Six known compounds daphneresinol (1), (+)-neo-olivil (2), methyl gallate (3), bergenin (4), asiatic acid (5) and blumenol A (6) were obtained from the organic extract of the leaves of Dipterocarpus obtusifolius Teijsm. Ex Miq. by various chromatographic techniques. Structural elucidation of the metabolites was carried out by analysis of their spectroscopic data and by comparison with those reported in the literature. Compounds 1-4 and 6 were isolated from this plant for the first time

Cuong, Nguyen Xuan

Dieu Thuan, Nguyen Thi

Hong Hanh, Tran Thi

Mai Huong, Pham Thi

Minh, Chau Van

Nam, Nguyen Hoai

Thanh, Nguyen Van

Toan Phan, Nguyen Huu

Vietnam Academy of Science and Technology: Journals Online

 137 
VIETNAM JOURNAL OF CHEMISTRY         VOL. 53(2e) 137-141                                            APRIL 2015 
DOI: 10.15625/0866-7144.2015-2e-032 
  
 
 
SECONDARY METABOLITES FROM  
DIPTEROCARPUS OBTUSIFOLIUS TEIJSM. ex MIQ. 
 
Nguyen Huu Toan Phan
1
, Nguyen Thi Dieu Thuan
1
, Pham Thi Mai Huong
2
, Tran Thi Hong Hanh
2
, 
Nguyen Xuan Cuong
2
, Nguyen Hoai Nam
2
, Nguyen Van Thanh
2*
, Chau Van Minh
2
  
 
1
Tay Nguyen Institute of Scientific Research, Vietnam Academy of Science and Technology (VAST)
  
2
Institute of Marine Biochemistry, VAST 
Received 23 January 2015; Accepted for Publication 18 March 2015 
 
 
Abstract 
Six known compounds daphneresinol (1), (+)-neo-olivil (2), methyl gallate (3), bergenin (4), asiatic acid (5) and 
blumenol A (6) were obtained from the organic extract of the leaves of Dipterocarpus obtusifolius Teijsm. Ex Miq. by 
various chromatographic techniques. Structural elucidation of the metabolites was carried out by analysis of their 
spectroscopic data and by comparison with those reported in the literature. Compounds 14 and 6 were isolated from 
this plant for the first time.    
Keywords. Dipterocarpus obtusifolius, Dipterocarpaceae, secondary metabolite. 
 
1. INTRODUCTION 
 
Dipterocarpus obtusifolius (Dipterocarpaceae) is 
a woody plant that grows in areas of Western 
Highlands and Southern Vietnam. In traditional 
medicine, the oil of D. obtusifolius is used for the 
treatment of gonorrhea, pimples, and skin diseases 
[1]. Diterpenes,  sesquiterpenes  and  triterpenes 
have  been  separated  from the  leaves  of  this  plant 
and some of them were found to be cytotoxic against 
one or more human cancer cell lines [2]. In this 
paper, we reports the isolation and structure 
elucidation of six known compounds 16 from D. 
obtusifolius. These compounds have never been 
reported before from this plant except for the 
compound 5. 
 
2. EXPERIMENTAL 
 
2.1. General experimental procedures 
 
 The ESI-MS was measured on Agilent 1260 
series single quadrupole LC/MS systems. NMR 
spectra were recorded on a Bruker AM500 FT-NMR 
spectrometer (Bruker, Billerica, MA, U.S.A.) using 
TMS as an internal standard. Column 
chromatography (CC) was performed using a silica 
gel (Kieselgel 60, 70230 mesh and 230-400 mesh, 
Merck, Darmstadt, Germany) or YMC RP-18 resins 
(30-50 μm, Fuji Silysia Chemical Ltd, Aichi, Japan). 
Thin layer chromatography (TLC) used pre-coated 
silica gel 60 F254 (1.05554.0001, Merck, Darmstadt, 
Germany) and RP-18 F254S plates (1.15685.0001, 
Merck, Darmstadt, Germany) and compounds were 
visualized by spraying with aqueous 10% H2SO4 and 
heating for 3-5 minutes. 
 
