全 文 ： 2013年 1月 第 11卷 第 1期 Chin J Nat Med Jan. 2013 Vol. 11 No. 1 77

Chinese Journal of Natural Medicines 2013, 11(1): 00770080
doi: 10.3724/SP.J.1009.2013.00077
Chinese
Journal of
Natural
Medicines







Two new chromones and a new flavone glycoside
from Imperata cylindrica
LIU Xuan1, ZHANG Bin-Feng2, 3*, YANG Li2, 3, CHOU Gui-Xin2, 3, WANG Zheng-Tao1, 2, 3**
1 Department of Pharmacognosy, China Pharmaceutical University, Nanjing 210009, China;
2The MOE Key Laboratory of Standardization of Chinese Medicines, Shanghai University of Traditional Chinese Medicine, Shanghai
201210, China;
3Shanghai R＆D Center for Standardization of Chinese Medicines, 199 Guo Shoujing Road, Zhangjiang Hi-Tech Park, Shanghai 201203,
China
Available online 20 Jan. 2013
[ABSTRACT] AIM: To study the chemical constituents of the rhizomes of Imperata cylindrica. METHODS: The compounds were
isolated by silica gel and Sephadex LH-20 column chromatography. Their structures were elucidated mainly by spectroscopic analyses
including IR, HR-ESI-MS, 1D- and 2D-NMR. RESULTS: Two new chromones, 8-hydroxy-2-(2-phenylethyl)chromone (1) and
2-(2-phenylethyl) chromone-8-O-β-D-glucopyranoside (2), and a new flavone glycoside, 4’-methoxyflavone-6-O-β-D- glucopyranoside
(5), along with five known compounds, flidersiachromone (3), 5-hydroxy-2-(2-phenylethyl) chromone (4), flavone (6),
4’-hydroxy-5-methoxyflavone (7) and 5-hydroxyflavone (8) were isolated from Imperata cylindrica. CONCLUSION: Compounds 1,
2 and 5 were new compounds.
[KEY WORDS] Imperata cylindrica; Chromones; Flavonoids; Isolation and spectroscopic identification
[CLC Number] R284.1 [Document code] A [Article ID] 1672-3651(2013)01-0077-04

1 Introduction
Imperata plants (Poaceae) are distributed widely in Chi-
na[1], and the rhizomes of Imperata cylindrica Beauv. var.
major (Nees) C. E. Hubb. are recorded in the Chinese Phar-
macopeia for hematemesis, epistaxis and hematuria caused
by blood heat as well[2]. In previous phytochemical investiga-
tions, chromones[3], phenylpropanoids[4], pentacyclic triter-
penes and steroids[5] were reported. In the present study on I.
cylindrica, two new chromones, 8-hydroxy-2-(2-phenylethyl)
chromone (1), 2-(2-phenylethyl)chromone-8-O-β-D-gluco pyra-
noside (2) and one new flavone glycoside, 4’-methoxy-fla-
vone-6-O-β-D-glucopyranoside (5) were isolated, along with

[Received on] 07-Apr.-2012
[Research funding] The project was supported by the Shanghai
Science and Technology Development Foundation (No.
10DZ1970200) and the Program for Changjiang Scholars and Inno-
vative Research Team in University (No. IRT1071).
[*Corresponding author] WANG Zheng-Tao: Prof., Tel: 86-21-
51322507, Fax: 86-21-51322519, E-mail: wangzht@hotmail.com;
ZHANG Bin-Feng: Dr., Tel: 86-21-50805522-3037, Fax: 86-21-
50271708, E-mail: zbf2004@hotmail.com
These authors have no any conflict of interest to declare.
two known chromones, flidersiachromone (3)[6] and
5-hydroxy-2-(2-phenylethyl)chromone (4)[3], and three known
flavonoids, flavone (6)[7], 4’-hydroxy-5-methoxyflavone (7)[8]
and 5-hydroxyflavone (8)[9] (Fig. 1). Chromones were re-
ported rarely, besides two papers[3, 6], in which only five
compounds were reported from the genus Imperata. The two
new chromones are an interesting additionto the family of
chromones.
2 Experimental
2.1 General
Column chromatography (CC): silica gel (SiO2; 75−150 μm,
48−75 μm, 38−48 μm; Qingdao Marine Chemical Co., Ltd.,
China) or silica gel H (10−40 μm; Qingdao Marine Chemical
Co., Ltd. China) and SephadexTM LH-20 (GE Healthcare).
TLC: normal-phase silica gel GF254 on plates; detected under
UV light (254 or 365 nm) and sprayed with 10% H2SO4 in
EtOH (V/V), followed by heating. Optical rotation:
Krüss-P800-T polarimeter. IR spectra: Nicolet 380 spec-
trometer; as KBr pellets; in cm–1. The 1D- and 2D-NMR
spectra were acquired on Bruker DRX-400 spectrometers.
HR-ESI-MS: Waters UPLC Premior QTOF spectrometer; in
m/z. GC analysis was performed on a Thermo DSQ GC-MS
LIU Xuan, et al. /Chinese Journal of Natural Medicines 2013, 11(1): 7780
78 Chin J Nat Med Jan. 2013 Vol. 11 No. 1 2013年 1月 第 11卷 第 1期



