New phenolic glycosides from Polygonum cuspidatum

Article abstract of DOI:10.1080/10286020.2019.1646730

Two new isobenzofuranone derivatives, polyphthaliside A (1) and polyphthaliside B (2), and a new isocoumarin derivative, polyisocoumarin (3), were isolated from Polygonum cuspidatum. Their structures were elucidated by detailed spectroscopic analysis and chemical methods. The cytotoxicity activity and PTP1B inhibitory activity of compounds 1–3 were estimated and none of them exhibited activities at a concentration of 10 μM.

Full text of DOI:10.1080/10286020.2019.1646730

Journal of Asian Natural Products Research
ISSN: 1028-6020 (Print) 1477-2213 (Online) Journal homepage: https://www.tandfonline.com/loi/ganp20
New phenolic glycosides from Polygonum
cuspidatum
Jian-Shuang Jiang, Fu-Shuang Li, Zi-Ming Feng, Ya-Nan Yang & Pei-Cheng
Zhang
To cite this article: Jian-Shuang Jiang, Fu-Shuang Li, Zi-Ming Feng, Ya-Nan Yang & Pei-Cheng
Zhang (2019): New phenolic glycosides from Polygonumꢀcuspidatum, Journal of Asian Natural
Products Research, DOI: 10.1080/10286020.2019.1646730
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JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
https://doi.org/10.1080/10286020.2019.1646730
New phenolic glycosides from Polygonum cuspidatum
Jian-Shuang Jiang, Fu-Shuang Li, Zi-Ming Feng, Ya-Nan Yang and
Pei-Cheng Zhang
State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia
Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing
100050, China
ABSTRACT
ARTICLE HISTORY
Received 30 April 2019
Accepted 16 July 2019
Two new isobenzofuranone derivatives, polyphthaliside A (1) and
polyphthaliside B (2), and a new isocoumarin derivative, polyiso-
coumarin (3), were isolated from Polygonum cuspidatum. Their
structures were elucidated by detailed spectroscopic analysis and
chemical methods. The cytotoxicity activity and PTP1B inhibitory
activity of compounds 1–3 were estimated and none of them
exhibited activities at a concentration of 10 lM.
KEYWORDS
Polygonum cuspidatum;
isobenzofuranone; isocou-
marin; cytotoxicity
activity; PTP1B
1. Introduction
Polygonum cuspidatum is the dried rhizome of Polygonaceae and has been widely
reported for its various traditional biological activities, including suppurative derma-
titis, gonorrhea, chronic bronchitis, jaundice, amenorrhea, hypertension, hyperlip-
emia, and menopausal symptoms [1, 2]. Previous investigations have revealed that P.
cuspidatum contained a variety of phytochemical constituents such as flavonoids [3],
anthraquinones [4], stilbenes [1], and other phenols [5]. In the course of searching
for active components from this plant, two new isobenzofuranone derivatives and a
new isocoumarin derivative were isolated and named polyphthaliside A (1),
CONTACT Pei-Cheng Zhang
pczhang@imm.ac.cn
Jian-Shuang Jiang and Fu-Shuang Li contributed equally to this work.
Supplemental data for this article is available online at https://doi.org/10.1080/10286020.2019.1646730.
ß 2019 Informa UK Limited, trading as Taylor & Francis Group