2.2. Plant material 
 
The samples of the plant Dipterocarpus 
obtusifolius Teijsm. ex Miq. were collected in May 
2013 at Bao Lam, Lam Dong and identiﬁed by Dr. 
Nong Van Duy from the Tay Nguyen Institute of 
Scientific Research, VAST. A voucher specimen 
(No. TN3/242) was deposited at the Tay Nguyen 
Institute of Scientific Research, VAST. 
 
2.3. Extraction and isolation 
 
The air dried and powdered leaves of D. 
obtusifolius (4.5 kg) were  extracted  with  methanol  
at  40 
o
C  three  times. Methanolic extracts were 
combined and evaporated under vacuum. This 
extract (500 g) was suspended in water and 
partitioned in turn with n-hexane, CH2Cl2, and 
EtOAc to provide the corresponding extracts:         
n-hexane (H, 37 g), CH2Cl2 (C, 26 g), EtOAc (E, 95 
g) and a water layer. 
 138 
VJC, Vol. 53(2e), 2015                                                                                                Nguyen Van Thanh, et al. 
Extracts E were crudely separated by silica gel 
CC using a gradient concentration of MeOH in 
CH2Cl2 (0-100 %) to obtain nine fractions (E1E9). 
Fraction E4 (2.3 g) was further separated by YMC 
RP-18 CC and eluted with MeOHwater (1:2, v/v), 
followed by silica gel CC with n-hexaneEtOAc 
(1:3, v/v) to give compound 6 (7.0 mg) and 
subfraction E4A. Further purification of fraction 
E4A, using silica gel CC and n-hexaneEtOAc- 
methanol (1:1:0.1, v/v/v), produced compound 2 (40 
mg), compound 3 (10 mg) and compound 5 (12 mg). 
Fraction E6 (25 g) was subjected to a silica gel CC 
and eluted with CH2Cl2/MeOH (from 20:1 to 0:1, 
v/v) to afford six subfractions E6A-E6F. Subfraction 
E6D was separated by YMC using MeOH/H2O (1:5, 
v/v) as eluent to give compound 4 (12 mg) and 
compound 1 (4.0 mg). 
 
