The chiral interfaces fabricated by d/l-alanine-pillar[5]arenes for selectively adsorbing ctDNA

Article abstract of DOI:10.1039/c8cc09696a

In this paper, the d/l-AP5-interfaces are firstly fabricated by attaching d-alanine-pillar[5]arene and l-alanine-pillar[5]arene (d/l-AP5) onto the gold surface, and they exhibit a significantly different chiral influence on the morphology and the adsorpti

Full text of DOI:10.1039/c8cc09696a

Fitoterapia133(2019)146–149
Contents lists available at ScienceDirect
Fitoterapia
journal homepage: www.elsevier.com/locate/fitote
Three new hopane-type triterpenoids from the aerial part of Adiantum
capillus-veneris and their antimicrobial activities
Xia Zhanga,1, Hai-Li Chenc,1, Liu Honga, Lu-Lin Xuc, Xiao-Wei Gonga, Dong-Lai Zhua,
⁎⁎
Xiao-Hua Xua, Wei Zhaoa,⁎, Fei Wangd,⁎, Xiao-Long Yangb,c,
a Research &Development Center, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650201, China
b School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China
c Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
d BioBioPha Co., Ltd., 132 Lanhei Road, Kunming 650201, China
A R T I C L E I N F O
A B S T R A C T
Keywords:
Three new hopane-type triterpenoids (1–3), fern-7(8)-en-19α, 28-diol (1), pteron-14-ene-7α,19α,28-triol (2)
and 3β,4α,25-trihydroxyfilican (3), were isolated from the aerial parts of Adiantum capillus-veneris. Their
structures were determined by NMR spectroscopic and mass spectrometric data. Compounds 2 and 3 exhibited
remarkable antifungal activity against Helminthosporium maydis and Alternaria alternata with MIC values of
12.5–3.125 μg/mL, and compound 3 also against Verticillium dahliae Kleb with an MIC value of 3.125 μg/mL. In
addition, compounds 1–3 also displayed weak antibacterial activity against Micrococcus lysodeikticus, Bacterium
paratyphosum B and Pseudomonas aeruginosa with an MIC value of 100 μg/mL.
Adiantum capillus-veneris
Hopane-type triterpenoid
Antimicrobial activity
1. Introduction
2. Experimental
The genus Adiantum (Adiantaceae), commonly known as maiden-
hair ferns, has been used for medicinal and nutritive purpose, such as
respiratory problems treatment, and as an astringent, demulcent,
diuretic, emmenagogue, et al. [1] Until now, the chemical constituents
of 17 species of this genus have been investigated to afford over 135
compounds, and most of them belonged to the triterpenoids, flavonoids,
phenyl propanoids, phenolics, coumarins and phytosterols [1].
Adiantum capillus-veneris, one of the most common and widely dis-
tributed species, has been traditionally used as single medicine or in
multi-herbal formulations for the treatment of various diseases [2].
Previous phytochemical studies of A. capillus-veneris have resulted into
the isolation of many compounds, and most of which possessed diverse
pharmacological activities [3–11].
2.1. General methods
Optical rotations were recorded on a Rudolph Research Analytical
polarimeter. IR spectra (KBr pellets) were performed on a Bruker
TENSOR-27 spectrophotometer. HRESIMS were obtained from a Bruker
SolariX instrument. NMR spectroscopic data were acquired with a
Bruker AM-500 using TMS as the internal standard. Column chroma-
tography (CC) was carried out using silica gel (200–300 mesh, Qingdao
Marine Chemical Inc., Qingdao, China) and Sephadex LH-20 (GE
Healthcare, Uppsala, Sweden).
2.2. Plant material and microbial strains
As a part of our continuing works for searching new bioactive nat-
ural products from Chinese medicinal herbs, the chemical constituents
of A. capillus-veneris were investigated to yield three new triterpenoids
(1–3). Herein, the isolation, structural elucidation, and antimicrobial
activities of 1–3 are described.