2
J.-S. JIANG ET AL.
Figure 1. Chemical structures of compounds 1–3.
polyphthaliside B (2), and polyisocoumarin (3) (Figure 1). Additionally, compounds
1–3 were evaluated for the cytotoxicity activity and the PTP1B inhibition.
2. Results and discussion
Compound 1 was obtained as a white powder. The IR spectrum of 1 showed the
presence of hydroxyl groups (3384 cmꢀ1), carbonyl groups (1718 cmꢀ1), and aromatic
rings (1614, 1535, 1451 cmꢀ1). A molecular formula of C21H20O13 (X ¼ 12) was
1
deduced on the basis of HR-ESI-MS at m/z 479.0834 [M–H]–. The H NMR spec-
trum of 1 (Table 1) displayed the signals for aromatic protons at dH 6.95 (2H, s,
H-20,60), 6.59 (1H, s, H-4) and 6.35 (1H, s, H-6), an anomeric proton at dH 5.27 (1H,
d, J ¼ 8.5 Hz, H-100), and two oxygenated methylene protons at dH 5.16 (1H, d,
J ¼ 16.5 Hz, H-3a) and 5.13 (1H, d, J ¼ 16.5 Hz, H-3b). The 13C NMR spectrum of 1
(Table 1) showed 21 carbon signals including seven carbons of a galloyl group at dC
119.3 (C-10), 108.8 (C-20,60), 145.5 (C-30,50), 138.6 (C-40), 164.9 (C-70), six carbons of
a benzene ring at dC 100.2 (C-4), 163.1 (C-5), 103.5 (C-6), 158.1 (C-7), 105.8 (C-8),
151.4 (C-9), six carbons of a glycosyl moiety at dC 98.0 (C-100), 73.4 (C-200), 74.0
(C-300), 69.6 (C-400), 77.3 (C-500) and 60.3 (C-600), an ester carbonyl carbon at dC 168.2
(C-1), and an oxygenated methylene carbon at dC 68.5 (C-3) combining with 2D
NMR spectra. In HMBC spectrum (Figure 2), the cross-peaks between H-3 (dH 5.16
and 5.13)/C-1 (dC 168.2) demonstrated that the ester carbonyl carbon (C-1) was
linked to the C-3 position of the methylene by oxygen atom. Meanwhile, the methy-
lene was directly attached at C-9 of the benzene ring based on the correlations of H-
3 with C-4, C-8 and C-9 in the HMBC experiment. Therefore, compound 1 was con-
cluded to contain an isobenzofuranone group and the NMR spectral data due to the

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
3
Table 1. 1H (500M) and 13C NMR (125M) spectroscopic data of compounds 1–3 (DMSO-d6).
1
2
3
No.
dC
dH
dC
dH
dC
dH
1
2
3
168.2
168.4
166.5
68.5
5.16, d (16.5)
5.13, d (16.5)
6.59, s
68.0
5.05, d (16.0)
4.92, d (16.0)
6.50, s
152.1
4
5
6
7
8
9
100.2
163.1
103.5
158.1
105.8
151.4
98.4
163.6
104.3
155.6
105.6
151.2
109.3
104.1
164.8
102.8
162.8
100.8
140.1
111.8
157.6
100.7
159.7
108.8
139.6
20.3
6.66, s
6.75, d (2.0)
6.35, s
6.42, s
6.63, d (2.0)
11.06, s (OH)
10
10
20
30
40
50
600
700
100
2
119.3
108.8
145.5
138.6
145.5
108.8
164.9
98.0
73.4
74.0
69.6
77.3
119.1
108.5
145.7
138.7
145.7
108.5
165.7
99.9
73.1
76.3
69.8
73.9
6.95, s
6.95, s
6.96, s
6.96, s
9.57, s (OH)
6.25, d (1.5)
9.57, s (OH)
6.19, d (1.5)
2.13, s
5.27, d (8.5)
4.95, t (8.5)
3.59–3.61, m
3.34–3.36, m
3.49–3.51, m
3.56–3.58, m
3.74, d (11.0)
4.95, d (8.5)
100.4
73.6
77.7
70.0
77.0
5.04, d (7.0)
3.27–3.29, m
3.39–3.41, m
3.18–3.20, m
3.29–3.31, m
3.48–3.50, m
3.69–3.71, m
3.28–3.30, m
3.32–3.34, m
3.28–3.10, m
3.70, t (8.5)
4.17, dd (11.0, 6.5)
4.49, d (11.0)
300
400
500
600
60.3
63.5
61.0
Figure 2. Key HMBC (H!C) correlations of compounds 1–3.
group were in accord with those reported for 5,7-dihydroxy-1(3H)-isobenzofuranone [6].
Additionally, the glycosyl moiety was assigned to be b-form by the coupling constant
of the anomeric proton signal (J ¼ 8.5 Hz) and the glycosyl moiety was proved to be
D-glucose based on the GC analysis by acid hydrolysis of 1. Above all the informa-
tion indicated that the structure of 1 consisted of a glucosyl moiety, a galloyl group

