A New Coumarin Glycoside from Physochlaina physaloides

Article abstract of DOI:10.1007/s10600-019-02819-z

A new coumarin glycoside, namely physochloside A, together with four known compounds, was isolated from the ethanol extract of Physochlaina physaloides. The structure of physochloside A was identified by UV, IR, ESI-MS, 1D NMR, and 2D NMR.

Full text of DOI:10.1007/s10600-019-02819-z

DOI 10.1007/s10600-019-02819-z
Chemistry of Natural Compounds, Vol. 55, No. 5, September, 2019
A NEW COUMARIN GLYCOSIDE FROM Physochlaina physaloides
Qing-hu Wang,* Xiang He, Jun-sheng Hao,
Wen-qiang Bao, and Bi-li-ge-tu-lan Pa
A new coumarin glycoside, namely physochloside A, together with four known compounds, was isolated
from the ethanol extract of Physochlaina physaloides. The structure of physochloside A was identified by UV,
IR, ESI-MS, 1D NMR, and 2D NMR.
Keywords: Physochlaina physaloides, Solanaceae, physochloside A.
Physochlaina physaloides (Solanaceae) is found predominantly in the hill, gully, and grassland of Humeng and
Ximeng, Inner Mongolia. The roots of P. physaloides are utilized to treat many diseases, such as swelling, analgesia, and
spasmolysis [1]. Secondary metabolites, including alkaloids [2–4] and coumarins [5], have been reported from P. physaloides.
Alkaloids and coumarins are important secondary metabolites in plant that exhibit significant pharmacological activities
[
6–8], including antitumor, anti-inflammatory, analgesic, hypotensive, and anticoagulant, which prompted us to further study
this plant.
From the EtOH extract of P. physaloides, five compounds were obtained. On the basis of H, 13C NMR, COSY,
HSQC, and HMBC spectra, as well as by comparison with previous reports, compound (1) was identified as a new compound
while the remaining four compounds were found to be the known compounds 6-hydroxycoumarin-7-O-β-D-glucoside (2) [9],
1
6
-methoxycoumarin-7-O-β-D-glucoside (3) [9], scopolamine (4) [10], and hyoscyamine (5) [10].
Compound 1 was obtained as a white amorphous powder. The molecular formula was determined to be C H O
4
0 58 29
–
1
by HR-ESI-MS at m/z 1001.8622 [M – H] (calcd for C H O , 1002.8632). In the H NMR spectrum (Table 1), there are
4
0 58 29
two characteristic resonances for H-3 and H-4 of coumarin at δ 6.33 (1H, d, J = 9.5 Hz, H-3) and 7.97 (1H, d, J = 9.5 Hz,
H-4). The remaining aromatic signals at δ 7.32 (1H, s) and 7.20 (1H, s) were assigned to H-5 and H-8 based on the HMBC
correlations from H-5 (δ 7.32) to C-4 (δ 144.7), C-6 (δ 146.4), C-7 (δ 150.2), and C-9 (δ 149.4), and H-8 (δ 7.20) to C-6
(
δ 146.4), C-7 (δ 150.2), C-9 (δ 149.4), and C-10 (δ 112.8).
1
3
The C NMR spectrum showed 40 carbon signals, of which 10 were assigned to the aglycon part and 30 to the sugar
moiety. In the aglycon part, a methoxy carbon signal was present in addition to a coumarin skeleton carbon signals at δ 161.0
C-2), 113.8 (C-3), 144.7 (C-4), 110.1 (C-5), 146.4 (C-6), 150.2 (C-7), 103.4 (C-8), 149.4 (C-9), and112.8 (C-10). The HMBC
(
correlation (Fig. 1) from CH O- (δ 3.83) to C-6 (δ 146.4) indicated that the methoxyl group was attached to C-6.
3
Acid hydrolysis [11, 12] of compound 1 afforded sugar components identified as D-glucose and D-galactose by GC
analysis. The peaks of authentic samples of D-glucose and D-galactose after treatment in the same manner were detected at
1
9.6 and 20.7 min. The presence of five anomeric proton signals at δ 5.10 (1H, d, J = 7.5 Hz, H-1′), 4.26 (1H, d, J = 7.5 Hz,
H-1′′), 4.12 (1H, d, J = 7.5 Hz, H-1′′′), 4.90 (1H, d, J = 3.5 Hz, H-1′′′′), and 5.18 (1H, d, J = 3.5 Hz, H-1′′′′′) and of five
corresponding carbon signals at δ 99.9, 97.4, 104.5, 92.7, and 92.2 also indicated that compound 1 contained a pentasaccharide
of three D-glucoses and two D-galactoses. The α-anomeric configuration of the two D-galactoses was revealed by the coupling
constant (3.5 Hz). The large coupling constant (7.5 Hz) suggested that the anomeric configuration of the three D-glucoses
was β [13].
College of Traditional Mongolian Medicine, Inner Mongolia University for Nationalities, 028000, Tongliao,
P. R. China, fax: +86 0475 831424, e-mail: wqh196812@163.com. Published in Khimiya Prirodnykh Soedinenii, No. 5,
September–October, 2019, pp. 696–698. Original article submitted September 17, 2018.
©
806
0009-3130/19/5505-0806 2019 Springer Science+Business Media, LLC

