Phenylpropanoid glycosides from Conyza japonica

Article abstract of DOI:10.1007/s10600-012-0381-3

Three new phenylpropanoid glycosides, named 1-O-[3-O-acetyl-α-L- rhamnopyranosyl-(1→6)-β-D-glucopyranosyl]-3-hydroxycinnamaldehyde (1), 1-O-[2,3-O-diacetyl-α-L-rhamnopyranosyl-(1→6)-β-D- glucopyranosyl]-3-methoxycinnamaldehyde (2), and 1-O-[3-O-acetyl-α-L

Full text of DOI:10.1007/s10600-012-0381-3

Chemistry of Natural Compounds, Vol. 48, No. 5, November, 2012 [Russian original No. 5, September–October, 2012]
PHENYLPROPANOID GLYCOSIDES FROM Conyza japonica
Jiang Hu,1* Xiaodong Shi,1 Wei Ding,1,2
Jiangang Chen,1 and Changsheng Li1,3
UDC 547.284
Three new phenylpropanoid glycosides, named 1-O-[3-O-acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-
glucopyranosyl]-3-hydroxycinnamaldehyde (1), 1-O-[2,3-O-diacetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-
glucopyranosyl]-3-methoxycinnamaldehyde (2), and 1-O-[3-O-acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-
glucopyranosyl]-4-allyl-2-methoxyphenol (3), were isolated from the 95% EtOH extract of the dry fronds of
Conyza japonica. The structures of the new compounds were elucidated by spectral methods.
Keywords: Conyza japonica, phenylpropanoid glycosides, Compositae.
The genus Conyza comprises about 50 species, which grow mainly in tropical and subtropical areas [1]. Conyza
japonica (Thunb.) Less. is a perennial herbaceous plant distributed mainly in the southern regions of the Peopleꢃs Republic of
China at altitude 700–2500 m above sea level [2, 3]. In folk medicine, its aerial parts are used to treat some kinds of inflammatory
disease, especially chronic bronchitis [4–8]. The present study was undertaken to investigate the chemical constituents of the
95% EtOH extract of the dry fronds of C. japonica from Yuanjiang, Yunnan Province, which led to the isolation of three new
phenylpropanoid glycosides, named 1-O-[3-O-acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-hydroxycinnamaldehyde
(1), 1-O-[2,3-O-diacetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-methoxycinnamaldehyde (2), and 1-O-[3-O-
acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-4-allyl-2-methoxyphenol (3). This paper deals with the structural
elucidation on the basis of spectroscopic analysis, including 1D NMR, 2D NMR, and HR-ESI-MS.
6'
9
5
O
O
CHO
5''
1
5'
O
O
6''
HO
HO
HO
HO
O
O
1''
O
O
7
HO
HO
1'
3''
3
3'
OH
OH
R O
MeO
1
R O
AcO
2
OR
OH
3
1, 2
3
1: R = R = H, R = Ac
1
3
2
2: R = Me, R = R = Ac
1
2
3
Compound 1was obtained as a white amorphous solid, and its molecular formula was indicated as C23H30O13 by HR-ESI-MS
([M – H]– at m/z 513.1605; calcd 513.1608), corresponding to nine unsaturation degrees. Strong broad absorption at 3450 cm–1 and
1685 cm–1 in the IR spectrum of 1 indicated the presence of OH and CHO, respectively. The 13C NMR and DEPT spectra of 1
showed resonances characteristic of a phenylpropanoid, two hexoses, and oneAc group (Table 1). The 1H NMR spectrum displayed
signals for a 1,2,4-trisubstituted aromatic ring [ꢄ 6.72 (1H, d, J = 1.8 Hz), 6.62 (1H, dd, J = 8.2, 1.8 Hz), and 6.46 (1H, d, J = 8.2 Hz)],
two olefinic protons at 5.90 (d, J = 16.8 Hz) and 7.21 (dd, J = 16.8, 7.8 Hz) for a disubstituted trans double bond, and an aldehyde
group [9.68 (1H, d, J = 7.8 Hz)]. Acid hydrolysis of 1 with 1 M HCl in dioxane–H2O (1:1) gave cinnamaldehyde (C9H8O3),
D-glucose, and L-rhamnose as the carbohydrate components. The monosaccharides, including their absolute configurations, were
identified by direct HPLC analysis of the hydrolysate, with detection being carried out using an optical rotation (OR) detector.