4
J.-S. JIANG ET AL.
and a 5,7-dihydroxy-1(3H)-isobenzofuranone moiety. Furthermore, the HMBC corre-
lations between H-100/C-5, and H-200/C-70 confirmed that the glucosyl moiety and the
galloyl group were located at C-5 of the isobenzofuranone, and C-200 of the glucosyl,
respectively. Thus, compound 1 was defined and named polyphthaliside A.
Compound 2 was also isolated as a white powder. Its molecular formula of
C21H20O13 was determined by HR-ESI-MS. The IR spectrum showed the presence of
1
hydroxyl, carbonyl and aromatic groups. The H NMR spectral data (Table 1) showed
aromatic proton signals at dH 6.96 (2H, s, H-20,60), 6.50 (1H, s, H-4), and 6.42 (1H, s,
H-6), an anomeric proton signal at dH 4.95 (1H, d, J ¼ 8.5 Hz, H-100), and two methy-
lene proton signals at dH 5.05 (1H, d, J ¼ 16.0 Hz, H-3a) and 4.92 (1H, d, J ¼ 16.0 Hz,
H-3b). The 13C NMR spectrum of 2 showed 21 carbon signals (Table 1) comprising
seven carbons of a galloyl group, six carbons of a glycosyl moiety, and eight carbons
of 5,7-dihydroxy-1(3H)-isobenzofuranone coupling with 2D NMR spectra. These
observations suggested that compound 2 was still an isobenzofuranone derivative.
The 13C NMR spectrum of 2 was similar to the corresponding signals of compound 1
except of chemical shift of C-600 in the glucosyl group. This indicated that the galloyl
group was linked to the C-600 position based on the information that the chemical
shift was moved from dC 60.3 (C-600) in compound 1 to dC 63.5 (C-600) in compound
2. Additionally, b-D-pyranoglucose was confirmed by the acid hydrolysis and located
at C-5 by the correlation of H-100/C-5 in HMBC experiment (Figure 2). Finally, com-
pound 2 was characterized as depicted and named polyphthaliside B.
Compound 3 was obtained as a white powder. The IR spectrum of 3 showed the
presence of hydroxyl groups (3305 cmꢀ1), carbonyl groups (1667 cmꢀ1), benzene ring
(1509, 1465 cmꢀ1) and methyl (2932, 1347 cmꢀ1). 3 possessed a molecular formula of
1
C22H22O11 on the basis of HR-ESI-MS at m/z 463.1233 [M þ H]þ. The H NMR
spectrum (Table 1) showed three phenolic hydroxyl protons at dH 11.06 (1H, s, OH-
8) and 9.57 (2H, s, OH-20,40), two sets of meta-coupled aromatic protons at dH 6.75
(1H, d, J ¼ 2.0 Hz, H-5) and 6.63 (1H, d, J ¼ 2.0 Hz, H-7), and dH 6.25 (1H, d,
J ¼ 1.5 Hz, H-30) and 6.19 (1H, d, J ¼ 1.5 Hz, H-50), an olefin bond proton at dH 6.66
(1H, s, H-4), an anomeric proton at dH 5.04 (d, J ¼ 7.0 Hz, H-100), and a methyl pro-
ton at dH 2.13 (3H, s). Coupling with 2D NMR, the 13C NMR spectrum (Table 1)
displayed a set of saccharide carbon signals at dC 100.4 (C-100), 73.6 (C-200), 77.7
(C-300), 70.0 (C-400), 77.0 (C-500) and 61.0 (C-600). The saccharide moiety was assigned
to be b-form by the large coupling constant of the anomeric proton signal and the
13C NMR data. Furthermore, cellulose hydrolysis of 3 yielded D-glucose based on the
GC analysis, which suggested that there was a b-D-glucopyrancose in compound 3.
13
The C NMR and 2D NMR data of 3 further established a methyl at dC 20.3 (C-70),
and a tetrasubstituted phenyl at dC 111.8 (C-10), 157.6 (C-20), 100.7 (C-30), 159.7
(C-40), 108.8 (C-50) and 139.6 (C-60). In addition, the tetrasubstituted phenyl was con-
cluded to be 20,40-dihydroxy-60-methylphenyl coupling with the correlations of OH-20
(dH 9.57)/C-20, OH-40 (dH 9.57)/C-40, and H-CH3/C-10, C-50, C-60 in the HMBC
experiment (Figure 2). Except for 13 carbons of a glucosyl and 20,40-dihydroxy-60-
methylphenyl, the residual 9 carbon signals of 3 showed close similarities to those of
6,8-dihydroxy-3-(2-hydroxypropyl)-isocoumarin [7], which confirmed that compound
3 has a 3,6,8-trisubstituted isocoumarin group. Meanwhile, the HMBC correlations of

