A practical strategy enabling more reliable identification of ginsenosides from Panax quinquefolius flower by dimension-enhanced liquid chromatography/mass spectrometry and quantitative structure-retention relationship-based retention behavior prediction.

To accurately identify the metabolites is crucial in a number of research fields, and discovery of new compounds from the natural products can benefit the development of new drugs. However, the preferable phytochemistry or liquid chromatography/mass spectrometry approach is time-/labor-extensive or receives unconvincing identifications. Herein, we presented a strategy, by integrating offline two-dimensional liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry (2D-LC/IM-QTOF-MS), exclusion list-containing high-definition data-dependent acquisition (HDDDA-EL), and quantitative structure-retention relationship (QSRR) prediction of the retention time (tR), to facilitate the in-depth and more reliable identification of herbal components and thus to discover new compounds more efficiently. Using the saponins in Panax quinquefolius flower (PQF) as a case, high orthogonality (0.79) in separating ginsenosides was enabled by configuring the XBridge Amide and CSH C18 columns. HDDDA-EL could improve the coverage in MS2 acquisition by 2.26 folds compared with HDDDA (2933 VS 1298). Utilizing 106 reference compounds, an accurate QSRR prediction model (R2 = 0.9985 for the training set and R2 = 0.88 for the validation set) was developed based on Gradient Boosting Machine (GBM), by which the predicted tR matching could significantly reduce the isomeric candidates identification for unknown ginsenosides. Isolation and establishment of the structures of two malonylginsenosides by NMR partially verified the practicability of the integral strategy. By these efforts, 421 ginsenosides were identified or tentatively characterized, and 284 thereof were not ever reported from the Panax species. The current strategy is thus powerful in the comprehensive metabolites characterization and rapid discovery of new compounds from the natural products.

[Content determination of ten flavonoids and alkaloids in Gleditsiae Sinensis Fructus, Gleditsiae Fructus Abnormalis, and Gleditsiae Spina].

To study the quality control of three traditional Chinese medicines derived from Gleditsia sinensis [Gleditsiae Sinensis Fructus(GSF), Gleditsiae Fructus Abnormalis(GFA), and Gleditsiae Spina(GS)], this paper established a multiple reaction monitoring(MRM) approach based on ultra-high performance liquid chromatography-triple quadrupole-linear ion-trap mass spectrometry(UHPLC-Q-Trap-MS). Using an ACQUITY UPLC BEH C_(18) column(2.1 mm × 100 mm, 1.7 µm), gradient elution was performed at 40 ℃ with water containing 0.1% formic acid-acetonitrile as the mobile phase running at 0.3 mL·min~(-1), and the separation and content determination of ten chemical constituents(e.g., saikachinoside A, locustoside A, orientin, taxifolin, vitexin, isoquercitrin, luteolin, quercitrin, quercetin, and apigenin) in GSF, GFA, and GS were enabled within 31 min. The established method could quickly and efficiently determine the content of ten chemical constituents in GSF, GFA, and GS. All constituents showed good linearity(r>0.995), and the average recovery rate was 94.09%-110.9%. The results showed that, the content of two alkaloids in GSF(2.03-834.75 µg·g~(-1)) was higher than that in GFA(0.03-10.41 µg·g~(-1)) and GS(0.04-13.66 µg·g~(-1)), while the content of eight flavonoids in GS(0.54-2.38 mg·g~(-1)) was higher than that in GSF(0.08-0.29 mg·g~(-1)) and GFA(0.15-0.32 mg·g~(-1)). These results provide references for the quality control of G. sinensis-derived TCMs.