4
W. Xu eT AL.
3. Experimental
3.1. General experimental procedures
Optical rotations were measured on a Jasco DIP-140 digital polarimeter (Jasco, Tokyo, Japan)
at 20 °C. e 1D and 2D NMR spectra were recorded on a Bruker AV 500 spectrometer
(Bruker, Fallanden, Switzerland) in CD3OD. Chemical shifs were referenced to the mul-
tiplet signals of CD3OD residual (δH 3.31 and δC 48.7). e HR-ESI-MS data were meas-
ured on a ACQUITY I-Class UPLC®/Xevo® G2-S QTOF LC-MS system (Waters, Milford,
MA, USA) mass spectrometer. GC analysis for the determination of the sugar moiety was
performed on an Agilent GC-7820 A coupled with a FID detector with a HP-5 capillary
column (0.32 mm × 30 m, 0.25 μm, Agilent, Santa Clara, USA). Semi-preparative HPLC
was performed on a Hitachi instrument (pump LC-2130, UV detector LC-2030, Hitachi,
Tokyo, Japan) equipped with a YMC-Pack ODS-AM column (10 mm × 300 mm, 5 μm,
YMC, Tokyo, Japan) at a flow rate of 1.2 ml/min. Column chromatography was performed
on silica gel (100–200 mesh, Qingdao Marine Chemical Co., Ltd, Qingdao, China). in
layer chromatography (TLC) was conducted on silica gel plates (GF254, Qingdao Marine
Chemical Co., Ltd, Qingdao, China) and RP-18 F254 (Merck, Darmstadt, Germany).
3.2. Plant material
San Qi was purchased from Ji Lin An Pharmaceutical Co., Ltd. (Jilin Province, China)
in March, 2013. Authentication of San Qi was performed by professor Li-Li Weng from
Changchun University of Chinese Medicine. A voucher specimen (No. SQ03222013) was
deposited at College of Pharmacy, Changchun University of Chinese Medicine. NMFS was
obtained by biotransformation of notoginseng.
3.3. Extraction and isolation
e dried NMFS (5.0 kg) was powdered and extracted with 70% EtOH (40 L × 4, 2 h for
each time) at 80 °C. Afer removal of EtOH under the reduced pressure, the obtained
EtOH extract (980 g) was suspended in H2O (4 L) and then successively partitioned with
petroleum ether, EtOAc, and n-BuOH. e n-BuOH fraction (240 g) was separated into
50% EtOH fraction and 70% EtOH fraction by D101 macroporous resin. About 70% EtOH
fraction (93 g) was loaded onto silica gel column (2100 g, 100 mm × 650 mm) and eluted
with step gradient solvent system of CH2Cl2-MeOH (100:0 → 0:100) to yield 14 fractions
(Frs. A–N). Fr. J (3.5 g, CH2Cl2-MeOH 2:1) was chromatographed on open ODS (100 g,
28 mm × 230 mm), using a step gradient of MeOH-H2O (0:100 → 100:0) to yield 6 frac-
tions (Frs. JI–JVI). Fr. JIII (320 mg, MeOH-H2O 100:0) was purified by semi-prep. HPLC
(MeOH: H2O 70:30, flow rate of 1.2 ml/min) to afford 1 (3.6 mg, tR 33.6 min) and 2 (6.1 mg,
tR 37.0 min).
3.3.1. Ginsenoside Rk6 (1)
White amorphous powder; [ꢀ]D20 +20.2 (c 0.40, CH3OH). IR (KBr) νmax cm−1: 3390, 2926,
1650, 1455, and 1020. 1H NMR (500 MHz, CD3OD) and 13C NMR (125 MHz, CD3OD) spec-
tral data see Table 1; HR-ESI-MS: m/z 671.3929 [M + Cl]− (calcd for C36H60O9Cl, 671.3926).