Original Paper
Carboline Alkaloids from Trigonostemon lii
Authors
Xu-Jia Hu 1, 2, 3, Ying-Tong Di 1, Yue-Hu Wang 1, Ling-Yi Kong 3, Suo Gao 1, Chun-Shun Li 1, Hai-Yang Liu 1, Hong-Ping He 1,
Jian Ding 4, Hua Xie 4, Xiao-Jiang Hao 1
Affiliations
The affiliations are listed at the end of the article
Key words
" Trigonostemon lii
l
" Euphorbiaceae
l
" carboline alkaloids
l
" cytotoxic activity
l
Abstract
!
Three types with six new carboline alkaloids, trigonostemonines A – F (1–6), were isolated from the
roots and stems of Trigonostemon lii. Their structures were elucidated by spectroscopic analyses.
It is the first time that β-carboline alkaloids have
!
April 30, 2008
January 8, 2009
February 17, 2009
Bibliography
DOI 10.1055/s-0029-1185505
Published online March 26,
2009
Planta Med 2009; 75:
1157–1161 © Georg Thieme
Verlag KG Stuttgart · New York ·
ISSN 0032‑0943
Correspondence
Prof. Dr. Xiao-Jiang Hao
State Key Laboratory of Phytochemistry and Plant Resources
in West China
Kunming Institute of Botany
Chinese Academy of Sciences
Kunming 650204
Peopleʼs Republic of China
Phone: + 86 87 15 22 32 63
Fax: + 86 87 15 21 96 84
[email protected]
Supporting information available online at
http://www.thieme-connect.de/ejournals/toc/
plantamedica
1
Introduction
received
revised
accepted
been reported in Trigonostemon species. Trigonostemonine F (6) exhibited moderate cytotoxic activity against HL-60 with an IC50 value of 16 µM.
The genus Trigonostemon Bl. comprising about 50
species is mainly distributed in tropical and subtropical Asia, with 10 species being endemic to
South China [1]. Previous studies on the chemical
constituents and their activities from Trigonostemon reidioides have led to the isolation of several
classes of compounds including daphnane diterpenoids [2–5], a phenanthrenone [6] and a flavonoidal indole alkaloid [7]. During the course of
our investigation on the chemical constituents of
Trigonostemon lii Y. T. Chang, six new β-carboline
" Fig. 1),
alkaloids, trigonostemonines A – F (1−6; l
were isolated. To the best of our knowledge, the
present study is the first report of the occurrence
of β-carboline alkaloids in Trigonostemon species.
Herein we describe the isolation and structure
elucidation and cytotoxic activities of trigonostemonines A – F.
Material and Methods
!
General experimental procedures
Optical rotations were measured with a Horiba
SEAP-300 spectropolarimeter. UV spectra were
obtained using a Shimadzu double beam 210A
spectrophotometer. IR spectra were measured in
a Bio-Rad FTS-135 infrared spectrophotometer
with KBr pellets. ESI‑MS and HR‑ESI‑MS were recorded using a Finnigan MAT 90 instrument and
VG Auto Spec-3000 spectrometer, respectively.
H- and 13C‑NMR spectra were recorded on a
Bruker AM-400 spectrometer, while 2D NMR
spectra were recorded on a Bruker DRX-500 spectrometer. Chemical shifts were reported in ppm
using residual CHCl3 signals (δH = 7.26 for 1H and
δC = 77.0 for 13C) as internal references. Column
chromatography (CC) was performed on silica gel
(Qingdao Marine Chemical, Inc.), C18 reversedphase silica gel (Merck) and Sephadex LH-20
(Amershan Biosciences). HPLC separations were
performed on an HP 1100 apparatus equipped
with a diode array UV detector and Zorbax
SB‑C18 (10 µm, Agilent Co., Ltd.) column (i. d. 9.4 ×
250 mm). Precoated silica gel GF254 plates (Qingdao Haiyang Chemical Plant) were used for TLC.
Fractions were monitored by TLC, and spots were
visualized by spraying with Dragendorffʼs reagent.
Plant material
Air-dried roots and stems of T. lii Y. T. Chang were
collected in Xishuangbanna, Yunnan Province,
P. R. China, in October 2006. Voucher specimens
(KIB 20061011) of the plant were identified by
Prof. Hua Peng at Kunming Institute of Botany,
Chinese Academy of Sciences, and deposited at
the State Key Laboratory of Phytochemistry and
Plant Resources in West China, Kunming Institute
of Botany, Chinese Academy of Sciences, Peopleʼs
Republic of China.
