A new benzophenone glycoside from the leaves of Psidium guajava L.

Article abstract of DOI:10.1016/j.cclet.2010.09.029

A new benzophenone glycoside, 2,6-dihydroxy-4-O-β-d- glucopyranosylbenzophenone (1), was isolated from the leaves of guajava L. Its structure was elucidated by spectral and chemical methods. 1 showed significant activities to secretion of NO in mouse peritoneal macrophages in 10 μmol/L.

Full text of DOI:10.1016/j.cclet.2010.09.029

Available online at www.sciencedirect.com
Chinese Chemical Letters 22 (2011) 178–180
www.elsevier.com/locate/cclet
A new benzophenone glycoside from the leaves of
Psidium guajava L.
*
Hui Zheng Fu, Jing Zhi Yang, Chuang Jun Li, Dong Ming Zhang
Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College (Key Laboratory of
Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education), Beijing 100050, China
Received 28 May 2010
Abstract
A new benzophenone glycoside, 2,6-dihydroxy-4-O-b-D-glucopyranosylbenzophenone (1), was isolated from the leaves of
guajava L. Its structure was elucidated by spectral and chemical methods. 1 showed significant activities to secretion of NO in
mouse peritoneal macrophages in 10 mmol/L.
#
2010 Published by Elsevier B.V. on behalf of Chinese Chemical Society.
Keywords: Psidium guajava L.; Benzophenone glycoside; 2,6-Dihydroxy-4-O-b-D-glucopyranosylbenzophenone; NO
Psidium guajava L., a shrub or small tree, is grown throughout the tropics and subtropics and is known for its edible
fruits. Its leaves are used in folk medicine as an anti-inflammatory and hemostatic agent, and for treating pulmonary
diseases, coughs, vomiting and diarrhea [1]. Previous investigations on the leaves of P. guajava have led to the
isolation of several triterpenoids [2], flavonoids [3], tannins [4], and carotenoids [5], and meroterpenoids [6]. In our
preliminary screening, the EtOAc part of the 70% EtOH extract of the leaves of P. guajava showed the significant
anticancer activities. One of our efforts to discover biologically significant anticancer properties from plant resources
has led to the isolation of a new compound, 2,6-dihydroxy-4-O-b-D-glucopyranosylbenzophenone (1), from the leaves
of P. guajava. We report herein the isolation, structural elucidation and biological activity of 1.
The leaves of P. guajava were collected from Guangxi province of China, and authenticated by Professor Guang-ri
Nong of Guangxi Forestry Bureau of the People’s Republic of China. A voucher specimen (No. FSLY20070910) has
been deposited in Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical
College. The powdered dried leaves of P. guajava (8.0 kg) were extracted with 70% EtOH three times by heating, and
the gum (2658 g) obtained by concentrating the 70% EtOH extract in vacuo was partitioned with EtOAc and n-BuOH
successively. The EtOAc-soluble portion (386 g) was fractionated via silica gel column chromatography eluting with
CHCl –MeOH (100:0 to 9:1, v/v) to give eight major fractions A –A . Fraction A (2.2 g) was subjected to a Sephadex
3
1
8
5
LH-20 column eluting with methanol to give ten major fractions B –B . Fraction B (156 mg) was subjected to a
1
10
7
preparative reverse-phase HPLC using MeOH–H O–TFA (60:40:0.05) as a solvent system at a flow rate of 7 mL/min
2
to give compound 1 (20 mg) (Fig. 1).
*
Corresponding author.
E-mail address: zhangdm@imm.ac.cn (D.M. Zhang).
1001-8417/$ – see front matter # 2010 Published by Elsevier B.V. on behalf of Chinese Chemical Society.
doi:10.1016/j.cclet.2010.09.029