1) College of Biological Resources and Environment Science, Qujing Normal University, Sanjiang avenue, Unicorn
district, 655011, Qujing, Yunnan, P. R. China, fax: +86 874 8998627, e-mail: hujiang@ustc.edu; 2) Yunnan-Guizhou Plateau
Institute of Biodiversity, Qujing Normal University, 655011, Qujing, Yunnan, P. R. China; 3) Qujing Characteristic Food
Research Institute, Qujing Normal University, 655011, Qujing, Yunnan, P. R. China. Published in Khimiya Prirodnykh Soedinenii,
No. 5, September–October, 2012, pp. 699–701. Original article submitted May 11, 2011.
782
0009-3130/12/4805-0782 02012 Springer Science+Business Media New York

1
13
TABLE 1. H NMR and C NMR Data of Compounds 1–3 (CD OD, ꢄ, ppm, J/Hz)
3
1
2
3
C atom
ꢄC
ꢄH
ꢄC
ꢄH
ꢄC
ꢄH
1
2
3
4
5
6
7
8
146.7 (s)
149.4 (s)
115.1 (d)
127.8 (s)
123.0 (d)
116.5 (d)
151.9 (d)
129.0 (d)
191.2 (d)
–
–
146.5 (s)
151.3 (s)
114.8 (d)
128.0 (s)
122.8 (d)
116.8 (d)
152.1 (d)
129.0 (d)
190.0 (d)
–
–
146.2 (s)
151.0 (s)
114.3 (d)
136.6 (s)
122.1 (d)
118.6 (d)
40.8 (t)
–
–
6.72 (d, J = 1.8)
–
6.62 (dd, J = 8.2, 1.8)
6.46 (d, J = 8.2)
5.90 (d, J = 16.8)
7.21 (dd, J = 16.8, 7.8)
9.68 (d, J = 7.8)
6.78 (d, J = 1.8)
–
6.61 (dd, J = 8.2, 1.8)
6.51 (dd, J = 8.2, 1.8)
5.92 (d, J = 16.8)
7.22 (dd, J = 16.8, 7.8)
9.70 (d, J = 7.8)
6.83 (d, J = 1.8)
–
6.73 (dd, J = 8.2, 1.8)
7.04 (dd, J = 8.2, 1.8)
3.30 (d, J = 6.8)
5.94 (m)
139.0 (d)
115.9 (t)
9
5.05 (dd, J = 16.8, 2.3)
-Glc
-Rha
1ꢃꢃ
2ꢃꢃ
ꢃꢃ
ꢃꢃ
5ꢃꢃ
O
1ꢃ
2ꢃ
3ꢃ
4ꢃ
5ꢃ
104.8 (d)
74.8 (d)
77.3 (d)
71.8 (d)
77.9 (d)
66.7 (t)
4.78 (d, J = 8.0)
3.18 (m)
103.1 (d)
74.3 (d)
76.8 (d)
71.4 (d)
77.7 (d)
67.8 (t)
4.82 (d, J = 8.0)
3.17 (m)
103.9 (d)
75.0 (d)
77.1 (d)
71.7 (d)
77.8 (d)
68.2 (t)
4.80 (d, J = 8.0)
3.20 (m)
3.34 (m)
3.27 (m)
3.68 (m)
3.36 (m)
3.26 (m)
3.73 (m)
3.39 (m)
3.31 (m)
3.71 (m)
3.98 (dd, J = 13.0, 6.6)
3.63 (dd, J = 13.0, 6.6)
4.02 (dd, J = 13.0, 6.6)
3.69 (dd, J = 13.0, 6.6)
4.00 (dd, J = 13.0, 6.6)
3.68 (dd, J = 13.0, 6.6)
ꢃ
6
O
102.9 (d)
70.0 (d)
70.6 (d)
74.2 (d)
67.9 (d)
17.8 (q)
–
172.8 (s)
21.2 (q)
–
4.74 (d, J = 1.3)
103.6 (d)
70.2 (d)
69.0 (d)
72.6 (d)
65.6 (d)
17.8 (q)
56.8 (q)
173.0 (s)
21.3 (q)
171.9 (s)
20.7 (q)
4.78 (d, J = 1.3)
4.10 (m)
4.42 (m)
4.21 (m)
3.80 (m)
1.20 (d, J = 6.0)
3.82 (s)
–
102.0 (d)
69.8 (d)
70.2 (d)
73.6 (d)
67.6 (d)
17.8 (q)
56.8 (q)
172.5 (s)
21.1 (q)
–
4.72 (d, J = 1.3)
4.12 (m)
4.08 (m)
3.82 (m)
3.78 (m)
1.21 (d, J = 6.0)
3.84 (s)
–
4.13 (m)
4.10 (m)
3.86(m)
3.82 (m)
3
4
1.24 (d, J = 6.0)
6ꢃꢃ
–
–
OMe
C=O
Me
2.09 (s)
2.07 (s)
–
2.01 (s)
2.07 (s)
–
C=O
Me
–
–
–
–
–
The rhamnopyranosyl and glucopyranosyl units were in the ꢀ- and ꢂ-configurations, respectively, by the coupling constants of
their anomeric protons (Table 1). In the HMBC plot, the correlation between the anomeric proton (ꢄ 4.74) of the rhamnosyl
unit and C-6ꢃ (ꢄ 66.7) of the glucopyranosyl unit identified a rhamnosyl (1ꢁ6) glucopyranosyl linkage. The C-2ꢃꢃ location
