Five new phenolic glycosides from Hedyotis scandens

Article abstract of DOI:10.1016/j.bmcl.2012.12.077

Five new phenolic glycosides, hedyotosides A-E (1-5), including a new cyanogenic glycoside (1), along with 10 known compounds (6-15) were isolated from the whole plants of Hedyotis scandens. The structures of compounds 1-5 were established by extensive spectroscopic analyses and acid hydrolysis. All the isolated compounds were evaluated for their in vitro antiviral activity against respiratory syncytial virus (RSV) with cytopathic effect (CPE) reduction assay. Compounds 6 and 15 showed anti-RSV effects with IC₅₀ values of 20 and 25 μg/mL, respectively.

Full text of DOI:10.1016/j.bmcl.2012.12.077

Bioorganic & Medicinal Chemistry Letters 23 (2013) 1379–1382
Contents lists available at SciVerse ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Five new phenolic glycosides from Hedyotis scandens
⇑
,
⇑
Guo-Cai Wang , Tao Li , Fang-Ye Deng, Yao-Lan Li, Wen-Cai Ye
Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, China
Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drug Research, Guangzhou 510632, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Five new phenolic glycosides, hedyotosides A–E (1–5), including a new cyanogenic glycoside (1), along
with 10 known compounds (6–15) were isolated from the whole plants of Hedyotis scandens. The struc-
tures of compounds 1–5 were established by extensive spectroscopic analyses and acid hydrolysis. All the
isolated compounds were evaluated for their in vitro antiviral activity against respiratory syncytial virus
Received 14 November 2012
Revised 20 December 2012
Accepted 22 December 2012
Available online 5 January 2013
(RSV) with cytopathic effect (CPE) reduction assay. Compounds 6 and 15 showed anti-RSV effects with
IC50 values of 20 and 25 g/mL, respectively.
l
Keywords:
Ó 2012 Elsevier Ltd. All rights reserved.
Hedyotis scandens
Rubiaceae
Phenolic glycosides
Cyanogenic glycoside
Antiviral activity
The genus Hedyotis belongs to the family Rubiaceae and com-
prises 699 species, with 69 species found in China. Previous chem-
120 g) using gradient elution of CHCl
afford 9 (50 mg) and 14 (25 mg). Fraction 7 (6.8 g) was purified
by Sephadex LH-20 column (3 ꢀ 80 cm, CHCl /MeOH, 1:1) and
preparative RP-HPLC (Cosmosil 5C18-MS-|| waters column,
20 ꢀ 250 mm, MeOH/H O, 55:45) to yield 1 (12 mg), 3 (17 mg), 5
(14 mg) and 10 (15 mg), respectively. Fraction 8 (8.5 g) was puri-
fied by Sephadex LH-20 column (3 ꢀ 80 cm, CHCl /MeOH, 1:1)
and preparative RP-HPLC (Cosmosil 5C18-MS-|| waters column,
O) to give 8 (12 mg), 11 (40 mg), 12
3
/MeOH (98:2?80:20) to
1
ical investigations on this genus have led to the isolation of a series
of triterpenoids, iridoids, flavonoids, and anthraquinones. The
plant Hedyotis scandens Roxb. is widely distributed in tropic and
subtropic areas. The whole plants of H. scandens, called as ‘Li Fei
San’ in minority groups, have been widely used in Chinese folk
medicines for the treatment of respiratory diseases. Several triterp-
enoids and flavonoids had been reported from H. scandens in the
previous phytochemical studies.2 In the course of our ongoing
search for biologically active compounds from traditional Chinese
medicines, 15 more secondary metabolites including five new
phenolic glycosides (1–5) were isolated from the whole plants of
H. scandens (Fig. 1). Details of the isolation, structure elucidation
of these compounds, and their in vitro antiviral activities against
respiratory syncytial virus (RSV) are reported herein.
3
2
3
20 ꢀ 250 mm, MeOH/H
2
,3
(20 mg) and 13 (11 mg). The n-BuOH part (48 g) was fractionated
using a D101 resin column with a gradient system of ethanol/
H O (0:100; 30:70; 50:50; 70:30) to afford fractions A–D. Fraction
2
B and C were further separated by CC using ODS, Sephadex LH-20
and preparative RP-HPLC to obtain 2 (15 mg), 4 (8 mg), 6 (12 mg), 7
(20 mg), and 15 (5 mg).