Hu X-J et al. Carboline Alkaloids from …
Planta Med 2009; 75: 1157–1161
1157
1158
Original Paper
54 µm, 100 g; PE/Me2CO, 10 : 2.5, 3 L) to yield trigonostemonines
C (3, 50 mg), D (4, 40 mg), and E (5, 30 mg). Fr. 3 (8.4 g) was separated into 5 subfractions (T1 to T5) by silica gel CC (54–74 µm,
250 g; CHCl3/MeOH, 10: 1 to 4 : 1, 4 L). Subfraction T3 was repurified by Sephadex LH-20 CC (3.5 × 150 cm; CHCl3/MeOH, 1 : 1,
300 mL), and then preparative TLC (PE/Me2CO, 5 : 2.5, Rf = 0.42)
to afford trigonostemonine F (6, 20 mg).
Cytotoxicity assay
Fig. 1
The viability of HL-60 cells (ATCC) was determined by the MTT
assay [8]. Briefly, cells (1.6 × 105 cell/mL) were seeded in 96-well
plates, treated with a series of concentrations of the test compounds or positive control compound (etoposide; Sigma) [9].
After incubation for 24 h at 37 °C, 20 µL/well MTT (5 mg/mL) was
added to each well and cells were incubated for an additional 4 h.
Then, “triplex solution” (10% SDS, 5% isobutyl alcohol, 12 mM
HCl) was added to dissolve the formazan crystals overnight. Absorbance was measured at 570 nm by an enzyme immunoassay
instrument (SpectraMax; Molecular Devices). The inhibition rate
on cell proliferation was calculated as
Chemical structures of compounds 1–6.
(1 – A570-treated/A570-control) × 100%
Extraction and isolation
The air-dried roots and stems of T. lii (7 kg) were extracted with
95 % EtOH (16 L) under reflux for 3 × 4 h. The extracts were suspended in water (2 L), and separated using petroleum ether (60–
90 °C, 2 L × 3) and EtOAc (2 L × 4) successively. The EtOAc extract
(100 g) was chromatographyed over silica gel (75–150 µm,
2.0 kg) using a step gradient of PE/Me2CO (25 L) as eluent and
separated into three fractions (1–3). Fr. 1 (10.1 g) was subjected
to silica gel CC (54–74 µm, 300 g; PE/Me2CO, 5 : 1, 5 L) and Sephadex LH-20 CC (3.0 × 120 cm; MeOH, 500 mL), and further purified
by preparative HPLC on a Zorbax SB C-18 column (10 µm,
9.4 × 250 mm, Agilent; flow rate: 5 mL/min; MeOH/H2O, 60 : 40)
to afford trigonostemonines A (1, 5 mg, tR = 12.5 min,) and B (2,
7 mg, tR = 13.0 min). Fr. 2 (21.6 g) was also subjected to silica gel
CC (54–74 µm, 500 g; CHCl3/MeOH, 10 : 1 to 10 : 2.5, 8 L), and then
purified by using C18 reversed-phase silica gel CC (40–60 µm,
5 × 30 cm; MeOH/H2O, 1 : 9 to 4 : 6, 5 L) and silica gel CC (38–
Table 1
a
1
The IC50 value was obtained by the Logit method and was determined from the results of at least three independent tests.
Human lung adenocarcinoma A549 cell (ATCC) proliferation was
evaluated by the SRB assay [10]. Briefly, cells were seeded into
96-well plates and cultured for 24 h. The cells were then treated
with increasing concentrations of test compounds or positive
control compound (etoposide) and grown for a further 72 h. The
cells were then fixed and stained with SRB as described in the literature.
Trigonostemonine A (1): yellowish amorphous solid; UV (CHCl3):
λmax (log ε) = 244 (3.74), 280 (3.42), 307 (3.46) nm; IR (KBr):
νmax = 3458, 3347, 3215, 2913, 2046, 1637, 1589, 1550, 1451,
" Tables
1377, 1200, 1026 cm−1; 1H- and 13C‑NMR data given in l
+
1 and 2; ESI‑MS (positive): m/z = 364 [M + H] ; HR‑ESI‑MS: m/z =
364.1665 [M + H]+ (calcd. for C21H22 N3O3: 364.1661).
H‑NMR data [δH (J, Hz)] of compounds 1–5 at 400 MHz.
No.
