Bioassay-guided isolation of cyclooxygenase-2 inhibitory and antioxidant phenylpropanoid derivatives from the roots of Dendropanax dentiger

Article abstract of DOI:10.1016/j.bioorg.2020.104211

The root of Dendropanax dentiger (Harms) Merr. is a traditional Chinese medicine that has been used to treat inflammation-related diseases with little scientific validation. In this study, a bioassay-guided phytochemical investigation of D. dentiger led to the isolation of 19 phenylpropanoid derivatives including one new compound (1) and 18 known ones (2–19). Their structures were elucidated by NMR and HRMS as well as comparison with literature data. The ability of cyclooxygenase-2 (COX-2) inhibition and antioxidant of all isolated compounds were measured in vitro. Chlorogenic acid derivatives (14–19) exhibited outstanding COX-2 inhibitory (IC₅₀ = 5.1–93.4 μM) and antioxidant (IC₅₀ = 13.2–31.9 μM) activities. Moreover, the tight structure-activities relationships were proposed. This is the first report on the COX-2 inhibitory activity of phenylpropanoids and D. dentiger.

Full text of DOI:10.1016/j.bioorg.2020.104211

BioorganicChemistry104(2020)104211
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Bioorganic Chemistry
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Short communication
Bioassay-guided isolation of cyclooxygenase-2 inhibitory and antioxidant
phenylpropanoid derivatives from the roots of Dendropanax dentiger
⁎
Li Yanga, Shengzhang Liub, Ronghua Liua, Junwei Hec,
a Key Laboratory of Modern Preparation of TCM, Ministry of Education, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China
b College of Traditional Chinese Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China
c Research Center of Natural Resources of Chinese Medicinal Materials and Ethnic Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China
A R T I C L E I N F O
A B S T R A C T
Keywords:
The root of Dendropanax dentiger (Harms) Merr. is a traditional Chinese medicine that has been used to treat
inflammation-related diseases with little scientific validation. In this study, a bioassay-guided phytochemical
investigation of D. dentiger led to the isolation of 19 phenylpropanoid derivatives including one new compound
(1) and 18 known ones (2–19). Their structures were elucidated by NMR and HRMS as well as comparison with
literature data. The ability of cyclooxygenase-2 (COX-2) inhibition and antioxidant of all isolated compounds
were measured in vitro. Chlorogenic acid derivatives (14–19) exhibited outstanding COX-2 inhibitory
(IC50 = 5.1–93.4 μM) and antioxidant (IC50 = 13.2–31.9 μM) activities. Moreover, the tight structure-activities
relationships were proposed. This is the first report on the COX-2 inhibitory activity of phenylpropanoids and D.
dentiger.
Dendropanax dentiger
Phenylpropanoids
Chlorogenic acid derivatives
COX-2 inhibitory activity
Antioxidant activity
1. Introduction
and 18 known compounds (2–19) (Fig. 1) were isolated and identified
from the EtOAc and n-BuOH soluble fractions of DDR. Among them,
Dendropanax Decne. & Planch. a member of the family Araliaceae,
comprising 80 species distributed mainly in the tropical America and
eastern Asia. Moreover, 16 native species have been found in southwest
and southeast of China, and the most prevalent one of these is D. den-
tiger (Harms) Merr., which is widely cultivated in park and commonly
used as traditional Chinese medicine (TCM) [1–3]. In TCM, the root of
D. dentiger (DDR) is a popular traditional herb for inflammatory dis-
eases for centuries [4]. The previous phytochemical studies have found
that phenylpropanoids [5,6], polyacetylenes [7], triterpenoids [8] and
flavonoids [8] are the main active constituents of D. dentiger, which
showed potent anti-inflammatory, cytotoxic, antibacterial, antiviral,
and antioxidant activities [2,3]. To date, the COX-2 inhibitory activity
of D. dentiger has not yet been studied so far.
compounds 2, 8–10, 15, 16, 18 and 19 were found from the Liliaceae
family, while compound 17 from the genus Dendropanax for the first
time. Described herein are the isolation, structural elucidation, and
bioactivity evaluation of all isolated compounds from DDR.
2. Materials and methods
2.1. General experimental procedures
The NMR spectra were recorded on a Bruker AV 600 spectrometer
(Fallanden, Switzerland). HR-ESI-MS spectra were measured on a
Waters Synapt UPLC G2 TOF mass spectrometer (Manchester, UK).