4
Compound 1 was obtained as a black solid. The molecular for-
The dried plant material of H. scandens (9.0 kg) was powdered
and extracted with 95% EtOH by percolation at room temperature
for three times. After removal of the solvent in vacuo, the viscous
mula of 1 was established as C28
H
31NO12 by a quasi-molecular ion
ꢁ
at m/z 572.1769 [MꢁH] (calcd for C28
H30NO12: 572.1774) in HRE-
SIMS. The IR spectrum revealed the presence of hydroxyl (3442 cm
ꢁ1
), carbonyl (1635 cm ), and cyano (2362 cm ) groups. The 1
ꢁ1
ꢁ1
concentrate (380 g) obtained was suspended in H
2
O and then par-
H
titioned with petroleum ether, EtOAc, and n-BuOH consecutively.
The EtOAc part (120 g) was separated on silica gel column chroma-
tography (12 ꢀ 150 cm, 1500 g) and eluted with a gradient mixture
NMR spectrum (Table 1) displayed five olefinic protons at d
H
7.58
(2H, dd, J = 8.0, 2.0 Hz) and 7.43 (3H, m), suggesting the presence
of a single-substituted benzene ring. Four olefinic protons at d
7.44 (2H, m) and 6.80 (2H, m) indicated the existence of a p-disub-
stituted benzene ring. Two olefinic protons at d 7.66 (1H, d,
J = 16.0 Hz) and 6.37 (1H, d, J = 16.0 Hz) assignable to a trans dou-
H
3
of CHCl /MeOH (100:0?0:100) to generate fractions 1–10. Frac-
tion 6 (7.5 g) was chromatographed on silica gel (3 ꢀ 80 cm,
H
1
3
ble bond were also observed. The C NMR spectrum (Table 1)
showed 28 carbon signals, including three methylenes, 19
methines, and six quaternary carbons (including one ester car-
⇑
Corresponding authors. Tel./fax: +86 20 8522 1559.
E-mail addresses: twangguocai@jnu.edu.cn (G.-C. Wang), chywc@yahoo.com.cn
(
W.-C. Ye).
These two authors contributed equally to this work.
C C
bonyl at d 169.2 and one cyano group at d 119.5). The NMR data
0
960-894X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2012.12.077

1
380
G.-C. Wang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 1379–1382
OH
1
R O
O
O
9'
OH
A =
B =
1
7
R O
H
CN
O
O
O
1'
9
O
1
7'
O
OR2
3
R O
OH OH
OH
OR2
HO
HO
O
1
1
1
1
1
2
OCH3
R1 = CH CH CH CH
2
3
1
2
3
6
7
R
R
R
R
R
= p-coumaroyl
= caffeoyl
= p-coumaroyl
= H
R
R
R
R
= A
= B
= C
= B
5
9
R
R
= glc
= H
R
R
R
R
R
R
= H
= H
= H
= H
= H
= CH3
2
2
2
3
2
1
1
2
3
R
= H
C =
OCH3
2
R2 = H
3
10 R = CH3
2
11 R1 = CH CH CH CH
2
3
R
= H
= glc
= H
OCH3
2
2
2
3
R2 = B
12 R1 = CH
R
R
2
3
3
= p-coumaroyl
3
O
1
2
1
3 R = CH3
O
7'''
7'''
9'''
O
9
'''
1'''
8'''
1'''
4'''
8'''
HO
OH
3'''
HO 4'''
OH
HO
p-coumaroyl
caffeoyl
OH
14
O
7
8'
OH
7
1
'
'
9
O
1
OH
HO
O
OR
HO
HO
O
OH
OH
OH
OH
4
R = glc
R = H
15
8
Figure 1. The structures of compounds 1–15.