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
5
H-4/C-3, C-5 and C-10 indicated that the tetrasubstituted phenyl was located at C-3
of isocoumarin group. Additionally, the glucosyl was linked to C-6 by the correlation
of H-100/C-6 observed in the HMBC experiment. Consequently, compound 3 was
established and named polyisocoumarin.
Few literatures were reported about isobenzofuranone and isocoumarin from P.
cuspidatum. Compounds 1 and 2 were the kind of isobenzofuranone, and 3 was the
kind of isocoumarin, as determined by detailed spectroscopic means (NMR, and MS
et al.). These compounds rich the diversity of these ingredients in P. cuspidatum. A
modern study revealed that its extract exhibited antioxidaion, anti-tyrosinase, immune
stimulation, anticancer and antidiabetic activities [8,9]. Accordingly, all the isolated
compounds were evaluated for their cytotoxicity activity and PTP1B inhibitory effects,
but the results showed that these compounds exhibited no obvious activity.
3. Experimental
3.1. General experimental procedures
The optical rotations were measured on a Jasco P-2000 polarimeter (Jasco, Easton,
Japan). IR spectra were recorded on a Nicolet 5700 spectrometer (Thermo Scientific,
Waltham, USA). UV spectra were obtained on a JASCO V-650 spectrophotometer
(Jasco, Easton, Japan). 1H NMR (500 MHz), 13C NMR (125 MHz), HSQC, and
HMBC spectra were run on an INOVA-500 spectrometer (Bruker-Biospin, Billerica,
USA). High-resolution electrospray ionization mass spectrometry (HRESIMS) was
performed on an Agilent 1100 series LC/MSD ion trap mass spectrometer (Agilent
Technologies, Waldbronn, Germany). Column chromatography was performed with
Macroporous resin (Diaion HP-20, Mitsubishi Chemical Corp., Tokyo, Japan), Rp-18
(50 lm; YMC, Kyoto, Japan), and Sephadex LH-20 (Pharmacia Fine Chemicals,
Uppsala, Sweden). Preparative HPLC was carried out on a Shimadzu LC-6AD instru-
ment with a SPD-20A detector (Shimadzu, Tokyo, Japan), using a YMC-Pack ODS-A
column (250 ꢁ 20 mm, 5 lm).
3.2. Plant material
The rhizome of Polygonum cuspidatum was purchased from Beijing Pu Sheng Lin
Pharmaceutical Co., Ltd. of China, in Feb 2010. The plant material was identified by
associate professor L. Ma (Institute of Materia Medica, Peking Union Medical College
and Chinese Academy of Medical Sciences). A voucher specimen (ID number: ID-S-
2593) was deposited in the Herbarium of the Department of Medicinal Plants,
Institute of Materia Medica, Chinese Academy of Medical Sciences, and Peking
Union Medical College, Beijing, China.
3.3. Extraction and isolation
Powdered P. cuspidatum (20 kg) was extracted with 80% EtOH under reflux (3 ꢁ 2 h).
The EtOH extract was concentrated under reduced pressure to give a residue (4.2 kg),
which was suspended in H2O (4 L) and partitioned with, consecutively, petroleum

