Two sesquiterpenes as sinularianin D (1) and 1S*,4S*,5S*,10R*-4,10-guaianediol (2), and three sterols as 24-methylenecholestane-3β,5α,6β-triol-6-monoacetate (3), 3β,7α-dihydroxyergosta-5,24(28)-diene (4), and 3β-hydroxyandrost-5-ene-17-one (5), were isolated from a methanol extract of the soft coral Sinularia cruciata. Their structures were elucidated by 1D and 2D-NMR experiments and comparison of their NMR data with reported values. This is the first report of these compounds from S. cruciat

Cuong, Nguyen Xuan

Huong, Tran Thu

Kiem, Phan Van

Mai Huong, Pham Thi

Minh, Chau Van

Nam, Nguyen Hoai

Thanh, Nguyen Van

Thung, Do Cong

Tuan Anh, Hoang Le

Tung, Pham The

Vietnam Academy of Science and Technology: Journals Online

 107 
VIETNAM JOURNAL OF CHEMISTRY         VOL. 53(2e) 107-111                                            APRIL 2015 
DOI: 10.15625/0866-7144.2015-2e-025 
  
 
 
SESQUITERPENES AND STEROLS FROM THE SOFT CORAL  
SINULARIA CRUCIATA 
 
Pham The Tung
1
, Pham Thi Mai Huong
1
, Tran Thu Huong
2
, Do Cong Thung
3
,  
Nguyen Van Thanh
1
, Hoang Le Tuan Anh
1
, Nguyen Hoai Nam
1*
, Nguyen Xuan Cuong
1
,  
Phan Van Kiem
1
, Chau Van Minh
1
 
 
1
Institute of Marine Biochemistry, Vietnam Academy of Science and Technology 
2
School of Chemical Engineering, Hanoi University of Science and Technology 
3
Institute of Marine Environment and Resources, VAST 
Received 23 January 2015; Accepted for Publication 18 March 2015 
 
Abstract 
Two sesquiterpenes as sinularianin D (1) and 1S*,4S*,5S*,10R*-4,10-guaianediol (2), and three sterols as 24-
methylenecholestane-3β,5α,6β-triol-6-monoacetate (3), 3β,7α-dihydroxyergosta-5,24(28)-diene (4), and 3β-
hydroxyandrost-5-ene-17-one (5), were isolated from a methanol extract of the soft coral Sinularia cruciata. Their 
structures were elucidated by 1D and 2D-NMR experiments and comparison of their NMR data with reported values. 
This is the first report of these compounds from S. cruciata. 
Keywords. Sinularia cruciata, Alcyoniidae, soft coral, sesquiterpene, sterol.  
 
1. INTRODUCTION 
 
Soft corals are marine invertebrates of the order 
Alcyonacea, class Anthozoa, and phylum Cnidaria. 
These invertebrates are a rich source of secondary 
metabolites, such as diterpenoids and hydroxylated 
sterols [1]. Soft corals of the genera Lobophytum, 
Sarcophyton, and Sinularia are the most prolific [2].  
Sinularia cruciata presents a little investigated 
species with only four sterols (sarcoaldesterol B, 
ergosta-1β,3β,5α,6β-tetraol, cholesterol peroxide, 
and cholesterol) and two alcohols (batilol and 
chimyl alcohol) reported to date [3, 4]. 
As a part of our ongoing investigations on 
Vietnamese soft corals, we report herein the 
isolation and structure elucidation of two 
sesquiterpenes as sinularianin D (1) and 
1S*,4S*,5S*,10R*-4,10-guaianediol (2), and three 
sterols as 24-methylenecholestane-3β,5α,6β-triol-6-
monoacetate (3), 3β,7α-dihydroxyergosta-5,24(28)-
diene (4), and 3β-hydroxyandrost-5-ene-17-one (5) 
from the soft coral S. cruciata. 
 
