New iridoid and secoiridoid glucosides from the roots of Gentiana manshurica

Article abstract of DOI:10.1002/hlca.201100444

One new iridoid glucoside, 4″-O-β-D-glucosyl-6′-O-(4-O- β-D-glucosylcaffeoyl)linearoside (1), and two new secoiridoid glucosides, 6′-O-acetylsweroside (2) and 6′-O-acetyl-3′-O-[3-(β-D- glucopyranosyloxy)-2-hydroxybenzoyl]sweroside (3), were isolated from

Full text of DOI:10.1002/hlca.201100444

1
094
Helvetica Chimica Acta – Vol. 95 (2012)
New Iridoid and Secoiridoid Glucosides from the Roots of Gentiana
manshurica
a
a
b
a b
by Qing Liu ), Gui-Xin Chou* ) ), and Zheng-Tao Wang* ) )
a) Shanghai R&D Center for Standardization of Chinese Medicines, 199 Guo Shoujing Road,
Zhangjiang Hi-Tech Park, Shanghai 201203, P. R. China
b) Key Laboratory of Standardization of Chinese Medicines, Ministry of Education, Institute of Chinese
Materia Medica of Shanghai University of Traditional Chinese Medicine, Cai Lun Road 1200,
Zhangjiang, Shanghai, 201203, P. R. China
(
phone: þ 86-21-51322507 (Z.-T. W.), þ 86-21-50271706 (G.-X. C.); fax: þ 86-21-51322519 (Z.-T. W.),
þ 86-21-50271708 (G.-X. C.); e-mail: wangzht@hotmail.com, chouguixin@yahoo.com.cn)
One new iridoid glucoside, 4’’-O-b-d-glucosyl-6’-O-(4-O-b-d-glucosylcaffeoyl)linearoside (1), and
two new secoiridoid glucosides, 6’-O-acetylsweroside (2) and 6’-O-acetyl-3’-O-[3-(b-d-glucopyranosyl-
oxy)-2-hydroxybenzoyl]sweroside (3), were isolated from the dried roots of Gentiana manshurica
(
Gentianaceae), together with 11 known ones, including one iridoid glucoside, five secoiridoid
glucosides, and five triterpenes. The structures of the new compounds were determined on the basis of
detailed spectroscopic analyses and acidic hydrolysis.
Introduction. – In the Chinese Pharmacopoeia, the dried roots and rhizomes of four
species, namely Gentiana manshurica Kitag., G. scabra Bunge, G. triflora Pall., and
G. rigescens Franch., are used as the raw materials of Gentianae Radix et Rhizoma
(ꢀLong danꢁ in Chinese) [1] for the treatment of hepatitis, rheumatism, and
cholecystitis. Iridoid and secoiridoid glucosides, which showed antibacterial, antifungal,
anticancer, anti-inflammatory, and hepatoprotective activities [2] were reported as the
main constituents in Gentianae Radix et Rhizoma [3 – 5]. However, the data on the
chemical constituents of G. manshurica, one of the raw materials of Gentianae Radix et
Rhizoma, are scarce. As a part of ongoing search for active iridoid and secoiridoid
glucosides from the genus Gentiana, a detailed phytochemical investigation on G.
manshurica was carried out. This led to the isolation of one new iridoid glucoside 1, two
new secoiridoid glucosides 2 and 3, and 11 known compounds, including one iridoid
glucoside, five secoiridoid glucosides, and five triterpenes, i.e., 4 – 14 (Fig. 1).