Table 1
NMR spectroscopic data for compounds 1–3 in CD
a
3
OD
Position
1
2
3
d
C
d
H
(J in Hz)
d
C
d
H
(J in Hz)
d
C
H
d (J in Hz)
1
2
3
4
5
6
7
8
119.5
69.1
156.1
96.7
154.9
134.9
154.9
96.7
5.79, s
164.8
143.6
177.3
117.4
157.3
16.0
6.45, s
6.45, s
135.1
130.2
129.1
131.1
129.1
130.2
7.43, m
7.58, dd (8.0, 2.0)
7.43, m
7.58, dd (8.0, 2.0)
7.43, m
6.41, d (5.6)
7.92, d (5.6)
2.43, s
3
4
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
,5-OMe
-OMe
56.9
61.4
3.79, s
3.68, s
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
00
00
00
00
00
00
00
00
00
127.3
131.4
117.0
161.5
117.0
131.4
147.1
115.0
169.2
102.7
74.8
127.8
115.4
146.9
147.8
116.7
123.2
147.5
114.8
169.0
105.5
75.4
127.2
131.4
117.1
161.7
117.1
131.4
147.1
114.9
169.1
103.3
75.0
7.44, m
6.80, m
7.04, d (1.6)
6.78, d (8.0)
6.94, dd (8.0, 1.6)
7.57, d (16.0)
7.45, m
6.80, m
6.80, m
7.44, m
7.66, d (16.0)
6.37, d (16.0)
6.80, m
7.45, m
7.65, d (16.0)
6.34, d (16.0)
6.28, d (16.0)
4.29, d (7.2)
3.29, m
3.27, m
3.32, m
3.45, m
4.76, d (7.2)
3.31, m
3.40, m
3.41, m
3.45, m
3.97, dd (11.2, 2.0)
3.62, dd (11.2, 6.0)
4.99, d (2.0)
3.90, d (2.0)
4.79, d (7.6)
3.33, m
3.42, m
3.45, m
3.52, m
4.20, dd (11.2, 2.1)
3.84, dd (11.2, 6.0)
5.00, d (2.4)
3.90, d (2.4)
78.0
71.6
77.3
68.6
78.5
71.5
77.5
68.6
78.0
71.7
77.1
67.6
4.06, dd (11.2, 1.6)
3
.66, dd (11.2, 6.0)
0
0
0
0
0
0
0
0
1
2
3
4
110.7
78.6
79.2
75.2
5.09, d (2.4)
4.01, d (2.4)
110.7
78.0
80.6
75.0
110.6
78.7
79.1
75.1
4.11, d (9.6)
3.96, d (9.6)
3.83, d (9.6)
4.25, d (11.2)
4.06, d (9.6)
4.02, d (9.6)
4.26, d (11.6)
4.23, d (11.6)
3
.88, d (9.6)
0
0
5
67.7
4.32, m
65.7
68.5
4.22, d (11.2)
a
Recorded at 400 MHz ( H) and 100 MHz (13C).
1

G.-C. Wang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 1379–1382
1381
suggested the presence of two sugar moieties in 1. Acid hydrolysis
of 1 yielded -glucose and -apiose which were identified by re-
versed-phase HPLC after conversion of the sugars to thiocarba-
by acid hydrolysis and HPLC method mentioned above.6 The glu-
cose anomeric proton resonated at d 4.76 (1H, d, J = 7.2 Hz) and
the apiose anomeric carbon resonated at d 110.7 suggested that
the configuration of the anomeric carbons of the glucopyranosyl
D
D
H
C
moyl–thiazolidine derivatives.5 The
anomeric proton at d 4.29 indicated a b configuration for the glu-
copyranosyl moiety. The anomeric carbon of the apiofuranosyl unit
,6
J
value (7.2 Hz) of the
7
,12
H
moiety and the apiofuranosyl moiety both to be b.