[()TD$FIG]
H.Z. Fu et al. / Chinese Chemical Letters 22 (2011) 178–180
179
OH
6
'
4
'
5
'
O
HO
3
12
1
'
OH
HO
O
1
3
1
1
1
0
OH
2'
2
1
3'
4
H
5
8
7
9
6
OH
O
Fig. 1. Structure of compound 1.
2
D
0
Compound 1 was obtained as a yellow powder, mp 170–171 8C. ½aꢀ ꢁ80.4 (c 0.03, MeOH). UV (MeOH) l
max
ꢁ
1
(
log e): 298 (1.59), 250 (1.51) nm. The IR spectrum indicated the presence of hydroxy (3344 cm ). The negative
ꢁ
+
ESIMS of 1 gave a quasi-molecular ion peak at m/z 391.5 [MꢁH] , while the positive ESIMS exhibited [M+Na] at m/
+
z 415.1. The HRESIMS displayed a quasi-molecular ion at m/z 415.10012 [M+Na] (calcd. 415.10050 for
1
C H NaO ), indicating the molecular formula of 1 was C H O . The H NMR spectrum of 1 showed signals of two
magnetic equivalent phenolic hydroxyls (d 9.82, s, 2H) and two magnetic equivalent aromatic protons (d 6.08, s, 2H).
1
9
20
9
19 20 9
1
In the aromatic region of the H NMR spectrum, a set of aromatic signals at d 7.68 (d, 2H, J = 7.5 Hz, H-9 and H-13), d
7
aliphatic region, a characteristic doublet at 4.76 (d, 1H, J = 8.0 Hz, H-1 ) assignable to an anomeric proton indicated
.57 (t, 1H, J = 7.5 Hz, H-11), and d 7.46 (d, 2H, J = 7.5 Hz, H-10 and H-12) were assigned to a benzene ring. In the
0
1
3
the presence of sugar unit in the molecule, The C NMR spectrum displayed a signal at d 195.4, which was assigned to
the carbonyl group of a benzophenone [7–9], and six aliphatic carbon signals (d 100.3, 77.0, 76.5, 73.1, 69.4, and 60.4)
due to one sugar moiety. In addition 12 aromatic carbons were also detected, some of them being superimposed (d
1
60.1, 1C; 157.3, 2C; 138.5, 1C; 132.5, 1C; 128.7, 2C; 128.3, 2C; 108.8, 1C; 95.0, 2C), suggesting that there were two
aromatic rings. The acid hydrolysis of 1 with 5 mol/L HCl liberated D-glucose, which was identified by TLC analysis
and ORD in comparison with authentic D-glucose. In HMBC spectrum of 1 (Fig. 2), the aromatic protons at d 7.68 (H-
9
and H-13) show cross-peaks with the carbonyl carbon (d 195.4), two aromatic protons at d 6.08 (s, 2H) correlated
with C-1, 2, 3, 4, 5, 6 implied that the two aromatic protons were located at C-3 and C-5, while hydroxyl groups at d
.82 (s, 2H) showed correlations with C-1, 2, 3, 4, 5, 6, which suggested the two hydroxyl groups was placed at C-2 and
C-6. The anomeric proton at d 4.76 exhibited HMBC cross-peaks with a C-4 quaternary carbon at d 160.1, therefore C-
was identified as the linkage position of glucoside. The relative configuration of the anomeric carbon of glucosyl
residue was deduced to be b, based on the coupling constant value (J1
¼ 8:0 Hz) and comparison of the NMR spectra
9
4
0
;4
with those of known compounds [10]. In light of the evidence mentioned above, the structure of 1 was established as
2
,6-dihydroxy-4-O-b-D-glucopyranosylbenzophenone (Table 1).
The inhibitory activity on NO production was carried out according to the procedure described in the literature [11].
showed significant inhibition to secretion of NO in mouse peritoneal macrophages, inhibition rate was 38.60% in
0 mmol/L, and 1 did not show significant inhibition to the growth of mouse peritoneal macrophages.
1
1
[
(
)
T
D
$
F
I
G
]
OH
6
'
4
'
5
'
O
HO
3
12
1
'
OH
HO
O
1
3
1
1
1
0
OH
2
'
2
1
3
'
4
H
5
8
7
9
6
OH
O
Fig. 2. Key HMBC correlations of compound 1.

180
H.Z. Fu et al. / Chinese Chemical Letters 22 (2011) 178–180
Table 1
1
13
6
The H NMR (500 MHz) and C NMR (125 MHz) spectral data of compound 1 (DMSO-d , d).
Position
d
H
(mult., J in Hz)
d
C
Position
d
H
(mult., J in Hz)
d
C
1
2
3
4
5
6
7
8
9
108.8
157.3
95.0
11
12
13
7.57 (t, 1H, 7.5)
7.46 (t, 1H, 7.5)
7.68 (d, 1H, 7.5)
4.76 (d, 1H, 8.0)
3.19 (m, 1H)
132.5
128.3
128.7
100.3
73.1
9.82 (-OH)
6.08 (s, 1H)
0
160.1
95.0
1
0
6.08 (s, 1H)
9.82 (-OH)
2
0
157.3
195.4
138.5
128.7
128.3
3
3.26 (m, 1H)
76.5
0
4
3.21 (m, 1H)
69.4
0
5
3.22 (m, 1H)
77.0
0
7.68 (d, 1H, 7.5)
7.46 (t, 1H, 7.5)
6
3.53 (dd, 1H, 11.5, 4.0)
3.69 (d, 1H, 11.5)
60.4
1
0
Acknowledgments
We thank National Science and Technology Project of China (No. 2009ZX09311-004) for financial support. We are
grateful to Professor X.J. Jing for NMR measurements, Professor J.B. Li for ESI-MS measurements and Professor Q.
Hou for bioassays.
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