Results and Discussion. – The dried roots of G. manshurica were extracted three
times with MeOH under reflux. After removal of the organic solvent, the extract was
suspended in H O and extracted with AcOEt and BuOH, successively. The BuOH
2
fraction was subjected to column chromatography (CC; MCI-gel CHP20P, SiO , and
2
Daisogel ODS-AP), to afford compounds 1 – 4 and 7 – 9. The AcOEt fraction was also
subjected to CC (SiO , MCI-gel CHP20P, and Daisogel ODS-AP) to furnish
2
compounds 5, 6, and 10 – 14. Compounds 4 – 14 were known, and identified as 6’-O-
[
3-(b-d-glucopyranosyloxy)-2-hydroxybenzoyl]sweroside (4) [6], trifloroside (5) [7],
ꢂ 2012 Verlag Helvetica Chimica Acta AG, Zꢃrich

Helvetica Chimica Acta – Vol. 95 (2012)
1095
Fig. 1. Chemical constituents from G. manshurica
scabraside (6) [8], gentiopicroside (7), swertimarin (8), 4’’-O-b-d-glucopyranosylli-
nearoside (9) [9], ursolic acid (10), 3,24-dihydroxyurs-12-en-28-oic acid (11) [10],
chiratenol (12) [11], lup-20(29)-en-3-one (13) [12], and lupeol (14) [13] by comparison
of their spectroscopic data with those reported previously in the literature or by direct
comparison with authentic compounds. Compounds 1 – 3 were new iridoid and
1)
Trivial atom numbering; for systematic names, see Exper. Part.

1
096
Helvetica Chimica Acta – Vol. 95 (2012)
secoiridoid glucosides and identified as 4’’-O-b-d-glucosyl-6’-O-[(4-O-b-d-glucosyl)-
1
1
caffeoyl]linearoside ) (1), 6’-O-acetylsweroside ) (2) and 6’-O-acetyl-3’-O-[3-(b-d-
1
glucopyranosyloxy)-2-hydroxybenzoyl]sweroside ) (3) (sweroside ¼ (4aS,5R,6S)-5-
ethenyl-6-(b-d-glycopyranosyloxy)-4,4a,5,6-tetrahydro-1H,3H-pyrano[3,4-c]pyran-1-
one; linearoside ¼ (1S,4aS,6S,7R,7aS)-1-(b-d-glucopyranoxsyloxy)-1,4a,5,6,7,7a-hexa-
hydro-6-{[(2E)-3-(4-hydroxyphenyl)-1-oxoprop-2-en-1-yl]oxy}-7-methylcyclopenta[c]-
pyran-4-carboxylic acid). Their structures were established as follows.
Compound 1 was obtained as a white amorphous powder. Its molecular formula
ꢀ
C H O was determined on the basis of the HR-ESI-MS (m/z 1007.3023 ([M ꢀ H] )).
46
56 25
ꢀ
1
The IR spectrum showed absorptions at 3404, 1693, 1637, and 1605 cm , suggesting the
1
13
presence of OH and C¼O groups. The H- and C-NMR data (Table 1) exhibited the
signals arising from two benzene rings (d(H) 7.32 and 6.96, and 7.12, 6.96, and 6.92,
resp.), two C¼O groups at d(C) 168.9 (C(7’’)) and 168.7 (C(7’’’’)), two sets of olefinic
protons at two trans-C¼C bonds (d(H) 7.43 and 6.25, and 7.35 and 6.06, resp., J ¼
1
6.0 Hz), and three b-glucopyranosyl moieties (anomeric protons at d(H) 4.59 (d,
J ¼ 8.0 Hz, HꢀC(1’)), 4.80 (d, J ¼ 7.5 Hz, HꢀC(1’’’’’)), and 4.87 (d, J ¼ 7.0 Hz,
HꢀC(1’’’)), resp.). These signals indicated the presence of p-coumaroyl (¼ 3-(4-
hydroxyphenyl)-1-oxoprop-2-en-1-yl) and caffeoyl (¼ 3-(3,4-dihydroxyphenyl)-1-oxo-
Table 1. 1H- and 13C-NMR Data (CD OD, 500 and 125 MHz, resp.) of Compound 1 ). d in ppm, J in Hz.
