## 3 Results and Discussion  
A crude methanolic extract of the roots of _C. ussuriensis_ was tested for its inhibitory activity against bacterial neuraminidase. To assess the inhibitory potency of the extracts, they were subjected to column chromatography on octadecyl silica gel, followed by purification through repeated preparative high-performance liquid chromatography (Prp-HPLC) and gel filtration on Sephack LH-20, yielding two phenylpropanoids. By comparing their spectroscopic data (\({}^{1}\)H- and \({}^{13}\)C-NMR, UV, LC-QTOF/MS) with their values in the literature [9; 24], two phenylpropanoids were identified: ussurienoside I (compound **1**) and tanshenoside I (compound **2**). Compound **1** was obtained as a colorless gum that, after spraying with 10% H\({}_{2}\)SO\({}_{4}\) and heating, exhibited an olive-green color on TLC. High-resolution electrospray ionization MS revealed a molecular formula of C\({}_{42}\)H\({}_{46}\)O\({}_{20}\) from the pseudomolecular ion at \(m/z\) 515 [M\(-\)H]\({}^{-}\). The IR (\(v_{\rm max}\) 3368, 2938, 1716, 1586, and 1505 cm\({}^{-1}\)) and UV (\(\lambda_{\rm max}\) 220 and 267 nm) spectra showed hydroxyl, aromatic ring, carbonyl, and \(\alpha\),\(\beta\)-unsaturated absorption systems. The \({}^{1}\)H- and \({}^{13}\)C-NMR spectra (Table S1) exhibited characteristic signals that could be attributed to a 1,3,4,5-tetrasubstituted benzene ring (one aromatic proton at one glucose moiety with \(\delta\)H 6.78), two methoxyl groups (six proton singlets at \(\delta\)H 3.88), a pair of olefinic signals at \(\delta\)H 6.32 and \(\delta\)H 6.58, a 3-hydroxy-3-methyl-glutarate moiety (two pairs of methylene signals at \(\delta\)H 2.68 and 2.69, a methyl signal at \(\delta\)H 1.41, one acid signal at \(\delta\)C 171.0, and one ester carbonyl signal at \(\delta\)C 173.6), and a sugar moiety (anomeric proton signals at \(\delta\)H 4.90). The overall NMR characteristics suggested that compound **1** bore a phenylpropanol backbone. Spin-spin couplings and chemical signals were evaluated with the aid of 1H-1H correlated spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear multiple bond correlation experiments. Table S1 reveals the presence of one \(\beta\)-glucopyranosyl unit. It was discovered that compound **1** was a 3-hydroxy-3-methyl-glutarate ester of a phenylpropanol glycoside. This structure is typical of a tanshenoside skeleton. A long-range correlation was observed in the gradient heteronuclear multiple bond correlation (gHMBC) spectrum between the anomeric proton signal (H 4.90 (H-1\")) and the oxygenated quaternary carbon signal of the aglycon (C 134.7 (C-4)), indicating that the glucopyranose was linked to the hydroxyl group at C-4 (Figure 1). Furthermore, the association between the methoxy proton signal (H 3.88 (3,5-2 OCH3)) and the oxygenated quaternary carbon signal (C 152.9 (C-3,5)) revealed that the methoxy group was associated with C-3,5 (Figure 1). Accordingly, the structure of compound **1** was characterized as ussurienoside I. The identification of compound **2** as tangshenoside I was based on comparisons of its NMR and MS data with those reported in the literature (Figure 1) [24]. The calculated purity of each compound was greater than 95%, as determined using HPLC analysis (Figure 2). Figure 1: The chemical structures of compounds **1** and **2**, and the gHMBC correlation of compound **1**, which is shown by arrows. Figure 2: (**a**) High-performance liquid chromatography-photodiode array (HPLC-PDA) chromatogram (detection wavelength, 280 nm) of 50% (\(\
u/\
u\)) aqueous MeOH extract of dried roots of C. _ussuriensis_. (**b,c**) HPLC chromatogram and UV-Vis spectrum of the major compounds (tang-shenoside I and ussurienoside I with retention of 46.4 min and 53.6 min) with a maximum absorption at 220 nm wavelength. The enzyme assay was based on a reported phenomenon in which the hydrolysis of MU-Neu5 Ac is followed by an increase in fluorescence [21].