2. EXPERIMENTAL 
2.1. General experimental procedures 
The 
1
H NMR (500 MHz) and 
13
C NMR (125 
MHz) spectra were recorded on a Bruker AM500 
FT-NMR spectrometer, TMS was used as an internal 
standard. The electrospray ionization mass spectra 
(ESI-MS) were obtained on an Agilent 1260 series 
single quadrupole LC/MS system. Medium pressure 
liquid chromatography (MPLC) was carried out on a 
Biotage - Isolera One system (SE-751 03 Uppsala, 
Sweden). Column chromatography (CC) was 
performed on silica gel (Kieselgel 60, 70–230 mesh 
and 230-400 mesh, Merck) and YMC RP-18 resins 
(30-50 μm, Fuji Silysia Chemical Ltd.). Thin layer 
chromatography (TLC) used pre-coated silica gel 60 
F254 (1.05554.0001, Merck) and RP-18 F254S plates 
(1.15685.0001, Merck). Compounds were visualized 
by spraying with aqueous 10% H2SO4 and heating 
for 3-5 minutes.  
2.2. Marine materials 
The samples of soft coral S. cruciata were 
collected in Ha Long, Quang Ninh, Vietnam, in 
October 2013 and identified by Prof. Do Cong 
Thung (Institute of Marine Environment and 
Resources, VAST). Voucher specimens (No. SHM-
21) were deposited at the Institute of Marine 
Environment and Resources and the Institute of 
Marine Biochemistry, VAST, Vietnam. 
 
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VJC, Vol. 53(2e), 2015                                                                                                  Nguyen Hoai Nam, et al. 
2.3. Isolation 
Freeze-dried bodies of the soft coral S. cruciata 
(2.0 kg) were well grinded and extracted three times 
with MeOH in ultrasonic condition (3×1h) to obtain 
an extract (120.0 g, M), which was suspended in 
H2O (2.0 L) and then partitioned with CH2Cl2 (3 × 
2.0 L) to furnish CH2Cl2 residue (65.0 g, C) and 
water layer. Residue C (65 g) was crudely separated 
by silica gel MPLC using gradient concentrations of 
acetone in n-hexane (from 0 to 100 %) to give eight 
fractions (C-1→C-8). Fraction C-4 (5.0 g) was 
separated into five subfractions, C-4A to C-4E by 
YMC CC eluting with MeOHH2O (5:1). 
Compound 5 (2 mg) was purified from subfraction 
C-4B (0.38 mg) by silica gel CC using n-
hexaneethyl acetate (4:1) as eluent. Fraction C-5 
(6.0 g) was separated by YMC RP-18 MPLC using 
mobile phase of methanol–H2O (5:1) to obtain five 
subfractions,  C5A–C5E. Purification of subfraction 
C-5B (0.78 g) by silica gel CC eluting with n-
hexane-acetone (6:1) to obtain compounds 1 (5 mg) 
and 2 (7 mg). Fraction C-6 (12 g) was crudely 
separated into six subfractions C-6A-C-6E by YMC 
RP-18 MPLC using mobile phase of methanol–H2O 
(5:1).  Subfraction C6D (3.2 g) was further separated 
by silica gel CC eluding with n-hexane–ethyl acetate 
(3:1) to give four smaller fractions C6D1–C6D4. 
Fraction C6D3 (400 mg) furnished compounds 3 
(6.0 mg) and 4 (3.6 mg) after subjecting it to silica 
gel CC eluted with dicholoromethane–acetone (6:1), 
followed by Sephadex LH-20 CC with MeOH–H2O 
(3:1).  
 
Figure 1: Chemical structures of compounds 1-5 
Table 1: 
1
H-NMR (500 MHz) and 
13
C-NMR (125 MHz) data of 1, 2, and reported compounds 
 