1
3
Position
d(H)
d(C)
Position
d(H)
d(C)
HꢀC(1)
HꢀC(3)
C(4)
5.09 (d, J ¼ 5.0)
7.18 (s)
98.0
HꢀC(1’’’)
HꢀC(2’’’)
HꢀC(3’’’)
HꢀC(4’’’)
HꢀC(5’’’)
4.87 (d, J ¼ 7.0)
3.42 – 3.40 (m)
3.67 – 3.65 (m)
3.32 – 3.29 (m)
3.22 – 3.20 (m)
3.83 – 3.79 (m),
3.58 (dd, J ¼ 12.0, 5.0)
101.8
75.1
75.9
72.4
78.6
63.1
150.0
a
)
HꢀC(5)
3.14 (t, J ¼ 8.5)
33.9
41.0
79.2
41.4
47.7
14.4
CH (6)
2.36 – 2.33, 1.73 – 1.68 (2m)
5.15 – 5.13 (m)
2
HꢀC(7)
HꢀC(8)
HꢀC(9)
Me(10)
C(11)
CH (6’’’)
2
2.11 – 2.08 (m)
1.99 – 1.96 (m)
0.98 (d, J ¼ 6.5)
C(1’’’’)
131.2
116.3
149.0
149.5
118.4
122.4
168.7
104.0
75.1
78.6
71.9
77.7
62.8
HꢀC(2’’’’)
6.96 (br. s)
a
)
C(3’’’’)
HꢀC(1’)
HꢀC(2’)
HꢀC(3’)
HꢀC(4’)
HꢀC(5’)
4.59 (d, J ¼ 8.0)
3.14 (t, J ¼ 8.0)
3.31 – 3.28 (m)
3.21 – 3.19 (m)
3.67 – 3.65 (m)
4.76 (br. d, J ¼ 12.0),
100.5
75.0
78.3
71.6
75.9
65.0
C(4’’’’)
HꢀC(5’’’’)
HꢀC(6’’’’)
C(7’’’’)
7.12 (d, J ¼ 8.0)
6.92 (br. d, J ¼ 8.0)
HꢀC(1’’’’’)
HꢀC(2’’’’’)
HꢀC(3’’’’’)
HꢀC(4’’’’’)
HꢀC(5’’’’’)
4.80 (d, J ¼ 7.5)
3.45 (t, J ¼ 7.0)
3.22 – 3.20 (m)
3.21 – 3.19 (m)
3.46 – 3.43 (m)
3.83 – 3.79 (m),
3.64 (dd, J ¼ 12.0, 6.0)
6.06 (d, J ¼ 16.0)
7.35 (d, J ¼ 16.0)
6.25 (d, J ¼ 16.0)
7.43 (d, J ¼ 16.0)
CH (6’)
2
4.28 (dd, J ¼ 12.0, 8.0)
C(1’’)
130.2
131.0
118.4
160.7
168.9
HꢀC(2’’,6’’)
HꢀC(3’’,5’’)
C(4’’)
7.32 (d, J ¼ 8.5)
6.96 (d, J ¼ 8.5)
CH (6’’’’’)
2
C(7’’)
HꢀC(a)
HꢀC(b)
HꢀC(a’)
HꢀC(b’)
117.7
145.6
117.4
146.7
a) The signals of C(4) and C(11) were not detected in the 13C-NMR spectrum.

