Fatty Acid Anilides as Internal Standards for High Performance Liquid Chromatographic Analyses of Valeriana officinalis L. and Other Medicinal Plants

Abstract

Fatty acid anilides are proposed as internal standards for high performance liquid chromatographic (HPLC) analyses of medicinal plants. A one-pot synthesis of the C5 to C12 anilides is described. Reverse-phase HPLC showed that the synthesized anilides covered the optimum range of k′ values for mobile phases ranging from 50 to 90% acetonitrile in water. There was an approximately linear relationship between fatty acid chain length and log k′ under a variety of isocratic conditions. For a linear gradient of mobile phase composition, there was an approximately linear relationship between fatty acid chain length and k′. The development of an extraction and HPLC analysis method for the biologically active components valtrate and valerenic acid in Valeriana officinalis is described including use of C11 fatty acid anilide as an internal standard. The levels of these components were similar in both fresh and dried valerian.