## 3 Results and Discussion
Thus, we established the following constants for compound **1**: \(K_{\rm I}\) = 27.79 \(\upmu\)M and \(K_{\rm IS}\) = 92.0 \(\upmu\)M (Figure 3 (insets)). These findings reveal that the inhibitor's affinity for free enzymes was only slightly larger than its affinity for the enzyme-substrate complex. Accordingly, compound **1** was categorized as a type-I mixed inhibitor. LC/Q-TOF/MS technology is useful for identifying the components of a plant extract. The chemical constituents of _C. ussuriensis_ roots extracted using 50% MeOH were identified using a LC/Q-TOF/MS method that we developed in the negative ion mode. Figure 4 displays representative total ion chromatograms (TICs) with labeled peaks, indicating that an ion mode was used. Eight peaks were identified, including two for unknown compounds, as shown in Table 2. Their chemical structures are detailed in Supplementary Figure S8. Peak 1 (\(m/z\) 191.0198, C\({}_{6}\)H\({}_{8}\)O\({}_{7}\)-) exhibited a fragmentation pattern of [M\(-\)H\(-\)CO\({}_{2}\)]\({}^{-}\) followed by [M\(-\)H\(-\)H\({}_{2}\)O]\({}^{-}\) in the negative ionization mode as a result of the elimination of the CO\({}_{2}\) group (\(-\)44 Da) and the H\({}_{2}\)O molecule (\(-\)18 Da) from the deprotonated precursor ion (Supplementary Figure S8). The compound was identified as citric acid (peak 1); the MS/MS spectrum was reported previously [25]. Peak 2 (\(m/z\) 203.0827, C\({}_{11}\)H\({}_{12}\)N\({}_{2}\)O\({}_{2}\)-) initially produced an ion at \(m/z\) 159 due to CO\({}_{2}\) molecule loss (\(-\)44 Da), followed by a fragment ion at \(m/z\) 142 due to NH\({}_{3}\) and CO\({}_{2}\) molecule dissociation. The existence of the fragment ion at \(m/z\) 116, which was similar to indole's molecular weight (116 g/mol), suggested that the chemical was tryptophan. Peak 3 was identified in the negative ionization mode as transposable I (\(m/z\) 677 [M\(-\)H]\({}^{-}\) and \(m/z\) 1355 [2M\(-\)H]\({}^{-}\)), C\({}_{29}\)H\({}_{42}\)O\({}_{18}\)- and C\({}_{58}\)H\({}_{84}\)O\({}_{36}\)-). The precursor ion (M\(-\)H)\({}^{-}\) produced fragments at \(m/z\) 497 [C\({}_{23}\)H\({}_{29}\)O\({}_{12}\)]\({}^{-}\), \(m/z\) 261 [C\({}_{11}\)H\({}_{17}\)O\({}_{7}\)]\({}^{-}\), and \(m/z\) 99 [C\({}_{5}\)H\({}_{7}\)O\({}_{2}\)]\({}^{-}\), which are common fragmentation patterns of phenylpropanol glycosides. Peak 5 showed molecular ions at \(m/z\) 515.1777 [M\(-\)H]\({}^{-}\) and \(m/z\) 1030 [2M\(-\)H] in the negative ion mode, with the molecular formula C\({}_{22}\)H\({}_{33}\)O\({}_{55}\). Its MS\({}^{2}\) spectra exhibited ions at \(m/z\) 471.1 [M\(-\)H\(-\)CO\({}_{2}\)]\({}^{-}\), 371 (C\({}_{5}\)H\({}_{7}\)O\({}_{2}\)-), and 161 (C\({}_{6}\)H\({}_{10}\)O\({}_{5}\)-). Based on the fragmentation information, peak 5 was tentatively identified as ussurienoside I. In the negative ion mode, peak 6 displayed a format adduct molecular ion [M\(+\)HCOO]\({}^{-}\) at \(m/z\) 469.1355 and production at \(m/z\) 325.0, \(m/z\) 225.0, and 163.0. The detected diterpenoid trilactone was identified as ginkgolide B. For peak 8, adduct molecular ion \(m/z\) 441.1768 [C\({}_{44}\)H\({}_{44}\)O\({}_{44}\)]\({}^{-}\), molecular ion \(m/z\) 395.1705 [M\(-\)H]\({}^{-}\), fragment ion \(m/z\) 305 [M\(-\)H\(-\)C\({}_{7}\)H\({}_{6}\)]\({}^{-}\), and \(m/z\) 179 [M\(-\)H\(-\)C\({}_{4}\)H\({}_{16}\)O\({}_{2}\)]\({}^{-}\) were observed in the negative ion mode. Peak 8 was tentatively characterized as lobetyolin.