全 文 ： 药学学报 Acta Pharmaceutica Sinica 2014, 49 (12): 1689−1693 · 1689 ·




Twelve benzene derivatives from Clausena excavata
PENG Wen-wen1, 2, 3, SONG Wei-wu2, HUANG Mao-bo2, ZENG Guang-zhi2, TAN Ning-hua2*
(1. Jiangxi Key Laboratory of Natural Products and Functional Food, Jiangxi Agricultural University, Nanchang 330045, China;
2. State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of
Sciences, Kunming 650201, China; 3. College of Agriculture, Jiangxi Agricultural University, Nanchang 330045, China)
Abstract: A new phenethanol, (2R)-4-(2, 3-dihydroxy-3-methyl-butanoxy)-phenethanol (1), along with
other eleven known benzene derivatives (2−12) were isolated from the roots, stems and leaves of Clausena
excavata (Rutaceae). Compounds 3 and 4 are new natural products, and compounds 5−8, 10−12 were isolated
from C. excavata for the first time. Their structures were elucidated on the basis of MS, 1D and 2D NMR
spectroscopic analyses including HSQC, COSY and HMBC experiments. 1 was tested for its cytotoxicities
against A549, HeLa and BGC-823 cancer cell lines, and antimicrobial activities against Candida albicans and
Staphylococcus aureus. The results showed that 1 did not exhibit cytotoxic and antimicrobial activities.
Key words: Clausena excavata; phenethalol; benzene derivatives
CLC number: R284 Document code: A Article ID: 0513-4870 (2014) 12-1689-05
小叶臭黄皮中 12个苯环衍生物
彭文文 1, 2, 3, 宋卫武 2, 黄茂波 2, 曾广智 2, 谭宁华 2*
(1. 江西农业大学江西省天然产物与功能食品重点实验室, 江西 南昌 330045; 2. 中国科学院昆明植物研究所, 植物
化学与西部植物资源持续利用国家重点实验室, 云南 昆明 650201; 3. 江西农业大学农学院, 江西 南昌 330045)

摘要: 对小叶臭黄皮 (Clausena excavata) 根、茎和叶部位进行了化学成分研究, 经过一系列正相和反相色
谱柱和高效液相色谱等现代分离技术, 分离得到 12 个苯环衍生物 (1～12), 并通过 MS、NMR、IR 等波谱学方法
对这些化合物进行结构鉴定, 其中 (2R)-4-(2, 3-dihydroxy-3-methyl-butanoxy)-phenethanol (1) 为一个新化合物,
化合物 3和 4为两个新天然产物, 化合物 5～8、10～12均为首次从该植物中分离得到。测定了化合物 1对 A549、
HeLa和 BGC-823的细胞毒活性及其对 Candida albicans、Staphylococcus aureus的抑菌活性, 结果显示化合物 1
没有细胞毒和抑菌活性。
关键词: 小叶臭黄皮; 苯乙醇; 苯环衍生物

In our previous studies[1, 2] on the chemical
constituents of Clausena excavata Burm. f. (Rutaceae),
which has been used as a folk medicine for treatment
of dysentery, enteritis, and urethra infection[3, 4]. The

Received 2014-06-11; Accepted 2014-08-19.
Project supported by the National New Drug Innovation Major Project of
China (2011ZX09307-002-02) and the Natural Science
Foundation of Yunnan Province (2012GA003).
*Corresponding author Tel / Fax: 86-871-65223800,
E-mail: nhtan@mail.kib.ac.cn
isolation and structure elucidation of some carbazole
alkaloids and coumarins from its roots, leaves and
stems were reported. To continue our studies, the roots,
stems and leaves of C. excavata were investigated.
Herein, this paper described the isolation and structure
elucidation of a new phenethanol, (2R)-4-(2,
3-dihydroxy-3-methyl-butanoxy)-phenethanol (1),
along with other eleven known benzene derivatives
(2−12), and the evaluation of cytotoxic and antimi-
crobial activities of compound 1. Compounds 3 and 4
· 1690 · 药学学报 Acta Pharmaceutica Sinica 2014, 49 (12): 1689−1693

are new natural products, and compounds 5−8, 10−12
were isolated from C. excavata for the first time.

