A new alkylene dihydrofuran glycoside with antioxidation activity from the root bark of Morus alba L

Article abstract of DOI:10.1016/j.cclet.2010.02.016

A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3′-O-β-Dglucopyranoside (2), and moracin M-6, 3′-di-O-β-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2, 5-dihydrofuran-4-O-β-D- glucopyranoside on the basis of chemical and spectroscopic data including 1D and 2D NMR spectral analysis. In addition, the antioxidant activity of 1 was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC₅₀ values were 2.49 and 0.45 mg/mL, respectively.

Full text of DOI:10.1016/j.cclet.2010.02.016

Available online at www.sciencedirect.com
Chinese Chemical Letters 21 (2010) 821–823
www.elsevier.com/locate/cclet
A new alkylene dihydrofuran glycoside with antioxidation activity
from the root bark of Morus alba L.
*
Wei Fu, Yong Fang Lei, Ya Ling Cai, Dao Nian Zhou, Jin Lan Ruan
Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, College of Pharmacy,
Tongji Medical Center, Huazhong University of Science and Technology, Wuhan 430030, China
Received 21 October 2009
Abstract
0
A new alkylene dihydrofuran glycoside (1) was isolated from the root bark of Morus alba L., along with moracin M-3 -O-b-D-
0
glucopyranoside (2), and moracin M-6, 3 -di-O-b-D-glucopyranoside (3). Compound 1 was identified as 2-methylene-3-methoxy-2,
5-dihydrofuran-4-O-b-D-glucopyranoside on the basis of chemical and spectroscopic data including 1D and 2D NMR spectral
0
analysis. In addition, the antioxidant activity of 1 was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2 -azinobis-
3
-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The IC50 values were 2.49 and 0.45 mg/mL, respectively.
2010 Jin Lan Ruan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
#
Keywords: Morus alba L.; Dihydrofuran glycoside; Spectral analysis; Antioxidation activity
The plant Morus alba L. is widely distributed in eastern countries and mainly found in China, Japan and Korea [1].
Its root bark (‘Sang Bai Pi’ in China) has been used as a traditional Chinese medicine for the treatment of lung-heat,
cough, hematemesis, dropsy, and dysuria [2]. As a part of an investigation on Morus species, we examined the root
0
bark of M. alba L., and obtained a new dihydrofuran glycoside (1), along with moracin M-3 -O-b-D-glucopyranoside
0
(
2), and moracin M-6, 3 -di-O-b-D-glucopyranoside (3). In this paper, we report the isolation, structure elucidation and
0
radical scavenging abilities of compound 1 on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2 -azinobis-3-
ethylbenzothiazoline-6-sulphonic acid (ABTS) radicals.
The root bark of M. alba L. were collected at Kaili city, Guizhou Province, China, in December 2008. The plant was
identified by Prof. Changgong Zhang at the College of Pharmacy, Tongji Medical Center, Huazhong University of
Science and Technology. Avoucher specimen (No. SBP081201) has been deposited at the Herbarium of the College of
Pharmacy, Tongji Medical Center, Huazhong University of Science and Technology, Wuhan, China.
The dried root bark (3.7 kg) was extracted with 80% ethanol under reflux. The resulting extracts were combined and
concentrated under reduced pressure to obtain a residue (620 g). The residue was suspended in water and partitioned
with petroleum ether, EtOAc, and n-BuOH, successively. The n-BuOH fraction (85.4 g) was separated over silica gel
column gradiently eluted with CHCl –MeOH (40:1 to 1:1) to give 10 fractions (fractions 1–10), fraction 4 (1.84 g) was
3
separated further over silica gel column (CHCl :MeOH:H O, 5:1:0.1) and Sephadex LH-20 column (MeOH:H O, 1:1)
3
2
2
*
Corresponding author.
E-mail address: jinlan8152@163.com (J.L. Ruan).
1001-8417/$ – see front matter # 2010 Jin Lan Ruan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
doi:10.1016/j.cclet.2010.02.016

