Abstract:

By investigating the effects of different detection wavelength, mobile phase and solvent on the peak profile of gastrodin, the present study improved the traditional RP-HPLC method for determining gastrodin in Gastrodia elata Bl.. Also, the effects of extraction solvent, extraction temperature, solid-liquid ratio and extraction time on the extraction rate of gastrodin were discussed. The results showed that the optimal working conditions of RP-HPLC were as follows: using Diamonsil C18 column (150 mm×4.6 mm, 5 μm) at ambient temperature, acetonitrile-water (3:97, V/V) as the mobile phase, flow rate 1.0 ml/min, detection wavelength 220 nm, and acetonitrile-0.05% phosphoric acid (3:97, V/V) as the solvent of gastrodin. The calibration curve was well linear in the range of 10 to 80 μg/ml, the regression equation was y = 4.0264x + 0.6311 with a determination coefficient of 0.9992. The limit of detection of this method was 2 ng. The relative standard deviations (RSDs) of precision and repeatability were 0.41% and 0.86%, respectively (n = 6), and the average spike recovery rate was 98.4% with a RSD of 0.84% (n = 6). The optimum extraction conditions of gastrodin from Gastrodia elata Bl. were determined as follows: 50% alcohol as extraction solvent, temperature 70 ℃, ratio of solid to liquid 1:6 (g/ml), and extraction time 3 h.

Key words: Gastrodia elata Bl., gastrodin, RP-HPLC, extraction technology