From the wood of Mahonia nepalensis DC. 1821, two bisbenzylisoquinolines homoaromoline (1) and isotetrandrine (2) were isolated by using various chromatoghraphies. Their structures were characterized on the basis of the spectroscopic data (1D-NMR, HSQC, HMBC, ESI-MS) in comparison with the literature. This is the first report of 1 - 2 from Mahonia nepalensis. Keywords: Mahonia nepalensis, Isotetrandrine, Homoaromoline, Bisbenzylisoquinoline

Ban, Ninh Khac

Huong, Hoang Thanh

Kiem, Phan Van

Mai, Nguyen Thi

Minh, Chau Van

Tuan, Tran Anh

Vietnam Academy of Science and Technology: Journals Online

 368
Journal of Chemistry, Vol. 47 (3), P. 368 - 373, 2009 
 
 BISBENZYLISOQUINOLINE ALKALOIDS FROM  
MAHONIA NEPALENSIS  
Received 24 June 2008 
NGUYEN THI MAI1,2, TRAN ANH TUAN1, HOANG THANH HUONG1  
CHAU VAN MINH1, NINH KHAC BAN3, AND PHAN VAN KIEM1 
1Institute of Natural Products Chemistry, VAST 
2University of Transport and Communications 
3Institute of Ecology and Biological Resources, VAST 
 
ABSTRACT 
From the wood of Mahonia nepalensis DC. 1821, two bisbenzylisoquinolines homoaromoline 
(1) and isotetrandrine (2) were isolated by using various chromatoghraphies. Their structures 
were characterized on the basis of the spectroscopic data (1D-NMR, HSQC, HMBC, ESI-MS) in 
comparison with the literature. This is the first report of 1 - 2 from Mahonia nepalensis. 
Keywords: Mahonia nepalensis, Isotetrandrine, Homoaromoline, Bisbenzylisoquinoline. 
 
I - INTRODUCTION 
Mahonia nepalensis DC. 1821 (hoang lien o 
ro), synonym Mahonia annamica Ganep. 1908 
belonging to Berberidaceae family, is widely 
distributed in the high mountainous areas at 
altitudes 1700 – 1900 m of Vietnam as Lai 
Chau, Lao Cai, Ha Giang, Cao Bang, Bac Can 
and Lam Dong provinces. The stem bark and 
wood of Mahonia nepalensis were considered to 
have anti-inflammatory, anti-bacterial and anti-
fungal activities and they are used particularly 
for the treatment of skin diseases. They are 
indicated for treatment of the eczema, psoriasis, 
and other skin conditions [1 - 3]. Alkaloids 
representing as the main compounds in 
Mahonia genus, belong to two major classes the 
protoberberines and the bisbenzylisoquinolines 
[2, 4-6]. However, no study on chemical 
components and biological activities of species 
of M. nepalensis has been previously reported. 
Herein, we report the isolation and structural 
elucidation of two bisbenzylisoquinolines 
homoaromoline (1) and isotetrandrine (2) from 
the wood of M. nepalensis. Their chemical 
structures were elucidated based on the 1D-, 
2D-NMR, ESI-MS experiments in comparison 
with the previous literature.  
II - EXPERIMENTAL  
1. General experimental procedures 
Optical rotations were determined on a 
Jasco DIP-1000 KUY polarimeter. The 
Electrospray Ionization (ESI) mass spectrum 
was obtained using an AGILENT 1200 LC-
MSD Trap spectrometer. The 1H-NMR 
(500MHz) and 13C-NMR (125 MHz) spectra 
were recorded on Bruker AM500 FT-NMR 
spectrometer. Chemical shifts (δ) are reported in 
ppm using tetramethylsilane (TMS) as an 
internal standard. Column chromatography (CC) 
was performed on silica gel 230 - 400 mesh 
(0.040 - 0.063 mm, Merck) or YMC RP-18 
resins (30 - 50 μm, Fujisilica Chemical Ltd.). 
Thin layer chromatography (TLC) was 
performed on DC-Alufolien 60 F254 (Merck 
1.05715) or RP18 F254s (Merck) plates. Spots 
 369
were visualized by spraying 10% H2SO4 
aqueous and heating for 5 minutes and by 
Dragendoff reagent. 
2. Plant material 
The wood of Mahonia nepalensis species 
was collected in Ngan Son district, Bac Can 
province in March 2008 and identified by Dr 
Ninh Khac Ban, Institute of Ecology and 
Biological Resources, VAST. A voucher 
specimen (EN5-CB2006) was deposited at this 
institute.
 