Results and discussion
(2R)-4-(2, 3-dihydroxy-3-methyl-butanoxy)-phen-
ethanol (1), [α] 25.4D +2.06 (c 0.11, MeOH), was obtained
as pale yellow oil. Its molecular formula was determined
as C13H20O4 by the HR-EI-MS at m/z 240.136 4 ([M]+,
Calcd. 240.136 2). The IR spectrum indicated the
presence of OH at 3 406 cm−1. Its 1H NMR spectrum
(Table 1) revealed that it contained one 1, 4-disubsti-
tuted benzene ring (δH 7.12, 2H, d, J = 7.5 Hz; 6.86, 2H,
d, J = 7.5 Hz) and two CH3 (δH 1.25, 3H, s; 1.21, 3H, s).
The 13C NMR spectrum (Table 1) showed a total of
thirteen carbon signals corresponding to two CH3, three
CH2, five CH and three C. The 1H,1H-COSY (Figure
1) correlations of H-2, 6/H-3, 5 and H-7/H-8 showed
that 1 had a 1, 4-disubstituted benzene ring and a
[-CH2CH2OH] moiety. The correlations of H-1/(C-2,
C-3), H-2/(C-1, C-3), (H-4, H-5)/C-2 in the HMBC
spectrum (Figure 1) and the correlation of H-1/H-2
in the 1H, 1H-COSY spectrum indicated the presence
of a [-CH2CH(OH)C(CH3)2OH] unit. In addition,
The correlations of H-1/C-4 in the HMBC spectrum
indicated that [-CH2CH(OH)C(CH3)2OH] is attached
to C-4. In the same spectrum, the correlations of
H-7/C-1, C-2, C-6 and H-8/C-1 allowed the location
of [-CH2CH2OH] at C-1. The optical rotation [α] 25.4D
2.06 (c 0.11, MeOH) of 1 is opposite to the optical
rotations of known compounds lenisin A ([α] 30.3D −17.09)
and lenisin C ([α] 29.9D −27.41)[5]. It implied that the
absolute configurations of 1 at C-2, and lenisin A
and C at C-2 are different, because there is only one
chiral carbon in them. For the absolute configuration
of lenisin A and C at C-2 is S, that of 1 at C-2 should
be R. Therefore, the structure of 1 was established
to be a (2R)-4-(2, 3-dihydroxy-3-methyl-butanoxy)-

Figure 1 Key 1H-1H COSY, and HMBC correlations of
compound 1

phenethanol and as shown in Figure 2. 1H, 13C NMR
data of 1 see Table 1.
Lenisin A (2): pale yellow oil, [α] 22.9D −22.19 (c
0.21, MeOH); EI-MS m/z 296 [M]+, C16H24O5. 1H NMR
(CDC13, 400 MHz): δH 6.59 (2H, s, H-2, 6), 6.07 (1H,
m, H-8), 5.18 (2H, m, H-9), 4.86 (1H, dd, J = 10.0, 3.2
Hz, H-1a), 4.43 (1H, dd, J = 10.0, 8.2 Hz, H-1b), 4.28
(1H, dd, J = 8.2, 3.2 Hz, H-2), 3.72 (6H, s, 2CH3), 3.37
(2H, d, J = 6.7 Hz, H-7), 1.54 (3H, s, H-5), 1.52 (3H, s,
H-4); 13C NMR (CDC13, 100 MHz): δC 152.6 (s, 2×C-
3, 5), 136.9 (s, C-1), 136.2 (d, C-8), 134.9 (s, C-4),
116.2 (t, C-9), 105.2 (d, 2×C-2, 6), 75.7 (d, C-2), 75.4
(t, C-1), 71.4 (s, C-3), 55.9 (q, 2×OCH3), 40.5 (t, C-7),
26.7 (q, C-5), 24.9 (q, C-4)[5].
3-Methylbut-2-enyl-4-hydroxybenzoate (3): col-
orless oil, EI-MS m/z 206 [M]+, C12H14O3. 1H NMR
(CDC13, 400 MHz): δH 8.05 (2H, d, J = 8.8 Hz, H-2, 6),
6.94 (2H, d, J = 8.8 Hz, H-3, 5), 5.49 (1H, m, H-2),
4.57 (2H, d, J = 6.7 Hz, H-1), 1.75 (3H, s, H-4), 1.64
(3H, s, H-5); 13C NMR (CDC13, 100 MHz): δC 171.9 (s,
CO), 163.3 (s, C-4), 138.9 (s, C-3), 132.3 (d, 2×C-2,
6), 121.5 (s, C-1), 118.9 (d, C-2), 114.3 (d, 2×C-3, 5),
64.9 (t, C-1), 25.8 (q, C-4), 18.2 (q, C-5)[6].
3-Methylbut-2-enyl 4-methoxybenzoate (4):
colorless oil, ESI-MS m/z 243 [M+Na]+, C13H16O3,
1H NMR (acetone-d6, 400 MHz): δH 7.94 (2H, m, H-2, 6),