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W. Fu et al. / Chinese Chemical Letters 21 (2010) 821–823
Table 1
1
13
6
NMR spectral data of compound 1 in DMSO-d ( H: 400 MHz, C: 100 MHz, d ppm, J in Hz).
Position
d
H
d
C
2
3
4
5
6
154.4
132.8
153.5
56.2
94.8
101.5
73.7
77.7
70.5
77.3
61.3
60.6
3.72 (s, 2H)
6.37 (s, 2H)
0
1
4.76 (d, 1H, J = 8.0)
3.1–3.5 (m, 1H)
0
2
0
3
3.1–3.5 (m, 1H)
0
4
3.1–3.5 (m, 1H)
0
5
3.1–3.5 (m, 1H)
0
6
4.40 (dd, 1H, J = 12.0, 2.0) 4.22 (dd, 1H, J = 12.0, 6.4)
3.57 (s, 3H)
3
-OMe
to yield compound 1 (115 mg), The separation of fraction 8 (1.63 g) was chromatographed on silica gel column
CHCl :MeOH:H O, 3:1:0.1), and Sephadex LH-20 column (CHCl :MeOH, 1:1) to yield 2 (38 mg) and 3 (45 mg).
(
3
2
3
2
0
ꢁ
Compounds 1 was obtained as yellow powder, mp 188–190 8C, ½aꢀ
þ 42:5 ðc0:10; MeOHÞ, Its molecular
D
+
formula was determined as C H O by HR-EI-MS ([M+Na] m/z 313.2132, calcd. 313.2062). The l at 300 nm in
1
2
18
8
max
UV spectrum revealed a conjugated double bond. The IR absorptions indicated the presence of methylene group
ꢂ1
ꢂ1
1
2936 cm ) and double bond (1654 cm ). The H and C NMR spectra (see Table 1), in combination with HSQC
13
(
experiment, showed the presence of one terminal double bond [d 6.37 (s, 2H, H-6), d 154.4 (C-2), d 94.8 (C-6)], one
H
C
C
double bond [d 132.8 (C-3), d 153.5 (C-4)], one methyleneoxy group [d 3.72 (3H, s, H-5), d 60.6 (C-5)], one
C
C
H
C
methoxyl group [d 3.57 (2H, s), d 56.2], and a sugar group. The aglycone of 1 may be a substituted dihydrofuran, this
C
H
assumption was subsequently confirmed by HMBC correlations: H-5/C-2, C-4; and H-6/C-2, C-3 (Fig. 1). Thus, the
aglycone of 1 was elucidated as a methylene dihydrofuran. Compound 1 was hydrolyzed with 10% hydrochloric acid
to yield glucose identified by comparing with the authentic samples on TLC, and D-glucose was confirmed by GC
1
3
1
0
analysis after acid hydrolysis. The C NMR data and the H NMR signal at d 4.76 (d, 1H, J = 8.0 Hz, H-1 ) suggested
0
the glucose was b configurated. The 4-O-glycopyranosyl and 3-OMe were determined on the HMBC correlations H-1
(d 4.76) and C-4 (d 153.5), OMe (d 3.57) and C-3 (d 132.8). Therefore, compound 1 was identified as 2-methylene-3-
methoxy-2, 5-dihydrofuran-4-O-b-D-glucopy-ranoside (Fig. 1). To the best of our knowledge, it is the first report of
alkylene dihydrofuran glycoside as natural product.
The antioxidant activity of the compound 1 was investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and
0
2
1
,2 -azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) method [3,4], with TRLOX as positive controls (IC50
.90 mg/mL for DPPH, 0.29 mg/mL for ABTS). Compound 1 showed potential activity, with the IC50 values of 2.49
and 0.45 mg/mL, respectively.
0
0
Moracin M-3 -O-b-D-glucopyranoside (2), and moracin M-6, 3 -di-O-b-D-glucopyranoside (3) were identified by
comparing their spectral data with those reported [5].
Fig. 1. Structure and key HMBC correlations of compound 1.

W. Fu et al. / Chinese Chemical Letters 21 (2010) 821–823
823
Acknowledgment
The author is grateful to Ping Lang (Department of Analysis, Huazhong University of Science and Technology) for
recording NMR spectra.
References
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[
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Chemical Industry Press, Beijing.
[
[
[
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