Simultaneous determination of three phytoecdysteroids in the roots of four medicinal plants from the genus Asparagus by HPLC

INTRODUCTION: The genus Asparagus is known to contain phytoecdysteroids that have been shown to exhibit many beneficial pharmacological properties such as improving lipid metabolism, modulating immunological responses, etc. Currently, knowledge about the contents of phytoecdysteroids in the roots of Asparagus species is limited and HPLC methods for their analyses are unsatisfactory. OBJECTIVE: To develop an HPLC method for the simultaneous determination of three phytoecdysteroids, 20-hydroxyecdysone, ecdysone and ajugasterone C, in the roots of four Asparagus species. METHODOLOGY: Reference standards of phytoecdysteroids were isolated from the roots of Asparagus filicinus by open column chromatography. HPLC analysis was performed on an Alltima C₁₈ column with gradient elution using aqueous 0.2% formic acid solution containing 0.2% isopropanol and acetonitrile. RESULTS: All calibration curves showed good linear correlation coefficients (r² > 0.9994) within the tested ranges. Limits of detection (S/N = 3) and quantification (S/N = 10) for the three analytes were less than 2.7 and 9.9 ng, respectively. Intra- and inter-day RSDs of retention times and peak areas were less than 2.61%. The recoveries were between 93.2 and 107.5%, and the RSDs were less than 3.83% for the root samples of A. filicinus. CONCLUSION: The HPLC method established is appropriate for the efficient quantitative and qualitative analyses of important phytoecdysteroids in Asparagus species. This study showed that A. filicinus is rich in phytoecdysteroids, especially 20-hydroxyecdysone. However the three studied phytoecdysteroids were not detected in A. cochinchinensis, A. officinalis and A. setaceus. Copyright © 2008 John Wiley & Sons, Ltd.