Table 1 1H, 13C NMR data of 1 at 400 and 100 MHz, in CD3OD, separately
No. δH δC No. δH δC
1 132.4 (s) 1 4.20 (1H, d, J = 9.4 Hz) 70.5 (t)
2 7.12 (1H, d, J = 7.5 Hz) 130.9 (d) 3.87 (1H, d, J = 9.4 Hz)
3 6.86 (1H, d, J = 7.5 Hz) 115.6 (d) 2 3.71 (1H, br. s) 77.7 (d)
4 159.0 (s) 3 72.8 (s)
5 6.86 (1H, d, J = 7.5 Hz) 115.6 (d) 4 1.25 (3H, s) 26.7 (q)
6 7.12 (1H, d, J = 7.5 Hz) 130.9 (d) 5 1.21 (3H, s) 25.0 (q)
7 2.74 (2H, t, J = 7.1 Hz) 39.4 (t)
8 3.67 (2H, t, J = 7.1 Hz) 64.5 (t)

PENG Wen-wen, et al: Twelve benzene derivatives from Clausena excavata · 1691 ·


Figure 2 Structures of compounds 1−12

7.01 (2H, m, H-3, 5), 5.46 (1H, m, H-2), 4.63 (2H, d,
J = 6.6 Hz, Hz, H-1), 3.82 (3H, s, 4-OCH3), 1.75 (3H,
s, H-4), 1.73 (3H, s, H-5); 13C NMR (acetone-d6, 100
MHz): δC 166.8 (s, C=O), 163.7 (s, C-4), 138.5 (s, C-3),
132.1 (d, 2×C-2, 6), 123.2 (s, C-1), 120.4 (d, C-2),
115.2 (d, 2×C-3, 5), 65.6 (t, C-1), 51.9 (4-OCH3), 25.7
(q, C-4), 18.1 (q, C-5)[7].
Isobutyl benzoate (5): colorless oil, EI-MS m/z
178 [M]+, C11H14O2, 1H NMR (CDCl3, 500 MHz): δH
8.10 (2H, m, H-2, 6), 7.91 (2H, m, H-3, 5), 7.63 (1H, m,
H-4), 4.45 (2H, d, J = 6.6 Hz, H-1), 2.41 (1H, m, H-2),
1.36 (6H, d, J = 6.7 Hz, 2CH3); 13C NMR (CDCl3, 125
MHz): δC 167.7 (s, CO), 132.3 (s, C-1), 130.9 (d, C-4),
130.8 (d, 2×C-2, 6), 128.8 (d, 2×C-3, 5), 71.8 (t, C-1),
27.7 (d, C-2), 19.1 (q, 2×CH3)[8].
Butyl benzoate (6): colorless oil, EI-MS m/z 178
[M]+, C11H14O2, 1H NMR (CDCl3, 400 MHz): δH 7.72
(2H, m, H-2, 6), 7.53 (2H, m, H-3, 5), 7.67 (1H, m,
H-4), 4.31 (2H, t, J = 6.7 Hz, H-1), 1.72 (2H, m, H-2),
1.45 (2H, m, H-3), 0.98 (3H, t, J = 7.4 Hz, 4-CH3);
13C NMR (CDCl3, 100 MHz): δC 167.7 (s, CO), 132.2
(s, C-1), 130.9 (d, C-4), 130.2 (d, 2×C-2, 6), 128.8 (d,
2×C-3, 5), 65.5 (t, C-1), 30.5 (t, C-2), 19.1 (t, C-3),