HPLC separation were performed on a Shimadzu LC-6AD system
(Kyoto, Japan) with a Gemini preparative HPLC (pre-HPLC) column
(5 μm, 21.2 × 250 mm, Phenomenex Inc., CA, USA) and a park ODS-A
semi-pre-HPLC column (5 μm, 10 × 250 mm, YMC Co., Ltd., Kyoto,
Japan). The silica gel (200–300 mesh) was purchased from Qingdao
Haiyang Chemical Group Corporation (Qingdao, China). The octodecyl
silica gel (ODS, 60–80 μm) and Sephadex LH-20 were purchased from
YMC Co., Ltd. (Tokyo, Japan).
Considering the wide utilization of D. dentiger in folk medicine and
phytotherapy as well as the recently documented bioactivities of several
Dendropanax species [3], we aims to isolate the bioactive secondary
metabolites in DDR with the COX-2 inhibitory and antioxidant activ-
ities. During our ongoing to search for the COX-2 inhibitory and anti-
oxidant activities secondary metabolites from TCMs [9–13], we found
that the ethyl acetate (EtOAc) and n-butanol (n-BuOH) soluble fractions
of DDR showed potential COX-2 inhibitory and antioxidant effects. As a
result, 19 phenylpropanoids including one new coumarin derivative (1)
L-ascorbic acid (Vc) was purchased from aladdin (Shanghai, China).
2,2-di-phenyl-1-picrylhydrazyl (DPPH) was purchased from Sigma
⁎ Corresponding author.
E-mail address: hjwjn2008@163.com (J. He).
https://doi.org/10.1016/j.bioorg.2020.104211
Received 2 February 2020; Received in revised form 8 August 2020; Accepted 18 August 2020
Availableonline04September2020
0045-2068/©2020ElsevierInc.Allrightsreserved.

L. Yang, et al.
BioorganicChemistry104(2020)104211
Fig. 1. Chemical structures of compounds 1–19 isolated from DDR.
Corporation (New York, USA), L-cysteine methyl ester and O-Tolyl
isothiocyanate were purchased from Meilun Biotech. Co. Ltd (Dalian,
China), D-glucose, L-glucose, D-rhamnose and
Sephadex LH-20 CC eluting with 90% MeOH to give 6 sub-fractions
(C751-C756). The separation of C753 (4.98 g) following a procedure
similar to that used for the fraction C45 gave 14 (364.8 mg), 15
(31.5 mg) and 16 (65.2 mg).
chased from Energy Chemical (Shanghai, ChLin-rah)a.mCnOoXse-2wienrheibpituorr-
screening assay kit was purchased from Beyotime Biotechnology
(Shanghai, China).
The EtOAc soluble fraction (B, 85.0 g) was subjected to a silica gel
CC eluting with a gradient elution (CH2Cl2/MeOH = 100:0 → 1:10, v/
v) to yield 6 fractions (B1-B6). Fraction B3 (2.16 g) was separated by an
ODS MPLC (20–50% MeOH) and pre-HPLC to yield 5 (20.7 mg), 6
(38.2 mg) and 12 (84.2 mg). Fraction B4 (51.0 g) was applied to an
ODS MPLC (20–50% MeOH) to get 7 fractions (B41-B47). The separa-
tion of B42 (4.0 g) by using a silica gel CC (CH2Cl2/MeOH = 30:1 →
5:1, v/v) and pre-HPLC afford 4 (10.6 mg) and 7 (315.6 mg). Fraction
B5 (8.1 g) was applied to an ODS MPLC (10–40% MeOH) to get 6
fractions (B51-B56). The separation of B52 (3.2 g) was applied to a
silica gel CC (CH2Cl2/MeOH = 50:1 → 10:1, v/v) and pre-HPLC to get
17 (17.4 mg), 18 (21.4 mg) and 19 (86.4 mg).
2.2. Plant material
The DDR was harvested from the town of Baidu, Baise City,
Guangxi, China, in October 2016. A botanical voucher specimen of this
plant (No. DD20161022) was deposited at authors’ laboratory, and was
identified by one of the authors Ronghua Liu.
