Abstract

Agastache rugosa, known as Korean mint, is a medicinal plant with many beneficial health effects. In this study, a simple and reliable HPLC-UV method was proposed for the quantification of rosmarinic acid (RA) in the aqueous extracts of A. rugosa. RA was selected as a quantification marker due to its easiness in procurement and analysis. The developed method involved chromatographic separation on a C18 column (250 × 4.6 mm, 5 μm) at room temperature. The mobile phase consisted of water and acetonitrile both containing 2 % acetic acid and was run at a flow rate of 1 mL min−1. The method was validated for specificity, linearity, precision, and accuracy. It was specific to RA and linear in the range of 50–300 μg mL−1 (r2 = 0.9994). Intraday, inter-day, and inter-analyst precisions were ≤ 0.91 % RSD, ≤ 1.40 % RSD, and 1.94 % RSD, respectively. Accuracy was 93.3–95.9 % (≤ 1.21 % RSD). The method could be applied to three batches of bulk samples and three batches of lab scale samples, which were found to be 0.64 (± 0.04) mg g−1 and 0.48 (± 0.02) mg g−1 for the dried raw materials of A. rugosa. The results show that the proposed method can be used as a readily applicable method for QC of health functional foods containing the aqueous extracts of A. rugosa.