13.7 (q, C-4)[9, 10].
(Z)-3-(4-Hydroxyphenyl)acrylic acid (7): pale
yellow oil, ESI-MS m/z 187 [M+Na]+, C9H8O3. 1H NMR
(CD3OD, 400 MHz): δH 7.59 (1H, d, J = 15.9 Hz, H-3),
7.44 (2H, J = 8.5 Hz, H-2, 6), 6.80 (2H, J = 8.5 Hz,
H-3, 5), 6.27 (1H, d, J = 15.9 Hz, H-2); 13C NMR
(CD3OD, 100 MHz): δC 171.1 (s, C-1), 161.2 (s, C-4),
146.7 (d, C-3), 131.1 (d, 2×C-2, 6), 127.2 (s, C-1),
116.8 (d, 2×C-3, 5), 115.6 (d, C-2)[11].
(E)-Methyl 3-(4-hydroxy-3-methoxyphenyl)acrylate
(8): pale yellow oil, ESI-MS m/z 231 [M+Na]+,
C11H12O4. 1H NMR (CDCl3, 400 MHz): δH 7.61 (1H,
d, J = 15.9 Hz, H-1), 7.06 (1H, dd, J = 8.2, 1.8 Hz,
H-5), 7.01 (1H, d, J = 1.8 Hz, H-3), 6.91 (1H, d, J = 8.2
Hz, H-6), 6.26 (1H, d, J = 15.9 Hz, H-2), 3.91 (3H, s,
2-OCH3), 3.79 (3H, s, 3-OCH3); 13C NMR (CDCl3, 100
MHz): δC 167.7 (s, CO), 147.9 (s, C-2), 146.7 (s, C-4),
144.9 (d, C-1), 126.8 (s, C-1), 123.0 (d, C-5), 115.1 (d,
C-6), 114.7 (d, C-2), 109.3 (d, C-3), 55.9 (q, 2-OCH3),
51.6 (q, 3-OCH3)[12].
4-Hydroxybenzaldehyde (9): colorless oil, ESI-
MS m/z 145 [M+Na]+, C7H6O2. 1H NMR (CDCl3, 400
MHz): δH 9.86 (1H, CHO), 7.81 (2H, d, J = 8.5 Hz, H-2,
6), 6.97 (2H, d, J = 8.5 Hz, H-3, 5); 13C NMR (CDCl3,
100 MHz): δC 191.6 (s, CHO), 162.1 (s, C-4), 132.9 (d,
2×C-2, 6), 130.2 (s, C-1), 116.4 (d, 2×C-3, 5)[13].
Methyl 4-hydroxybenzoate (10): colorless oil,
ESI-MS m/z 175 [M+Na]+, C8H8O3. 1H NMR (CDCl3,
400 MHz): δH 7.95 (2H, d, J = 8.2 Hz, H-2, 6), 6.87 (2H,
d, J = 8.2 Hz, H-3, 5), 3.89 (3H, s, OCH3); 13C NMR
(CDCl3, 100 MHz): δC 167.2 (s, CO), 160.1 (s, C-4),
131.9 (d, 2×C-2, 6), 122.4 (s, C-1), 115.2 (d, 2×C-3, 5),
52.1 (q, OCH3)[14].
Methyl syringate (11): colorless oil, ESI-MS m/z
235 [M+Na]+, C10H12O5. 1H NMR (CDCl3, 400 MHz):
· 1692 · 药学学报 Acta Pharmaceutica Sinica 2014, 49 (12): 1689−1693