N N
OCH3
O
H3CO
OCH3
H3C CH3
H H
O
HO
1
3
4
4a
5
6
7
8
8a
9
10
11
12
13
14
1'
3'
4'
4a'
5'
6'
7'
8'
8a'
9'
10'
11'
12'
13'
14'
15
16
17
15'
16'
α α'
N N
OCH3
OCH3
H3CO
OCH3
H3C CH3
H H
O
O
1
3
4
4a
5
6
7
8
8a
9
10
11
12
13
14
1'
3'
4'
4a'
5'
6'
7'
8'
8a'
9'
10'
11'
12'
13'
14'
15
16
17
18
15'
16'
α α'
1 2
R S
 
Fig. 1: The structures of 1 and  2 
  
3. Extraction and Isolation 
Dried wood pieces (3.0 kg) of Mahonia 
nepalensis were powdered and then extracted 
three times with MeOH in acetic acid (pH = 4). 
After removal the solvent, the extract (80 g) was 
suspended in water and partitioned with 
chloroform. After removal the chloroform layer, 
NH4OH was added to the water layer (pH = 10) 
and then partitioned in turn with chloroform and 
n-butanol to obtained chloroform (15 g), n-
butanol (30 g) fractions, and the water layer. 
The n-butanol (30 g) was crudely separated on 
normal silica gel column eluted with n-
hexane/acetone (gradient from 50/1 to 50/50, 
v/v) to give three sub-fractions HLC2A (3g), 
HLC2B (5g) and HLC2C (5g). The HLC2A (3g) 
sub-fraction was further separated on normal 
silica gel column eluting with 
chloroform/methanol (15/1 v/v) to give 2 (35 
mg) as yellow amorphous powder. The LIC2 
(5g) sub-fraction was chromatographed on a 
silica gel column eluted with 
chloroform/methanol (20/1 v/v) to give 1 (25 
mg) as yellow amorphous powder.  
Homoaromoline (thalrugosamine, 
homothalicrine, N-methyldaphnandrine (1): 
Yellow amorphous powder; mp. 235 - 237oC; 
positive ESI-MS: m/z 609 [M+H]+, negative 
ESI-MS: m/z 607 [M-H]-, (C37H40N2O6, M=608). 
13C-NMR (125MHz, CDCl3) and 
1H-NMR (500 
MHz, CDCl3) see table 1. 
Isotetrandrine (O-methylberbamine) (2): 
Yellow amorphous powder; mp. 182-183oC; 
positive ESI-MS: m/z 623 [M+H]+, (C38H42N2O6, 
M= 622); 13C-NMR (125MHz, CDCl3) and 
1H-
NMR (500 MHz, CDCl3) see Table 2. 
III - RESULTS AND DISCUSSION 
Compound 1 was obtained as a yellow 
amorphous powder. The molecular formula of 1 
was suggested to be C37H40N2O6, from the 
exhibition of the quasi molecular ion peaks at 
m/z 609 [M+H]+ (positive ion mode) and 607 
[M-H]- (negative ion mode) with the strongest 
intensity in the ESI-MS. The 13C-NMR spectrum 
of 1 showed signals of 37 carbon atoms 
including 5 methyl, 6 methylene, 12 methine, 
and 14 quaternary carbons, determining from 
the DEPT 95o and DEPT 135o experiments. Two 
methyl groups bearing nitrogen atoms were at δ 
44.13 and 42.42, four methylene groups at δ 
51.52, 45.57, 28.92 and 25.13, in which signals 
at δ 51.52 and 45.57 suggested that these two 
methylene groups bearing nitrogen atoms. The 
above evidence together with two methine 
signals at δ 64.47 and 61.51 suggested the 
presence of a bisbenzylisoquinoline compound 
[6] having three methoxyl groups at δ 56.68, 
56.35 and 55.73. In the 1H-NMR spectrum, 
three aromatic signals at δ 6.38, 6.68, 6.34 as 
 370
singlets, signals at δ 5.65 (s), 6.78 (d, J = 8.5 
Hz) and 6.80 (d, J = 8.5 Hz) suggesting a 1,2,4-
trisubstituted aromatic ring, and four the other 
aromatic ring signals at δ 6.42 (dd, J = 8.0, 2.0 
Hz), 6.92 (dd, J = 8.0, 2.0 Hz), 6.93 (dd, J = 
8.0, 2.0 Hz) and 7.40 (dd, J = 8.0, 2.0 Hz) 
confirming the presence of the typical para-
subtituted aromatic ring [6]. Three methoxyl 
groups were recognized at δ 3.88, 3.76, 3.60 and 
two N-Me groups were assigned at δ 2.59 and 
2.55. All the carbons were assigned to relevant 
protons through an HSQC experiment and the 
NMR data of 1 were compared to those of 
homoaromoline [6] and found to match well 
(Table 1). Furthermore, the HMBC experiment 
was taken to determine all the chemical shifts of 
1. The key correlations observed in the HMBC 
spectrum were shown in table 1. 
 