 
Figure 1: Structures of compounds 16 
 
Daphneresinol (1): Yellow oil; 
1
H-NMR (500 
MHz, CD3OD) and 
13
C-NMR (125 MHz, CD3OD) 
see table 1; Positive ESI-MS m/z 379 [M+H]
+
.  
(+)-neo-olivil (2): White powder; 
1
H-NMR (500 
MHz, CD3OD) and 
13
C-NMR (125 MHz, CD3OD) 
see table 2. Positive ESI-MS m/z 377 [M+H]
+
. 
Methyl gallate (3): White solid; 
1
H-NMR (500 
MHz, CD3OD): δH 3.83 (3H, s, H-8), 7.07 (2H, s,   
H-2, 6). 
Bergenin (4): White needles; Positive ESI-MS 
m/z 429 [M+H]
+
. 
1
H-NMR (500 MHz, CD3OD) δ 
7.11 (1H, s, H-4), 4.98 (1H, d, J = 10.5 Hz, H-9), 
3.68 (overlap signal, H-11), 3.45 (1H, t, J = 9.0 Hz, 
H-12), 3.83 (1H, t, J = 9.0 Hz, H-13), 4.08 (1H, dd, 
J = 9.5 Hz, J = 10.5 Hz, H-14), 3.93 (3H, s, H-15), 
3.70 (overlap signal, H-16a), 4.06 (1H, dd, J = 4.0 
Hz, J = 11.0 Hz, H-16b); 
13
C-NMR (125 MHz, 
CD3OD) δ 165.75 (C-2), 152.35 (C-3), 111.05 (C-4), 
142.30 (C-5), 149.45 (C-6), 117.31 (C-7), 119.44 
(C-8), 74.26 (C-9), 83.06 (C-11), 71.92 (C-12), 
75.63 (C-13), 81.44 (C-14), 60.88 (C-15), 62.67    
(C-16).  
Asiatic acid (5): White powder; Positive ESI-
MS m/z 511 [M+Na]
+
; 
1
H-NMR (500 MHz, 
CD3OD) δ 1.04 (1H, m, H-1a), 1.97 (1H, m, H-1b), 
3.72 (1H, m, H-2), 3.38 (1H, d, J = 9.5 Hz, H-3), 
1.31 (1H, m, H-5), 1.42 (1H, m, H-6a), 1.47 (1H, m, 
H-6b), 1.33 (1H, m, H-7a), 1.68 (1H, m, H-7b), 1.68 
(1H, m, H-9), 1.02 (1H, m, H-10), 2.0 (2H, m, H-
11), 5.26 (1H, t, J = 3.3 Hz, H-12), 1.11 (1H, m, H-
15a), 1.95 (1H, m, H-15b), 1.66 (1H, m, H-16a), 
2.06 (1H, m, H-16b), 2.23 (1H, d, J = 11.5 Hz, H-
18), 1.00 (1H, m, H-19), 1.40 (1H, m, H-20), 1.37 
(1H, m, H-21a), 1.52 (1H, m, H-21b), 1.65 (1H, m, 
H-22a), 1.72 (1H, m, H-22b), 3.29 (1H, d, J = 11.3 
Hz, H-23a), 3.53 (1H, d, J = 11.3 Hz, H-23b), 0.72 
(3H, s, H-24), 1.07 (3H, s, H-25), 0.88 (3H, s, H-26), 
1.16 (3H, s, H-27), 0.91 (3H, d, J = 6.5 Hz, H-29), 
0.99 (3H, s, H-30); 
13
C-NMR (125 MHz, CD3OD) δ 
48.05 (C-1), 69.70 (C-2), 78.24 (C-3), 43.40 (C-4), 
48.04 (C-5), 19.08 (C-6), 33.66 (C-7), 40.80 (C-8), 
48.82 (C-9), 38.99 (C-10), 24.46 (C-11), 126.61 (C-
12), 139.89 (C-13), 43.40 (C-14), 29.19 (C-15), 
25.35 (C-16), 48.50 (C-17), 54.41 (C-18), 40.42 (C-
19), 40.44 (C-20), 31.80 (C-21), 38.14 (C-22), 66.38 
(C-23), 13.91 (C-24), 17.67 (C-25), 17.88 (C-26), 
24.14 (C-27), 180.52 (C-28), 17.67 (C-29), 21.57 
(C-30). 
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VJC, Vol. 53(2e), 2015                                                                                        Secondary metabolites from… 
Blumenol A (6): White amorphous powder; 
Positive ESI-MS m/z 225 [M+H]
+
; 
1
H-NMR (500 
MHz, CD3OD) δ 2.18 (1H, d, J = 17.0 Hz, H-2a), 
2.53 (1H, d, J = 17.0 Hz, H-2b), 5.90 (1H, t, J = 1.3 
Hz, H-4), 5.81 (1H, overlap signal, H-7), 5.82 (1H, 
overlap signal, H-8), 4.34 (1H, dd, J = 4.5 Hz; J = 
6.5 Hz, H-9), 1.26 (3H, d, J = 6.5 Hz, H-10), 1.06 
(3H, s, H-11), 1.03 (3H, s, H-12), 1.94 (3H, s, H-
13); 
13
C-NMR (125 MHz, CD3OD) δ 42.42 (C-1), 
50.73 (C-2), 201.27 (C-3), 127.10 (C-4), 167.48 (C-
5), 79.95 (C-6), 130.10 (C-7), 136.92 (C-8), 68.72 
(C-9), 23.82 (C-10), 23.46 (C-11), 24.47 (C-12), 
19.56 (C-13).  
 