Helvetica Chimica Acta – Vol. 95 (2012)
1097
prop-2-en-1-yl) moieties. In the up-field region, the HSQC experiments demonstrated
the presence of one Me (d(C) 14.4 (C(10))), one CH (d(C) 41.0 (C(6))), and three CH
2
groups (d(C) 47.7 (C(9)), 41.4 (C(8)), and 33.9 (C(5))). These NMR characteristics
resembled those of 9 [9]. However, compared with 9, 1 had an additional caffeoyl and
an additional glucosyl moiety. Acidic hydrolysis of 1 gave d-glucose as the sugar
moiety. In the HMBC spectrum of 1, the correlations HꢀC(1’) (d(H) 4.59)/C(1) (d(C)
9
8.0), CH (6’) (d(H) 4.76 and 4.28) and HꢀC(a’) (d(H) 6.25)/C(7’’’’) (d(C) 168.7), and
2
HꢀC(b’) (d(H) 7.43)/C(1’’’’) (d(C)131.2) and C(6’’’’) (d(C) 122.4) demonstrated that a
caffeoyloxy moiety was attached to C(6’), and the glycosyloxy group C(1’) was attached
to C(1) of the aglycone. The HMBCs HꢀC(1’’’) (d(H) 4.87)/C(4’’) (d(C) 160.7) and
HꢀC(a) (d(H) 6.06)/C(7’’) (d(C) 168.9) indicated that a glucosyloxy group was
attached to C(4’’) of the p-coumaroyl unit. In addition, the HMBCs HꢀC(1’’’’’) (d(H)
4
.80), HꢀC(2’’’’) (d(H) 6.96), and HꢀC(6’’’’) (d(H) 6.92)/C(4’’’’) (d(C) 149.5), and
HꢀC(2’’’’) (d(H) 6.96) and HꢀC(5’’’’) (d(H) 7.12)/C(3’’’’) (d(C) 149.0) were also
observed, indicating that the glucosyloxy residue C(1’’’’’) was at C(4’’’’) of the caffeoyl
unit. Other HMBCs (Fig. 2) further confirmed the structure of 1. Accordingly,
compound 1 was established to be 4’’-O-b-d-glucosyl-6’-O-(4-O-b-d-glucosylcaffeoyl)-
linearoside.
Compound 2 was a white amorphous powder. The molecular formula C H O was
1
8
24 10
13
þ
1
deduced from the HR-ESI-MS (m/z 423.1270 ([M þ Na] )). The H- and C-NMR
data of 2 (Table 2) revealed the presence of an Ac group (d(H) 2.05 (s, 3 H); (d(C)
Fig. 2. Key HMBC (H ! C) features of compounds 1 – 3

1
098
Helvetica Chimica Acta – Vol. 95 (2012)
Table 2. 1H- and 13C-NMR Data (CD OD, 500 and 125 MHz, resp.) of Compounds 2 and 3. d in ppm,
3
J in Hz.
Position
2
3
d(H)
d(C)
d(H)
d(C)
HꢀC(1)
HꢀC(3)
C(4)
5.38 (d, J ¼ 2.0)
7.58 (s)
98.6
154.1
106.4
28.7
5.29 (br. s)
7.50 (s)
98.7
154.1
106.4
28.7
HꢀC(5)
3.15 – 3.11 (m)
1.79 – 1.76 (m),
3.06 – 3.03 (m)
1.70 – 1.66 (m),
CH (6)
26.2
26.2
2
1
.70 (dt, J ¼ 12.5, 4.0)
1.60 (dd, J ¼ 12.5, 5.0)
CH (7)
4.40 – 4.33 (m)
70.0
133.6
44.2
4.37 – 4.34 (m)
70.0
133.6
44.2
2
HꢀC(8)
HꢀC(9)
5.55 (ddd, J ¼ 10.0, 10.0, 3.0)
5.49 – 5.42 (m)
2.62 – 2.60 (m)
2.71 – 2.68 (m)
CH (10)
5.30 (dd, J ¼ 25.5, 2.0),
121.2
5.23 (br. d, J ¼ 17.0),
120.4
2
5
.27 (dd, J ¼ 18.5, 1.5)
5.19 (br. d, J ¼ 18.0)
C(11)
168.7
100.2
74.9
75.9
71.7
168.7
100.2
74.9
78.0
71.7
HꢀC(1’)
HꢀC(2’)
HꢀC(3’)
HꢀC(4’)
HꢀC(5’)
4.68 (d, J ¼ 7.5)
3.18 (t, J ¼ 7.5)
3.39 – 3.36 (m)
3.36 – 3.33 (m)
3.51 – 3.49 (m)