Table 1: The NMR data and HMBC results of 1 
Homoaromoline [6] 1 
C δC#  δH #  δC  δH  HMBC (H to C) 
(1) (2) (3) (4) (5) (6) 
1 64.26 3.63 dd (4, 2.6) 64.77 3.61* 8 
3 51.10 2.73 m / 3.02 m 51.52 2.45 m / 2.78 m  
4 28.45 2.40 m 28.92 2.40 m  
4a 130.56 - 131.73 -  
5 111.10 6.33 s 111.71 6.36 s 6, 7, 8a 
6 148.50 - 148.85 -  
7 143.96 - 144.32 -  
8 116.93 6.66 s 117.78 6.68 s 4a, 6 
8a 128.02 - 128.75 -  
α 38.32 2.94 dd (14, 1.4) / 
2.68 m 
38.64 3.05 m / 2.79 m  
9 130.95 - 131.73 -  
10 117.00 5.54 brs 117.78 5.6 s  
11 48.70 - 148.85 -  
12 146.64 - 147.28 -  
13 110.71 6.74 d (8.4) 111.45 6.80 d (8.5) 9, 11 
14 123.65 6,70 dd (8.4, 2.3) 124.05 6,80 d (8.5) α, 10, 12 
15 43.72 2.53 s 44.13 2.59 s 1, 3 
16 55.21 3.60 s 55.73 3.60 s 6 
17 55.79 3.88 s 56.68 3.88 s 12 
1’ 60.46 4.13 d (6.5) 61.51 4.18 d (7.0) α’, 8’, 9’, 4a’ 
3’ 44.96 2.55 m / 2.86 m 45.57 2.89 m / 3.21 m 1’, 4a’, 4’ 
4’ 24.96 3.08 m / 2.73 m 25.13 3.05 m / 2.67 m 8a’ 
4a’ 122.99 - 123.54 -  
5’ 104.50 6.20 s 105.26 6.34 s 4’, 6’, 7’, 8a’ 
6’ 147.61 - 147.28 -  
7’ 133.39 - 134.10 -  
8’ 142.37 - 141.82 -  
 371
(1) (2) (3) (4) (5) (6) 
8a’ 122.91 - 123.54 -  
α’ 38.20 2.61 m / 3.22 d 
(13.8) 
38.64 2.79 m / 3.3 d 
(14.0) 
1’, 8a’, 9’, 10’,14’ 
9’ 138.17  137.82   
10’ 131.48 6.95 dd (2.2, 8.4) 131.73 6.93 dd (2.5, 8.0) α’, 9’, 11’, 12’ 
11’ 121.12 6.40 dd (2.2, 8.4) 121.37 6.42 dd (2.0, 8.0) 9’, 13’ 
12’ 152.74  153.20   
13’ 121.90 6.91 dd (2.2, 8.4) 122.32 6.92 dd (2.5, 8.0)  
14’ 128.34 7.33 dd (2.2, 8.4) 128.75 7.40 dd (2.0, 8.0) α’, 10’, 12’ 
15’ 41.50 2.43 s 42.42 2.55 s 1’, 3’ 
16’ 55.68 3.76 s 56.35 3.76 s 6’ 
#δC of homoaromoline [6], aMeasured in CDCl3, b125 MHz, c500 MHz, δ: ppm. 
 
