The rapid profiling and simultaneous determination of 12 major alkaloids in Nauclea officinalis by UPLC-Q-TOF-MS and HPLC-ESI-MS/MS

For the first time, we determined the phytochemical profile of alkaloids from N. officinalis using ultraperformance liquid chromatography-quadrupole-time-of-flight-tandem mass spectrometry (UPLC-Q-TOF-MS/MS). A rapid, specific, and sensitive high-performance liquid chromatography-tandem mass spectrometry method was subsequently developed and fully validated for the simultaneous determination of 12 major alkaloid constituents in N. officinalis: pumiloside; naucleoxoside A; naucleoxoside B; nauclefine; angustidine; angustoline; (3S,19S)-3,14-dihydroangustoline ([alpha]20(D): (-)191 degrees); (3S,19R)-3,14-dihydroangustoline ([alpha]20(D): (-)294.7 degrees); strictosamide; angustine; vincosamide; and 3,14-dihydroangustine. The analytes were detected with an electrospray ionization (ESI) source and multiple reaction monitoring (MRM) using positive scanning mode. Three pairs of epimers (naucleoxoside A and naucleoxoside B; (3S,19S)-3,14-dihydroangustoline ([alpha]20(D): (-)191 degrees) and (3S,19R)-3,14-dihydroangustoline ([alpha]20(D): (-)294.7 degrees); and strictosamide and vincosamide) were successfully separated using an ACQUITY UPLC (R) BEH C-18 column (2.1 mm x 100 mm, 1.7 mu m) at 30 degrees C, with a gradient mobile phase consisting of 0.1% formic acid aqueous solution (A) and acetonitrile (B), a flow rate of 0.2 mL min(-1), and a total run time of 30 min. All calibration curves exhibited excellent linear regression (r > 0.999) within the test range. The precision, repeatability, and stability of the method toward the 12 alkaloid compounds were less than 2.0% in terms of the relative standard deviation (RSD) values. The mean recoveries for all compounds were between 98.7% and 101.1%, with RSD values ranging from 0.55% to 1.7% for N. officinalis samples.

Automated summary

A new method was developed for the simultaneous determination of 12 major alkaloid constituents in N. officinalis, characterized by its rapid, specific, and sensitive nature. Through optimization of the mobile phase and temperature, successful separation of three pairs of epimers was achieved, with good accuracy and stability of the method.