Quantitative analysis of coumarins from Angelica gigas using ¹H-NMR

¹H-Nuclear magnetic resonance (NMR) spectrometry was applied to the quantitative analysis of coumarins in the roots of Angelica gigas without any chromatographic purification. The experiment was performed by the analysis of each singlet germinal methyl, which was well separated in the range of 1.0-2.0 ppm in the ¹H-NMR spectrum. The quantity of the compounds was calculated by the ratio of the intensity of each compound to the known amount of internal standard (dimethyl terephthalate). These results were compared with the conventional gas chromatography (GC) method. The contents of decursin and decursinol angelate in A. gigas were determined 1.98±0.07, 1.13±0.08% in quantitative ¹H-NMR method and 2.06±0.24, 1.17±0.24% in GC method, respectively. The advantages of quantitative ¹H-NMR analysis are that can be analyzed to identify and quantify, and no reference compounds required for calibration curves. Besides, it allows rapid and simple quantification for coumarins with an analysis time for only 10 min without any preprocessing.