The phytochemical investigation of the ethyl acetate extract of Pinus kesiya Royle ex Gordon roots led to the isolation of two abietane diterpenes, 7-oxo-15-hydroxy-dehydroabietic acid (1) and dehydroabietic acid (2) as well as two neolignans, cedrusin (3) and cedrusin-4-O-β-D-glucopyranoside (4). Their structures were determined by combination of spectral analysis and comparison with reported data. Among them, compound 1 was isolated from the genus Pinus for the first time. Keywords. Pinus kesiya, abietane diterpenes, neolignans, dehydroabietic acid, cedrusin

Hoang Anh, Nguyen Thi

Quan, Tran Duc

Sa, Nguyen Hoang

Sung, Tran Van

Tam, Nguyen Thanh

Thien, Dao Duc

Thuy, Trinh Thi

English

Vietnam Academy of Science and Technology: Journals Online

 Vietnam Journal of Chemistry, International Edition, 55(2): 240-243, 2017 
DOI: 10.15625/2525-2321.2017-00452 
240 
 
 
 
Abietane diterpenoids and neolignans from the roots of Pinus kesiya 
Nguyen Hoang Sa
1,3
, Nguyen Thanh Tam
1,2
, Nguyen Thi Hoang Anh
1,2
, Tran Duc Quan
2
,  
Dao Duc Thien
2
, Tran Van Sung
2
, Trinh Thi Thuy
1,2*
  
1Graduate University of Science and Technology, Vietnam Academy of Science and Technology  
2Institute of Chemistry, Vietnam Academy of Science and Technology 
3Khanh Hoa University 
Received 30 March 2017; Accepted for publication 11 April 2017 
 
Abstract 
The phytochemical investigation of the ethyl acetate extract of Pinus kesiya Royle ex Gordon roots led to the 
isolation of two abietane diterpenes, 7-oxo-15-hydroxy-dehydroabietic acid (1) and dehydroabietic acid (2) as well as 
two neolignans, cedrusin (3) and cedrusin-4-O-β-D-glucopyranoside (4). Their structures were determined by 
combination of spectral analysis and comparison with reported data. Among them, compound 1 was isolated from the 
genus Pinus for the first time. 
Keywords. Pinus kesiya, abietane diterpenes, neolignans, dehydroabietic acid, cedrusin. 
 
1. INTRODUCTION 
 
Pinus is the largest genus in the pine family 
(Pinaceae), comprising 114 species [1]. There are 
eight Pinus species in Vietnam and Pinus kesiya 
Royle ex Gordon (local name known as Thong ba la, 
Xa nu, Xa nui, Ngo or Tong thu) mostly distributed 
among Langbiang plateau. This is a large tree, up to 
over 30 m tall with a bole free of branches for 15-20 
m and up to 100 cm in diameter, with a thick, 
reticulately and deeply fissured bark [2]. In the folk 
medicine, the turpentine obtained from the resin of 
pine trees is antiseptic, diuretic. It is also a valuable 
remedy used internally in the treatment of kidney, 
bladder complaints, rheumatic affections, coughs, 
colds, influenza and tuberculosis [3]. So far, only 
one publication on the chemical composition of this 
species has been reported. From pinecone of Pinus 
kesiya R. collected in China, three diterpenoids 
named 15-hydroxydehydroabietic acid, 15-
hydroxylabd- 8(17)-en-19-oic acid, junicedric acid 
and β-sitosterol, daucosterol have been isolated [4]. 
In our recent previous paper we described the 
isolation and structural elucidation of four phenolic 
compounds from the roots of P. kesiya [5]. In 
continuation of the study on this plant, two abietane 
diterpenoids and two lignans were isolated and 
identified from the same plant materials. 
2. EXPERIMENTAL 
 
2.1. General 
 
NMR spectra were recorded on Bruker Avance 
500 Ultrashield NMR Spectrometer. ESI-MS: 
Agilent LC-MSD-Trap SL. Optical rotation was 
measured with a JASCO P2000 Polarimeter at 25°C 
and D line of the sodium spectrum. TLC: Silica gel 
60 F254 (0.25 mm, Merck); reversed phase RP18 F254S 
(0.25 mm, Merck). CC: Silica gel 60 (230-400 mesh, 
Merck) for the first column, silica gel 60, 40-63 m 
(Merck) and Sephadex LH-20 for the following 
columns. 
 
2.2. Plant material 
 
Roots of P. kesiya were collected in August 
2015 in Dac Lac province of Vietnam and 
determined by Dr. Nguyen Tien Hiep, Vietnam 
National Museum of Nature, Vietnam Academy of 
Science and Technology (VAST). A voucher 
specimen (VNMN.B000005007) is deposited at 
Vietnam National Museum of Nature, VAST. 
 