1a
2b
3a
4b
5b
3
4
5
6
7
8
9
2′
3′
4′
5′
6′
7′
8′
9′
OCH3
NH2
NH
3.80 (t, 7.0)
3.01 (t, 7.0)
7.54 (d, 7.8)
7.11 (t, 7.8)
7.26 (t, 7.8)
7.41 (d, 7.8)
9.31 (s)
3.68 (t, 7.1)
2.88 (t, 7.1)
7.31 (d, 8.8)
6.68 (dd, 8.8, 2.1)
8.55 (d, 5.2)
8.02 (d, 5.2)
8.12 (d, 8.8)
6.99 (dd, 8.8, 2.0)
6.79 (d, 2.1)
4.14 (t, 8.8)
3.13 (t, 8.8)
7.68 (br d, 8.0)
7.13 (ddd, 8.0, 8.0, 1.2)
7.24 (ddd, 8.0, 8.0, 1.2)
7.30 (br d, 8.0)
6.04 (d, 2.5)
6.58 (d, 7.5)
7.16 (t, 7.5)
6.52 (t, 7.5)
7.66 (d, 7.5)
7.11 (d, 2.0)
12.0 (s)
8.24 (d, 4.0)
7.36 (d, 4.0)
8.48 (d, 5.2)
8.16 (d, 5.2)
8.22 (d, 8.0)
7.30 (t, 8.0)
7.50 (t, 8.0)
7.49 (d, 8.0)
8.86 (d, 4.4)
7.56 (d, 4.4)
8.79 (d, 4.4)
7.40 (d, 4.4)
6.20 (dd, 9.0, 2.5)
7.71 (d, 9.0)
3.28 (t, 7.0)
3.92 (t, 7.0)
3.76 (s)
6.40 (br s)
9.31 (br s)
3.23 (t, 6.9)
3.81 (t, 6.9)
3.75 (s)
7.68 (dd, 8.4, 1.2)
7.35 (ddd, 8.4, 8.4, 1.2)
7.38 (ddd, 8.4, 8.4, 1.2)
7.70 (dd, 8.4, 1.2)
7.64 (d, 9.2)
7.14 (dd, 9.2, 2.4)
7.71 (d, 9.2)
7.16 (dd, 9.2, 2.4)
7.41 (d, 2.4)
7.35 (d, 2.4)
3.89 (s)
3.94 (s)
3.92 (s)
12.0 (br s)
b
Measured in CDCl3. Measured in CDCl3-CD3OD (1 : 1)
Hu X-J et al. Carboline Alkaloids from …
Planta Med 2009; 75: 1157–1161
Original Paper
a
No.
1a
2b
3a
4b
5b
1
3
4
4a
4b
5
6
7
8
8a
9a
1′
2′
3′
4′
4a′
5′
6′
7′
8′
8a′
9′
OCH3
161.5 s
49.4 t
20.9 t
118.4 s
125.3 s
120.2 d
120.1 d
124.8 d
112.3 d
137.3 s
127.2 s
112.6 s
152.9 s
99.4 d
164.5 s
161.8 s
49.0 t
20.5 t
119.2 s
119.2 s
120.6 d
111.1 d
158.3 s
94.2 d
138.5 s
125.3 s
117.3 s
150.4 s
117.1 d
134.3 d
139.1 s
138.9 d
114.1 d
130.0 s
115.0 s
122.7 d
109.9 d
161.2 s
94.7 d
143.3 s
135.4 s
140.1 s
138.3 d
115.8 d
131.1 s
121.6 s
122.4 d
120.7 d
129.6 d
112.6 d
142.4 s
135.6 s
160.2 s
49.2 t
20.0 t
118.3 s
125.7 s
120.7 d
120.9 d
125.7 d
113.2 d
138.8 s
129.0 s
104.6 d
133.5 d
199.1 s
37.7 t
115.4 d
130.9 d
200.8
37.5 t
148.4 d
121.9 d
145.0 s
126.3 s
125.8 d
127.2 d
129.4 d
128.3 d
147.1 s
150.6 d
120.4 d
144.9 s
122.3 s
127.6 s
121.1 d
161.8 s
107.0 s
150.4 s
150.5 d
119.1 d
144.4 s
121.9 s
127.2 d
121.2 d
162.0 s
107.0 d
150.5 s
43.9 t
55.2 q
43.3 t
55.1 q
55.6 q
55.8 q
55.8 q
Table 2 13C‑NMR data [δC] of
compounds 1–5 at 100 MHz.