δH 7.32 (2H, s, H-2, 6), 5.95 (1H, br s, OH-4), 3.93
(6H, s, 2×MeO-3, 5), 3.89 (3H, s, COOCH3); 13C NMR
(CDCl3, 100 MHz) δC: 121. 2 (s, C-1), 166.9 (s, CO),
146. 7 (s, 2×C-3, 5) , 139. 3 (s, C-4), 106. 8 (d, 2×C-2,
6), 56.5 (q, 2×MeO-3, 5), 52.1 (q, COOCH3)[15].
1-Methoxy-4-phenethylbenzene (12): pale yellow
oil, EI-MS m/z 212 [M]+, C15H16O. 1H NMR (CDC13,
400 MHz): δH 7.69 (2H, d, J = 7.3 Hz, H-3, 5), 7.48
(1H, t, J = 7.3 Hz, H-4), 7.40 (2H, d, J = 7.3 Hz, H-2,
6), 7.08 (2H, d, J = 8.4 Hz, H-3, 5), 6.86 (2H, d, J = 8.4
Hz, H-2, 6), 3.80 (3H, s, OCH3), 3.68 (2H, t, J = 6.5 Hz,
H-2), 2.87 (2H, t, J = 6.5 Hz, H-1); 13C NMR (CDC13,
100 MHz): δC 158.3 (s, C-1), 143.9 (s, C-1), 134.6 (s,
C-4), 131.4 (d, 2×C-3, 5), 129.7 (d, 2×C-3, 5), 128.5
(d, 2×C-2, 6), 126.8 (d, C-4), 114.1 (d, 2×C-2, 6), 55.2
(q, OCH3), 41.3 (t, C-2), 34.7 (t, C-1)[16].
Compound 1 was tested for its cytotoxic activities
against A549, Hela and BGC-823 cancer cell lines, and
antimicrobial activities against Candida albicans and
Staphylococcus aureus[17]. The results showed that 1
did not exhibit cytotoxic and antimicrobial activities.