HMBC corre-
0
0
000
lations from d
H
4.25 (H-5 ) to d
C
169.0 (C-9 ) and from d 4.76 (H-
H
0
0
7
0
resonated at d
C
110.7 verifying a b configuration at C-1 . HMBC
1 ) to d
C
143.6 (C-3) indicated that the caffeoyl group was con-
000
000
00
0
correlations (Fig. 2) from d
H
7.66 (H-7 ) to d
C
169.2 (C-9 ) and
nected to C-5 and the maltol group was attached to C-1 . Correla-
000
000
000
000
00
0
1
31.4 (C-2 /C-6 ), and from d
H
6.37 (H-8 ) to d
C
127.3 (C-1 )
H C
tion in HMBC spectrum from d 4.99 (H-1 ) to d 68.6 (C-6 )
indicated the presence of a p-coumaroyl fragment. The HMBC
connected the two sugar moieties. The structure of compound 2
00
000
0
cross-peak of d
H
4.32 (H-5 )/d
C
169.2 (C-9 ) suggested that the
was therefore elucidated as maltol 6 -O-(5-O-caffeoyl)-b-
D-apiofur-
00
p-coumaroyl unit was attached to apiose at C-5 . The location of
anosyl-b-
hedyotoside B.
HRESIMS of 3 showed a quasi-molecular ion at m/z 647.1948
D-glucopyranoside, and assigned the common name
the apiose moiety at C-6 of glucose was deduce from the HMBC
0
0
0
13
cross-peak of d
H
5.09 (H-1 )/d
C
68.6 (C-6 ). The whole structure
5.79
+
of 1 was established by the HMBC correlations from d
102.7 (C-1 ), 119.5 (C-1), 135.1 (C-3), and 130.2
C-4/C-8). The glucose anomeric proton (H-1 ) at d
H
[M+Na] corresponding to a molecular formula of C29
36
H O15 (calcd
0
(
H-2) to d
C
for C29 36NaO15, 647.1946). The NMR data (Table 1) were similar
H
0
(
H
4.29 suggested
to those of 1 except that 3 showed signals for a 3,4,5-trimethoxy-
the chirality of the cyanogenic center (C-2) to be R in 1, based on
phenyl group instead of a benzeneacetonitrile group in 1. The
0
the significant difference of the glucose anomeric resonance
HMBC correlation (Fig. 2) between d
H
4.79 (H-1 ) and d
C
156.1
8
–10
previously observed between R and S configurations at C-2.
Thus, compound was elucidated as benzeneacetonitrile
-O-(5 -O-p-coumaroyl)-b- -apiofuranosyl-b- -glucopyranoside,
and ascribed the trivial name hedyotoside A.
(C-1) indicated that the 3,4,5-trimethoxyphenyl group was con-
nected to the glucose via an ether bond. The sugar moieties were
1
0
00
6
D
D
also determined to be b-D-glucose and b-D-apiose by methods
6
mentioned above. Therefore, compound 3 was determined to be
1
1
0
Compound 2 was isolated as a brown oil, and its molecular
formula was determined to be C26 15 on the basis of HRESIMS,
which showed a quasi-molecular ion peak at m/z 605.1477
M+Na]+ (calcd for C26
30NaO15, 605.1477). The IR spectrum of 2
displayed absorptions characteristic of hydroxyl and carbonyl
3,4,5-trimethoxyphenyl 6 -O-(5-O-p-coumaroyl)-b-
D
-apiofurano-
H
30
O
syl-b-
The HRESIMS of 4 displayed a quasi-molecular ion at m/z
D-glucopyranoside and named hedyotoside C.
1
4
+
[
H
499.1210 [M+Na] (calcd for C23
with the molecular formula C23
H24NaO11, 499.1211), consistent
H
24
O
11. The IR spectrum showed
ꢁ1
1
ꢁ1
groups at 3383 and 1697 cm . The H NMR spectrum of 2 (Table 1)
showed two olefinic protons at d 7.92 (1H, d, J = 5.6 Hz) and 6.41
1H, d, J = 5.6 Hz), and one methyl group at d 2.43 (3H, s), suggest-
ing the presence of a maltol group, which was confirmed by the
NMR data (Table 1) and HMBC correlations (Fig. 2). Similarly, five
olefinic protons at d 7.04 (1H, d, J = 1.6 Hz), 6.94 (1H, dd, J = 8.0,
.6 Hz), 6.78 (1H, d, J = 8.0 Hz, 7.57 (1H, d, J = 16.0 Hz), and 6.28
absorption bands corresponding to hydroxyl (3442 cm ) and car-
ꢁ
1
H
bonyl (1635 cm ) groups. The NMR spectra (Table 2) of 4 resem-
1
5,16
(
H
bled those of nepetoidin B (8),
a sugar moiety, which was determined to be b-
basis of the J value (7.2 Hz) of the anomeric proton and acid hydro-
except the additional signals for
1
3
C
D-glucose on the
6
00
H
H C
lysis. The HMBC correlation from d 4.85 (H-1 ) to d 147.4 (C-3)
1
allowed the assignment of the glucose to C-3. Accordingly, the
structure of compound 4 (hedyotoside D) was elucidated as shown
in Figure 1.