2.3. Extraction and isolation
The dried DDR (10.0 kg) were extracted with 95% EtOH (60 L × 3)
and subsequently 50% EtOH (60 L × 3) by maceration at room tem-
perature for 7 days. The ethanol crude extract of DDR (1275 g, 12.75%)
was suspended in water (2.5 L) and partitioned successively with pet-
roleum ether, EtOAc, and n-BuOH to afford four fractions (A-D).
The n-BuOH soluble fraction (C, 216.0 g) was subjected to a silica
gel chromatographic column (CC) by using CH2Cl2/MeOH gradient
elution (100:0 → 0:100, v/v) to yield 9 fractions (C1-C9). Fraction C7
(70.0 g) was applied to a silica gel CC eluting with CH2Cl2/MeOH
(20:1 → 1:1, v/v) to get 5 sub-fractions (C71-C75). Fraction C74
(23.2 g) was isolated by a Sephadex LH-20 CC eluting with 90% MeOH
to give 3 sub-fractions (C741-C743). Fraction C742 (4.92 g) was further
separated by a silica gel CC (CH2Cl2/MeOH = 20:1 → 10:1, v/v) and
pre-HPLC to get 1 (12.5 mg), 2 (31.7 mg), 9 (25.4 mg), 10 (6.5 mg) and
11 (3.8 g). The C4 fraction (4.2 g) was subjected to a silica gel CC
eluting with a gradient elution (CH2Cl2/MeOH = 100:0 → 5:1, v/v) to
obtain 8 sub-fractions (C41-C48). Compound 3 (100.0 mg) was ob-
tained with pre-HPLC from C44 (256 mg). Fraction C45 (1.42 g) was
separated by an ODS MPLC (10–30% MeOH) and pre-HPLC to yield 13
(120.8 mg) and 8 (45.8 mg). Fraction C75 (40.2 g) was purified by a
2.4. Acid hydrolysis and HPLC analysis
The absolute configurations of the sugar moieties in compound 1
were described in our previously papers [9,10]. Briefly, Compound 1
(3 mg) was dissolved in 2 mol/L HCl and heated for 2 h at 90 °C. The
solvent was evaporated to dryness under vacuum, the residue was
dissolved in anhydrous pyridine (1 mL) and then mixed with L-cysteine
methyl ester (1 mg), the mixture was heated at 60 °C for one hour.
Subsequently, o-Tolyl isothiocyanate (5 mL) was added and heated at
60 °C for another one hour. Lastly, the reaction mixture was directly
analyzed by HPLC analysis under the following conditions: Phenom-
enex reversed-phase C18 column (250 × 4.6 mm, 5 μm); detection:
254 nm; mobile phase: CH3CN-H2O (25:75, v/v) containing 0.1%
formic acid; flow rate: 0.8 mL/min; temperature: 35 °C.
2.5. In vitro COX-2 inhibitory assay
The inhibitory activity of the sample toward COX-2 activity was
determined using colorimetric COX inhibitor screening assay kit (no.
2

L. Yang, et al.
BioorganicChemistry104(2020)104211
S0168) following the manufacturer’s instructions, with celecoxib as the
positive control.
Table 2
1H NMR (600 MHz) and 13C NMR (150 MHz) for compound 1 in DMSO‑d6 (δ in
ppm).
2.6. DPPH free radical scavenging activity
No.
δC
δH (mult, J in Hz)
No.
δC
δH (mult, J in Hz)
a
2
159.8
114.8
144.4
105.4
149.5
141.5
140.3
142.3
114.8
102.4
74.0
–
4′
5′
6′
69.8
75.7
66.5
3.09–3.11 (2H, m)
3.18 (1H, m)
The DPPH radical scavenging assay was used for the evaluation of
antioxidant activity according to the method previously described
[9–11]. Briefly, 150 μL of DPPH solution (dissolved 0.2 mM in me-
thanol) was mixed with 50 μL of the sample at different concentrations,
then incubated in the dark at 30 °C for 30 min and the absorbance was
determined at 517 nm (Asample). The absorbance of a blank (Ablank) and
control (Acontrol) composed of only the sample and DPPH solutions were
also determined, respectively. The DPPH radical scavenging ac-
tivity = [1 - (Asample – Ablank)/Acontrol] × 100%. Vc was used as the
positive control in this work.