6
J.-S. JIANG ET AL.
ether (PE) (3 ꢁ 4 L), EtOAc (3 ꢁ 4 L), and n-BuOH (3 ꢁ 4 L). After evaporation of the
n-BuOH solvent under reduced pressure, the extract (1.4 kg) was suspended in H2O
(2 L) and subjected to column chromatography over macroporous resin, eluting suc-
cessively with H2O, 30% EtOH, 50% EtOH, 70% EtOH, and 95% EtOH (30 L each).
The 30% EtOH was removed under reduced pressure and the fraction (86.4 g) was
subjected to chromatography over Sephadex LH-20 with H2O–MeOH in gradient as
the mobile phase to yield 25 fractions (Fr.A–Fr.Y) on the basis of HPLC-
DAD analysis.
Fr.G (0.2 g) was purified by preparative RP-HPLC using MeOH–H2O (35:65, with
a flow rate of 5.0 ml/min, 280 nm) as the mobile phase to yield 2 (4.0 mg, retention
time: 36.7 min). Fr.H (0.3 g) was purified by preparative RP-HPLC using MeOH–H2O
(55:50, with a flow rate of 5.0 ml/min, 280 nm) as the mobile phase to yield 3
(30.0 mg, retention time: 38.7 min). Fr.I (2.0 g) was subjected to Sephadex LH-20 col-
umn and eluted with MeOH–H2O (from 20:80 to 60:40) to afford 20 fractions (Fr.I-
1–I-20). Fr.I-15 (0.3 g) was further purified using preparative RP-HPLC with
MeOH–H2O (20:80, with a flow rate of 5.0 ml/min, 280 nm) as the mobile phase to
yield 1 (9.0 mg, retention time: 41.6 min).
3.3.1. Polyphthaliside A (1)
20
White powder; ½aꢂD –27.3 (c 0.02, H2O); UV (MeOH) kmax: 214, 252, 288 nm; IR
1
ꢀmax: 3384, 1718, 1614, 1535, 1451 cmꢀ1; H NMR (DMSO-d6, 500 MHz) and 13C
NMR (DMSO-d6, 125 MHz) spectral data see Table 1. HR-ESI-MS: m/z 479.0834 [M-
H]– (calcd for C21H19O13, 479.0831).
3.3.2. Polyphthaliside B (2)
20
White powder; ½aꢂD –23.3 (c 0.01, H2O); UV (MeOH) kmax: 214, 252, 288 nm; IR
1
ꢀmax: 3397, 1723, 1614, 1506, 1452 cmꢀ1; H NMR (DMSO-d6, 500 MHz) and 13C
NMR (DMSO-d6, 125 MHz) spectral data see Table 1.
3.3.3. Polyisocoumarin (3)
20
White powder; ½aꢂD –59.9 (c 0.05, H2O); UV (MeOH) kmax: 236, 256, 336 nm; IR
1
ꢀmax: 3305, 2932, 1667, 1590, 1465, 1347 cmꢀ1; H NMR (DMSO-d6, 500 MHz) and
13C NMR (DMSO-d6, 125 MHz) spectral data see Table 1.
3.4. Acid hydrolysis of compounds
Compound 1 (2 mg) was dissolved in 1 mol/L HCl–dioxane (1:1, 3 ml) and main-
tained at 60 ꢃC for 6 h. After drying in vacuum, the residue was partitioned in H2O
(3 ml) and extracted thrice with EtOAc (3 ml). The aqueous solution was evaporated
in vacuum to obtain the monosaccharide residue. The configurational assignment of
glucose was established by comparing the retention times of their chiral derivatives
with those of standard substances, which were prepared using the identical procedure
(D-glucose 20.56 min) [10]. The same operating procedure was used for compound 2.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
7
3.5. Cellulose hydrolysis of compound 3
A solution of 3 (2 mg) in 2 ml 0.1 M HOAc–NaOAc buffer (pH ¼ 4.5) was incubated
at 40 ꢃC with cellulose (2 mg) for 5 h. The reaction was monitored by HPLC-DAD
analysis. After cooling, the reaction mixture was extracted with EtOAc (3 ꢁ 5 ml). The
aqueous layer was evaporated under vacuum to furnish a crude sugar fraction.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was financially supported by the National Natural Science Foundation of China
(No. 81274066) and Natural Science Foundation of Beijing Municipality (No. 7112094).
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