1
3
(
1H, d, J = 16.0 Hz) were assigned to a caffeoyl group. The
C
NMR spectrum (Table 1) showed 26 carbons containing one
methyl, three methylenes, 14 methines, and eight quaternary car-
bons. The NMR data of 2 also indicated the presence of two mono-
1
7
Compound 5 was isolated as a yellow oil, and its HRESIMS
showed an [M+Na]+ ion peak at m/z 601.1891 (calcd for
saccharides, which were determined to be
D-glucose and
D
-apiose
28
C H34NaO13, 601.1892), establishing a molecular formula of
OH
HO 4'''
HO 4'''
1
'''
1'''
7
'''
7'''
O
3''
O
O
O
''
O
6
O
O
4'
9
'''
4
9'''
O
5
5''
4
O
1''
1''
6'
6'
O
O
O
'
O
6
1
3
''
4'
8
O
2
OH OH
2
OH OH
1'
H
HO
OH
HO
OH
CN
HO
HO
3'
7
3'
1
1
2
HO 4'''
1'''
7'''
O
OCH3
4
O
9
'''
O
5''
O
1''
1
6'
O
O
OCH3
OCH3
3''
1'
OH
4
'
OH OH
HO
HO
3'
3
Figure 2. Key HMBC (H?C) correlations of compounds 1–3.

1
382
G.-C. Wang et al. / Bioorg. Med. Chem. Lett. 23 (2013) 1379–1382
Table 2
NMR spectroscopic data for compounds 4–5 in CD
were obtained from this material. Therefore, the isolated com-
pounds were submitted to in vitro antiviral evaluation against
RSV with cytopathic effect (CPE) reduction assay. However, all
the caffeoyl and coumaroyl compounds did not show inhibitory
activity against RSV at their maximal non-toxic concentrations
a
3
OD
2
9
Position
4
5
d
C
d
H
(J in Hz)
d
C
d
H
(J in Hz)
1
2
3
4
5
6
7
8
9
127.8
117.9
147.4
146.1
116.4
127.1
148.5
114.6
165.8
128.0
117.3
146.1
151.9
117.7
123.1
113.3
133.0
128.0
116.5
147.2
151.5
117.6
126.5
147.4
115.4
168.3
128.8
118.4
146.3
145.6
117.8
122.0
38.1
(
MNCC). Only compounds 6 and 15 showed weak anti-RSV effects
7.64, d (2.0)
7.54, d (2.0)
with IC50 values of 20 and 25 g/mL, respectively. The IC50 value of
l
ribavirin (positive control in the experiment) was tested as 1.5
lg/
6.76, d (8.0)
6.87, d (8.0)
mL.
7.24, dd (8.0, 2.0)
7.76, d (16.0)
6.53, d (16.0)
7.20, dd (8.0, 2.0)
7.61, d (16.0)
6.38, d (16.0)
Acknowledgments
0
1
This work was supported by the Fundamental Research Funds
for the Central Universities (21612417), the National Natural
Science Foundation (No. 81001374), Program for Changjiang
Scholars and Innovative Research Team in University (IRT0965)
and Research Team Program of Natural Science Foundation of
Guangdong Province (No. 8351063201000003).
