Journal of Asian Natural Products Research
7
and spectroscopic data with those reported
in the literature, respectively.
Materials in Chengdu, Sichuan Province,
China, and identified by Professor Minglu
Deng, Changchun University of Chinese
Medicine. A voucher specimen (No.
3
.
Experimental
2
009012) has been deposited in the
3
.1 General experimental procedures
Phytochemistry Laboratory of Jilin Acad-
emy of Chinese Medicine Sciences.
Melting points were determined on an X-6
microscope apparatus and are uncorrected
(Beijing Fukai Instrument Co., Ltd, Beij-
ing, China). Optical rotations were deter-
mined on a WZZ-2SS auto-polarimeter
3.3 Extraction and isolation
The dried and powdered tubers of O.
japonicus (10 kg) were exhaustively
extracted with 70% EtOH. The extract
was concentrated under vacuum to give a
water solution which was then chromato-
graphed on macroporous resin D21 (10 kg),
eluting with water until the eluate was
colorless and then with 80% EtOH (80 l).
The 80% EtOH solution was concentrated
and partitioned with EtOAc and n-BuOH,
successively, to yield EtOAc extract (11 g)
and n-BuOH layer extract (20 g). The
n-BuOH extract was chromatographed on
(Shanghai Jingke Scientific Instrument
Co., Ltd, Shanghai, China). UV and CD
spectra were obtained on a JASCO J-820
spectrometer (JASCO International Co.
Ltd, Tokyo, Japan). NMR spectra were
obtained on Bruker AV600 and AV400
instruments (Bruker Corporation, Rhein-
stetten, Switzerland), using tetramethylsi-
lane as the internal standard. The HR-ESI-
MS was recorded on an IonSpec HiResESI
FTICR instrument (IonSpec Co., Lake
Forest, CA, USA). ESI-MS were recorded
on Finnigan Mat LCQ mass spectrometry
silica gel eluted with CHCl :MeOH (11:1).
3
(Thermo Fisher Scientific, Inc., West Palm
Fr. 189–Fr. 196 was separated by HPLC
–1
Beach, FL, USA). High-performance
liquid chromatography (HPLC) (Shi-
madzu Corporation, Kyoto, Japan) was
carried out using an octadecylsilane-
bonded silica gel column (Megres-C ,
(
to yield 1 (17.8 mg, t : 15.465 min) and 2
v: 4.5 ml min ) with MeCN:H O (34:56)
2
R
(7.0 mg, t : 17.565 min). Fr. 291–Fr. 300
was separated by HPLC (v: 4.5 ml min
R
–1
)
with MeCN:H O (35:55) to yield 3 (70 mg,
1
8
2
2
50 mm £ 4.6 mm, 5 mm). Prep-HPLC
tR: 7.782 min). The EtOAc extract was
chromatographed on silica gel eluted with
(NP 7000, Hanbon Sci & Tech Co., Ltd,
Huaian, Jiangsu, China) was carried out
using an octadecylsilane-bonded silica gel
column (Megres-C , 250 mm £ 10 mm,
CHCl :MeOH (12:1) and ODS silica gel
3
with MeOH–H O (8:2). Fr. 33–Fr. 50 was
2
–1
separated by HPLC (v: 4.5 ml min ) with
1
8
5
mm). Column chromatography was car-
MeOH:H O (78:22) to yield 4 (72 mg, t :
R
2
ried out on macroporous resin D101 made
in Shandong Lu Neng Gel Co. (Shandong,
China), silica gel (200–300 mesh, Qing-
dao Oceanic Chemical Industry, Qingdao,
China), and reversed-phase silica gel
1
8.432 min), 5 (93 mg, t : 13.996 min), and
R
6
was separated by HPLC (v: 4.0 ml min
(98 mg, t : 20.132 min). Fr. 51–Fr. 61
–1
R
)
with MeOH:H O (78:22) to yield 7 (78 mg,
2
t : 23.848 min). Fr. 83–Fr. 95 was
R
(
50 mm, YMC Co., Ltd, Kyoto, Japan).
TLC was carried out on aluminum sheets
20 £ 20 cm, RP-18F254S, MERCK KGaA,
Darmstadt, Germany).
–1
separated by HPLC (v: 4.5 ml min
with MeOH:H O (75:25) to yield 8
)
2
(
(13.2 mg, t : 20.198 min).
R
3
.2 Plant material
3.3.1 Compound 1
The tubers of O. japonicus were purchased
from the Company of Chinese Medicinal
Amorphous powder; m.p. 131.1–132.38C;
2
7
½aꢀ 259.3 (c ¼ 0.30, 30% aqueous
D