2.3. Extraction and isolation 
 
The dried roots of P. kesiya (2 kg) were ground, 
then extracted three times (each in 3 days) with 90 
% MeOH. Evaporation of the solvent under reduced 
 VJC, 55(2), 2017  Trinh Thi Thuy et al. 
241 
pressure gave a crude methanolic extract (200 g). 
The extract was added to H2O and partitioned in turn 
between n-hexane, EtOAc, n-butanol. The extracts 
were then concentrated under reduced pressure at 45 
0C to give the corresponding residues. The EtOAc 
extract residue (19 g) was subjected to a silica gel 
column chromatography using a gradient mixture of 
CH2Cl2-MeOH-H2O (100:5:0 to 25:10:1) as eluent 
to give seven fractions (F1-F7). Fraction F1 was 
purified on Sephadex LH-20 (MeOH) to give 2 (15 
mg). Fraction F2 was chromatographed over silica 
gel column using the CH2Cl2-MeOH-H2O mixtures 
(2:1:0 to 1:1:0.2) to yield five subfractions F2.1-
F2.5. The subfraction F2.4 was purified on an RP18 
column with MeOH:H2O (2:3) as eluent to afford 1 
(12 mg). Fraction F3 was subjected to CC over 
Sephadex LH-20 (MeOH) to give three subfractions 
(F.3.1-F.3.3). The subfraction F3.2 was 
rechromatographed on a silica gel column using 
CH2Cl2:EtOAc:MeOH (10:10:1) to yield 3 (15 mg). 
Fraction F6 was subjected to a Sephadex LH-20 
column (MeOH) to afford four subfractions (F.6.1-
F.6.4). The subfraction F6.1 was fractionated on 
RP18 column with MeOH:H2O (2:3) as eluent, and 
then rechromatographed on a silica gel column with 
CH2Cl2-MeOH (5:1) to afford 4 (13 mg).  
 
2.4. Spectral data of isolated compounds 
 
7-Oxo-15-hydroxy-dehydroabietic acid (1): 
yellowish solid, mp. 119 oC; [α]25D +2.1 (c 0.5 in 
MeOH); 1H- and 13C-NMR, see table 1. 
Dehydroabietic acid (2): yellowish solid, mp. 
172 oC; 1H- and 13C-NMR, see table 1. 
(+)-Cedrusin (3): white amorphous powder; 
[α]D = +4.8 (c 0.6 in MeOH); 
1H-NMR (CD3OD, 
500 MHz): δH 7.00 (1H, d, J = 1.5 Hz, H-2), 6.86 
(1H, dd, J = 8.0 Hz, 1.5 Hz, H-6), 6.79 (1H, d, J = 
8.5 Hz, H-5), 6.62 (1H, s, H-6′), 6.59 (1H, s, H-2′), 
5.51 (1H, d, J = 6.0 Hz, H-7), 3.86 (1H, dd, J = 11.0 
Hz and 5.0 Hz, H-9a), 3.80 (3H, s, 3-OCH3), 3.58 
(2H, t, J = 6.5 Hz, H-9′), 3.77 (1H, dd, 11.0 Hz and 
7.5 Hz, H-9b), 3.47 (1H, br q, J = 6.0 Hz, H-8), 2.58 
(2H, t, J = 7.5 Hz, H-7′), 1.81 (2H, quintet, J = 7.0 
Hz, H-8′); 13C-NMR (CD3OD, 125 MHz): δC 135.1 
(C-1), 110.6 (C-2), 149.0 (C-3), 147.3 (C-4), 116.1 
(C-5), 119.7 (C-6), 88.7 (C-7), 55.7 (C-8), 65.1 (C-
9), 136.7 (C-1′), 117.0 (C-2′), 141.8 (C-3′), 146.6 
(C-4′), 129.8 (C-5′), 116.7 (C-6′), 32.7 (C-7′), 35.8 
(C-8′), 62.3 (C-9′), 56.4 (3-OCH3). 
Cedrusin-4-O-β-D-glucopyranoside (4): white 
amorphous powder; 1H-NMR (CD3OD, 500 MHz): 
δH 7.16 (1H, d, J = 8.5 Hz, H-5), 7.09 (1H, d, J = 1.5 
Hz, H-2), 6.98 (1H, dd, J = 8.5 Hz, 1.5 Hz, H-6), 
6.61 (1H, s, H-6′), 6.60 (1H, s, H-2′), 5.57 (1H, d, J 
= 5.5 Hz, H-7), 3.85 (3H, s, 3-OCH3), 3.57 (2H, t, J 
= 6.5 Hz, H-9′), 2.58 (2H, t, J = 7.5 Hz, H-7′), 1.81 
(2H, quintet, J = 6.5 Hz, H-8′); glucose:  4.98 (1H, 
d, J = 7.0 Hz, glc H-1), 3.36-3.83 (glc H-2 - H-6); 
13C-NMR (CD3OD, 125 MHz): δC 138.7 (C-1), 
111.1 (C-2), 150.8 (C-3), 147.4 (C-4), 118.0 (C-5), 
119.3 (C-6), 88.1 (C-7), 55.9 (C-8), 62.5 (C-9), 
136.9 (C-1′), 117.1 (C-2′), 142.0 (C-3′), 146.4 (C-
4′), 129.4 (C-5′), 116.6 (C-6′), 32.7 (C-7′), 35.7 (C-
8′), 62.3 (C-9′), 56.7 (3-OCH3); glucose: 102.8 (glc 
C-1), 74.9 (glc C-2), 77.8 (glc C-3), 71.3 (glc C-4), 
78.1 (glc C-5), 65.2 (glc C-6). 
 
