Steroids glycosylated with both d- and l-arabinoses from the South China Sea gorgonian Dichotella gemmacea

Article abstract of DOI:10.1021/np300906b

Three new 19-hydroxy steroidal glycosides, namely, junceellosides E-G (2-4), were isolated together with the known analogue junceelloside C (1) from the South China Sea gorgonian Dichotella gemmacea. The structures of these compounds were elucidated by a combination of detailed spectroscopic analyses, chemical methods, and comparison with reported data. These glycosides are found to have sugar moieties of both β-l- and β-d-arabinopyranoses by HPLC analysis of their thiocarbamoyl-thiazolidine derivatives and those of authentic d- and l-arabinoses, leading to the structure revision of junceelloside C (1). This is the first report of steroidal glycosides from the gorgonian D. gemmacea and the first report of glycosides with β-l-arabinopyranose from marine sources.

Full text of DOI:10.1021/np300906b

Note
pubs.acs.org/jnp
Steroids Glycosylated with Both D- and L‑Arabinoses from the South
China Sea Gorgonian Dichotella gemmacea
Mei Jiang, Peng Sun, Hua Tang, Bao-Shu Liu, Tie-Jun Li, Cui Li, and Wen Zhang*
Research Center for Marine Drugs and Department of Pharmacology, School of Pharmacy, Second Military Medical University, 325
Guo-He Road, Shanghai 200433, People’s Republic of China
S
* Supporting Information
ABSTRACT: Three new 19-hydroxy steroidal glycosides, namely,
junceellosides E−G (2−4), were isolated together with the known
analogue junceelloside C (1) from the South China Sea gorgonian
Dichotella gemmacea. The structures of these compounds were
elucidated by a combination of detailed spectroscopic analyses,
chemical methods, and comparison with reported data. These
glycosides are found to have sugar moieties of both β-L- and β-D-
arabinopyranoses by HPLC analysis of their thiocarbamoyl-
thiazolidine derivatives and those of authentic D- and L-arabinoses,
leading to the structure revision of junceelloside C (1). This is the first
report of steroidal glycosides from the gorgonian D. gemmacea and the first report of glycosides with β-L-arabinopyranose from
marine sources.
teroids with a 19-hydroxy group have received considerable
Sattention since the first 19-hydroxylated steroid, 24-
methylenecholest-5-ene-3β,7β,19-triol, was isolated from Lito-
phyton viridis and helped to explain the biosynthesis of 19-nor
steroids.1 Since then, an increasing number of 19-hydroxy
sterols have been found mainly from black coral,2 soft corals,3
sponges,4 and gorgonians.5 These metabolites were reported to
exhibit cytotoxic activities toward the P-388, HT-29, A549, and
KB tumor cell lines.6 Recently, several 19-hydroxy steroidal
glycosides were reported from gorgonian corals Junceella
juncea7,8 and Dichotella fragilis.9 Some of the glycosides
displayed brine shrimp lethality and antifouling activity.9
In the course of our ongoing screening for biologically active
secondary metabolites from marine sources,10−13 we made
several collections of the gorgonian Dichotella gemmacea from
the coast of Beihai, China. Chemical investigations of this
species have uncovered briarane diterpenoids,11−16 an alkane,14
Freshly collected specimens of D. gemmacea were immedi-
ately frozen at −20 °C and stored at this temperature before
and fatty acids.17 Our earlier investigation of the extract of D.
gemmacea led to the isolation and structure determination of 28
briarane diterpenoids.11−13 Our continuing investigation of the
EtOAc-soluble fraction from the acetone extract of D.
gemmacea has now led to the isolation of the 19-hydroxy
steroidal glycoside junceelloside C (1) together with three new
analogues, namely, junceellosides E−G (2−4). The structures
of these compounds were elucidated by a combination of
chemical methods and detailed analysis of their spectroscopic
data, aided by the comparison with reported data. This is the
first report of 19-hydroxy steroidal glycosides from the
gorgonian D. gemmacea and the first report of glycosides with
β-L-arabinopyranose from marine sources. We herein report the
isolation, structure elucidation, and bioactivity of these
compounds.
extraction. Frozen material was cut into small pieces and
extracted with acetone. The EtOAc-soluble portion of the
acetone extract was subjected to repeated column chromatog-
raphy on silica gel, Sephadex LH-20, and RP-HPLC to afford
four pure steroid glycosides (1−4).
Compound 1 was isolated as an optically active, white,
amorphous solid. The molecular formula of 1 was established as
C34H56O8 from the pseudomolecular ion at m/z 615.3870 [M +
Na]+ in the HRESIMS spectrum, indicating seven degrees of
double-bond equivalents. The IR spectrum showed the
presence of hydroxy (3370 cm−1) and ketone (1734 cm−1)
Received: December 25, 2012
Published: March 11, 2013
© 2013 American Chemical Society and
American Society of Pharmacognosy
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dx.doi.org/10.1021/np300906b | J. Nat. Prod. 2013, 76, 764−768