3
6.39 (1H, d, 9.5)
7.94 (1H, d, 9.5)
7.11 (1H, s)
4
3.69 (1H, d, 10.9)
3.39 (1H, m)
5
a
6
–
1″
100.6
70.3
70.5
71.7
68.2
17.8
56.5
61.3
4.39 (1H, s)
a
7
–
2″
3.23–3.26 (4H, m)
a
8
–
3″
a
9
–
4″
3.09–3.11 (2H, m)
3.23–3.26 (4H, m)
0.98 (3H, d, 6.1)
3.82 (3H, s)
a
10
1′
2′
3′
–
5″
5.07 (1H, d, 7.2)
3.23–3.26 (4H, m)
3.23–3.26 (4H, m)
6″
6-OMe
8-OMe
76.3
3.90 (3H, s)
a
no signal.
3. Results and discussion
protons (δH 7.97 and 6.39) definitely indicated the double bond with Z
geometry. Its 13C NMR data (Table 2) exhibited 23 carbon resonances,
12 of which were attributable to two sugar moieties (δC 102.4, 100.6,
76.3, 75.7, 74.0, 71.7, 70.5. 70.3, 69.8, 68.2, 66.5 and 17.8), the re-
maining 11 carbon signals were assigned to one C6-C3 unit (δC 159.8,
149.5, 144.4, 142.3, 141.5, 140.3, 114.8, 114.8 and 105.4), and two
methoxy groups (δC 61.3 and 56.5).
3.1. Bioactivity-guided isolation
The EtOAc and n-BuOH soluble fractions from an ethanol crude
extract of DDR showed potential COX-2 inhibitory and antioxidant
activities with IC50 values of 40.7
COX-2 assay, as well as 146.7
3.5 and 28.6
1.9 μg/mL for
9.2 μg/mL for
8.6 and 206.3
DPPH assay, respectively, whereas the petroleum ether and aqueous
soluble fractions were found to be inactive (Table 1). Therefore, EtOAc
and n-BuOH fractions were selected for further separation. In this way,
19 phenylpropanoid derivatives (1–19) were isolated and identified
(Fig. 1).
The 1H and 13C NMR data of 1 were similar to those of hapoperoside
A (compound 2) [15], except for the presence of an additional methoxy
group [δH 3.90 (3H, s) and δC 61.3, 8-OCH3] in 1. Moreover, the ad-
ditional methoxy group positioned at C-8 was confirmed by the HMBC
correlation from 8-OCH3 to C-8 (δC 140.3). Attached positions of the
glucose at C-7 and the rhamnose at C-6′ were indicated by HMBC
correlations from H-1′ (δH 5.07) to C-7 (δC 148.8) and from H-1″ (δH
4.39) to C-6′ (δC 66.5), respectively. Detailed analysis of the 1H–1H
COSY, HSQC and HMBC spectra (Fig. 2) further confirmed the structure
of 1. The β-anomeric form of glucose was deduced based on the cou-
3.2. Spectroscopic data
Dendrocoumarin A (1): white amorphous powder; UV (MeOH) λmax
:
207, 257, 294, and 337; 1H and 13C NMR spectroscopic data see
Table 2; HR-ESI-MS: m/z 531.17083 [M+H]+ (calcd. for C23H31O14
,
pling constant (3J1′,2′
= 7.2 Hz), whereas the D-configuration
531.17066).
(19.5 min) and α-L-rhamnose (32.8 min) were determined using HPLC
analysis after the acid hydrolysis of 1, while the peaks of the standard
monsaccharide derivatives were recorded at tR 17.9 (L-glucose), 19.5 (D-
glucose) and 32.8 (L-rhamnose) min. On the basis of above evidence,
compound 1 was determined to be 6,8-dimethoxy-coumarin-6-O-α-L-
3.3. Structure elucidation
Compound 1 was obtained as white amorphous powder. The HR-
ESI-MS with the positive ion at m/z 531.17083 [M+H]+ (calcd.
rhamnopyranosyl-(1
drocoumarin A.
→ 6)-β-D-glucopyranoside, and named Den-
531.17066) indicated that the molecular formula of 1 was C23H30O14
.