3. RESULTS AND DISCUSSION 
 
Compound 1, a yellow oil, exhibited a molecular 
ion peak [M + H]
+
 at m/z 379 in ESI-MS, suggesting 
a molecular formula of C20H26O7. The 
13
C NMR 
spectrum exhibited 20 carbon resonances, consisting 
of six sp
2
 methines, six sp
2
 quaternary signals, two 
methoxy groups, three sp
3 
methines and three 
oxymethylene carbon signals. The 
1
H-NMR 
spectrum showed signals for two methoxy group at δ 
3.85 (3H, s), 3.85 (3H, s) and two ABX coupling 
system at δ 6.97 (1H, d, J = 2.0 Hz, H-2), 6.73 (1H, 
d, J = 8.0 Hz, H-5), 6.85 (1H, dd, J = 2.0, J = 8.0 
Hz, H-6) and δ 6.96 (1H, d, J = 2.0 Hz, H-2'), 6.71 
(1H, d, J = 8.0 Hz, H-5'), 6.84 (1H, dd, J = 2.0, J = 
8.0 Hz, H-6'), that indicated the existence of two 
1,3,4-trisubstituted benzene rings. In the aliphatic 
region, three methine proton signals at δ 4.01 (1H, d, 
J = 12.0 Hz, H-7), 2.65 (1H, m, H-8), 1.98 (1H, m, 
H-9), together three oxymethylene proton signals 
observed at δ 3.74 (2H, m, H-10), δ 3.64 (1H, dd, J 
= 4.5, J = 11.5 Hz, Ha-11)/3.72 (1H, m, Hb-11) and δ 
3.41 (1H, dd, J = 6.0, J = 11.5 Hz, Ha-12)/3.56 (1H, 
dd, J = 2.0, J = 11.5, Hb-12) suggesting the presence 
of 2,3-dihydroxymethylbutanol fragment. This 
fragment was linked to two benzene ring base on the 
long-range correlations (Fig. 2) from H-7 to C-1, C-
2, C-6, C-1', C-2', C-6', C-8, C-9, C-12, from H-12 
to C-9, C-7, and from H-11 to C-8, C-10. The 
HMBC correlations from proton 3-OMe to C-3 and 
from proton 3-OMe to C-3 confirmed the positions 
of two methoxy group. The absolute configuration 
of 1 was determined on the basis of the good 
agreement of NMR spectral data with those of 
daphneresinol. Therefore, compound 1 was 
identified to be daphneresinol [3]. 
Table 1: The 
1
H (500 MHz, CD3OD) and 
13
C-NMR (125 MHz, CD3OD) data of compound 1 
C aC
 C
 H 
(mult., J = Hz) 
C aC C
 H 
(mult., J = Hz) 
1 137.8 137.17 - 11 59.9 59.71 
3.64 (1H, dd, 4.5, 11.5) 
3.72 (1H, m) 
2 113.3 113.03 6.97 (1H, d, 2.0) 12 60.4 60.15 
3.41 (1H, dd, 6.0, 11.5) 
3.56 (1H, dd, 2.0,11.5) 
3 149.1 149.04 - 1' 137.2 137.76 - 
4 145.9 145.80 - 2' 113.1 112.82 6.96 (1H, d, 2.0) 
5 116.4 116.28 6.73 (1H, d, 8.0) 3' 148.9 148.83 - 
6 121.9 121.74 6.85 (1H, dd, 2.0, 8.0) 4' 145.8 145.69 - 
7 52.2 52.1 4.01 (1H, d, 12.0) 5' 116.3 116.14 6.71 (1H, d, 8.0) 
8 45.1 44.99 2.65 (1H, m) 6' 121.5 121.33 6.84 (1H, dd, 2.0, 8.0) 
9 44.0 43.91 1.98 (1H, m) 3-OMe 56.6 56.46 3.86 (3H, s) 
10 63.8 63.65 3.74 (2H, m) 3'-OMe 56.6 56.40 3.85 (3H, s) 
aC of daphneresinol recorded in CD3OD [3]. 
Compound 2 was obtained as a white powder. 
The ESI-MS spectra of 2 exhibited a ion peak [M + 
H]
+
 at m/z 377, which is in agreement with the 
molecular formula C20H24O8. In the 
13
C NMR, there 
were only ten carbon signals, suggesting that 2 
might be a symmetrical lignan structure. The 
1
H 
NMR spectrum revealed the presence of two 1,3,4-
trisubstituted symmetrical aromatic rings at δ 7.05 
(2H, d, J = 2.0 Hz, H-2, H-2'), 6.81 (1H, d, J = 8.0 
Hz, H-5, H-5'), 6.90 (1H, dd, J = 2.0, J = 8.0 Hz, H-
6, H-6'), together two oxymethylene groups at δ 3.62 
(2H, dd, J = 5.0, J = 11.5 Hz, Ha-9, Ha-9') and 3.72 
(2H, dd, J = 3.5, J = 11.5 Hz, Hb-9, Hb-9'), two 
oxygenated methine groups at δ 4.95 (2H, d, J = 8.5 
Hz, H-7, H-7'), two methine groups at δ 2.34 (2H, m, 
H-8, H-8') and two methoxy groups at δ 3.90 (6H, 
s). From these functionalities, compound 2 was 
suggested to be a 2,5-diaryl tetrahydrofuranoid-type 
 140 
VJC, Vol. 53(2e), 2015                                                                                                Nguyen Van Thanh, et al. 
lignan. It was also confirmed by the cross peak 
between H-7 and C-2, C-6, C-8, C-9, C-8', as well as 
between H-7' and C-2', C-6', C-8', C-9', C-8. The 
relative configurations between H-7 and H-8, and H-
7' and H-8' were established as trans-configurations 
due to the large coupling constant (J = 8.5 Hz) 
between H-7 (or H-7') and H-8 (or H-8'). On the 
basis of the above evidence, the structure of 2 was 
identified as (+)-neo-olivil by comparison of spectral 
data with those reported in the literature [4]. 
Table 2: The 
1
H (500 MHz, CD3OD) and 
13
C-NMR (125 MHz, CD3OD) data of compound 2 
C aC
 C
 H 
(mult., J = Hz) 
C aC C
 H 
(mult., J = Hz) 
1, 1' 134.9 134.97 - 6, 6' 120.5 120.52 6.90 (1H, dd, 2.0, 8.0) 
2, 2' 111.1 111.23 7.05 (1H, d, 2.0) 7, 7' 84.4 84.43 4.95 (1H, d, 8.5) 
3, 3' 149.1 149.12 - 8, 8' 55.4 55.43 2.34 (1H, m) 
4, 4' 147.6 147.36 - 9, 9' 61.7 61.86 
3.62 (1H, dd, 5.0, 11.5) 
3.72 (1H, dd, 3.5, 11.5) 
5, 5' 116.0 116.05 6.81 (1H, d, 8.0) 3, 3'-OMe 56.4 56.45 3.90 (3H, s) 
aC of (+)-neo-olivil recorded in CD3OD [4]. 
 
