Chemical Differentiation of the Raw Materials between Ligusticum chuanxiong and Angelicasinensis by HPLC-DAD-MS and FTIR Spectroscopy Combined with Cluster Tree Analysis

The rhizome of Ligusticum chuanxiong Hort (Chinese Chuanxiong, CX) and the root of Angelica sinensis (Oliv.) Diels (Chinese Danggui, DG) are widely used as herbs in some countries. Their therapeutic effects are different in Chinese medicine practice [1], but their chemical constituents are reported to be similar resulting in their problematic identification by chemical method [2,3]. In this study, 30 CX samples and 40 DG samples were collected from different areas in China and analyzed by high-performance liquid chromatography (HPLC) – diode array detection (DAD) – mass spectrometry (MS), one and two-dimensional Fourier Transform Infrared Spectroscopy (1D and 2D-FTIR). The HPLC chromatogram profiles of CX and DG were found different. The relative peak intensity of senkyunolide A in CX was over 30 times of that in DG resulting in their unequivocally differentiation. The similarity of whole chromatograms was calculated and expressed as correlation coefficient (R) and cluster tree by software. Both R data and cluster tree clearly showed the difference between the two herbs. 11 main peaks in their HPLC chromatograms were identified by UV and MS data. In 1D-FTIR spectra, the variety in peak intensities at 3563 (O-H), 3390, 3338 (O-H), 2928 (CH2), 1745 (C=O), 1653–1639 (γC=O), 1541 (δNH+γCN), 1068 and 1052 cm-1 (C-C-O, C–O-O) between CX and DG implied the contents of carbonyl compound, glycoprotein and sucrose were significantly different. The 1D-FTIR spectra of CX and DG were located in different clusters in their cluster tree. It indicated CX and DG could be rapid differentiated by FTIR technique. References: [1] The State Pharmacopoeia Commission (2005) Chinese Pharmacopoeia. Chemical Industry Press. Beijing. [2] Lin LZ, et al. (1998) J. Chromatogr. A 810: 71–79. [3] Li SL, et al. (2003) Planta Med. 69: 445–451.