Chinese Medicine: Constituent Compounds of Lindera Reflexa Root

Lindera reflexa Hemsl. is a medicinal plant associated with Chinese medicine and prescribed to treat gastritis and peptic ulcers. Sun et al. (2016) recently applied ultra-high-performance liquid chromatography (UHPLC) linear trap quadrupole (LTQ) Orbitrap mass spectrometry (MS) to examine fragmentation behaviors for 12 known Lindera reflexa root compounds, as well as to identify unknown compounds associated with the medicinal plant.¹

To do this, the team used an optimized Dionex UltiMate 3000 UHPLC system coupled with an LTQ Orbitrap XL Hybrid Ion Trap-Orbitrap mass spectrometer (both Thermo Scientific). The researchers recorded and processed the data using Xcalibur and Mass Frontier software revisions 3.0 and 7.0, respectively (both Thermo Scientific). The 12 reference compounds comprised five types: stilbene, flavonoid, alkaloid, pyranone I and pyranone II.

Table 1. Reference compounds

Type	Compounds
stilbene	pinosylvin 3-methoxy-5-hydroxy-trans-stilbene β,β’-pinosylvin diglucoside reflexanbene I reflexanbene II
flavonoid	pinocembrin pinostrobin
alkaloid	norbracteoline laetanine launobine
pyranone I	reflexan A
pyranone II	katsumadain

The research team was able to detect the 12 standards, construct fragmentation pathways and confirm the structures of their derivatives, using Mass Frontier software to assist in this undertaking. Combining the MS(n) data, accurate mass measurements and retention times, they were able to identify (unambiguously or tentatively) 42 total constituent compounds in the Lindera reflexa root sample. These included eight stilbenes, eight flavonoids, nine alkaloids, 10 pyranone I compounds, and seven pyranone II compounds. Of these, they report 24 to be novel identifications.

Table 2. Novel compounds

Type	Potential novel compounds (retention time, measured mass, molecular formula)
stilbene	10.83 min, 535.21545, C₂₇H₃₅O₁₁ 20.98 min, 349.21570, C₂₄H₂₉O₂ 24.97 min, 349.21622, C₂₄H₂₉O₂
flavonoid	16.83 min, 283.09644, C₁₇H₁₅O₄ 17.61 min, 281.08081, C₁₇H₁₃O₄ 21.51 min, 393.20514, C₂₅H₂₉O₄ 26.32 min, 393.20575, C₂₅H₂₉O₄ 26.80 min, 407.22098, C₂₆H₃₁O 26.94 min, 393.20599, C₂₅H₂₉O₄
pyranone I	18.26 min, 439.24759, C₂₇H₃₅O₅ 20.33 min, 397.23657, C₂₅H₃₃O₄ 20.53 min, 397.23709, C₂₅H₃₃O₄ 22.42 min, 439.24765, C₂₇H₃₅O₅ 23.27 min, 439.24768, C₂₇H₃₅O₅ 23.68 min, 439.24771, C₂₇H₃₅O₅ 24.14 min, 303.12268, C₁₇H₁₉O₅ 26.02 min, 439.24762, C₂₇H₃₅O₅ 26.45 min, 439.24762, C₂₇H₃₅O₅
pyranone II	21.91 min, 351.19540, C₂₃H₂₇O₃ 23.47 min, 351.19516, C₂₃H₂₇O₃ 23.93 min, 351.19547, C₂₃H₂₇O₃ 24.40 min, 351.19537, C₂₃H₂₇O₃ 25.27 min, 351.19531, C₂₃H₂₇O₃ 27.08 min, 351.19540, C₂₃H₂₇O₃

Sun et al. report their UHPLC-LTQ-Orbitrap-MS protocol to be both efficient and sensitive, as well as a first application of this method to identify the chemical constituents of Lindera reflexa root. They indicate that the data here is useful for better understanding the medicinal plant, for further studies examining pharmacokinetics and metabolomics, and for quality control during the production of this Chinese medicine.

Reference
1. Sun, X., et al. (2016) “Characterization and identification of the chemical constituents in the root of Lindera reflexa Hemsl. using ultra-high performance liquid chromatography coupled with linear trap quadrupole orbitrap mass spectrometry,” Journal of Pharmaceutical and Biomedical Analysis, 126 (pp. 34–47).