4.47 – 4.44 (m),
4.59 (d, J ¼ 8.0)
3.10 (t, J ¼ 8.0 )
3.29 (t, J ¼ 9.0)
3.24 – 3.21 (m)
78.0
64.8
3.44 – 3.41 (m)
75.9
64.9
CH (6’)
4.36 – 4.34 (m),
4.13 (dd, J ¼ 12.0, 5.5)
2
4.23 (dd, J ¼ 12.0, 6.0)
MeꢀC¼O
MeꢀC¼O
C(1’’)
C(2’’)
C(3’’)
HꢀC(4’’)
HꢀC(5’’)
HꢀC(6’’)
C(7’’)
173.0
21.0
173.0
21.0
2.05 (s)
1.96 (s)
115.0
153.2
147.5
124.0
121.2
124.9
170.6
103.4
75.0
71.7
78.0
78.6
62.8
7.31 (d, J ¼ 8.0)
6.77 (t, J ¼ 8.0)
7.50 (dd, J ¼ 8.0, 2.5)
HꢀC(1’’’)
HꢀC(2’’’)
HꢀC(3’’’)
HꢀC(4’’’)
HꢀC(5’’’)
4.80 (d, J ¼ 7.5)
3.44 – 3.41 (m)
3.23 – 3.21 (m)
3.39 – 3.36 (m)
3.32 – 3.29 (m)
3.78 (br. d, J ¼ 12.5),
CH (6’’’)
2
3
.59 (dd, J ¼ 12.5, 4.5)
1
73.0 and 21.0), a b-glucopyranosyl moiety (anomeric H-atom at d(H) 4.68 (d, J ¼
7.5 Hz), and C-atoms at d(C) 100.2 (C(1’)), 74.9 (C(2’)), 75.9 (C(3’)), 71.7 (C(4’)),
7
3
8.0 (C(5’)), and 64.8 (C(6’))). The NMR characteristics were very similar to those of
’-O-acetylsweroside [14]. However, H, H-COSY and HMBC data (Fig. 2) demon-
1
1
strated that the AcO group was attached to C(6’) of the glucosyl moiety. Acidic
hydrolysis of 2 gave d-glucose as the sugar moiety. Based on the above evidences, 2 was
determined to be 6’-O-acetylsweroside.
Compound 3 was isolated as a white amorphous powder. The molecular formula
was determined to be C H O based on the HR-ESI-MS data (m/z 721.1976 ([M þ
31
38 18

Helvetica Chimica Acta – Vol. 95 (2012)
1099
þ
ꢀ1
Na] )). The IR spectrum showed absorptions at 3421, 1734, 1684, and 1617 cm ,
1
13
suggesting the presence of OH and C¼O groups. The H- and C-NMR data (Table 2)
indicated the presence of a 1,2,3-trisubstituted benzene ring (d(H) 7.50 (dd, J ¼ 8.0 and
2
1
4
.5 Hz), 7.31 (d, J ¼ 8.0 Hz), and 6.77 (t, J ¼ 8.0 Hz)), two C¼O groups (d(C) 173.0 and
70.6), and two b-glucosyl moieties (anomeric protons at d(H) 4.80 (d, J ¼ 7.5 Hz), and
.59 (d, J ¼ 8.0 Hz)), which were further confirmed to derive from d-glucose by acidic
hydrolysis. The above and other NMR characteristics resembled those of gentistrami-
noside A [15]. However, in contrast to gentistraminoside A, the HMBCs (Fig. 2) of
CH (6’) (d(H) 4.36 – 4.34, 4.13) and MeCO (d(H) 1.96)/MeCO (d(C) 173.0), revealed
2
that the Ac group was attached to C(6’). In addition, the C(3’) signal of 3 was shifted
downfield (Dd ¼ 2.6 ppm), while the C(4’) signal was shifted upfield (Dd ¼ 3.1 ppm),
suggesting that C(3’) was esterified with the 3-(b-d-glucopyranosyloxy)-2-hydroxy-
benzoyl residue. The HMBCs, HꢀC(6’’) (d(H) 7.50)/C(7’’) (d(C) 170.6), and HꢀC(4’’)
(
d(H) 7.31) and HꢀC(1’’’) (d(H) 4.80)/C(3’’) (d(C) 147.5) were also observed. Thus, the
structure of 3 was established as 6’-O-acetyl-3’-O-[3-(b-d-glucopyranosyloxy)-2-
hydroxybenzoyl]sweroside.