3. RESULTS AND DISCUSSION 
 
Compound 1 was assigned a molecular formula 
of C20H26O4 by combination of its NMR data and 
ESI-MS pseudo-molecular ion peak at m/z 331.2 
[M+H]+. The 1H-NMR spectrum showed signals for 
four quaternary methyl groups [δH 1.28 (3H, s, H-
20), 1.31 (3H, s, H-19) and 1.54 (6H, s, H-16 and H-
17)], a 1,2,4-trisubstituted benzene ring at δH 8.07 
(1H, d, 2.0 Hz, H-14), 7.73 (1H, dd, 8.5 Hz and 2.5 
Hz, H-12) and 7.44 (1H, d, 8.5 Hz, H-11). The 13C-
NMR, DEPT and HSQC spectra indicated 20 
carbons attributable to four methyls, four 
methylenes, four methines (including three aromatic 
protons) and eight quaternary carbons (containing 
two carbonyl groups). These spectroscopic data 
indicated 1 is an abietane diterpenoid. Besides, the 
sp3quaternary carbon with a chemical shift at δC 72.6 
helped to infer that 1 have a hydroxyl group at C-15. 
The position of each hydrogen to corresponding 
carbon in 1 were assigned by cross-peaks in the 
HSQC spectrum. The HMBC spectrum showed the 
long-range correlations between H-5 and C-19, C-
20, C-10, C-6 and C-7; between H-11 and C-13, C-8 
and C-10; between H-12 and C-14, C-9 and C-15; 
H-14 and C-7, C-9 and C-12; between H-16 and H-
17 and C-13. Comparison of the NMR spectral data 
of 1 (Table 1) with those of 7-oxo-15-hydroxy-
dehydroabietic acid [6], indicated that they were the 
same compound. 
 
 
Figure 1: Structures of compounds 1-4 from the 
roots of Pinus kesiya 
Compound 2 was assigned the molecular 
 VJC, 55(2), 2017  Abietane diterpenoids and neolignans… 
242 
formula C20H28O2 by NMR data and ESI-MS with a 
pseudo-molecular ion peak at m/z 301.4 [M+H]+ in 
ESI-MS spectrum. The 13C-NMR and HSQC spectra 
showed the presence of four methyls, five 
methylenes, five methines (including three aromatic 
protons) and six quaternary carbons (containing a 
carbonyl group). The NMR data (table 1) indicated a 
structure closely similar to 1. Nevertheless, there 
were some significant differences in the chemical 
shifts between 2 and 1. Differences in the 1H and 13C 
NMR spectra were noted at C-7 and C-15. First, at 
C-7 of 2 a methylene group (δH 2.87 and δC 31.2) 
was present, instead of a carbonyl group (δC 202.1) 
in 1. Second, the C-15 signals of 2 showed a 
methine group (δH 2.80, septet, J = 7.0 Hz and δC 
34.8), while this signal indicated an oxygenated 
quaternary carbon (δC 72.6) in 1. The above 
spectroscopic data resemble those of dehydroabietic 
acid [7, 8]. So, 2 was determined to be 
dehydroabietic acid, which is common in the resins. 
 