Measured in CDCl3. b Measured in CDCl3-CD3OD (1 : 1)
Trigonostemonine B (2): yellowish amorphous solid; UV (CHCl3):
λmax (log ε) = 205 (3.52), 240 (3.79), 318 (3.68) nm; IR (KBr):
νmax = 3457, 3346, 3215, 2913, 2046, 1637, 1589, 1450, 1377,
" Tables 1 and
1188, 1026 cm−1; 1H- and 13C‑NMR data given in l
+
2; ESI‑MS (positive): m/z = 364 [M + H] ; HR‑ESI‑MS: m/z =
364.1669 [M + H]+ (calcd. for C21H22 N3O3: 364.1661).
Trigonostemonine C (3): yellow amorphous solid; UV (CHCl3): λmax
(log ε) = 242 (4.27), 307 (3.93) nm; IR (KBr): νmax = 3423, 3135,
3059, 3002, 2955, 2871, 2833, 2770, 2049, 1926, 1627, 1419,
1378, 1237, 1200, 1160, 1029, 948, 822, 803, 760, 440 cm−1; 1H" Tables 1 and 2; ESI‑MS (positive):
and 13C‑NMR data given in l
+
m/z = 326 [M + H] ; HR‑ESI‑MS: m/z = 326.1289 [M + H]+ (calcd.
for C21H16 N3O: 326.1293).
Trigonostemonine D (4): yellow amorphous solid; UV (CHCl3):
λmax (log ε) = 221 (2.73), 226 (3.72), 243 (4.09), 291 (3.64), 339
(3.42) nm; IR (KBr): νmax = 3745, 3425, 3197, 3118, 3079, 3053,
2893, 2854, 2798, 2766, 2670, 2541, 1912, 1621, 1503, 1426,
" Ta1319, 1023, 830, 739 cm−1; 1H- and 13C‑NMR data given in l
bles 1 and 2; ESI‑MS (positive): m/z = 326 [M + H]+; HR‑ESI‑MS:
m/z = 326.1286 [M + H]+ (calcd. for C21H16 N3O: 326.1293).
Trigonostemonine E (5): yellow amorphous solid; UV (CHCl3):
λmax (log ε) = 242 (4.06), 322 (3.74) nm; IR (KBr): νmax = 3423,
3101, 3061, 3023, 2933, 2832, 2747, 1924, 1620, 1584, 1540,
1429, 1353, 1225, 941, 854, 746, 665, 616, 516 cm−1; 1H- and
13
" Tables 1 and 2; ESI‑MS (positive): m/
C‑NMR data given in l
z = 328 [M + H]+; HR‑ESI‑MS: m/z = 328.1447 [M + H]+ (calcd. for
C21H18 N3O: 328.1449).
Trigonostemonine F (6): yellow amorphous solid; UV (CHCl3):
λmax (log ε) = 240 (3.87), 268 (3.68), 291 (3.56) nm; IR (KBr):
νmax = 3410, 2924, 2847, 1725, 1630, 1500, 1456, 1363, 1263,
1231, 1155, 1030, 943, 827, 802, 743 cm−1; 1H‑NMR (CDCl3,
400 MHz): δ = 7.88 (s, H-13), 7.78 (s, H-14), 7.48 (br d, J = 7.6 Hz,
H-9), 7.38 (d, J = 8.4 Hz, H-4), 7.31 (br d, J = 7.6 Hz, H-12), 7.17
(ddd, J = 7.6, 7.6, 1.2 Hz, H-11), 7.12 (1H, ddd, J = 7.6, 7.6, 1.2 Hz,
H-10), 6.88 (d, J = 2.4 Hz, H-1), 6.79 (dd, J = 8.4, 2.4 Hz, H-3), 4.08
(br d, J = 14.0 Hz, Ha − 7), 3.86 (s, OCH3), 3.75 (br d, J = 14.0 Hz,
Hb − 7), 3.75 (m, H-13b), 3.28 (dd, J = 11.2, 4.0 Hz, Ha − 6), 3.23
(dd, J = 14.8, 2.8, Ha − 8), 3.05 (m, Ha − 5), 2.85 (dd, J = 11.2, 3.6 Hz,
Hb − 6), 2.85 (m, Hb − 8), 2.78 (dd, J = 11.4, 3.6 Hz, Hb − 5); 13C NMR
(CDCl3, 125 MHz) δ = 156.2 (C-2), 137.1 (C-14a), 136.0 (C-12a),
133.4 (C-13c), 131.6 (C-13a), 127.0 (C-8b), 121.6 (C-4a), 121.6 (C11), 119.5 (C-10), 118.8 (C-4), 117.8 (C-9), 110.9 (C-12), 108.9 (C3), 108.3 (C-4b), 107.6 (C-8a), 95.1 (C-1), 55.8 (OCH3), 56.7 (C13b), 52.9 (C-6), 52.3 (C-7), 27.6 (C-8), 21.7 (C-5); ESI‑MS (positive): m/z = 344 [M + H]+; HR‑ESI‑MS: m/z = 344.1762 [M + H]+
(calcd. for C22H22 N3O: 344.1757).