The aerial parts of A. capillus-veneris were collected in April 2014
from Dali, Yunnan, P. R. China, which was identified by Mr. Yu Chen
(Kunming Institute of Botany). A voucher specimen (BBP0542) was
preserved at Biobiopha Co., Ltd. All microbial strains for biological
studies were gifted by Dr. Fei Cao (College of Pharmaceutical Sciences,
Hebei University).
⁎ Corresponding authors.
⁎⁎ Correspondence to: Xiao-Long Yang, School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China.
E-mail addresses: zhaowei@ynzy-tobacco.com (W. Zhao), f.wang@mail.biobiopha.com (F. Wang), yxl19830915@cqu.edu.cn (X.-L. Yang).
1 These authors contributed equally to this work.
https://doi.org/10.1016/j.fitote.2019.01.006
Received 6 December 2018; Received in revised form 2 January 2019; Accepted 11 January 2019
Availableonline14January2019
0367-326X/©2019PublishedbyElsevierB.V.

X. Zhang et al.
Fitoterapia133(2019)146–149
Table 1
solvent system of CHCl3/acetone (50:1, v/v), and further purified by
repeated Sephadex LH-20 (MeOH) to afford compound 3 (6.3 mg).
1H and 13C NMR data for compounds 1–3 (δ in ppm, J in Hz).
20.8
Fern-7(8)-en-19α, 28-diol (1). White amorphous powder; [α]D
No. 1a
2b
3b
−72.3° (c 0.1, MeOH); IR (KBr) νmax 3210 (OH), 2922, 1471, 1455,
1383, 1366, 1066, 1018 cm−1; for 1H (pyridine-d5, 500 MHz) and 13C
NMR (pyridine-d5, 125 MHz) spectroscopic data, see Table 1; positive
δH
δC
δH
δC
δH
δC
1
1.58, m
39.1, CH2 1.57, m
0.90, brd
39.3, CH2 1.57, m
1.76, brd
17.3, CH2
HRESIMS m/z 465.3705 [M + Na]+ (calcd for C30H50O2Na+
,
0.88, brd
(3.8)
465.3703).
(3.6)
(3.3)
2
3
1.54, m
1.42, m
1.14, m
1.39, m
19.8, CH2 1.60, m
1.43, m
42.9, CH2 1.21, m
1.39, m
18.5, CH2 1.66, m
1.95, m
41.9, CH2 3.55, m
31.1, CH2
76.5, CH
Pteron-14-ene-7α,19α,28-triol (2). White amorphous powder;
[α]D20.8 −80.6° (c 0.13, MeOH); IR (KBr) νmax 3355 (OH), 2929, 1470,
1441, 1389, 1046 cm−1; for 1H (CDCl3, 500 MHz) and 13C NMR (CDCl3,
125 MHz) spectroscopic data, see Table 1; positive HRESIMS m/z
481.3650 [M + Na]+ (calcd for C30H50O3Na+, 481.3652).
3β,4α,25-Trihydroxyfilican (3). White amorphous powder;
[α]D20.4 + 2.0° (c 0.1, MeOH); IR (KBr) νmax 3395 (OH), 2946, 1468,
1452, 1377, 1055, 1034 cm−1; for 1H (CDCl3, 500 MHz) and 13C NMR
(CDCl3, 125 MHz) spectroscopic data, see Table 1; positive HRESIMS
m/z 483.3806 [M + Na]+ (calcd for C30H52O3Na+, 483.3809).
4
5
6
33.7, C
32.6, C
47.4, CH
24.1, CH2 1.48, m
76.2, C
41.7, C
34.5, CH2
1.36, m
2.16, m
1.88, m
52.0, CH
1.49, m
25.3, CH2 1.85, m
1.69, dd
(13.0, 1.1)
117.6, CH 3.87, m
7
5.46, brd
(3.4)
72.7, CH
1.44, m
1.40, m
1.69, m
17.0, CH2
8
9
10
11
145.9, C
45.5, C
42.1, CH
38.0, C
49.5, CH
42.0, C
53.3, CH
30.0, CH2
2.53, m
1.68, m
1.57, m
49.0, CH
36.2, C
2.13, m
2.4. Antifungal assay
16.9, CH2 1.82, m
1.48, m
32.2, CH2 2.07, m
1.31, m
37.6, C
43.6. C
15.4, CH2 1.85, m
1.05, m
32.2, CH2 1.51, m
Compounds 1–3 were evaluated for their antifungal activity against
eight agricultural pathogenic fungi, including Sclerotinia sclerotiorun,
Helminthosporium maydis, Verticillium dahliae Kleb, Phytophthora para-
sitica, Gibberella saubinetii, Alternaria alternata, Botrytis cinerea Pers., and
Colletotrichum acutatum Simmonds, by using the microbroth dilution
method according to the procedures previously described in the lit-
erature [12,13].