In the present work, we investigated the chemical constituents of G. manshurica in
detail, which led to the isolation of one new iridoid glucoside, 4’’-O-b-d-glucosyl-6’-O-
[
(4-O-b-d-glucosyl)-caffeoyl]linearoside (1), two new secoiridoid glucosides, 6’-O-
acetylsweroside (2) and 6’-O-aceyl-3’-O-[2-(b-d-glucopyranosyloxy)-2-hydroxyben-
zoyl]sweroside (3), and 11 known ones, including one iridoid glucoside, five secoiridoid
glucosides, and five triterpenes. Similar to other raw materials of Gentianae Radix et
Rhizoma, iridoid and secoiridoid glucosides were the main constituents in the title plant
[
3 – 5]. Moreover, a number of other O-acylsecoiridoids (see 4 – 6) were also isolated.
The results were in agreement with the use of G. manshurica as Gentianae Radix et
Rhizoma. Triterpenes 10 – 14 were isolated for the first time from G. manshurica.
However, in contrast to other sources of Gentianae Radix et Rhizoma [16], no
dammarane-type triterpenes were obtained in the present investigation.
Expertimental Part
General. TLC: HSGF254 plates (Yantai Jiangyou Silica Gel Development Co., Ltd.), eluent CHCl3/
MeOH/H O 8 :2 :0.2; spots were detected by spraying with 10% H SO soln. followed by heating.
2
2
4
Column chromatography (CC): MCI gel CHP20P (Mitsubishi Chemical Co.), silica gel (SiO ; 200 – 300
2
mesh; Qingdao Makall Group Co., Ltd.), and Daisogel ODS-AP (40 – 60 mm, Daiso Co., Ltd.). GC:
Thermo-TR-5 MS spectrometer. Optical rotations: Krꢀss-P800-T polarimeter. UV Spectra: Jasco-J-180
ꢀ1
spectrometer; lmax (log e) in nm. IR Spectra: Nicolet-380 spectrometer; ˜n in cm . 1D- and 2D-NMR
1
13
Spectra: Bruker-DRX-500 instrument at 500 ( H) and 125 MHz ( C); d in ppm rel. to Me Si as internal
4
standard, J in Hz. HR-ESI-MS: Waters-UPLC-Premior-QTOF spectrometer; in m/z.
Plant Material. The dried roots of G. manshurica were collected in August 2009 in Taikang City,
Heilongjiang, China, and authenticated by Dr. Li-Hong Wu, Institute of Chinese Materia Medica,
Shanghai University of Traditional Chinese Medicine. A voucher specimen (No. LD-090808) was
deposited with the Herbarium of the Shanghai R&D Center for Standardization of Chinese Medicines.
Extraction and Isolation. The dried roots of G. manshurica (4.5 kg) were extracted three times with
MeOH (20 l) under reflux (each 2 h). After evaporation of the org. solvent, the extract was suspended in
H O (5 l) and extracted four times with AcOEt (5 l) and BuOH (5 l), successively, to give an AcOEt
2
fraction (135 g) and a BuOH fraction (240 g). The BuOH fraction (150 g) was subjected to CC (MCI gel
CHP20P, MeOH/H O 0 :1 ! 8 :2): Fractions 1 – 4. Further CC (SiO , CHCl /MeOH 15 :1 ! 3 :2, then
2
2
3

1
100
Helvetica Chimica Acta – Vol. 95 (2012)
Daisogel ODS-AP, MeOH/H O 1:9 ! 5 :5) afforded 1 (9 mg), 2 (89 mg), 3 (53 mg), 4 (110 mg), and 9
2
(
152 mg) from Frs. 3 (9.5 g) and 4 (3.1 g). CC (MCI gel CHP20P, MeOH/H O 0 :1 ! 5 :5, then SiO ,
2
2
AcOEt/MeOH/H O 15 :1:0.5) gave 8 (88 mg) from Fr. 1 (8.2 g). CC (MCI gel CHP20P, MeOH/H O
2
2
0
:1 ! 4 :6) gave 7 (8.8 g) from Fr. 2 (10.3 g). The AcOEt fraction (85 g) was subjected to CC (SiO ,
2
CHCl /MeOH 100 :1 ! 9 :1): Fractions 5 – 10. Further CC (MCI gel CHP20P, MeOH/H O 4 :6 ! 9 :1)
3
2
afforded 5 (820 mg) and 6 (491 mg) from Fr. 9 (5.8 g). CC (SiO , petroleum/AcOEt 9 :1 ! 6 :4, then
2
Daisogel ODS-AP, MeOH/H O 7:3 ! 1:0) gave 10 (76 mg), 11 (41 mg), and 12 (62 mg) from Fr. 7
2
(
9.8 g). Compounds 13 (490 mg) and 14 (630 mg) were obtained from Fr. 5 (7.7 g) by CC (SiO ,
2
petroleum/AcOEt 100 :1 ! 25 :1) and recrystallization in CHCl /MeOH 1:1.
