Quantitative Determination and Validation of Four Ketones in Salvia miltiorrhiza Bunge Using Quantitative Proton Nuclear Magnetic Resonance Spectroscopy

Salvia mltiorrhiza Bunge (SMB) is native to China, whose dried root has been used as medicine. A few chromatographic- or spectrometric-based methods have already been used to analyze the lipid-soluble components in SMB. However, the methodology of qNMR on the extracts of fresh SMB root has not been verified so far. The purpose of this study was to establish a fast and simple method to quantify the tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone in fresh Salvia Miltiorrhiza Bunge root without any pre-purification steps using 1H-NMR spectroscopy. The process is as follows: first, 70% methanol aqueous extracts of fresh Salvia Miltiorrhiza Bunge roots were quantitatively analyzed for tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone using 1H-NMR spectroscopy. Different internal standards were tested and the validated method was compared with HPLC. 3,4,5-trichloropyridine was chosen as the internal standard. Twelve samples of Salvia Miltiorrhiza Bunge were quantitatively analyzed by qNMR and HPLC respectively. Then, the results were analyzed by chemometric approaches. This NMR method offers a fast, stable, and accurate analysis of four ketones: tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone in fresh roots of Salvia Miltiorrhiza Bunge.