aδC 
bδC 
1
c dδC 
2
c 
δC δH (J = Hz) δC δH (J = Hz) 
1 78.5  78.4 78.36 - 50.7 50.74 1.88 m 
2 41.8 43.1 43.10 1.80 m/1.94 m 21.5 21.54 1.65 m/1.77 m 
3 25.3 25.9 25.92 1.23 m/2.03 m 40.4 40.51 1.63 m/1.70 m 
4 40.9 41.8 41.85 2.91 m  80.2 80.25 - 
5 137.3 137.5 137.49 - 50.3 50.37 2.17 m 
6 117.2 117.2 117.20 5.25 dd (2.0, 4.0) 121.3 121.31 5.50 br d (2.0) 
7 39.7 39.4 39.42 1.93 m/2.52 m 149.6 149.70 - 
8 85.5 85.6 85.59 - 25.1 25.11 1.94 m/2.19 m 
9 56.6 55.5 55.50 1.55 d (13.0) 42.6 42.65 1.48 m/1.81 m 
10 26.0 28.5 28.46 1.27 s  75.2  75.27 - 
11 20.2 20.5 20.46 1.74 s  37.3  37.32 2.24 m 
12 152.2 150.9 150.93 7.03 d (1.5)  21.4  21.41 0.98 d (7.0) 
13 129.1 129.7 129.67 -  21.3  21.20 0.98 d (7.0) 
14 173.8 174.0 173.53 - 22.5   22.59 1.21 s 
15 10.6 10.6 10.63 1.94 d (1.5) 21.2 21.44 1.29 s 
aC of sinularianin B [5], 
bC of sinularianin D [6],  
c
recorded in CDCl3, 
dC of 1S*,4S*,5S*,10R*-4,10-guaianediol [7]. 
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VJC, Vol. 53(2e), 2015                                                                                   Sesquiterpenes and sterols from… 
Table 2: 
1
H-NMR (500 MHz) and 
13
C-NMR (125 MHz) data of 3, 4, and reported compounds 
C 
a
δC 
b
δC 
3
c
 d
δC 
4
c
 
