GC–MS method for determination and pharmacokinetic study of seven volatile constituents in rat plasma after oral administration of the essential oil ofRhizoma Curcumae
Rhizoma Curcumae (RC) is perennial herbaceous plant mainly present in China, India and Malaysiabelong, which is belong to the family Zingiberaceae. The rhizomes of RC have been used as a famous traditional Chinese medicine for the treatment of syndrome of blood stasis. A selective, sensitive and accurate gas chromatography–mass spectroscopy (GC–MS) method was developed and validated in this paper for the simultaneous determination and pharmacokinetic study of α-Pinene, 1,8-Cineole, Borneol, β-Elemene, Curcumol, Germacrone, and Curdione in rat plasma. The GC–MS system was operated under selected ion monitoring (SIM) mode using a DB-5 (30 m × 0.25 mm (ID) × 0.25 μm (film thickness)) column. Linearity, intra-day and inter-day precisions, accuracy, extraction recovery and stability were used to validate the current GC/MS assay. The lowest limit of quantifications (LLOQ) of α-Pinene, 1,8-Cineole, Borneol, β-Elemene, Curcumol, Germacrone, Curdione were 2.71 ng/mL, 7.76 ng/mL, 3.37 ng/mL, 21.68 ng/mL, 40.21 ng/mL, 24.84 ng/mL and 47.78 ng/mL respectively. After oral administration 1.0 g/kg of RC rhizomes to the rats, the maximum plasma concentration (Cmax) was 34.72 ± 9.97 ng/mL for α-Pinene, 99.86 ± 5.54 ng/mL for 1,8-Cineole, 16.10 ± 3.37 ng/mL for Borneol, 248.98 ± 86.19 ng/mL for β-Elemene, 673.75 ± 104.15 ng/mL for Curcumol, 2353.64 ± 637.83 ng/mL for Germacrone and 2420.04 ± 708.51 ng/mL for Curdione. The time to reach the maximum plasma concentration (Tmax) was 2.33 ± 0.29 h for α-Pinene, 0.67 ± 0.29 h for 1,8-Cineole, 1.33 ± 0.58 h for Borneol, 1.83 ± 0.76 h for β-Elemene, 0.83 ± 0.29 h for Curcumol, 0.89 ± 0.98 h for Germacrone and 1.17 ± 0.76 h for Curdione. In this study, a validated GC–MS method for simultaneous determination of seven volatile oil compounds in rat plasma after oral administration of the extract of RC rhizomes and research on their pharmacokinetics was validated. The recovery and stability results were satisfactory in this study.