of the acetyl group in the rhamnosyl unit was confirmed by HMBC correlation of H-2ꢃꢃ (ꢄ 4.13) with the carbonyl carbons
(ꢄ 172.8) of the acetyl group. Furthermore, the sugar chain was linked to C-1 of the aglycone by HMBC correlation of the
anomeric proton (ꢄ 4.78) of the glucopyranosyl unit and C-1 (ꢄ 146.7) of the aglycone. Accordingly, the structure of 1 was
established as 1-O-[3-O-acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-hydroxycinnamaldehyde.
Compound 2, a white amorphous powder, was established as C26H34O14 according to its HR-ESI-MS (m/z 569.1867
[M – H]–; calcd 569.1870). Comparison of the NMR data of 2 with those of 1 revealed that the only significant difference is
that there is one more acetyl group and one more methoxy group in 2. The HMBC correlations of H-2ꢃꢃ (ꢄ 4.10) and H-3ꢃꢃ
(ꢄ 4.42) with the two carbonyl carbons (ꢄ 171.9 and 173.0) of the acetyl groups, respectively, indicated the C-2ꢃꢃ and C-3ꢃꢃ
locations of the acetyl groups in the rhamnosyl unit. The HMBC correlations between OMe with C-2 suggested that OMe was
linked at C-2 of the aglycone. All of these data for 2 were consistent with the structure of 1-O-[2,3-O-diacetyl-ꢀ-L-
rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-methoxycinnamaldehyde.
Compound 3, a white amorphous powder, was assigned the molecular formula C24H34O12 on the basis of its
HR-ESI-MS (m/z 513.1978 ([M – H]–, calcd 513.1972). The 1H and 13C NMR data of the aglycone of 3 were closely similar
to those of 2, except that the signals of the fragment –CH=CH–CHO in 2 were replaced by the signals of the –CH2–CH=CH2
in 3. The HMBC correlations of H-2ꢃꢃ (ꢄH 4.12) with the carbonyl carbons (ꢄ 172.5) of the acetyl group indicated the C-2ꢃꢃ
locations of the acetyl group in the rhamnosyl unit. Thus, the structure of 3 was determined as 1-O-[3-O-acetyl-ꢀ-L-
rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-4-allyl-2-methoxyphenol.
783

EXPERIMENTAL
General Procedures. Column chromatography (CC): silica gel (200–300 mesh, 10–40 ꢅm; Qingdao Marine Chemical
Factory, Qingdao, P. R. China), C18 reverse-phase silica gel (60 mm; Merck), Sephadex LH-20 (Amersham Pharmacia Biotech,
Sweden). Thin-layer chromatography (TLC): silica gel GF254 (10–40 ꢅm; Qingdao Marine Chemical Factory, Qingdao,
P. R. China). MCI Gel CHP20P (75–150 ꢅm; Mitsubishi Kasei Chemical Industries), C18 reversed-phase silica gel (20–45 um;
Fuji Silysia Chemical Ltd.). All solvents were distilled before use. HPLC (anal. and prep.): Shimadzu model LC-8A on YMC-pack,
R & D ODS column (250 ꢆ 4.6 mm, 250 ꢆ 20 mm) and UV detector Shimadzu SPD-10AVP. Melting points: Tempo
melting-point apparatus, uncorrected. Optical rotations: JASCO-20C digital polarimeter. UV spectra: Hewlett-Packard-8452A
1
diode-array spectrophotometer. IR spectra: Perkin–Elmer 577 spectrometer, in cm–1. H and 13C NMR spectra: Bruker
AM-400 spectrometer, ꢄ in ppm, J in Hz. MS: VG AutoSpec-3000 mass spectrometer, in m/z. HR-ESI-MS: API QSTAR
Pulsar-1 mass spectrometer.