3
4
’’-O-b-d-Glucosyl-6’-O-(4-O-b-d-glucosylcaffeoyl)linearoside (¼(1S,4aS,6S,7R,7aS)-1-{{6-O-{(2E)-
3
-[4-(b-d-Glucopyranosyloxy)-3-hydroxyphenyl]-1-oxoprop-2-en-1-yl}-b-d-glucopyranosyl}oxy}-6-
{
{(2E)-3-[4-(b-d-glucopyranosyloxy)phenyl]-1-oxoprop-2-en-1-yl}oxy}-1,4a,5,6,7,7a-hexahydro-7-meth-
25
ylcyclopenta[c]pyran-4-carboxylic acid; 1): White amorphous powder. [a] ¼ ꢀ67.0 (c ¼ 0.12, MeOH).
D
1
UV (MeOH): 289 (4.60), 204 (4.59), 192 (4.35). IR (KBr): 3404, 1693, 1637, 1605, 1509, 1074, 621. H-
13
ꢀ
ꢀ
55 25
and C-NMR: Table 1. HR-ESI-MS: 1007.3023 ([M ꢀ H] , C H O ; calc. 1007.3032).
46
6
’-O-Acetylsweroside (¼(4aS,5R,6S)-6-[(6-O-Acetyl-b-d-glucopyranoysl)oxy]-5-ethenyl-4,4a,5,6-
25
tetrahydro-1H,3H-pyrano[3,4-c]pyran-1-one; 2): White amorphous powder. [a]
D
¼ ꢀ225.5 (c ¼ 0.11,
1
MeOH). UV (MeOH): 241 (4.06), 203 (4.00). IR (KBr): 3413, 1739, 1693, 1617, 1268, 1075. H- and
13
þ
þ
C-NMR: Table 2. HR-ESI-MS: 423.1270 ([M þ Na] , C H O Na ; calc. 423.1267).
18
24 10
6
’-O-Acetyl-3’-O-[3-(b-d-glucopyranosyloxy)-2-hydroxybenzoyl]sweroside (¼(4aS,5R,6S)-6-{{6-O-
Acetyl-3-O-[3-(b-d-glucopyranosyloxy)-2-hydroxybenzoyl]-b-d-glucopyranosyl}oxy}-5-ethenyl-4,4a,5,6-
2
5
tetrahydro-1H,3H-pyrano[3,4-c]pyran-1-one; 3): White amorphous powder. [a] ¼ ꢀ142.0 (c ¼ 0.10,
D
1
MeOH). UV (MeOH): 245 (4.23), 208 (4.58). IR (KBr): 3421, 1684, 1617, 1251, 1073, 592. H- and
13
þ
þ
C-NMR: Table 2. HR-ESI-MS: 721.1976 ([M þ Na] , C H O Na ; calc. 721.1956).