The UV spectrum showed the absorption characteristics of coumarin
with λmax 207, 257, 294, and 337 nm [14]. The 1H NMR spectrum of 1
(Table 2) showed two methoxy signals at δH 3.90 and 3.82 (each, 3H, s,
8/6-CH3, respectively), two anomeric protons at δH 5.07 (1H, d,
J = 7.2 Hz, H-1′) and 4.39 (1H, s, H-1″), and three olefinic proton
signals at δH 7.97 (1H, d, J = 9.5 Hz, H-4), 7.11 (1H, s, H-5) and 6.39
(1H, d, J = 9.5 Hz, H-3). The coupling constant of the two olefinic
Additionally, 18 known compounds were identified as hapoperoside
A (2) [15], scopoletin (3) [16], β-hydroxypropiovanillone (4) [17],
ferulaldehyde (5) [18], sinapaldehyde (6) [18], caffeic acid (7) [19],
caffeic acid ethyl ester (8) [19], 3,5-dimethoxy-1-(3-hydroxy-propen-1-
yl)phenyl-4-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside (9)
[20], tinoscorside D (10) [21], syringin (11) [21], pinoresinol (12)
[22], syringaresinol (13) [23], chlorogenic acid (14) [24], neo-
chlorogenic acid (15) [25], cryptochlorogenic acid (16) [26], 3,4-di-O-
caffeoylquinic acid (17) [26], 3,5-di-O-caffeoylquinic acid methyl ester
(18) [26], and 4,5-di-O-caffeoylquinic acid methyl ester (19) [26], re-
spectively, based on analysis of their physical and spectroscopic data
with those reported earlier. To the best of our knowledge, this is the
Table 1
Anti-inflammatory and antioxidant activities of four fractions from DDR.a
Fractions
COX-2 inhibitory assay
DPPH assay
IC50 (μg/mL)
Petroleum ether extract
EtOAc extract
n-butanol extract
Water extract
Vcb
174.6
40.7
9.4
3.5
1.9
15.4
> 1000
146.7
206.3
496.1
6.0
8.6
28.6
9.2
171.9
20.5
c
–
0.2
c
Clecoxibb
(22.4
1.4) × 10−3
–
a
Values are mean
SD of three experiments, with each data point done in
triplicate.
b
c
Positive control.
Fig. 2. 1H–1H COSY and key HMBC correlations of compound 1.
Not tested.
3

L. Yang, et al.
BioorganicChemistry104(2020)104211
Table 3
Anti-inflammatory and antioxidant activities of compounds 1–19.a
Compound
COX-2 inhibitory assay
DPPH assay
Compound
COX-2 inhibitory assay
DPPH assay
IC50 (μM)
IC50 (μM)
> 100
1
58.6
93.4
> 100
> 100
45.6
17.5
11.7
12.1
65.5
69.4
5.6
8.5
> 200
> 200
> 200
> 200
> 200
> 200
> 200
> 200
> 200
> 200
11
> 200
> 200
> 200
2
12
28.8
5.1
2.1
3
13
0.4
0.7
0.4
0.3
0.3
0.7
0.9
4
14
8.1
31.9
18.0
21.2
13.2
13.2
17.2
1.6
1.0
1.0
0.8
0.7
0.9
5
4.2
1.2
0.9
1.0
5.7
6.1
15
6.0
6
16
5.3
7
17
5.5
8
18
7.8
9
19
9.9
c
10
Vcb
Clecoxibb
(34.7
2.2) × 10−3
–
c
–
33.9
1.1
a
b
c
Values are mean
SD of three experiments, with each data point done in triplicate.
Positive control.
Not tested.
first report on compounds 2, 8–10, 15, 16, 18 and 19 from the Liliaceae
14–16 with one 1,2-diphenol, while compounds 1–13 with no or one
phenolic hydroxyl group were inactive. Therefore, the number and
position of phenolic hydroxyl groups of compounds are directly related
to their in vitro antioxidant effects, which were consistent with reported
papers [9,27].
family, and compound 17 from the genus Dendropanax.
3.4. COX-2 inhibitory activity
In order to compare the anti-inflammatory activities in vitro of the
secondary metabolites and to select the most promising bio-con-
stituents, the COX-2 inhibitory activities of all isolated compounds were
evaluated at the concentration of 100 μM. Celecoxib was used as the
positive control, which was a selective COX-2 inhibitor [9].