12
30.1, CH2
13
14
15
36.6, C
154.3, C
39.0, C
39.7, C
29.2, CH2
1.57, m
1.72, m
2.48, m
1.79, m
32.1, CH2 5.36, t (3.7) 118.6, CH 1.97, m
16
44.5, CH2 2.13, m
2.02, m
48.0, C
40.0, CH2 1.62, m
35.8, CH2
17
18
44.9, C
42.7, C
51.6, CH
1.54,
58.2, CH
1.36, brs.
4.39, m
61.7, CH
70.7, CH
1.55, m
1.33, m
2.5. Antibacterial assay
overlap
4.55, m
1.78, m
1.50, m
1.01, m
2.18, m
0.84, s
0.90, s
0.83, s
19
20
70.5, CH
19.9, CH2
28.4, CH2
35.5, CH2 2.43, m
1.39, m
43.7, CH2 1.83, m
1.18, m
Compounds 1–3 were also evaluated for their antibacterial activity.
Eight bacterial strains, including Micrococcus lysodeikticus, Micrococcus
luteus, Bacillus megaterium, Bacterium paratyphosum B, methicillin-re-
sistant Staphyloccocus aureus, Pseudomonas aeruginosa, Escherichia coli,
and Vibrio Parahemolyticus, were used in this study. The minimum in-
hibitory concentrations (MIC) of samples and positive control were
determined in sterile 96-well plates by the modified broth dilution test
as previously described procedures [12,13].
21
22
23
24
25
59.7, CH
30.5, CH
1.08, m
1.89, m
58.2, CH
29.7, CH
0.97, m
1.42, m
60.0, CH
30.8, CH
21.5, CH3
18.0, CH3
64.2, CH2
33.4, CH3 0.87, s
21.8, CH3 0.81, s
13.6, CH3 0.88, s
33.0, CH3 1.23, s
21.5, CH3 1.13, s
15.4, CH3 3.89, d
(11.8)
3.82, d
(11.8)
26
27
28
1.16, s
1.74, s
3.90, d
(11.6)
4.33, d
(11.6)
1.06, d
(6.5)
24.9, CH3 1.04, s
23.8, CH3 1.49, s
63.2, CH2 3.84, d
(11.4)
28.1, CH3 0.94, s
22.4, CH3 0.96, s
63.3, CH2 0.77, s
15.1, CH3
15.8, CH3
16.3, CH3
3. Results and discussion
Compound 1 was obtained as a white amorphous powder. Its mo-
lecular formula, C30H50O2, was determined by (+) HRESIMS at m/z
465.3705 [M + Na]+ (calcd for C30H50O2Na+, 465.3703), suggesting 6
indices of hydrogen deficiency. The IR spectrum showed the presence of
3.73, d
(11.4)
29
30
24.2, CH3 0.97, d (6.5) 22.8, CH3 0.82, d
22.9, CH3
21.9, CH3
(6.5)
23.7, CH3 0.89, d (6.5) 22.8, CH3 0.88, d
(6.5)
0.96, d
(6.5)
hydroxy group (3210 cm−1
) and aliphatic CeH stretching group
(2922 cm−1). The 1H NMR data of 1 (Table 1) revealed characteristic
resonances for two secondary methyls [δH 1.06 (d, H3–29) and 0.96 (d,
H3–30)], five tertiary methyls [δH 0.84 (s, H3–23), 0.90 (s, H3–24), 0.83
(s, H3–25), 1.16 (s, H3–26) and 1.74 (s, H3–27)], a pair of oxygenated
methylenes (δH 3.89, 4.33), an oxygenated methine (δH 4.55), and one
olefinic proton (δH 5.46). Its 13C NMR spectroscopic data (Table 1)
exhibited 30 carbons, which were assigned to a trisubstituted double
bond, seven methyls, ten methylenes (including one oxygenated), six
methines (one of which was oxygenated), and five sp3 quaternary car-
bons. Comparison of the NMR data of 1 with those of one closely related
compound, fern-9(11)-en-28-ol previously reported from this plant [8],
revealed that both compounds possessed the same hopane-type tri-
terpene skeleton, as confirmed by 2D NMR experiments (Figs. 2 and 3).