Fig. 1 Structures of compounds 1-8

instrument equipped with a Thermo TR-5MS (60 m  0.25
mm i.d., 2.5 m) column.
2.2 Plant material
The rhizomes of Imperata cylindrica Beauv. var. major
(Nees) C. E. Hubb. were collected from Hubei Province,
China in April 2010, and identified by Dr. WU Li-Hong
(Shanghai R&D Center for Standardization of Chinese Medi-
cines, Shanghai, China). A voucher specimen (No.
bmg-100419) was deposited in the Shanghai R&D Center for
Standardization of Chinese Medicines.
2.3 Extraction and isolation
The rhizomes of I. cylindrica (13.5 kg), as a powder,
were extracted with 70% aq. EtOH (twice, 81 and 54 L each,
1 h for each time) under reflux, and recovered from solvent
under reduced pressure. The extract was partitioned with
petroleum ether, EtOAc, and n-BuOH, successively. The
EtOAc portion (48.0 g) was subjected to silica gel (75−150
μm chromatography, eluted with CH2Cl2-CH3OH (100 :
0–50 : 1–10 : 1–0 : 100) to afford eleven fractions. Fraction 8
(10.3 g) was subjected to silica gel (48−75 μm) chromatog-
raphy (CH2Cl2) to yield 8 subfractions. Subfr. 3 (2.2 g) was
subjected to flash chromatography (FC) (silica gel H,
PE-EtOAc (30 : 1) and CH2Cl2−CH3OH (150 : 1 and 50 : 1))
and purified by Sephadex LH-20 (CH2Cl2-CH3OH (1 : 1)) to
obtain compounds 3 (2.1 mg) and 6 (1.0 mg). Subfr. 6 (0.2 g)
was subjected to FC (silica gel H, CH2Cl2-CH3OH (150 : 1))
and Sephadex LH-20 (CH2Cl2−CH3OH (1 : 1)) to obtain 1
(1.1 mg). Fraction 9 (15.7 g) was subjected to FC (silica gel
H, CH2Cl2−CH3OH (40 : 1 and 10 : 1)) to get 6 subfractions.
Subfr. 4 (2.8 g) was subjected to FC (silica gel H, PE-acetone
(10:3)), Sephadex LH-20 (CH2Cl2−CH3OH (1:1)) to yield 7
(3.5 mg). Fraction 10 (6.9 g) was further subjected to Sepha-
dex LH-20 (CH2Cl2−CH3OH (1 : 1)), FC (silica gel H,
CH2Cl2−CH3OH- H2O (20 : 1 : 0.1)) and purified by Sepha-
dex LH-20 (CH3OH) to obtain 2 (1.7 mg). Fraction 11 (6.7 g)
was subjected to Sephadex LH-20 (CH2Cl2−CH3OH (1:1)),
FC (silica gel H, CH2Cl2−CH3OH-H2O (10:1.5:0.1)) and
purified by Sephadex LH-20 (CH3OH) to give 5 (2.5 mg).
The petroleum ether fraction (1.0 g) was subjected to FC
(silica gel H, PE-EtOAc (100 : 0–50 : 1–3 : 1)), silica gel
(38−48 μm) chromatography (PE−EtOAc (50 : 1)) and puri-
fied by Sephadex LH-20 (CH2Cl2−CH3OH (1 : 1)) to obtain 4
(2.8 mg) and 8 (2.0 mg).
2.4 Acid hydrolysis of compounds 2 and 5
Compound 2 (1.0 mg) was hydrolyzed with 3 molL1
aqueous CF3COOH (2 mL) at 120 °C for 2 h, after which the
solvent was evaporated. The following solutions were added:
(I) 1 : 8 (S)-1-amino-2-propanol-MeOH (20 L); (II) 1:4
AcOH-MeOH (17 L); and (III) 3% NaBH3CN in MeOH (17
L). The mixture was allowed to react for 1.5 h at 65 °C, and
the mixture was then cooled to room temperature and 3 M
aqueous CF3COOH was added dropwise until the pH was 1−2.
The mixture was evaporated and co-evaporated with acetoni-
trile (5  0.8 mL). Trace solvent was further removed over-
night in a desiccator. The residue was treated with 1 : 1 pyri-
dine–Ac2O (0.4 mL) for 45 min at 100 °C. After cooling, the
derivatives were extracted with CHCl3 (1 mL) and washed
with 0.5 mol·L-1 Na2CO3 (3  1 mL) and H2O (3  1 mL).
The organic phase was dried (anhydrous Na2SO4) and sub-
jected to GC analysis using a Thermo TR-5MS column (60
m  0.25 mm, 2.5 m) with He as carrier gas at a flow rate of
1.0 mL·min-1 to identify the monosaccharides. The oven
temperature was started at 140 °C and was increased to 198
°C at a rate of 3 °C/min, keeping it at 198 °C for 4 min, in-
creased to 214 °C at a rate of 4 °C/min, and then increased to
217 °C at a rate of 1 °C/min, keeping it at 217 °C for 4 min,
increased to 250 °C at a rate of 3 °C/min, keeping it at 250 °C
for 5 min, and finally, increased to 280 °C at a rate of 2
°C/min, keeping it at 280 °C for 5 min. The same procedure
was applied to compound 5 (1.0 mg) and the authentic sam-
ples, D- and L-glucose. D-Glucose (tR-2, 42.33 min; tR-5,
42.33 min) was identified from compounds 2 and 5[10-12], by
comparison with the retention times of authentic samples
(tR-D-glucose, 42.33 min; tR-L-glucose, 42.43 min).
3 Structural Identification
Compound 1 was obtained as a yellow powder, UV λmax
(MeOH) (nm): 233, 310. The IR spectrum revealed the pres-
ence of hydroxyl (3 431 cm1), aromatic ring (1 559 cm1)
and carbonyl (1 633 cm1) groups. Its molecular formula was
deduced to be C17H14O3 on the basis of HR-ESI-MS (m/z
289.084 7 [M + Na]+, Calcd. as 289.084 1).
The 1H and 13C NMR data (Table 1), combined with
HSQC, indicated the presence of a 1, 2, 3-trisubstituted aro-
matic ring [δ: 7.70 (1H, dd, J = 7.6, 1.6 Hz, H-5), 7.25 (1H, m,
H-6), and 7.23 (1H, dd, J = 7.6, 1.6 Hz, H-7); δ: 116.7 (C-5),
125.1 (C-6) and 118.8 (C-7)] and an α, β-unsaturated car-
bonyl group [δ: 6.20 (1H, s, H-3); δ: 167.4 (C-2), 110.5 (C-3)
and 178.0 (C-4)] forming a chromone core, a monosubsti-
tuted aromatic ring [δ: 7.25-7.36 (5H, m, H-2,6); δ: 139.8
LIU Xuan, et al. /Chinese Journal of Natural Medicines 2013, 11(1): 7780
2013年 1月 第 11卷 第 1期 Chin J Nat Med Jan. 2013 Vol. 11 No. 1 79