δC δH mult. (J = Hz) δC δH mult. (J = Hz) 
1 31.9  31.99 1.56/1.43 m 37.1 37.04 1.86/1.14 m 
2 30.6  30.75 1.83/1.50 m 31.4 31.40 1.86/1.52 m 
3 67.2  67.24 4.07 m 71.4 71.37 3.58 m 
4 40.5  40.45 1.59/1.82 m 42.1 42.04 2.19/2.24m 
5 75.2  75.20 - 146.3 146.26 - 
6 76.0  76.13 4.72 br s 123.9 123.89 5.60 dd (1.5, 5.0) 
7 31.4  31.43 1.55/1.66 m 65.4 65.36 3.85 br s 
8 31.0  30.55 1.61 m 37.6 37.55 1.48 m 
9 44.9  45.25 1.33 m 42.3 42.30 1.23 m 
10 38.4  38.43 - 37.4 37.42 - 
11 20.9 21.0 21.11 1.33/1.40 m 20.8 20.73 1.50/1.54 m 
12  39.5 39.92 1.16/2.00 m 39.2 39.21 1.18/2.01 m 
13  42.9 42.77 - 42.2 42.21 - 
14  55.2 55.83 1.08 m 49.5 49.45 1.45 m 
15  26.3 24.09 1.02/1.54 m 24.3 24.30 1.15/1.72 m 
16  28.5 28.19 1.26/1.84 m 28.3 28.26 1.31/1.92 m 
17  55.9 56.03 1.12 m 55.7 55.71 1.21 m 
18  11.8 12.18 0.68 s 11.7 11.65 0.69 s 
19 16.4  16.43 1.14 s 18.3 18.26 1.00 s 
20  35.7 35.77 1.40 m 35.8 35.73 1.43 m 
21  18.7 18.64 0.93 d (7.0) 18.8 18.75 0.96 d (7.0) 
22  34.6 34.69 1.53/1.14 m 34.7 34.70 1.57/1.18 m 
23  30.9 31.03 2.10/1.86 m 30.9 30.86 2.18/1.89 m 
24  156.8 156.82 - 157.0 156.88 - 
25  33.7 33.79 2.23 m 33.9 33.83 2.23 m 
26  22.0 21.99 1.02 d (7.0) 22.1 22.02 1.03 d (7.0) 
27  21.8 21.86 1.01 d (7.0) 22.1 21.88 1.02 d (7.0) 
28  105.8 105.97 4.65 d (0.5)/4.71 brs 106.0 105.99 4.66/4.71 brs 
1 170.6  170.44 -    
2 21.4  21.45 2.06 s    
aC of punicin [8],
 bC of 3β,7β-dihydroxyergosta-5,24(28)-dien [9], 
c
recorded in CDCl3, 
dC of 3β,7α-dihydroxyergosta-
5,24(28)-dien [9].   
Sinularianin D (1): Colorless oil; 
1
H-NMR (500 
MHz, CDCl3) and 
13
C-NMR (125 MHz, CDCl3), see 
table 1; ESI-MS: m/z 247 [MH] (C15H20O3, M = 
248). 
1S*,4S*,5S*,10R*-4,10-Guaianediol (2): White 
powder; 
1
H-NMR (500 MHz, CDCl3) and 
13
C-NMR 
(125 MHz, CDCl3), see table 1; ESI-MS: m/z 237 
[MH] (C15H26O2, M = 238). 
24-Methylenecholestane-3β,5α,6β-triol-6-
monoacetate (3): White powder; 
1
H-NMR (500 
MHz, CDCl3) and 
13
C-NMR (125 MHz, CDCl3), see 
table 2; ESI-MS: m/z 475 [M+H]
+
 (C30H50O4, M = 
474). 
3β,7α-Dihydroxyergost-5,24(28)-diene (4): 
White powder; 
1
H-NMR (500 MHz, CDCl3) and 
13
C-NMR (125 MHz, CDCl3), see table 2; ESI-MS: 
m/z 397 [MH2O+H]
+
 (C28H46O2, M = 414).  
3β-Hydroxyandrost-5-ene-17-one (5): White 
powder; 
1
H-NMR (500 MHz, CDCl3): H 1.10 (1H, 
m, Ha-1), 1.86 (1H, m, Hb-1), 1.52 (1H, m, Ha-2), 
1.84 (1H, m, Hb-2), 3.53 (1H, m, H-3), 2.25 (1H, m, 
Ha-4), 2.33 (1H, m, Hb-4), 5.38 (1H, m, H-6), 1.64 
(1H, m, Ha-7), 2.12 (1H, m, Hb-7), 1.68 (1H, m, H-
8), 1.01 (1H, m, H-9), 1.50 (1H, m, Ha-11), 1.68 
(1H, m, Hb-11), 1.28 (1H, m, Ha-12), 1.84 (1H, m, 
Hb-12), 1.28 (1H, m, H-14), 1.55 (1H, m, Ha-15), 
1.95 (1H, m, Hb-15), 2.07 (1H, m, Ha-16), 2.46 (1H, 
m, Hb-16), 0.89 (3H, s, H-18), and 1.04 (3H, s, H-
19); 
13
C-NMR (125 MHz, CDCl3): C 37.20 (C-1), 
31.59 (C-2), 71.59 (C-3), 42.22 (C-4), 141.05 (C-5), 
120.91 (C-6), 30.79 (C-7), 31.52 (C-8), 50.27 (C-9), 
36.65 (C-10), 20.37 (C-11), 31.46 (C-12), 47.54 (C-
13), 51.79 (C-14), 21.88 (C-15), 35.83 (C-16), 
221.08 (C-17), 13.54 (C-18), and 19.42 (C-19); ESI-
MS: m/z 289 [M+H]
+
 (C19H28O2, M = 288). 
 110 
VJC, Vol. 53(2e), 2015                                                                                                  Nguyen Hoai Nam, et al. 
3. RESULTS AND DISCUSSION 
 
