Quantification of root chicoric acid in purple coneflower by near infraredreflectance spectroscopy

Purple coneflower [Echinacea purpurea (L.) Moench] is an increasingly popul ar crop because of its value in the U.S. botanical industry. At present, th ere is no rapid method of analyzing it for chicoric acid, the predominant p henolic acid associated with immunostimulation in humans. The objective of this study was to quantify chicoric acid in purple coneflower roots by near infrared (NIR) reflectance spectroscopy. One hundred sixty-nine plants wer e harvested and their root tissues analyzed for chicoric acid by high perfo rmance liquid chromatography (HPLC). Root samples were scanned between 1100 and 2498 run and reflectance data recorded. The HPLC data were regressed a gainst infrared spectra to develop empirical prediction equations. The opti mum prediction equation produced coefficients of determination for calibrat ion and cross validation of 0.90 and 0.86, respectively. The mean chicoric acid concentration was 8.29 g kg DM-1, and the standard errors of calibrati on and cross validation were 0.89 and 1.06 g kg DM-1, respectively. We conc lude that NIR reflectance spectroscopy can accurately quantitate chicoric a cid in purple coneflower.