Figure 2: Key HMBC correlations of compounds 1 and 2 
 
Compound 3-6 were identified as methyl gallate 
(3) [5], bergenin (4) [6], asiatic acid (5) [7], and 
blumenol A (6) [8] by comparing the NMR spectral 
data with those reported in literature.  
 
4. CONCLUSION  
 
From the MeOH extract of the leaves of 
Dipterocarpus obtusifolius, using column 
chromatography, six known compounds 
daphneresinol (1), (+)-neo-olivil (2), methyl gallate 
(3), bergenin (4), asiatic acid (5), and blumenol A 
(6) were isolated. Based on 1D NMR and 2D NMR 
as well as comparison with published data, their 
chemical structures were elucidated. Compounds 
14 and 6 have not been previously isolated from D. 
obtusifolius.  
 
Acknowledgements. This work was financially 
supported by a Vietnam national project of the Tay 
Nguyen 3 Program, code: TN3/T14. The authors are 
grateful to Institute of Chemistry, VAST for 
measuring NMR spectra. 
 
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Corresponding author:  Nguyen Van Thanh 
Institute of Marine Biochemistry, Vietnam Academy of Science and Technology 
18, Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 
E-mail: thanhcmgu@yahoo.com 
Tel. 0988091377. 
 
 


Secondary metabolites from Dipterocarpus obtusifolius Teijsm. Ex Miq

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Secondary metabolites from Dipterocarpus obtusifolius Teijsm. Ex Miq

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