Standardization of the root extracts (high-performance liquid chromatography (HPLC) chromatogram). Compounds were detected with a photodiode array. X-axis, retention time; Y-axis, wavelength; and Z-axis, absorbance unit. The analytic conditions were as follows: column, C18 Φ 4 × 250 mm; mobile phase, 1% phosphoric acid (H3PO4; solvent A) and acetonitrile (CH3CN; solvent B); flow rate, 1 ml/min; and eluting gradient, 5% to 50% of solvent B in A (during minutes 1–60), followed by standing 70% of solvent B in A (during minutes 61–85).
Jung et al. Arthritis Research & Therapy 2007 9:R64 doi:10.1186/ar2222