction

Abstract

Introduction. The expansion of the range of herbal medicinal products requires the availability of a large number of different reference standards for their analysis. A possible solution is the use of herbal reference standards (HRS), which, in turn, requires the development of simple production methods that meet all the requirements for reference standards. Material and methods. Using ten plant species containing polyphenolic compounds, a general scheme for preparing HRS was developed and tested, which includes extraction of plant material with low concentrations of a polar organic solvent (usually 20% isopropanol), subsequent salting-out of the organic phase with ammonium sulfate, and drying the organic extract on the surface of anhydrous lactose. The composition of the obtained HRS and intermediates was determined by high-performance liquid chromatography using primary chemical reference standards. Results. For all studied plant species, satisfactory values of the yield of target components, good solubility of the prepared HRS, and similarity of the chromatographic profiles of HRS and the corresponding plant material were obtained. Conclusions. A simple and inexpensive method for preparing HRS, based on salting-out solvent extraction of target components, is proposed.