1
13
TABLE 1. H (500 MHz) and C NMR (125 MHz) Data of Compound 1 (DMSO-d , δ, ppm, J/Hz)
6
C atom
δH
δC
C atom
δH
δC
2
3
4
5
6
7
8
9
–
161.0
113.8
144.7
110.1
146.4
150.2
103.4
149.4
112.8
56.5
99.9
83.0
75.8
72.4
5′′
6′′
3.40 (m)
3.68 (dd, J = 8.0, 5.0)
3.01 (d, J = 8.0)
4.12 (d, J = 7.5)
3.02 (m)
77.2
66.1
6.33 (d, J = 9.5)
7.97 (d, J = 9.5)
7.32 (s)
1′′′
2′′′
3′′′
4′′′
5′′′
104.5
73.5
77.0
70.7
77.5
61.0
92.7
69.9
71.0
73.8
72.0
62.5
92.2
69.6
70.3
73.5
71.8
62.5
–
–
7.20 (s)
3.07 (m)
3.13 (m)
3.16 (m)
–
–
1
0
6′′′
3.64 (d, J = 9.0); 3.42 (m)
4.90 (d, J = 3.5)
3.27 (m)
OCH
3
3.83 (s)
1′′′′
2′′′′
3′′′′
4′′′′
5′′′′
6′′′′
1′′′′′
2′′′′′
3′′′′′
4′′′′′
5′′′′′
6′′′′′
1
′
5.10 (d, J = 7.5)
3.53 (m)
3.57 (m)
3.14 (m)
3.39 (m)
3.88 (dd, J = 8.5, 5.0)
2
′
3.01 (m)
2.98 (m)
3.18 (m)
3
′
4
′
5
′
77.1
68.6
3.56(d, J = 8.0); 3.37 (m)
5.18 (d, J = 3.5)
3.30 (m)
3.12 (m)
2.97 (m)
3.20(dd, J = 7.0, 6.5)
3.54 (d, J = 8.0); 3.38 (m)
6′
3
.67 (d, J = 8.5)
4.26 (d, J = 7.5)
1
2
3
4
′′
′′
′′
′′
97.4
82.4
75.6
72.8
3.52 (m)
3.59 (m)
3.38 (m)
OH
HO
HO
OH
3'''
O
'''
1
OH
O
O
5
3
H CO
HO
HO
HO
3
O
3''''
1''''
3'
7
O
O
O
HO
O
1'
O
1
OH
O
OH
OH
1
''
O
1'''''
HO
O
3
''
3'''''
OH
HO
OH
1
Fig. 1. Selected HMBC correlations for 1.
The sequence of the pentasaccharide moiety was determined by the long-range correlations of H-1′ (δ 5.10) of the
β-glucose unit 1 and C-7 (δ 150.2) of the aglycon, H-1′′ (δ 4.26) of the β-glucose unit 2 with C-2′ (δ 83.0) of the β-glucose
unit 1, H-1′′′ (δ 4.12) of the β-glucose unit 3 with C-6′ (δ 68.6) of the β-glucose unit 1, H-1′′′′ (δ 4.90) of the D-galactose
unit 1 with C-6′′ (δ 66.1) of the β-glucose unit 2, and H-1′′′′′ (δ 5.18) of the D-galactose unit 2 with C-2′′ (δ 82.4) of the
β-glucose unit 2 in the HMBC spectrum. Mutual coupling between H-1′ and H-2′, H-1′′ and H-2′′, H-1′′′ and H-2′′′, H-1′′′′
1
1
and H-2′′′′, and H-1′′′′′ and H-2′′′′′ observed in the H– H COSY spectrum, and the coupling between H-1′ and C-1′ (δ 99.9),
H-2′ and C-2′ (δ 83.0), H-1′′ and C-1′′ (δ 97.4), H-2′′ and C-2′′ (δ 82.4), H-1′′′ and C-1′′′ (δ 104.5), H-2′′′ and C-2′′′ (δ 73.5),
H-1′′′′ and C-1′′′′ (δ 92.7), H-2′′′′ and C-2′′′′ (δ 69.9), H-1′′′′′ and C-1′′′′′ (δ 92.2), and H-2′′′′′ and C-2′′′′′ (δ 69.6) was
observed in the HMQC spectrum. Thus, the structure of compound 1 was determined to be 6-methoxycoumarin-7-O-[6-O-β-
D-glucopyranosyl-2-O-(2-O-α-D-galactopyranosyl-6-O-α-D-galactopyranosyl)-β-D-glucopyranosyl]-β-D-glucopyranoside
and named physochloside A.
807