Table 2: The NMR data of 2 in comparison with the literature 
Tetrandrine [6] 2 
C δC #  δH # mul (J in Hz)  δC## [8] δC  δH mul (J in Hz) 
(1) (2) (3) (4) (5) (6) 
1 61.19 3.72 d (9.5) 63.4 61.99 3.68 dd (10.0, 14.0) 
3 43.91 2.87 m 45.5 45.72 2.79 - 2.95 * 
4 21.28 2.39 m / 2.89 m 24.9 25.33 2.79 - 2.95 * 
4a 127.72 - 130.5 129.40 - 
5 105.55 6.26 s 107.1 106.00 6.27 s 
6 151.18 - 153.5 151.86 - 
7 137.63 - 138.4 137.07 - 
8 148.19 - 149.3 148.20 - 
8a 122.64 - 121.6 120.60 - 
α 41.70 2.48 dd (1.8, 14) 
2.67 dd (10, 14) 
38.9 38.59 2.41* 
2.62 dd (10.0, 14.0) 
9 134.68 - 136.5 137.07 - 
10 115.99 6.52 d (2.2) 117.4 116.00 6.54 s 
11 149.12 - 151.0 149.51 - 
12 146.83 - 148.9 147.00 - 
13 111.33 6.82 d (8.2) 113.4 111.37 6.84 d (8.2) 
14 122.56 6.86 dd (2.2, 8.2) 124.5 122.83 6.89 dd (2.2, 8.2) 
15 42.05 2.3 s 43.1 42.62 2.26 s 
16 55.55 3.70 s 56.3 55.71 3.75 s 
17 59.99 3.15 s 61.0 60.40 3.13 s 
18 55.87 3.88 s 56.8 56.05 3.91 s 
1’ 63.64 3.84 dd (5.9, 11.0) 64.4 63.61 3.88* 
3’ 45.00 2.83 m / 3.39 m 46.2 45.72 2.79 - 2.95* 
4’ 25.92 2.91 m / 3.47 m 26.2 25.33 2.79 - 2.95* 
4a’ 127.72 - 129.9 128.52 - 
5’ 112.50 6.48 s 112.6 111.23 6.41 s 
6’ 148.39 - 151.3 149.96 - 
 372
(1) (2) (3) (4) (5) (6) 
7’ 143.57 - 145.0 143.66 - 
8’ 119.96 5.96 s 121.2 119.80 5.98 s 
8a’ 127.84 - 127.22 127.22 - 
α’ 37.93 2.75 dd (11, 12.3) 
3.22 dd (5.9, 12) 
37.3 37.61 2.77  
3.42 m 
9’ 134.91 - 136.4 135.00 - 
10’ 132.42 6.27 dd (2.3, 8.2) 133.5 132.04 6.41 dd (2.3, 8.2) 
11’ 121.63 6.76 dd (2.3, 8.2) 122.5 120.00 6.79 dd (2.3, 8.2) 
12’ 153.58 - 155.9 154.14 - 
13’ 121.63 7.10 dd (2.3, 8.2) 122.3 121.60 7.14 dd (2.3, 8.2) 
14’ 129.90 7.30 dd (2.3, 8.2) 131.5 130.52 7.33 dd (2.3, 8.2) 
15’ 42.32 2.58 s 42.7 42.41 2.57 s 
16’ 55.56 3.33 s 55.9 55.53 3.61 s 
  #δ of tetrandrine [6], ## δC of isotetrandrine [8] aMeasured in CDCl3, b125 MHz, c500 MHz, δ: ppm. 
 