The key differences were found that the chemical shifts at C-7, C-8, C-9,
C-11, and C-19 in 1 were quite different from those of fern-9(11)-en-28-
ol. The observed HMBC correlations (Fig. 2) of H-7 with C-5 and C-9, H-
19 with C-13, C-17 and C-21, in conjunction with 1H, 1H COSY corre-
lations (Fig. 2) of H-5/H2-6/H-7 and H-18/H-19/H2-20/H-21/H-22/H3-
29(/H3-30), revealed that the Δ9,11 double bond in fern-9(11)-en-28-ol
a
b
Measured in pyridine-d5.
Measured in CDCl3.
2.3. Extraction and isolation
The air-dried and powdered plants of A. capillus-veneris (9.5 kg)
were extracted three times with 95% EtOH (15 L/each time), and the
combined extracts were evaporated in vacuum to afford 1.17 kg of
crude extract. The crude extract was directly subjected to chromato-
graphy column (CC) on silica gel using a petroleum ether/acetone
gradient elution to yield ten fractions (A1-A10) according to TLC de-
tection on silica gel plates. Subfraction A3 (3.5 g) was fractionated by
Sephadex LH-20 (MeOH), and further purified by silica gel CC (petro-
leum ether/acetone, 10:1, v/v) to yield compound
2 (10 mg).
Compound 1 (8.5 mg) was isolated from subfraction A5 (15.8 g) by
repeated silica gel CC and Sephadex LH-20 (CHCl3/MeOH, 1:1, v/v).
Subfraction A8 (10.3 g) was separated by silica gel CC eluted with a
147

X. Zhang et al.
Fitoterapia133(2019)146–149
HO
19
20
21
HO
27
12
18
29
OH
11
25
13
22
25
17
28
H
H
H
26
1
4
9
14
H
30
16
2
3
OH
10
8
15
OH
H
H
5
H
26
7
HO
6
OH
H
HO
H
24
23
24
23
3
1
2
Fig. 1. Structures of compounds 1–3.
HO
HO
OH
OH
OH
HO
OH
OH
3
1
2
1H-COSY
1H,
HMBC
Fig. 2. 1H, 1H COSY and key HMBC correlations of compounds 1–3.
Fig. 3. NOESY correlations of compounds 1–3.
was shifted at C-7 and C-8 in 1, as well as the hydroxyl group was
substituted at C-19 in 1. Therefore, the gross structure of 1 was char-
acterized as shown in Fig. 1. The relative stereochemistry of C-5, C-10,
C-13, C-14, C-17, C-21, and C-28 were determined to be
5S*,10S*,13S*,14S*,17S*, 21R* by comparison of NMR data in con-
junction with NOESY experiment (Fig. 3), which was the same as those
found in fern-9(11)-en-28-ol as well as in agreement with hopane-type
triterpene skeleton. Furthermore, the observation of NOESY correla-
tions of H-9 with H-5 and H3–27, and H-19 with H-8 and H-21, sug-
gested the relative configurations of C-9 and C-19 should be 9R*,19R*.
Thus, compound 1 was established as fern-7(8)-en-19α, 28-diol (Fig. 1).