(C-1), 128.3 (C-2), 128.8 (C-3), 126.8 (C-4), 128.8 (C-5)
and 128.3 (C-6)], and a -CH2 CH2- chain [δ: 3.10 (2H, t, J =
6.5 Hz, H-7) and 3.03 (2H, t, J = 6.5 Hz, H-8); δ: 33.4 (C-7)
and 35.6 (C-8)].
HMBC correlations (Fig. 2) from H-3 to C-8, CH2-8 to
C-2 and C-3, H-2 and H-6 to C-7, CH2-7 to C-1, C-2 and
C-6’ revealed that the chromone core was connected with the
monosubstituted aromatic ring by the -CH2 CH2- chain. The
OH group was located at C-8 based on the presence of a cor-
relation between H-5 and C-4 in the HMBC spectrum and the
correlations of H-5/H-6 and H-6/H-7 in the 1H-1H COSY
spectrum (Fig. 2).
Therefore, the structure of 1 was determined to be
8-hydroxy-2-(2-phenylethyl)chromone.
Compound 2 was obtained as a yellow powder, [α]D20 +
8.6° (c 0.030, MeOH), and UV λmax (MeOH) (nm): 233, 306.
The IR spectrum revealed the presence of hydroxyl (3 450
cm1), aromatic ring (1 578 and 1 494 cm1) and carbonyl (1
637 cm1) groups. Its molecular formula was deduced to be
C23H24O8 on the basis of HR-ESI-MS (m/z 451.137 1
[M + Na]+, Calcd. as 451.136 9), which indicated an extra
glucosyl moiety than 1.
The 1H and 13C NMR spectral data (Table 1) of 2 were
similar to those of 1, except for an extra β-D-glucopyranosyl
group, connecting at C-8 by an O-atom, and supported by the
downfield shift of C-8 from δC 144.6 to δC 147.8, and con-
firmed by the HMBC correlation between the anomeric pro-
ton at δ: 5.09 (1H, d, J = 7.2 Hz, H-1) and δ: 147.8 (C-8).
The absolute configuration of glucose was determined to be
D by GC–MS analysis of the chiral derivatives of the sugar
in an acidic hydrolysate (experimental part). The configura-
tion of the anomeric proton of D-glucopyranose was deduced