Compound 2 was obtained as a yellow 
amorphous powder. The molecular formula of 2 
was suggested to be C38H42N2O6, from the 
exhibition of the quasi molecular ion peak at 
m/z 623 [M+H]+ (positive ion mode) with the 
strongest intensity in the ESI-MS. The 13C-NMR 
spectrum of 2 showed signals of 38 carbon 
atoms including 6 methyl, 6 methylene, 12 
methine, and 14 quaternary carbons, 
determining from the DEPT 95o and DEPT 135o 
experiments. Two methyl groups bearing 
nitrogen atoms were at δ 42.41 and 42.62, four 
methylene groups at δ 45.72 × 2, and 25.33 × 2, 
in which signals at δ 45.72 suggested that these 
two methylene groups bearing nitrogen atoms. 
The above evidence together with two methine 
signals at δ 61.98 and 63.61 suggested the 
presence of a bisbenzylisoquinoline compound 
[6]. In the 1H-NMR spectrum, singlet signals at 
δ 2.26 and 2.57 (3H × 2) correspond to two NMe 
groups, four singlet signals at δ 3.91, 3.75, 3.61 
and 3.13 (3H × 4) were assigned for 4 methoxyl 
groups. Aromatic singlet signals at δ 6.41, 6.27, 
and 5.98, a para-substituted aromatic ring was 
at δ 7.28, 7.11, 6.64, and 6.41 (4 × dd, J = 2.3, 
8.2 Hz), and signals at δ 6.80 (2H) and 6.54 
(1H) displayed for the 1,2,4-trisubstituted 
aromatic ring of the bisbenzylisoquinoline 
compound [6]. This evidence led to suggest that 
compound 2 was isotetrandrine or tetrandrine. 
The NMR data of 2 were further compared to 
those of isotetrandrine and tetrandrine (table 2). 
The chemical shift and the J coupling constant 
of H-1 and H-α of 2 [δ 2 3.68 dd (J = 10.0, 14.0 
Hz)] differed from that of tetrandrine [δ 3.72 d 
(J = 9.5 Hz)] confirming that the configuration 
at C-1 was R. Furthermore, the melting point of 
2 was 235 - 237oC, similar to that of 
isotetrandrine (1R,1’S) [8], and differed from 
that of tetrandrine (1S,1’S) 215 - 217oC [6]. 
From all the above data, compound 2 was 
identified as isotetrandrine, which was isolated 
from many Mahonia species such as M. 
japonica, M. lomariifolia, M. morrisonensis, M. 
philippinensis, [7], however, which was first 
isolated from M. nepalensis. Besides, this 
compound was also isolated from Atherosperma 
moschatum, Cyclea barbata, Doryphora 
aromatica, Isopyrum thalictroides, Laurelia 
sempervirens and many Berberis species, and it 
has been reported showing in vitro 
antineoplastic activity against HeLa cells and 
Ehrlich ascites, anti-inflammatory, 
antihypertensive agent, and active against gram-
positive bacteria [7]. 
REFERENCES 
1. Vietnam Red Data Book, Science and 
Technology Publishing House p. 133 
(2007). 
2. Bich, D. H., Chung, D. Q., Chuong, B. X., 
Dong, N. T., Dam, D. T., Hien, P. V., Lo, V. 
 373
N., Mai, P. D., Man, P. K., Nhu, D. T., Tap, 
N., Toan, T., Medicinal Plants and Animals 
in Vietnam. Hanoi Science and Technology 
Publishing House, Vol. 2, 130 - 133 (2004). 
3. Chi, V. V., Vietnamese Medical Plant 
Dictionary. Medicinal Publishing House, 
566 - 567 (1997). 
4. R. H. A. M. Janssen, R. J. J. C. Lousberg, P. 
Wijkens, C. Kruk, and H. G. Theuns.  
Phytochemistry, Vol. 28(10), 2833 - 2839 
(1989). 
5. R. Marek, P. Seckarova, D. Hulova, J. 
Marek, J. Dostal, and V. Sklenar. J. Nat. 
Prod. Vol. 66, 481 - 486 (2003). 
6. P. L. Schiff. J. Nat. Prod, 60, 934 - 953 
(1997). 
7. Dictionary of Natural Products on CD-
ROM, Version 15:1, Copyright @ 1982-
2007 Chapman & Hall/CRC 
8. T. Tanahashi, Y. Su, N. Nagakura, and H. 
Nayeshiro. Chem. Pharm. Bull., Vol. 48(3), 
370 - 373 (2000). 
 
Corresponding author: Phan Van Kiem 
           Vietnam Academy of Science and Technology. 
 
 


Bisbenzylisoquinoline alkaloids from Mahonia nepalensis

http://vjs.ac.vn/index.php/vjchem/article/download/4599/4351

Bisbenzylisoquinoline alkaloids from Mahonia nepalensis

Abstract

Similar works

Full text

Available Versions

Vietnam Academy of Science and Technology: Journals Online