Experiment section
General experiment procedures Optical rotations
were measured with a Horiba SEPA-300 polarimeter.
UV spectra were obtained using a Shimadzu UV-2401-A
spectrophotometer. IR spectra were recorded with a
Tensor 27 FT-IR spectrometer with KBr pellets. The
1H and 13C NMR spectra were acquired with a Bruker
AM-400 (1H: 400 MHz, 13C: 100 MHz) or DRX-500
(1H: 500 MHz, 13C: 125 MHz) spectrometer in acetone-d6
or CD3OD with TMS as the internal standard at room
temperature. MS were recorded on an API QSTAR
Pular-1 mass spectrometer. Column chromatography
(CC) was performed on silica gel (100−200 mesh,
200−300 mesh, and 10−40 μm, Qingdao Marine Chem-
ical, Inc., China) and Lichroprep RP-18 gel (40−63 mm,
Merck, Darmstadt, Germany). TLC was car-
ried out on precoated silica gel GF254 glass plates
(Qingdao Marine Chemical, Inc., China) and chromo-
genic agent (5% H2SO4-dehydrated alcohol).
Semi-preparative HPLC was performed on an Agilent
1100 apparatus equipped with a UV detector and an
YMC-Pack ODS-A (YMC, 1×15 cm) column at a flow
rate of 2 mL·min−1.
Plant material The roots, stems and leaves of
C. excavata were collected at Xishuangbanna, Yunnan
Province, P. R. China, in August 2010, which were
identified by Prof. Yu-min Shui of Kunming Institute
of Botany. A voucher specimen (No.2010813)
has been deposited in the State Key Laboratory of
Phytochemistry and plant Resources in West China,
Kunming Institute of Botany, Chinese Academy of
Sciences.
Extraction and isolation The air-dried and
powdered stems and leaves of C. excavata (32 kg)
were extracted by refluxing 95% methanol three times
(35 L×3). The methanol extract was submitted to the
liquid-liquid fractionation with the solvents petroleum
ether (PE), AcOEt, and BuOH. The EtOAc soluble
fraction (1.1 kg) was applied to silica gel (100−200
mesh) column chromatography, eluting with PE/acetone
(10∶1−0∶1) to yield 5 fractions (Fr. 1−Fr. 5). Fr. 2 (33 g)
by silica gel (200−300 mesh) column chromatography
eluted with PE/acetone (5∶1) gave sub-fractions (Fr.
2.1 to Fr. 2.4). Further separation of Fr. 2.2 (0.9 g) was
subjected to a reversed-phase column (RP-18) eluting
with MeOH−H2O (30%−90%) to afford 5 subfractions
(Fr. 2.2.1−Fr. 2.2.5). Fr. 2.2.2 (81 mg) was subjected to
semipreparative reversed-phase HPLC (75% MeOH-
H2O) to give 12 (17 mg), 10 (11 mg) and 8 (9 mg).
Fr. 3 (52 g) was subjected to silica gel (200−300 mesh)
column chromatography eluted with PE/acetone (4∶1)
gave sub-fractions (Fr. 3.1 to Fr. 3.5). Fr. 3.1 (0.8 g)
was subjected to a reversed-phase column (RP-18)
eluting with MeOH-H2O (30%−90%) to afford 4
subfractions (Fr. 3.1.1−Fr. 3.1.4). Fr. 3.1.3 (90 mg) was
subjected to semipreparative reversed-phase HPLC
(65% MeOH-H2O) to give 9 (10 mg), 11 (8 mg) and 2
(10 mg). Fr. 5 (21 g) was subjected to silica gel
(200−300 mesh) column chromatography eluted with
PE/acetone (2∶1) gave sub-fractions (Fr. 5.1 to Fr. 5.3).
Fr. 5.3 (120 mg) was subjected to a reversed-phase
column (RP-18) eluting with MeOH-H2O (30%−90%)
to afford 3 subfractions (Fr. 5.3.1−Fr. 5.3.3). Fr. 5.3.3
(32 mg) was subjected to semipreparative reversed-
phase HPLC (50% MeOH-H2O) to give 3 (8 mg), 7
(6 mg) and 1 (16 mg).
The air-dried and powdered roots of C. excavata
(13 kg) were extracted with 95% EtOH under reflux
for three times. The filtrates were combined and
evaporated to a small volume, followed by successive
partition with petroleum ether (PE), EtOAc and BuOH.
The EtOAc soluble fraction (600 g) was applied to
silica gel (200−300 mesh) column eluting gradiently
with CHCl3-MeOH (10∶0, 9∶1, 8∶2, 7∶3, 1∶1,
0∶1), to give six fractions, A−F. The separation of
fraction C (18 g) over silica gel column was eluted with
PENG Wen-wen, et al: Twelve benzene derivatives from Clausena excavata · 1693 ·

PE−acetone (10∶1−1∶2) to yield fractions C1−C6.
Fraction C2 (1.1 g) was subjected to a silica gel column
eluted with PE−acetone (5∶ 1−1∶ 1) to give four
subfractions (C2-1−C2-4). C2-4 (65 mg) was subjected
to semipreparative reversed-phase HPLC (55% MeOH-
H2O) to give 6 (9 mg), 5 (14 mg) and 4 (20 mg).
(2R)-4-(2, 3-dihydroxy-3-methyl-butanoxy)-phen-
ethanol (1): pale yellow oil, [α] 25.4D +2.06 (c 0.11, MeOH);
UV (MeOH) λmax (log ε): 201 (4.07), 224 (4.12), 276
(3.37) nm; IR (KBr): νmax 3 406, 2 971, 2 936, 2 879,
1 612, 1 513, 1 462, 1 384, 1 299, 1 245, 1 177, 1 096,
1 042, 827 cm−1; 1H NMR (400 Hz, CD3OD) and
13C NMR (100 Hz, CD3OD): See Table 1; ESI-MS: m/z
263 [M+Na]+; HR-EI-MS: m/z 240.136 4 ([M]+, C13H20O4,
Calcd. 240.136 2).
Acknowledgments: The authors are grateful to the members
of the analytical group from the State Key Laboratory of
Phytochemistry and Plant Resources in West China, Kunming
Institute of Botany, Chinese Academy of Sciences, for measuring
the [α], IR, UV, NMR and MS spectra.
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