EXPERIMENTAL
General Experimental Procedures. IR spectra were recorded on aThermo Nicolet 200 double beam spectrophotometer.
HR-ESI-MS spectra were measured on a Waters Xevo G2-S QTOF spectrometer. The LC system consisted of a LC-20AT pump
1
(
Shimadzu, Kyoto, Japan), Shimadzu SPD-20A detector, and Shimadzu CBM-20A software for data processing. H NMR,
1
3
1
1
C NMR, H– H COSY, HSQC, and HMBC spectra were recorded in CD OD using a 500 Hz Bruker NMRAvance spectrometer.
3
Plant Material. The roots of P. physaloides were collected in Humeng, Inner Mongolia of China, in July 2016.
The plant material was identified by Prof. Wuxiangjie (Inner Mongolia University for Nationalities) and a voucher
No. 20160720) has been deposited in the School of Traditional Mongolian Medicine of Inner Mongolia University for
Nationalities.
Extraction and Isolation of Five Compounds. The roots of P. physaloides (1000 g) were crushed and extracted
(
twice with EtOH under reflux. The filtrates were combined and concentrated to dryness under reduced pressure. The EtOH
extract (10.0 g) was divided by column chromatography on silica gel and gradiently eluted with CHCl –MeOH (50:1 to 5:1)
3
to give five fractions (Frs. C1–5). Fraction C (206 mg, CHCl –MeOH, 20:1 eluate) was further chromatographed on a Sephadex
3
3
LH-20 column, eluting with MeOH, and then separated by semipreparative HPLC (CH OH–H O, 45:55) yielding 5 (28 mg)
3
2
and 4 (32 mg). Fraction C (420 mg, CHCl –MeOH, 10:1 eluate) was further separated by semipreparative HPLC
4
3
(
CH OH–H O, 39:61) to yield 3 (53 mg) and 2 (27 mg). Fraction C (510 mg, CHCl –MeOH, 10:1 eluate) was further
3 2 5 3
separated by semipreparative HPLC (CH OH–H O, 29:71) to give 1 (61 mg). The purity of each compound was determined
3
2
to be above 98% by normalization of the peak areas detected by HPLC.
Acid Hydrolysis of 1 and Sugar Analysis. Asolution of compound 1 (2.0 mg) in 2 M HCl (2 mL) was stirred at 80°C
in a stoppered vial for 2 h. The solution after cooling was evaporated under a stream of N .Anhydrous pyridine solutions (1.0 mL)
2
of the residue and L-cysteine methyl ester hydrochloride (1.5 mg) were mixed and warmed at 60°C for 2 h. After drying the
solution, trimethylsilyl imidazole (150 μL) was added to the mixture, which was warmed at 60°C for another 1 h and then
partitioned between H O (500 μL) and cyclohexane (500 μL). The cyclohexane layer was concentrated and analyzed by GC
2
using an HP-5 column. The temperatures of the injector and detector were 260 and 280°C, respectively. Atemperature gradient
system was used for the oven, starting at 100°C and increasing up to 140°C at a rate of 4°C/min, and then increasing up to
1
70°C for 8 min at a rate of 13°C/min, and finally, increasing up to 200°C at a rate of 5°C/min.
ACKNOWLEDGMENT
This work was supported by the Science and Technology Major Project of Inner Mongolia Mongolian Medicine
in China (No. GCY201508020).
REFERENCES
1
2
3
4
5
.
.
.
.
.
Y. Huang, J. H. Wang, and T. F. Yu, Beifangyaoxue, 11, 94 (2014).
R. X. Zhang, Zhongguoyaopinbiaozhun, 12, 419 (2011).
Y. L. Liu and F. Z. Xie, Yaoxuexuebao, 14, 497 (1979).
R. Reinouts van Haga, Nature, 174, 833 (1954).
C. Kofinas, I. Chinou, A. Loukis, C. Harvala, C. Roussakis, M. Maillard, and K. Hostettmann, Planta Med., 64,
1
74 (1998).
6
7
8
9
0.
1.
2.
3.
.
.
.
.
J. S. Agarwal and R. P. Rastogi, Ind. J. Chem., 13, 758 (1975).
J. Han, Y. Guo, and H. T. Wan, Zhongyiyaoxuekan, 24, 2326 (2006).
L. X. Xia, Y. B. Wang, W. L. Huang, and H. Qian, Chin. J. New Drug., 22, 2392 (2013).
S. Narantuyaa, D. Batsuren, Y. V. Rashkes, and E. G. Mil′grom, Chem. Nat. Compd., 30, 197 (1995).
J. J. Shao, Y. Peng, C. N. He, L. J. Xu, X. Xiao, and Y. S. Li, J. Shen. Pharm. Univ., 30, 840 (2013).
Y. Dai, G. X. Zhou, H. Kurihara, W. C. Ye, and X. S. Yao, J. Nat. Prod., 69, 1022 (2006).
S. Hara, H. Okbae, and K. Mihashi, Chem. Pharm. Bull., 34, 1843 (1986).
1
1
1
1
L. H. Yan, L. Z. Xu, J. Lin, S. L. Yang, and Y. L. Feng, J. Asian Nat. Prod. Res., 11, 332 (2009).
808