The validation of HPLC analytical method for Allium hookeri Thwaites and Curcuma longa complex extract as functional ingredients

This study was preformed to establish a simple and reliable HPLC/UV analytical method to determine p-coumaric acid contents for the standardization of water extracts of Allium hookeri and Curcuma longa complex as functional health food ingredients. The quantitative HPLC method was optimized using a reversed-phase C18 column at 35°C with methanol and H2O (30:70, v/v) as the gradient mobile phase at a flow rate of 1.0 mL/min and along with detection wavelength of UV 300 nm. This HPLC/UV analytical method exhibited good specificity and high linearity in the tested range of 1.0–10.0 mg/mL with excellent coefficient of determination (R2) of 1.0. The limit of detection and limit of quantification were 0.08 and 0.24 μg/mL, respectively. In addition, the relative standard deviation values from the intra and inter-day precision measurements were 0.4 and 0.1%, respectively. These results indicate that the established HPLC/UV analytical method is simple, specific, precise, accurate, and reproducible and so could be employed in the quantitative analysis of p-coumaric acid as a functional compound in Allium hookeri Thwaites and Curcuma longa complex.