Rapid HPLC determination of gastrodin in Gastrodiae Rhizoma

Gastrodin is a major biologically active ingredient in members of the genus Gastrodia. For this reason, there are many reports on the quantification of gastrodin in Gastrodiae Rhizoma (GR) and in GR-containing herbal preparations. HPLC, HPLC–MS, and TLC are the major approaches for gastrodin quantification; however, they usually require complicated pre-treatment, lengthy analysis, and expensive instruments. Therefore, a rapid and reliable method for determining gastrodin in GR is necessary. Optimal HPLC separation was achieved using a Chromolith Performance RP-18e (4.8 × 100 mm, 5 μm) stationary phase. The optimal mobile phase was a mixture of water (A) and acetonitrile (B) with a gradient of 1 % B at 0–8 min, 20 % B at 8–10 min, 80–100 % B at 10–12 min, and 100 % B at 12–13 min, followed by equilibration with 1 % B for 2 min at a flow rate of 1.5 mL/min. The detection wavelength was UV220 nm. Gastrodin appeared within 4 min under the above conditions. The calibration curve of gastrodin showed good linearity in the 0.25–10.0 range (r² = 0.9998). The limit of detection (0.13 μg), limit of quantification (0.25 μg), and reproducibilities of area and retention time (0.04 and 3.24 %, respectively) were within acceptable ranges. In addition, the intra-day precision and accuracy of gastrodin were 0.74 and 100.63 ± 0.04 %, respectively, while the inter-day precision and accuracy were 0.06 and 99.25 ± 0.05 %, respectively. The range of mean gastrodin content in six GR samples, which were cultivated at different sites, was 0.37–0.79 %. This result may be a guideline for the quality control of GR and GR-containing medicinal preparations.