Table 1 1H and 13C NMR spectral data of compounds 1, 2 and 5 (recorded at 400 MHz for 1H NMR and 100 MHz for 13C NMR,
J in Hz)
1a) 2b) 5b)
Position δH δC δH δC δH δC
2 167.4 171.5 164.2
3 6.20 (1H, s) 110.5 6.15 (1H, s) 110.7 6.81 (1H, s) 108.3
4 178.0 180.4 180.3
5 7.70 (1H, dd, J = 7.6, 1.6) 116.7 7.72 (1H, dd, J = 8.0, 1.0) 119.2 7.59 (1H, m) 133.0
6 7.25 (1H, m) 125.1 7.36 (1H, t, J= 8.0) 126.2 149.1
7 7.23 (1H, dd, J = 7.6, 1.6) 118.8 7.62 (1H, dd, J = 8.0, 1.0) 122.1 7.77 (1H, d, J = 9.3) 125.7
8 144.6 147.8 7.50 (1H, d, J = 9.3) 115.2
9 145.0 149.0 154.2
10 124.3 125.0 119.0
1 139.8 141.4 132.5
2 7.25 (1H, m) 128.3 7.25 (1H, m) 129.5 8.03 (1H, dd, J = 8.0, 2.1) 127.4
3 7.36 (1H, m) 128.8 7.25 (1H, m) 129.6 7.59 (1H, m) 130.3
4 7.30 (1H, m) 126.8 7.16 (1H, m) 127.4 149.4
5 7.36 (1H, m) 128.8 7.25 (1H, m) 129.6 7.59 (1H, m) 130.3
6 7.25 (1H, m) 128.3 7.25 (1H, m) 129.5 8.03 (1H, dd, J = 8.0, 2.1) 127.4
7 3.10 (2H, t, J = 6.5) 33.4 3.13 (2H, t, J = 7.2) 33.8
8 3.03 (2H, t, J = 6.5) 35.6 3.05 (2H, t, J = 7.2) 37.0
1 5.09 (1H, d, J = 7.2) 103.0 5.00 (1H, d, J = 7.4) 103.4
2 3.62 (1H, t, J = 8.4) 75.0 3.57 (1H, t, J = 8.8) 75.0
3 3.51 (1H, t, J = 8.4) 78.2 3.51 (1H, t, J = 8.2) 78.1
4 3.43 (1H, t, J = 8.4) 71.3 3.47 (1H, br d, J = 9.8) 71.3
5 3.48 (1H, m) 78.2 3.44 (1H, br d, J = 7.6) 78.4
3.89 (1H, dd, J = 12.0, 1.7) 3.91 (1H, dd, J = 12.0, 1.4)
6 3.71 (1H, dd, J = 12.0, 4.9) 62.5 3.73 (1H, dd, J = 12.0, 5.0) 62.5
4-MeO 3.98 (3H, s) 62.7
a) Recorded in CDCl3. b) Recorded in CD3OD