4. Conclusion
In this work, 19 phenylpropanoids (1–19) including one new cou-
marin derivative (1) were isolated and identified from DDR through
bioactivity-guided separation. All isolated compounds were evaluated
for their COX-2 inhibitory and antioxidant activities in vitro, and the
tight structure-activities relationships were proposed. Moreover, 6
chlorogenic acid derivatives (14–19) exhibited outstanding COX-2 in-
hibitory (IC50 = 5.1–93.4 μM) and antioxidant (IC50 = 13.2–31.9 μM)
activities. This is the first report on the COX-2 inhibitory activity of
phenylpropanoids and D. dentiger. Our findings suggested that the anti-
inflammatory and antioxidant effects of DDR were partly attributed to
these phenylpropanoids especially chlorogenic acid derivates, and
support the claim as sources of important folk medicine in TCM used to
treat inflammation-related diseases for centuries.
As shown in Table 3, compounds 1, 2, 5–10 and 12–19 exhibited
potential anti-inflammatory effect against COX-2 with IC50 values <
100 μM, while 3, 4 and 11 have no activities with IC50 values > 100
μM. It is worth mentioning that compounds 13 and 14–19 exhibited
outstanding potency with IC50 values less than 10 μM, while 6–8
showed strong activities with IC50 values from 11.7 to 17.5 μM. In
addition, compounds 5 and 12 displayed obvious inhibitory activities
against COX-2 with IC50 values of 45.6
4.2 and 28.8
2.1 μM,
respectively. Meanwhile, 1, 2, 9 and 10 showed moderate effects with
IC50 values of 58.6–93.4 μM. This is the first reported on the COX-2
inhibitory activities of phenylpropanoids.
Based on the above results, 16 phenylpropanoid derivatives, in-
cluding 1, 2, 5–10 and 12–19, were identified as the bio-constituents
that contributes to the anti-inflammatory effect against COX-2 of DDR.
By comparison of the structure type and COX-2 inhibitory activity data
of the bioactive secondary metabolites, it was found that the COX-2
inhibitory potency of 13 and chlorogenic acid derivates (14–19) were
better than the others. In addition, phenylpropanoids showed COX-2
inhibitory activities, which were also reported for the first time.
Declaration of Competing Interest
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influ-
ence the work reported in this paper.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (No. 81760705) and the Natural Science
3.5. Antioxidant activity
Foundation
of
Jiangxi
Province
(Nos.
20192BBHL80008,
The antioxidant activity of all isolated compounds was also assessed
by DPPH radical scavenging assay, and the result were summarized in
Table 3. The results showed that only chlorogenic acid derivates
(14–19) exhibited potential antioxidant effects with IC50 values in the
range of 13.2–31.9 μM, while other phenylpropanoids (1–13) have no
activities (IC50 values > 200 μM). Compounds 14–19 showed sig-
nificant antioxidant activities with IC50 values from 13.2 to 31.9 μM, of
which 17 and 18 had the strongest activities with IC50 values of
20171BAB215063 and 20192BAB215059), and the Research Project of
Jiangxi Health Department (No. 2016A038).
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.bioorg.2020.104211.
13.2
0.8 and 13.2
0.7 μM, respectively.
References
Based on the above results, six chlorogenic acid derivates (14–19)
were identified as the antioxidant secondary metabolites of DDR. The
common structural feature of these compounds is that they all have the
group of 1,2-diphenols. By comparison, 17–19 with two 1,2-diphenols
(four phenolic hydroxyl groups) had stronger antioxidant capacity than
[1] Editorial Committee of the Flora of China of Chinese Academy of Science, Zhongguo
Zhiwu Zhi (Flora of China), vol. 54, Science Press, Beijing, China, 1978, pp. 62.
[2] L. Yang, Y.Q. Wang, S.C. Liu, J.W. He, Chin. J. Exp. Tradit. Med. Form. 22 (2016)
191–196.
4

L. Yang, et al.
BioorganicChemistry104(2020)104211
[3] X.M. Wang, L. Yang, J.W. He, G. Ren, M. Yang, G.Y. Zhong, Chin. J. Exp. Tradit.
Med. Form. 21 (2015) 229–234.
[16] Q. Wu, L. Zou, X.W. Yang, D.X. Fu, J. Asian Nat. Prod. Res. 11 (2009) 85–90.
