Stachys sieboldii MIQ. (Labiatae) is native to Northern China and widely distributed in North America, Asia, and Europe. 1 S. sieboldii has been used in Chinese folk medicine for the treatment of ischemic stroke, senile dementia, and various gastrointestinal problems. 2 Previous phytochemical and pharmacological studies on this plant reported the isolation of terpenes, 3 flavonoids, 4 and phenolic compounds, 5 and it having antimicrobial, 6 antioxidant, 7 and antitumor activities. 8 In our

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... nuing efforts to study the secondary metabolites of natural plant sources, the MeOH extract of S. sieboldii was investigated, and a new triterpene saponin, Sieboldii saponin A (1), was isolated, together with five known compounds (2-6). The structures of the isolates (1-6) were elucidated by means of spectroscopic methods and chemical evidences. Sieboldii saponin A (1) was isolated as a colorless gum. The molecular formula was determined to be C 42 H 66 O 15 from the molecular ion peak [M + H] + at m/z 811.4480 (calcd. for C 42 H 67 O 15 : 811.4480) in the positive-ion HR-FABMS. The IR spectrum at 3421 cm −1 indicated that 1 possessed hydroxyl group. The 1 H-NMR spectrum of 1 (Table 1) displayed the signals of an olefinic proton at δ H 5.30 (1H, br t, J = 3.5 Hz, H-12), a couple of exomethylene protons at δ H 4.72 and 4.67 (each 1H, br s, H-30), two oxygenated methine protons at δ H 3.92 (1H, m, H-2) and 3.82 (1H, m, H-3), a couple of oxymethylene protons at δ H 3.55 and 3.28 (each 1H, d, J = 11.2 Hz, H-23), one methine proton at δ H 2.30 (1H, d, J = 11.9 Hz, H-18), four tertiary methyl protons at δ H 1.21 (3H, s, H-27), 1.07 (3H, s, H-25), 0.86 (3H, s, H-26), and 0.82 (3H, s, H-24), one secondary methyl proton at δ H 1.05 (3H, d, J = 6.3 Hz, H-29), and two sugar anomeric protons at δ H 5.45 (1H, d, J = 7.7 Hz, H-1′) and 4.77 (1H, d, J = 7.7 Hz, H-1′′) . The 13 C-NMR spectrum showed a total of 42 carbon signals, of which 30 carbons were to be assigned to the aglycone and the remaining 12 carbons to the sugar moieties. The 13 C-NMR and DEPT spectra included one carboxylic carbon at δ C 175.9, five methyl carbons at δ C 22.7, 16.5, 16.2, 16.0, and 15.3, four olefinic carbons at δ C 152.9, 138.9, 125.8, and 104.1, two oxygenated methine carbons at δ C 77.3 and 65.8, one oxygenated methylene carbon at δ C 69.9, four methine carbons at δ C 54.9, 47.3, 42.9, and 37.1, eight methylene carbons at δ