Validation of High-Performance Liquid Chromatography (HPLC) Method for Quantification of Ethyl p-Methoxycinnamate in Kaempferia galanga Extract

Kaempferia galanga has the potential to be developed as a raw material for traditional medicine because it has pharmacological activities such as analgesic and anti-inflammatory. Ethyl p-methoxycinnamate (EPMC) is one of the marker compounds for determining the dosage of traditional medicine. Determination of EPMC content in the Kaempferia galanga extract is important for the standardization of the extract. This study aims to validate the high-performance liquid chromatography (HPLC) method for determining EPMC content in Kaempferia galanga extract. Separation was performed on the C18 column)5 μm, 4.6 mm x 150 mm), using an isocratic mobile phase consisting of water: acetonitrile (40:60) at 30^oC temperature. The flow rate was 1 mL/min with an injection volume of 10 μL. Detection was performed using a photodiode array (PDA) set at 308 nm. The method was validated as per the guidelines given by International Conference on Harmonization guidelines. The retention time of EPMC on standard EPMC and Kaempferia galanga was 6.22 and 6.25 minutes, respectively. The linearity calibration curve was 10-60 µg/mL (r=0.9988) with the limit of detection (LOD) of 0.0011 µg/mL and limit of quantification (LOQ) of 0.0037 µg/mL. Adequate results were obtained for precision with a relative standard deviation (RSD) of 1.19%-2.37% and accuracy with a recovery of 94.07%-113.82%. The average EPMC content in Kaempferia galanga was 54.13%. Therefore, this finding demonstrated that the method was proved selective for the quantification of EPMC in Kaempferia galanga extract.