[17] B.H. Qin, Q.Y. Yuan, W.K. Yuan, H.Y. Han, X.Q. Liu, Chin. Med. Mat. 40 (2017)
2081–2083.
[4] Editorial Committee of Traditional Chinese Medicine, Chinese Materia Medica, vol.
5, Shanghai Science & Technology Press, Shanghai, China, 1999, pp. 793-794.
[5] G. Ren, Z.P. Luo, W.Y. Li, G.H. Zhu, F. Shao, H.L. Huang, R.H. Liu, Chin. J. Exp.
Tradit. Med. Form. 19 (2013) 80–83.
[18] L.F. Ding, H.Y. Wang, K. Wang, Y.D. Guo, X.D. Wu, L.D. Song, Chin. Traditi. Pat.
Med. 38 (2016) 2610–2614.
[19] L.L. Ge, H.Q. Wan, S.M. Tang, H.X. Chen, J.M. Li, K.D. Zhang, B.P. Zhou, J. Fei,
S.P. Wu, X.B. Zeng, RSC Adv. 8 (2018) 35373–35385.
[20] Y.N. Sun, W. Li, X.T. Yan, S.Y. Yang, S.B. Song, Y.H. Kim, Biosci. Biotech. Bioch. 78
(2014) 374–377.
[6] Y.C. Lai, S.S. Lee, Nat. Prod. Commun. 8 (2013) 363–365.
[7] S.C. Chien, Y.H. Tseng, W.N. Hsu, F.H. Chu, S.T. Chang, Y.H. Kuo, S.Y. Wang, Nat.
Prod. Commun. 9 (2014) 1589–1590.
[8] L.P. Zheng, Z.G. He, Z.J. Wu, C. Zhang, Chem. Nat. Compd. 48 (2012) 883–885.
[9] J.W. He, L. Yang, Z.Q. Mu, Y.Y. Zhu, G.Y. Zhong, Z.Y. Liu, Q.G. Zhou, F. Cheng, RSC
Adv. 8 (2018) 18175–21879.
[21] P.V. Kiem, C.V. Minh, N.T. Dat, L.V. Kinh, D.T. Hang, N.H. Nam, N.X. Cuong,
H.T. Huong, T.V. Lau, Fitoterapia 81 (2010) 485–489.
[22] J.H. Kwak, M.W. Kang, J.H. Roh, S.U. Choi, O.P. Zee, Arch. Pharm. Res. 32 (2009)
1681–1687.
[10] L. Yang, S.T. Jiang, Q.G. Zhou, G.Y. Zhong, J.W. He, Molecules 22 (2017) 1825.
[11] J.W. He, X.Y. Huang, Y.Q. Wang, J. Liang, R.H. Liu, G.Y. Zhong, L. Yang, Nat. Prod.
Res. 33 (2019) 1599–1604.
[23] A. Ito, R. Kasai, K. Yamasaki, N.M. Guc, N.T. Nham, Phytochemistry 37 (1994)
1455–1458.
[12] L. Yang, Y.M. Lin, Z.W. He, T.F. Zhang, Y. Li, X.T. Xie, Y.F. Wu, J.W. He, Med.
Chem. Res. 29 (2020) 426–430.
[24] M.R. Delnavazi, A. Hadjiakhoondi, A. Delazar, Y. Ajani, N. Yassa, Med. Chem. Res.
24 (2015) 787–796.
[13] L. Yang, Y.Y. Zhu, Z.W. He, T.F. Zhang, Z.X. Xiao, R.L. Xu, J.W. He, Nat. Prod. Res.,
2020, online, DOI: 10.1080/14786419.2020.1713121.
[25] F. Bohlmann, U. Fritz, Phytochemistry 17 (1978) 1769–1772.
[26] Y. Zhou, T. Zeng, L.M. Li, Chin. Tradit. Herbar Drugs 47 (2016) 1496–1500.
[27] M. Musialik, R. Kuzmicz, T.S. Pawlowski, G. Litwinienko, J. Org. Chem. 74 (2009)
2699–2709.
[14] J.W. He, D.P. Qin, H. Gao, R.Q. Kuang, Y. Yu, X.Z. Liu, X.S. Yao, Molecules 19
(2014) 20880–20887.
[15] J. Liu, C.J. Li, J.Z. Yang, J. Ma, D.M. Zhang, J. Pharm. Res. 35 (2016) 125–128.
5