Targeted Separation of Sesquiterpenoids From Dalbergia odorifera T. Chen by High-Speed Countercurrent Chromatography for the Quality Control of Xiangdan Injection

Abstract

This study developed an efficient separation strategy combining high-speed countercurrent chromatography and semi-preparative HPLC for the isolation of sesquiterpenoids from the volatile oil of Dalbergia odorifera, thereby improving the quality control of Xiangdan injection. Initially, the enriched volatile oil was processed using high-speed countercurrent chromatography with a solvent system of n-hexane/ethyl acetate/acetonitrile/water (6:1:6:2, v/v/v/v). Within 350 min, four nerolidol oxides were successfully separated, and a sesquiterpenoid compound was markedly enriched. Then, the enriched compound was further purified using semi-preparative HPLC. HPLC analysis indicated that the strategy successfully separated five sesquiterpenoid compounds from D. odorifera with purities exceeding 91%. Electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy were employed to confirm the structures of five isolated compounds. The five isolated compounds were identified as dalberpene (Compound I), nerolidol oxide I (Compound II), nerolidol oxide II (Compound III), nerolidol oxide III (Compound IV), and nerolidol oxide IV (Compound V). Subsequently, based on the HPLC characteristic chromatogram, the isolated compounds, including dalberpene, nerolidol oxide I, nerolidol oxide II, nerolidol oxide IV, and commercially purchased elemicin, were selected as five target analytes for the quality control of D. odorifera components in Xiangdan injection. The previously developed dispersive liquid–liquid microextraction-back extraction method was further optimized and rigorously validated. The results indicated that the average concentrations of five target analytes in Xiangdan injection samples ranged from 0.105 to 4.990 µg/mL. Compared with previous studies, this study significantly improved the specificity and accuracy of quality control for D. odorifera components in Xiangdan injection.