31
38 18
Acidic Hydrolysis of Compounds 1 – 3. A soln. of 1, 2 or 3 (each 2 – 3 mg) in 3m aq. CF COOH (3 ml)
3
was heated for 2 h at 1208. Then, the mixture was cooled and concentrated. To this hydrolyzate were
added the following solns.: (2S)-1-aminopropan-2-ol/anh. MeOH 1:8 (20 ml), AcOH/anh. MeOH 1:4
(
17 ml), and 3% NaBH CN in anh. MeOH (17 ml). The mixture was allowed to react for 2 h at 658. After
3
3
cooling, 3m aq. CF COOH was added dropwise until the pH dropped to 1 – 2. Then, the mixture was
evaporated, and the residue was dried overnight in a desiccator. Pyridine/Ac O 1:1 (0.5 ml) was added,
2
and the mixture was allowed to react at 1008 for 1 h. After addition of 1 ml of CHCl , the mixture was
3
washed three times with sat. Na CO soln. and H O successively. The org. phase was dried (Na SO ) and
2
3
2
2
4
subjected to GC/MS (Thermo TR-5 MS, 60 m ꢁ 0.25 mm ꢁ 2.5 mm); carrier gas He, flow rate 1 ml/min;
oven temp.: 180 ! 2208 (48/min), 2208 for 2 min, 220 ! 2708 (18/min), and 2708 for 1 min). By
comparison with the retention times of authentic samples (t (d-glucose) 54.88 min, and t (l-glucose)
R
R
5
5.08 min), the configuration of the sugar moieties were determined to be d.
REFERENCES
[
1] ꢀPharmacopoeia of P. R. Chinaꢁ, Editorial Board of Chinese Pharmacopoeia, Chinese Medical
Science and Technology Press, Beijing, 2010, Vol. 1, p. 89.
[2] B. Dinda, D. R. Chowdhury, B. C. Mohanta, Chem. Pharm. Bull. 2009, 57, 765.
[3] R. Kakuda, T. Iijima, Y. Yaoita, K. Machida, M. Kikuchi, J. Nat. Prod. 2001, 64, 1574.
[4] M. Kikuchi, R. Kakuda, M. Kikuchi, Y. Yaoita, J. Nat. Prod. 2005, 68, 751.
[5] R.-W. Jiang, K.-L. Wong, Y.-M. Chan, H.-X. Xu, P. P.-H. But, P.-C. Shaw, Phytochemistry 2005, 66,
2674.
[
[
6] G. Chen, S.-H. Wei, C.-Y. Yu, Biochem. Syst. Ecol. 2009, 37, 766.
7] R.-X. Tan, J.-L. Wolfender, L. X. Zhang, W. G. Ma, N. Fuzzati, A. Marston, K. Hostettmann,
Phytochemistry 1996, 42, 1305.
[
[
8] J.-A. Kim, N. S. Son, J. K. Son, Y. Jahng, H. W. Chang, T. S. Jang, M. K. Na, S.-H. Lee, Arch. Pharm.
Res. 2009, 32, 863.
9] C. Bergeron, A. Marston, R. Gauthier, K. Hostettmann, Phytochemistry 1997, 44, 633.

Helvetica Chimica Acta – Vol. 95 (2012)
1101
[
10] Y. Sashida, K. Ogawa, T. Yamanouchi, H. Tanaka, Y. Shoyama, I. Nishioka, Phytochemistry 1994, 35,
77.
3
[
[
[
11] R. Kakuda, T. Iijima, Y. Yaoita, K. Machida, M. Kikuchi, Phytochemistry 2002, 59, 791.
12] A. Hisham, G. J. Kumar, Y. Fujimoto, N. Hara, Phytochemistry 1995, 40, 1227.
13] D. Burns, W. F. Reynolds, G. Buchanan, P. B. Reese, R. G. Enriquez, Magn. Reson. Chem. 2000, 38,
488.
[
[
[
14] M.-I. Chung, C.-N. Lin, J. Nat. Prod. 1993, 56, 982.
15] M. Xu, M. Zhang, Y.-J. Zhang, C.-R. Yang, Helv. Chim. Acta 2009, 92, 321.
16] M. Xu, D. Wang, Y.-J. Zhang, C.-R. Yang, J. Nat. Prod. 2007, 70, 880.
Received November 15, 2011