0
2
7.35, d (2.0)
6.73, d (2.0)
0
3
0
4
0
5
6.89, d (8.0)
6.86, dd (8.0, 2.0)
5.61, d (7.2)
6.70, d (8.0)
6.58, dd (8.0, 2.0)
3.03, m
0
6
0
7
0
8
7.23, d (7.2)
75.0
5.16, m
0
9
171.9
104.4
75.1
78.6
71.7
0
0
0
0
0
0
0
0
0
0
0
0
1
2
3
4
5
6
104.4
75.0
78.7
71.7
77.7
62.8
4.85, d (7.2)
3.52, m
3.56, m
3.42, m
3.53, m
4.73, d (7.6)
3.49, m
3.55, m
3.41, m
3.51, m
3.96, dd (12.2, 1.9)
3.73, dd (12.2, 6.0)
4.09, m
1.55, m
1.31, m
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2012.
12.077. These data include MOL files and InChiKeys of the most
important compounds described in this article.
77.8
62.7
4.01, dd (12.1, 2.0)
3.74, dd (12.1, 6.0)
0
0
0
0
00
00
00
00
1
2
3
4
66.3
31.8
20.2
14.1
References and notes
0.90, t (6.4)
1
.
Wang, R. J.; Zhao, N. X. J. Trop. Subtrop. Bot. 2001, 9, 219.
a
Recorded at 400 MHz ( H) and 100 MHz (13C).
1
2. Jabbar, A.; Akhteruzzaman, S. M.; Rashid, M. A. Fitoterapia 1996, 67, 278.
3
.
.
Deng, F. Y.; Wang, G. C.; Wang, C. H.; Ye, W. C. Chin. Tradit. Herb. Drugs 2012, 43,
61.
8
2
5
4
Hedyotoside A (1): Black solid; mp 147–148 °C; ½
a
ꢂ
ꢁ33.8 (c 0.06, MeOH); UV
D
28 34
C H O13. The NMR spectroscopic data (Table 2) of 4 were similar
(
MeOH) kmax: 207, 314 nm; IR (KBr)
m
max: 3442, 2362, 1635, 1607, 1516,
18
ꢁ1
1
13
ꢁ
to those of butyl rosmarinate (11), except that 4 showed signals
1071 cm
;
H and C NMR data, see Table 1; HRESIMS m/z 572.1769 [MꢁH]
30NO12, 572.1774).
Tanaka, T.; Nakashima, T.; Ueda, T.; Tomii, K.; Kouno, I. Chem. Pharm. Bull. 2007,
5, 899.
(
calcd for C28H
due to an additional sugar moiety. Coupling constant of the ano-
meric proton (7.6 Hz) and acid hydrolysis identified the sugar as
5
.
5
000
a b-
and d
D
-glucose residue.6 HMBC correlation between d
H
4.75 (H-1 )
6. Acid hydrolysis and HPLC analysis of 1–5. Each compound (2.0 mg) was
dissolved in 2 mol/L HCl (10 mL) and heated at 80 °C for 5 h. The mixture was
C
147.2 (C-3) suggested that the glucose moiety was con-
evaporated to dryness, and the residue was partitioned between CH
O. The aqueous phase was concentrated to furnish a residue. After drying
under vacuum, anhydrous pyridine (1.0 mL) and -cysteine methyl ester
2 2
Cl and
nected to the aglycon at C-3. Full assignment of the NMR data
was based on HSQC and HMBC correlations. The structure of com-
pound 5 was therefore determined as shown in Figure 1, and
H
2
D
hydrochloride (4.0 mg) were added to the residue and the mixture was heated
at 60 °C for 1 h. After the reaction mixture was evaporated to dryness, o-tolyl
isothiocyanate (10 lL) was then added, and the mixture was heated at 60 °C for
1 h. The reaction mixture was directly analyzed by standard C18 HPLC, which
was performed on an Agilent 1260 HPLC system (Agilent Technologies Inc.,
USA) equipped with a photodiode array detector and a Capcell pak C18 column
named hedyotoside E.
0
The structures of the known compounds maltol 6 -b-
D
-apiofur-
anosyl-b-
b- -apiofuranosyl-b-
8),1
marinate (11), salviaflaside methyl ester (12), methyl isoferu-
D
-glucopyranoside (6),12 maltol 6 -O-(5-O-p-coumaroyl)-
0
12
D
D
-glucopyranoside
(7),
nepetoidin
B
(
4.6 ꢀ 250 mm, 5
formic acid solution for 40 min at a flow rate of 0.8 mL/min. The injection
volume was 10 L, and peaks were detected at 250 nm. The reaction conditions
for authentic samples were the same as described above. -Glucose (20.2 min)
and -apiose (33.8 min) were detected in 1–3, and -glucose (20.2 min) was
detected in 4–5.