Compound 1 was obtained as a colorless oil. 
The 
13
C-NMR spectrum exhibited 15 carbon signals 
indicating for presence of a sesquiterpene. The 
1
H 
and 
13
C-NMR spectra confirmed the presence of two 
quaternary oxygenated carbons [C 78.36 (C-1) and 
85.59 (C-8)], two trisubstituted double bonds [C 
137.49 (s, C-5) and 117.20 (d, C-6)/H 5.25 (1H, dd, 
J = 2.0, 4.0 Hz, H-6) and C 150.93 (d, C-12)/H 
7.03 (1H, d, J = 1.5 Hz, H-13)], three tertiary methyl 
groups [C 28.46 (C-10), 20.46 (C-11), and 10.63 
(C-15)/H 1.27 (3H, s, H-10), 1.74 (3H, s, H-11), and 
1.94 (3H, d, J = 1.5 Hz, H-15)], and a lactone 
carbonyl [C 173.53 (C-14)]. Consideration of the 
1
H-NMR chemical shifts of three methyl protons at 
H 1.27, 1.74, and 1.94 suggesting their locations on 
a quaternary oxygenated carbon, on a double bond, 
and adjacent to the lactone carbonyl, respectively. 
From the above observation, the 
13
C-NMR data of 1 
were compared with those of sinularianin B [5] and 
found to be similar. However, a close inspection of 
their 
13
C-NMR data revealed some significant 
difference: C-9 and C-10 were shifted from C 56.6 
to 55.50 and from C 26.0 to 28.4, respectively (see 
table 1). This suggested that 1 is a configuration 
isomer of sinularianin B. The 
13
C-NMR data of 1 
were further compared with those of sinularianin D 
[6] and found to match. Moreover, detailed analysis of the 
HMBC correlations (see figure 2) confirmed the 
elucidation of 1 as sinularianin D. 
 
 
Figure 2: Key HMBC correlations of 1 and 2 
The NMR features of 2 were also indicative of a 
sesquiterpene. Two quaternary oxygenated carbons 
[C 80.25 (C-4) and 75.27 (C-10)], a trisubstituted 
double bond [C 121.31 (d, C-6)/H 5.50 (1H, br d, J 
= 2.0 Hz, H-6)], and two tertiary methyl groups [C 
22.59 (C-14), and 21.44 (C-15)/H 1.21 (H-14) and 
1.29 (H-15), each 3H, s] were observed. In addition, 
two secondary methyl groups were identified by a 
proton signal at 0.98 (6H, d, J = 7.0 Hz, H-12 and H-
13). The good agreement of the 
13
C-NMR data of 2 
with the reported values (see table 1) and 
combination with 2D-NMR data confirmed its 
structure as 1S*,4S*,5S*,10R*-4,10-guaianediol [7]. 
Compound 3 was obtained as a white powder. 
The 
1
H and 
13
C-NMR data were typical for a 24-
methylenecholestane-type sterol [9] with typical 
signals of a terminal disubstituted double bond [C 
156.82 (s, C-24) and 105.97 (t, C-28)/H 4.65 (1H, d, 
J = 0.5 Hz, Ha-28) and 4.71 (1H, br s, Hb-28)], two 
tertiary methyl [C 12.18 (C-18) and 16.43 (C-19)/H 
0.68 (H-18) and 1.14 (H-19), each 3H, s], and three 
secondary methyl groups [C 18.64 (C-21), 21.99 
(C-26), and 21.86 (C-27)/H 0.93 (H-21), 1.02 (H-
26), and 1.01 (H-27), each 3H, d, J = 7.0 Hz].  
 
 
Figure 3: Key HMBC correlations of 3 
In addition, two oxymethine groups [C 67.24 
(C-3)/4.07 (1H, m, H-3) and 76.13 (C-6)/H 4.72 
(1H, br s, H-6)], a quaternary oxygenated carbon [C 
75.20 (C-5)], and an acetate group [C 170.44 (s, C-
1) and 21.45 (q, C-2)/H 2.06 (3H, s, H-2)] were 
identified in the 
1
H and 
13
C-NMR spectra of 3. The 
oxygenated positions at C-3 and C-5 and acetylated 
position at C-6 were assigned by a good agreement 
of the 
13
C-NMR data for the A and B rings of 3 with 
those of punicin [8], which was further confirmed by 
HMBC experiment (see figure 3). Thus, compound 3 
was elucidated as 24-methylenecholestane-3β,5α,6β-
triol-6-monoacetate. This compound was first 
isolated from the soft coral Sinularia dissecta in 
1976 [10] and recently found from Sinularia sp. in 
2012 [11]. However, this is the first report of 3 from 
S. cruciata and its full 
1
H and 
13
C-NMR were 
reported here for the first time. 
Compounds 4 and 5 were elucidated as 3β,7α-
dihydroxyergosta-5,24(28)-dien [9] and 3β-
hydroxyandrost-5-en-17-one [12] by comparison of 
its 
13
C-NMR data with the reported values and 
combination with 2D-NMR data. This is the first 
report of compounds 1-5 from the soft coral S. 
cruciata. 
 