Table 1: 13C- and 1H-NMR data of compounds 1 and 2 (125/500 MHz, CD3OD, δ ppm) 
C 
1 2 
DEPT δC δH (J, Hz) DEPT δC δH (J, Hz) 
1 CH2 38.7 
2.41, d (12.0) 
1.62, m 
CH2 39.5 
2.35, br d (12.5) 
1.45, m 
2 CH2 19.9 
1.87, m 
1.75, m 
CH2 19.7 
1.84, m 
1.72, m 
3 CH2 38.5 1.66, m CH2 38.1 
1.82, m  
1.71, m 
4 C 46.0 - C 47.4
* - 
5 CH 45.8* 2.79, dd (14.0, 2.0) CH 46.6 2.18, dd, (12.5, 2.0) 
6 CH2 39.2 
2.73, dd (16.5, 14.0) 
2.52, dd (17.0, 1.5) 
CH2 39.7 
1.87, m 
1.17, m 
7 C=O 202.1 - CH2 31.2 2.87, m 
8 C 131.7 - C 135.7 - 
9 C 156.4 - C 146.9 - 
10 C 38.8 - C 35.6 - 
11 CH 124.9 7.44, brd (8.5) CH 125.2 7.16, d (8.0) 
12 CH 132.0 7.73, dd (8.5, 2.5) CH 124.9 6.97, br d (8.5) 
13 C 148.9 - C 145.7 - 
14 CH 124.0 8.07, d (2.0) CH 127.8 6.86, br s 
15 C 72.6 - CH 34.8 2.80, septet (7.0) 
16 CH3 31.7 1.54, brs CH3 24.8 1.22, d (7.0) 
17 CH3 31.7 1.54, brs CH3 24.8 1.22, d (7.0) 
18 C=O 186.0* - C=O 183.0* - 
19 CH3 17.9 1.31, brs CH3 17.1 1.28, brs 
20 CH3 23.9 1.28, brs CH3 25.5 1.22, brs 
The ESI-MS spectrum of 3 showed a pseudo-
molecular ion peak at m/z 347.2 [M+H]+, 
corresponding to the molecular formula of C19H22O6. 
The 1H-NMR spectrum exhibited the attendance of 
five aromatic protons [δH 7.00 (1H, d, 1.5 Hz, H-2), 
6.86 (1H, dd, 8.0 Hz and 1.5 Hz, H-6), 6.79 (1H, d, 
8.5 Hz, H-5), 6.62 (1H, s, H-6′) and 6.59 (1H, s, H-
2′)], two methines [δH 5.51 (1H, d, 6.0 Hz, H-7) and 
3.47 (1H, br q, 6.0 Hz, H-8)], a hydroxymethyl [δH 
3.77 (1H, dd, 11.0 Hz and 7.5 Hz, H-9) and 3.86 
(1H, dd, 11.0 Hz and 5.0 Hz, H-9) and a methoxy 
group [δH 3.80 (3H, s, 3-OCH3)]. Other signals at δH 
3.58 (2H, t, 6.5 Hz, H-9′), 1.81 (2H, quintet, J = 7.0 
Hz, H-8′) and 2.58 (2H, t, J = 7.5 Hz, H-7′) indicated 
the presence of an n-propanol side-chain. In the 13C-
NMR and HSQC spectra, along with the 
methoxycarbon, 18 skeletal carbons were appeared. 
These spectral characteristics showed that 3 was a 
dihydro[b]benzofuran neolignan. In addition, these 
spectroscopic data were similar to those of cedrusin 
from Cedrus deodara [9]. Accordingly, compound 3 
was confirmed as (+)-cedrusin.  
The NMR spectral data of 4 were similar to 
those of 3 except the additional signals of a glucose 
moiety (δH 3.36-4.98 and δC 65.2-102.8 in the HSQC 
spectrum). The -configuration of glucose was 
confirmed by the coupling constant of the anomeric 
proton (δH 4.98, d, J = 7.0 Hz). By means of the 
 VJC, 55(2), 2017  Trinh Thi Thuy et al. 
243 
analysis of NMR spectra and comparing with the 
data in reference [9], the structure of 4 was deduced 
as cedrusin-4-O-β-D-glucopyranoside.  
 
Acknowledgment. We would like to thank the 
National Foundation for Science & Technology 
Development (NAFOSTED) of Vietnam for financial 
support for this research (code: 104.01-2013.62). 
 
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Corresponding author: Trinh Thi Thuy 
Institute of Chemistry 
Vietnam Academy of Science and Technology 
No. 18, Hoang Quoc Viet, Cau Giay District, Ha Noi 
E-mail: thuy@ich.vast.vn.
 


Abietane diterpenoids and neolignans from the roots of Pinus kesiya

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Abietane diterpenoids and neolignans from the roots of Pinus kesiya

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