Supporting information
1D NMR spectra for compoundS 1–6 and 2D NMR spectra for
compounds 1, 3 and 6 are available as Supporting Information.
Results and Discussion
!
The 95 % EtOH extract of the roots and stems of T. lii was suspended in H2O and then partitioned successively with petroleum
ether, EtOAc and BuOH. The EtOAc extract (100 g) was further
separated by a series of column chromatography including silica
gel, Sephadex LH-20 and reversed-phase columns to yield compounds 1–6.
Trigonostemonine A (1) was obtained as a yellowish amorphous
solid with the molecular formula of C21H21 N3O3, as determined
by positive HR‑ESI‑MS ([M + H]+ at m/z = 364.1665). Its IR spectrum showed absorption bands at 3458 cm−1 (NH), 3347 cm−1
(NH2) and 1637 cm−1 (N‑C=O). UV absorptions at 244, 280, and
307 nm suggested the presence of a β-carboline chromophore
" Table 1), seven signals for aro[11]. In its 1H‑NMR spectrum (l
matic protons were observed, of which four signals [δ = 7.54 (1H,
d, J = 7.8 Hz), 7.11 (1H, t, J = 7.8 Hz), 7.26 (1H, t, J = 7.8 Hz) and 7.41
(1H, d, J = 7.8 Hz)] characterized an unsubstituted benzene ring of
a β-carboline, and the other three signals [δ = 7.71 (1H, d,
J = 9.0 Hz), 6.20 (1H, dd, J = 9.0, 2.5 Hz), 6.04 (1H, d, J = 2.5 Hz)] in-
Hu X-J et al. Carboline Alkaloids from …
Planta Med 2009; 75: 1157–1161
1159
1160
Original Paper
dicated a 1,2,4-substituted benzene ring. In addition, eight aliphatic protons between δH = 3.92 and 3.01, a methoxy signal
[δ = 3.76 (3H, s)], an NH2 signal [δ = 6.40 (2H, br s)] and a NH sig" Table
nal [δ = 9.31 (1H, br s)] were observed. 13C‑NMR spectra (l
2) of 1 displayed 21 carbon signals, which included 14 aromatic
carbons, 4 aliphatic carbons, an amide carbonyl (δC = 161.5), a ketone carbonyl (δC = 199.1), and a methoxy signal (δC = 55.2). Anal" Fig. 2) reysis of the 1H-1H COSY, HSQC and HMBC spectra (l
vealed the presence of two molecular fragments, i.e., fragment
(C-1 to C-9a) was established by comparing the spectral data with
those of a 1-oxo-β-carboline series [12] and another fragment (C1′ to C-9′) was deduced as 4′-O-methylkynuramine [13]. Based on
the HMBC correlation between H-3 and C-9′, 4′-O-methylkynuramine moiety was located on N-2 of a 1,2,3,4-tetrahydro-1-oxoβ-carboline unit through C-9′. Thereby, the structure of 1 was es" Fig. 1.
tablished as shown in l
Trigonostemonine B (2) was obtained as a yellowish amorphous
solid, which possessed the same molecular formula as 1 being deduced from positive HR‑ESI‑MS (C21H22 N3O3, [M + H]+ at m/
" Tables 1 and 2) closely rez = 364.1669). The NMR features of 2 (l
sembled those of 1 except for some minor differences of partial
chemical resonances, supporting the fact that compound 2
should have the same skeleton as 1, which was further confirmed
by 2D‑NMR experiments. Furthermore, the methoxy group was
located at C-7, which were determined by an NOE correlation between the methoxy group (δH = 3.75) and H-8 (δH = 6.79).