 111 
VJC, Vol. 53(2e), 2015                                                                                   Sesquiterpenes and sterols from… 
Acknowledgements. This work was financially 
supported by Vietnam Academy of Science and 
Technology, codes: VAST.TÐ.ÐAB.02/13–15 and 
Project between IMBC and KIOST  
 
REFERENCES 
 
1. J. C. Coll. The chemistry and chemical ecology of 
octocorals (Coelenterata, Anthozoa, Octocorallia). 
Chem. Rev., 92(4), 613-631 (1992). 
2. X. T. Liang, W. S. Fang. Medicinal Chemistry of 
Bioactive Natural Products, New Jersey: John Wiley 
& Sons, 257-300 (2006). 
3. V. Q. Hung, N. T. Hoai. Two polyoxygenated 
steroids from Vietnamese soft coral Sinularia 
cruciata, Journal of Medicine and Pharmacy, 
2012(9), 57-62 (2012). 
4. V. Q. Hung, N. D. P. Nhi, N. D. Q. Phu, H. T. D. 
Tram, N. T. Hoai. Anti-cancer compounds isolated 
from soft coral Sinularia cruciata - Alcyoniidae, 
Journal of Practical Medicine, 2012(818-819), 7-11 
(2012). 
5. C.-H. Chao, C.-H. Hsieh, S.-P. Chen, C.-K. Lu, C.-
F. Dai, J.-H. Sheu. Sinularianins A and B, novel 
sesquiterpenoids from the Formosan soft coral 
Sinularia sp., Tetrahedron Lett., 47(33), 5889-5891 
(2006). 
6. B. Yang, S. Liao, X. Lin, J. Wang, J. Liu, X. Zhou, 
X. Yang, Y. Liu. New sinularianin sesquiterpenes 
from soft coral Sinularia sp., Mar. Drugs, 11(12), 
4741-4750 (2013). 
7. G. W. Zhang, X. Q. Ma, J. Y. Su, K. Zhang, H. 
Kurihara, X. S. Yao, L. M. Zeng. Two new bioactive 
sesquiterpenes from the soft coral Sinularia sp., Nat. 
Prod. Res., 20(7), 659-664 (2006). 
8. R. d. A. Epifanio, L. F. Maia, A. C. Pinto, I. Hardt, 
W. Fenical. Natural products from the gorgonian 
Lophogorgia punicea: Isolation and struture 
elucidation of an unusual 17-hydroxy sterol, J. Braz. 
Chem. Soc., 9(2), 187-192 (1998). 
9. F. De Riccardis, L. Minale, M. Iorizzi, C. Debitus, 
C. Lévi. Marine sterols. Side-chain-oxygenated 
sterols, possibly of abiotic origin, from the new 
Caledonian sponge Stelodoryx chlorophylla, J. Nat. 
Prod., 56(2), 282-287 (1993). 
10. M. Bortolotto, J. C. Braekman, D. Daloze, B. 
Tursch. Chemical studies of marine invertebrates. 
XVIII: Four novel polyhydroxylated steroids from 
Sinularia dissecta (Coelenterata, Octocorallia. 
Alcyonacea), Bull. Soc. Chim. Belg., 85(1-2), 27-34 
(1976). 
11. R. Li, C.-L. Shao, X. Qi, X.-B. Li, J. Li, L.-L. Sun, 
C.-Y. Wang. Polyoxygenated sterols from the south 
China sea soft coral Sinularia sp., Mar. Drugs, 
10(7), 1422-1432 (2012). 
12. J. W. Blunt, J. B. Stothers. 
13
C-NMR spectra of 
steroids - a survey and commentary, Org. Magn. 
Reson., 9(8), 439-464 (1977). 
 
Corresponding author: Nguyen Hoai Nam 
                       Institute of Marine Biochemistry, Vietnam Academy of Science and Technology 
                       18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 
                        E-mail: namnguyenhoai@imbc.vast.vn. 
 


Sesquiterpenes and sterols from the soft coral Sinularia cruciata

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Sesquiterpenes and sterols from the soft coral Sinularia cruciata

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