7. Rockenbach, J.; Nahrstedt, A.; Wray, V. Phytochemistry 1992, 31, 567.
3
lm) at 25 °C with isocratic elution of 25% CH CN in 0.1%
5,16
19
20
(
rosmarinic acid (9), methyl rosmarinate (10), butyl ros-
1
8
21
l
22
19
D
loyl-7-(3,4-dihydroxyphenyl) lactate (13), caffeic acid (14),
D
D
2
3
and grevilloside G (15) (Fig. 1) were identified by comparing
their spectroscopic data with reported values.
Cyanogenic glycosides are traditionally viewed as plant defen-
sin and present in at least 2650 plant species from 130 fami-
They are considered important for plant defense against
herbivores because of their bitter taste and ability to release toxic
hydrogen cyanide (HCN) as well as ketones or aldehydes upon tis-
sue disruption. Only about 60 naturally occurring cyanogenic
though the number still contin-
ues to grow with four new cyanogenic glycosides recently identi-
8.
Yang, C. J.; Wang, Z. B.; Zhu, D. L.; Yu, Y.; Lei, Y. T.; Liu, Y. Molecules 2012, 17,
396.
5
9.
Miller, R. E.; Stewart, M.; Capon, R. J.; Woodrow, I. E. Phytochemistry 2006, 67,
2
4,25
lies.
1365.
1
1
0. Seigler, D. S.; Pauli, G. F.; Nahrstedt, A.; Leen, R. Phytochemistry 2002, 60, 873.
25
1. Hedyotoside B (2): Brown oil; ½
a
ꢂ
ꢁ26.4 (c 0.05, MeOH); UV (MeOH) kmax: 206,
ꢁ1 1
D
2
52, 293, 330 nm; IR (KBr) max: 3383, 1697, 1607, 1458, 1071, 838 cm ; H
m
2
4
13
+
and C NMR data, see Table 1; HRESIMS m/z 605.1474 [M+Na] (calcd for
30NaO15, 605.1477).
2. Li, H. Z.; Nakashima, T.; Tanaka, T.; Zhang, Y. J.; Yang, C. R.; Kouno, I. J. Nat. Med.
008, 62, 75.
13. Hedyotoside C (3): Black oil; ½
228, 314 nm; IR (KBr) max: 3371, 1697, 1606, 1518, 1071, 838 cm
C NMR data, see Table 1; HRESIMS m/z 647.1948 [M+Na]+ (calcd for
glucosides have been reported,2
4,26
26
C H
1
2
8
,26
2
5
fied.
To the best of our knowledge, six cyanogenic glucosides
have been isolated from the family Rubiaceae in the previous stud-
aꢂ
ꢁ48.2 (c 0.05, MeOH); UV (MeOH) k : 206,
ꢁ1 1
D
max
m
; H and
13
7
,27
ies,
and this study constitutes the first report of cyanogenesis in
C
29
H
36NaO15, 647.1946).
4. Hedyotoside D (4): Yellow oil; ½
209, 320 nm; IR (KBr)
the genus Hedyotis.
25
D
1
aꢂ
ꢁ36.2 (c 0.06, MeOH); UV (MeOH) kmax
:
ꢁ
1
1
H and 13C
It has been reported that some caffeoyl derivatives showed
m
max: 3442, 1635, 1516, 1431, 1071 cm
;
NMR data, see Table 2; HRESIMS m/z 499.1210 [M+Na]+ (calcd for
2
8
anti-RSV activity. In addition, the whole plants of H. scandens
are traditionally used to treat respiratory diseases in China. In this
study, several caffeoyl and coumaroyl compounds (1–5, 7–14)
23
C H24NaO11, 499.1211).
15. Nakanishi, T.; Nishi, M.; Inada, A.; Obata, H.; Tanabe, N.; Abe, S.; Wakashiro, M.
Chem. Pharm. Bull. 1990, 38, 1772.