Compound 2 was also isolated as a white amorphous powder. It was
assigned the molecular formula C30H50O3 on the basis of its (+)
deduced from COSY correlations of H-5/H2–6/H-7 and HMBC correla-
tions of H-7 with C-5, C-9 and C-14. Thus, the gross structure of 2 was
elucidated. The relative stereochemistry of 2 were determined to be
5S*,7R*,8R*,9R*,10S*,13S*,17S*18S*,19R*,21R* by comparison of
NMR data with one related known compound, pteron-14-en-7-ol pre-
viously reported from this plant [8], combing with NOE correlations of
H-5 with H-9, CH3–27 with H-9 and H2-28, H-7 with CH3-25 and CH3-
26, H-18 with H-19, H-21 and CH3–26. Finally, compound 2 was elu-
cidated as pteron-14-ene-7α,19α,28-triol.
Compound 3 was isolated as a white amorphous powder, with
molecular formula C30H52O3 as determined by (+) HRESIMS at m/z
483.3806 [M + Na]+ (calcd for C30H52O3Na+
, 483.3809), corre-
sponding to 5 degrees of unsaturation. The 13C NMR data showed 30
carbon signals, which were categorized into seven methyls, eleven
methylenes (one of which was oxygenated), six methines (one of which
was oxygenated), and six quaternary carbons including one oxyge-
nated. Detailed analysis of its 1H and 13C NMR data revealed that
compound 3 closely resembled to one known compound, 3,4-dihy-
droxyfilicane [6]. The only difference was found that the tertiary me-
HRESIMS at m/z 481.3650 [M + Na]+ (calcd for C30H50O3Na+
,
481.3652), requiring 6 degrees of unsaturation. The 13C NMR spec-
troscopic data of 2 (Table 1) displayed the presence of 30 carbon sig-
nals, which were classified into a trisubstituted double bond, seven
methyls, nine methylenes (one of which was oxygenated), seven sp3
methines (two of which were oxygenated), and five sp3 quaternary
carbons. Detailed by comparison of its 1H and 13C NMR data with those
of 1, we found that the structure of 2 is very similar to that of 1, except
for the differences in the locations of a trisubstituted double bond and a
tertiary methyl, and the presence of one additional hydroxy group in 2.
The trisubstituted double bond at C-7 and C-8 in 1 was shifted to C-14
and C-15 in 2, as evident from HMBC correlations of H-15 with C-8, C-
13 and C-17, together with COSY correlation of H-15/H2-16. Further-
more, key HMBC correlations of H-26 with C-7, C-9 and C-14 implied
that a tertiary methyl at C-14 in 1 was migrated at C-8 in 2. In addition,
the position of the additional hydroxy group was located at C-7, as
thyl at C-9 in 3,4-dihydroxyfilicane was replaced by
a hydro-
xymethylene group in 3, as supported by HMBC correlations of H-25
with C-8, C-10 and C-11. The relative stereochemistry of 2 were de-
termined to be 3S*,4S*,5S*,8R*,9S*,10S*, 13S*,14R*,17R*,18R*,21R*
by comparison of NMR data and NOESY experiment. Thus, compound 3
was determined to be 3β,4α,25-trihydroxyfilicane.
Compounds 1–3 were evaluated for their antimicrobial activity
against eight agricultural pathogenic fungi and eight human pathogenic
bacteria (see Tables S1-S2). The antifungal assays indicated that com-
pound 1 displayed moderate activity against H. maydis, V. dahliae Kleb
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X. Zhang et al.
Fitoterapia133(2019)146–149
and B. cinerea Pers. with an MIC value of 50 μg/mL (positive control
ketoconazole: 0.78125, 1.5625, and 0.78125 μg/ml, respectively),
while compounds 2 and 3 exhibited significant activity against H.
maydis and A. alternata with MIC values of 12.5–3.125 μg/mL (keto-
conazole: 0.78125 μg/mL). In addition, compound 3 also showed sig-
nificant activity against V. dahliae Kleb with an MIC value of 3.125 μg/
mL (ketoconazole: 1.5625 μg/mL). The antibacterial assays indicated
that compounds 1–3 showed weak activity against M. lysodeikticus, B.
paratyphosum B and P. aeruginosa with an MIC value of 100 μg/mL
(positive control ciprofloxacin: 0.78125 μg/mL).
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Conflict of interest
Authors declare no conflict of interest.
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Appendix A. Supplementary data
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.fitote.2019.01.006.
149