Simultaneous quantification of ligustilide, DL-3-n-butylphthalide and senkyunolide A in rat plasma by GC-MS and its application to comparative pharmacokinetic studies of Rhizoma chuanxiong extract alone and Baizhi Chuanxiong Decoction.

The herb couple has special clinical significance in reducing the toxicity and increasing the efficacy of drugs. The combination of Radix Angelicae Dahuricae (Baizhi, BZ) and Rhizoma Chuanxiong (ChuanXiong, CX) is a traditional herb couple. The combination performs better than the CX extract alone in the treatment of migraine and has been used for thousands of years. However, the specific compatibility mechanisms are still unclear. Ligustilide, dl-3-n-butylphthalide and senkyunolide A are the major active ingredients in CX and BZ-CX decoction. However, a comprehensive study of the pharmacokinetics of CX has not been carried out. A gas chromatography-mass spectroscopy (GC-MS) method with high selectivity, sensitivity and accuracy was developed. An SH-Rxi-5Sil (30 m x 0.25 mm i.d., and 0.25 mu m film thickness) column was employed in the GC separation. Selectivity, linearity, precision, accuracy, recovery, matrix effect and stability were used to validate the current GC-MS method. Using the validated method, this is the first time to study on the comparative pharmacokinetics of ligustilide, dl-3-n-butylphthalide and senkyunolide A from CX alone and BZ-CX decoction in rat plasma. The pharmacokinetic parameters (C-max, T-max, T-1/2, AUC(0-t), AUC(0-infinity) and CLz/F) of all of the detected ingredients showed significant differences between the two groups (P < 0.05). The results are helpful for further investigation of the compatibility mechanism of BZ-CX decoction.