Objective: To conduct a qualitative analysis on the chemical constituents of the aqueous extract from raw Nauclea officinalis by using ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS/MS) method. Method: Chromatographic separation was performed on AcclaimTM RSLC 120 C18 column(2.1 mm×100 mm

2.2 μm)with 0.2% ammonium formate buffer salt solution-0.2% ammonium formate buffer salt methanol solution as the mobile phase for gradient elution. The column temperature was maintained at 30℃

and the analytes were determined by a positive and negative ionization electrospray mass spectrometer with electro-spray ionization source. Result: The 47 chemical constituents including 26 indole alkaloids

15 organic phenolic acids and glycosides

2 isoquinoline alkaloids

2 triterpenes

1 flavonoids and 1 iridoid glycoside were identified from the aqueous extract of N. officinalis or tentatively characterized by comparing their mass spectra information with those of reference substances and literature data. Nine compounds were reported for the first time from N. officinalis

namely quinic acid

3

4-dihydroxy cinnamic acid

barbinervic acid

nauclefiline

vanillic acid

3

4

5-trimethoxy phenol

3

4-dihydroxy benzoic acid methyl ester

2

3-dihydroxy benzoic acid amide and naucleactonin A isomers. Conclusion: In this study

the main chemical components from the aqueous extract of N. officinalis were rapidly identified as indole alkaloids

organic phenolic acids and glycosides by using UPLC-Q-TOF-MS/MS. Nine compounds were reported from N. officinalis for the first time.