Trigonostemonines C (3) and D (4) were isolated as yellow amorphous solids with the same molecular formulae were established
to be C21H15 N3O by positive HR‑ESI‑MS ([M + H]+ at m/z =
326.1289) and positive HR‑ESI‑MS ([M + H]+ at m/z = 326.1286),
respectively. The spectroscopic data of compounds 3 and 4
showed a high similarity to those of the known compound nitrar" Tables 1 and 2)
idine [14]. A direct comparison of 1D NMR data (l
of compounds 3 and 4 with those of nitraridine revealed that
both compounds had the same 1-(quinolinyl)-β-carboline skeleton with a methoxy group at a different position. The methoxy
group of compound 3 was located at C-7, which was determined
by an ROE correlation of H-8/OCH3 (δH = 3.89). Thereby, the structure of 3 was established as 7-methoxy-1-(quinolin-4′-yl)-β-carboline. As for compound 4, the methoxy signal (δH = 3.94) was located at C-7′ due to ROE correlation between the methoxy group
and H-8′ (δH = 7.41). Thus, compound 4 was finally assigned as 1(7′-methoxyquinolin-4′-yl)-β-carboline.
Trigonostemonine E (5) was isolated as a yellow amorphous solid,
the molecular formula was established to be C21H17 N3O by positive HR‑ESI‑MS ([M + H]+ at m/z = 328.1447). The NMR features of
" Tables 1 and 2) closely resembled those of 4 except for two
5 (l
methylenes in 5 instead of one double bond in 4. Cross peaks between aliphatic protons (δH = 4.14 and 3.13) in the 1H-1H COSY
spectrum indicated that the corresponding carbons (δC = 49.2
and 20.0) were joined together, and were located at C-3 and C-4
due to HMBC correlations from H2-3 to C-4a and H2-4 to C-9a.
Thus, the structure of compound 5 was assigned as 1-(7′-methoxy-quinolinyl-4′-yl)-3,4-dihydro-β-carboline.
Trigonostemonine F (6) was isolated as a yellow amorphous solid.
It displayed an [M + H]+ ion at m/z = 364.1762 in the positive
HR‑ESI‑MS, allowing a molecular formula of C22H21 N3O to be assigned, corresponding to 14 degrees of unsaturation. Its UV absorptions at 240, 268, and 291 nm suggested the presence of a βcarboline chromophore. The 1H‑NMR and 13C‑NMR spectra of
compound 6 exhibited characteristic signals for a 1,2-disubstituted benzene ring of a β-carboline, a 1,2,4-trisubstituted benHu X-J et al. Carboline Alkaloids from …
Planta Med 2009; 75: 1157–1161
Fig. 2 1H-1H COSY (bold) and key HMBC (arrows) correlations of compounds 1, 3 and 6.
zene ring of a β-carboline and a methoxy group. The COSY spec" Fig. 2) also indicated that the molecule contained two
trum (l
identical partial structures -CH2CH2N-. All these data were in
close agreement with the reported data for 5,6,7,8,13,13b-hexahydro-14H-bisindolo[3,2-a][2,3-h]quinolizine prepared from a
synthetic source [15], with the exception of an additional methoxy group [δH = 3.86 (3H, s), δC (55.8, q)]. This substituent was
deduced to be at C-2 by the HMBC correlation between the me" Fig. 2). Accordingly, the structure of 6
thoxy protons and C-2 (l
was identified to be 2-methoxy-5,6,7,8,13,13b- hexahydro-14Hbisindolo[3,2-a][2,3-h]quinolizine. It is the first compound bearing this basic skeleton to be identified from natural sources.
The cytotoxicities of compounds 1–6 were tested against human
leukemia HL-60 and human lung adenocarcinoma A549 cell lines
using the MTT [8] and SRB [9] methods, respectively. Only compound 6 showed moderate activity against HL-60 cells
(IC50 = 16 µM; positive control compound etoposide, IC50 =
0.16 µM).
Acknowledgements
!
This research work was financially supported by the Natural Science Foundation of China (project No. 30801434). The authors
are grateful to Prof. Hua Peng, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), for the identification of the
plant material, and the analysts of State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute
of Botany, CAS, for the spectral measurements.
Affiliations
1
2
3
4
State Key Laboratory of Phytochemistry and Plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P. R.
China
Yunnan Institute of Food and Drug Control, Kunming, P. R. China
Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, P. R. China
Shanghai Institute of Materia Medica, SIBS, Chinese Academy of Sciences,
Shanghai, P. R. China
Original Paper
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