Fig. 2 1H, 1H-COSY (H H) and Key HMBC (HC) correlations of compounds 1, 2 and 5
LIU Xuan, et al. /Chinese Journal of Natural Medicines 2013, 11(1): 7780
80 Chin J Nat Med Jan. 2013 Vol. 11 No. 1 2013年 1月 第 11卷 第 1期

to be β, based on the 1H NMR coupling constant (J1;2 = 7.2
Hz). Therefore the structure of 2 was determined to be
2-(2-phenylethyl) chromone-8-O-β-D-glucopyranoside.
Compound 5 was obtained as a yellow gel, [α]D20 +88.1°
(c 0.227, MeOH), and UV λmax (MeOH) (nm): 265, 302. The
IR spectrum revealed the presence of hydroxyl (3 401 cm1),
aromatic ring (1 478 cm1) and carbonyl (1 633 cm1) groups.
Its molecular formula was deduced to be C22H22O9 on the
basis of HR-ESI-MS (m/z 453.117 6 [M + Na]+, Calcd. as
453.116 2).
The NMR spectral data (Table 1), combined with HSQC,
indicated the presence of one A2B2 system [δ: 8.03 (2H, dd, J
= 8.0, 2.1 Hz, H-2 and 6), δ: 127.4 (C-2 and 6); δ: 7.59 (2H,
m, H-3 and 5)], δ: 130.3 (C-3 and 5)], a trisubstituted aro-
matic ring [δ: 7.59 (1H, m, H-5), δ: 133.0 (C-5); δ: 7.77 (1H,
d, J = 9.3 Hz, H-7), δ: 125.7 (C-7) and δ: 7.50 (1H, d, J = 9.3
Hz, H-8), δ: 115.2 (C-8)], and an α,β-unsaturated carbonyl
group [δ: 6.81 (1H, s, H-3); δ: 164.2 (C-2), δ: 108.3 (C-3) and
δ: 180.3 (C=O)]. The above analysis revealed the presence of
a skeleton of flavone (C6-C3-C6). The remaining data showed
a β-D-glucopyranosyl group [δ: 5.00 (1H, d, J = 7.4 Hz, H-1)
and δ: 3.44-3.91 (6H, H-2-6); δ: 103.4 (C-1), 75.0 (C-2),
78.1 (C-3), 71.3 (C-4), 78.4 (C-5) and 62.5 (C-6)], which
was confirmed by GC–MS analysis of the chiral derivatives
of the sugar in an acidic hydrolysate (experimental part), and
one OMe group [δ: 3.98 (3H, s, OCH3), δ: 62.7 (OCH3)].
The 1H and 13C NMR spectral data (Table 1) of 5 were
similar to those of 6[7], except for an extra β-D-glucopyranosyl
group connected at C-6 by an O-atom, and supported by the
downfield shift of C-6from δC 125.2 to δC 149.1. This was
confirmed by the HMBC correlation (Fig. 2) from the ano-
meric proton (δH 5.00) to C-6 (δC 149.1), and an extra OMe
group connecting at C-4’, as deduced from the HMBC corre-
lation between OMe (δH 3.98) and C-4’ (δC 149.4). Therefore,
5 was determined to be 4’-methoxyflavone-6-O-β-
D-glucopyranoside.
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白茅根中两个新的色原酮和一个新的黄酮苷
刘 轩 1, 张彬锋 2, 3 *, 杨 莉 2, 3, 侴桂新 2,3, 王峥涛 1, 2, 3**
1中国药科大学生药教研室, 南京 210009;
2上海中医药大学 中药标准化教育部重点实验室, 上海 201210;
3上海中药标准化研究中心, 上海 201203
【摘 要】 目的: 研究白茅根 Imperata cylindrica Beauv. var. major (Nees) C. E. Hubb.化学成分。方法: 应用硅胶和 Sephadex
LH-20 柱色谱法对白茅根提取物进行分离和纯化，应用红外光谱、高分辨质谱和核磁共振波谱法对分离得到的成分进行结构鉴
定。结果: 分离得到 2个新的色原酮类成分, 分别为 8-hydroxy-2-(2-phenylethyl)chromone (1), 2-(2-phenylethyl)chromone-8-O-β-D-
glucopyranoside (2), 和 1个新的黄酮苷类成分, 4’-methoxyflavone -6-O-β-D-glucopyranoside (5)。同时还包括 5个已知的黄酮及色
原酮类成分, 分别为 flidersiachromone (3), 5-hydroxy-2-(2-phenylethyl) chromone (4), flavone (6), 4’-hydroxy-5-methoxyflavone (7)
和 5-hydroxyflavone (8)。结论: 化合物 1、2和 5为新化合物。
【关键词】 白茅根; 色原酮; 黄酮; 分离与鉴定

【基金项目】 上海科学技术发展基金(No.10DZ1970200), 长江学者创新团队项目（No. IRT1071）资助