Plant Material and Extraction and Isolation. The fronds of C. japonica were collected in Yuanjiang, Yunnan
Province, P. R. China, in July 2010. A specimen (CJ20100701), identified by one of the authors (J. G. Chen), was deposited in
the Herbarium of the College of Biological Resources and Environment Science, Qujing Normal University, Qujing,
P. R. China. The dry fronds of C. japonica (1.0 kg) were extracted with 95% EtOH (3 ꢆ 5 L) for 24 h at r.t. After removal of
EtOH under reduced pressure, the aqueous brownish syrup (1 L) was suspended in H2O (500 mL) and then partitioned with
AcOEt to afford an AcOEt extract (35 g). The AcOEt-soluble extract was subjected to chromatography over SiO2 column, eluting
with gradient CHCl3–MeOH to afford six fractions, Frs.1-6. Fractions 3 (61 g) and 4 (6.3 g) were repeatedly purified by SiO2
column chromatography (Sephadex LH-20, RP-18) and semi-preparative HPLC to yield 1 (6.8 mg), 2 (7.1 mg), and 3 (7.9 mg).
1-O-[3-O-Acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-hydroxycinnamaldehyde (1). White
20
amorphous powder; [ꢀ] –159.03ꢇ (c 0.003, MeOH). UV (MeOH, ꢈmax, nm) (log ꢉ): 205 (2.78). IR (KBr, ꢊmax, cm–1): 3450,
D
2940, 2870, 1685, 1460, 1390, 1027. 1H and 13C NMR data are shown in Table 1. FAB-MS (neg.): 513 [M – H]–; HR-ESI-MS:
m/z 513.1605 [M – H]–; calcd 513.1608.
1-O-[2,3-O-Diacetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-3-methoxycinnamaldehyde (2). White
20
amorphous powder; [ꢀ] –200.01ꢇ (c 0.025, MeOH). UV (MeOH, ꢈmax, nm) (log ꢉ): 205 (2.15). IR (KBr, ꢊmax, cm–1): 3450,
D
2938, 2876, 1685, 1455, 1380, 1020. 1H and 13C NMR data are shown in Table 1; FAB-MS (neg.): 569 [M – H]–; HR-ESI-MS:
m/z 569.1867 [M – H]–; calcd 569.1870.
1-O-[3-O-Acetyl-ꢀ-L-rhamnopyranosyl-(1ꢁ6)-ꢂ-D-glucopyranosyl]-4-allyl-2-methoxyphenol (3). White
20
amorphous powder; [ꢀ] –213.03ꢇ (c 0.004, MeOH). UV (MeOH, ꢈmax, nm) (log ꢉ): 204 (3.15). IR (KBr, ꢊmax, cm–1): 3350,
D
2942, 2873, 1700, 1664, 1461, 1389, 1094, 1027. 1H and 13C NMR data are shown in Table 1. FAB-MS (neg.): 513 [M – H]–;
HR-ESI-MS: m/z 513.1978 [M – H]–; calcd 513.1972.
ACKNOWLEDGMENT
The above research was made possible by a grant from the Key Projects in Scientific Research of Qujing Normal
University (2011ZD003).
REFERENCES
1.
2.
3.
4.
5.
A. M. Galal, E. Abdel-Sattar, F. El-Feraly, and J. S. Mossa, Phytochemistry, 48, 159 (1998).
R. Torrenegra, J. Robles, R. Waibel, M. Lowel, and H. Achenbach, Phytochemistry, 35, 195 (1994).
A. Urzua and L. Mendoza, Phytochemistry, 39, 1489 (1995).
F. Bohlmann and J. Jakupovic, Phytochemistry, 18, 1367 (1979).
U. C. Pandey, A. K. Shinghal, N. C. Barua, R. P. Sharma, J. N. Baruah, K. Watanabe, P. Kulanthaivel,
and W. Herz, Phytochemistry, 23, 391 (1984).
6.
7.
8.
M. A. Metwally and A. A. Dawidar, Pharmazie, 39, 575 (1984).
M. A. Metwally and A. M. Dawidar, Pharmazie, 42, 355 (1987).
C. Zdero, A. A. Ahmed, F. Bohlmann, and G. M. Mungai, Phytochemistry, 29, 3167 (1990).
784