Journal of Natural Products
Note
1
functionalities. This observation was in agreement with the
signals in the 13C and DEPT spectra (Table 1) for three sp2
Table 2. H NMR Data for Compounds 1−4 (in pyridine-
a
d5)
b
c
c
b
1
2
3
4
Table 1. 13C NMR Data for Compounds 1−4 (in pyridine-
a
position δH (J in HZ) δH (J in HZ)
δH (J in HZ)
δH (J in HZ)
d5)
1α
2.30 brd
(13.2)
2.30 brd
(13.2)
2.30 brd (13.2) 2.30 brd
(13.2)
b
c
c
b
1
2
3
4
1β
2α
2β
3
1.10, ov
2.17, ov
1.85, ov
3.87, m
1.10, ov
2.15, ov
1.83, ov
3.87, m
1.06, ov
2.08, ov
1.90, ov
3.87, m
1.10, ov
2.10, ov
1.88, ov
3.80, m
position
δC, type
δC, type
δC, type
δC, type
C-1
34.4, CH2
31.1, CH2
78.0, CH
40.1, CH2
138.2, C
34.4, CH2
31.1, CH2
78.0, CH
40.1, CH2
138.2, C
34.4, CH2
31.2, CH2
77.9, CH
40.1, CH2
138.2, C
34.4, CH2
30.9, CH2
77.9, CH
39.9, CH2
137.8, C
C-2
C-3
4α
2.60, dd
(10.8, 10.8)
2.60, dd
(11.2, 11.2)
2.60, dd (11.2,
11.2)
2.60, dd
(11.2, 11.2)
C-4
C-5
4β
2.75, dd
(12.8, 2.8)
2.74, dd
(13.2, 3.0)
2.74, dd (13.7,
3.0)
2.74, dd
(13.2, 3.0)
C-6
125.8, CH
32.8, CH2
33.7, CH
51.6, CH
42.6, C
125.7, CH
32.8, CH2
33.7, CH
51.6, CH
42.6, C
125.7, CH
32.5, CH2
33.7, CH
51.6, CH
42.6, C
126.0, CH
32.5, CH2
33.7, CH
51.6, CH
42.6, C
C-7
6
5.66 brs
2.07, ov
1.62, ov
2.06, m
0.96, m
1.75, m
2.04, m
1.25, ov
2.12, ov
0.93, m
1.62, m
1.11, m
1.90, m
1.28, m
1.17, m
0.83, s
5.66 brs
2.15, ov
1.60, ov
2.06, m
0.96, m
1.75, m
2.06, m
1.30, ov
2.05, ov
0.93, m
1.53, m
1.15, m
1.75, m
1.50, m
1.17, m
0.83, s
5.66 brs
2.17, ov
1.57, ov
2.06, m
0.96, m
1.75, m
2.03, m
1.28, ov
2.05, ov
0.93, m
1.58, m
1.12, m
1.75, m
1.50, m
1.17, m
0.83, s
5.66 brs
2.07, ov
1.62, ov
2.06, m
C-8
7α
C-9
7β
C-10
C-11
C-12
C-13
C-14
C-15
C-16
C-17
C-18
C-19
C-20
C-21
C-22
C-23
C-24
C-25
C-26
C-27
C-28
1′
8
22.5, CH2
41.0, CH2
43.2, C
22.5, CH2
41.0, CH2
43.2, C
22.7, CH2
40.8, CH2
43.2, C
22.7, CH2
40.8, CH2
43.2, C
9
0.96, m
11α
11β
12α
12β
14
1.75, m
2.04, m
58.2, CH
24.9, CH2
28.9, CH2
56.7, CH
12.9, CH3
63.5, CH2
36.6, CH
19.4, CH3
35.8, CH2
27.9, CH2
41.2, CH2
82.7, C
58.2, CH
24.9, CH2
28.9, CH2
56.7, CH
12.9, CH3
63.5, CH2
36.6, CH
19.4, CH3
35.8, CH2
27.9, CH2
154.2, C
58.2, CH
24.9, CH2
29.5, CH2
56.3, CH
12.9, CH3
63.4, CH2
41.0, CH
21.4, CH3
141.8, CH
122.8, CH
44.1, CH2
82.4, C
58.0, CH
24.9, CH2
28.9, CH2
56.8, CH
12.7, CH3
63.3, CH2
36.4, CH
19.2, CH3
36.9, CH2
21.2, CH2
41.7, CH2
82.7, C
1.25, ov
2.12, ov
0.93, m
15α
15β
16α
16β
17
1.62, m
1.11, m
1.90, m
1.28, m
1.17, m
18
0.83, s
19a
19b
20
4.15, d (11.4) 4.15, d (11.4) 4.15, d (11.4)
3.89, d (11.4) 3.89, d (11.4) 3.89, d (11.4)
4.15, d (11.4)
3.89, d (11.4)
1.52, m
82.4, C
1.52, m
1.52, m
2.05, m
26.5, CH3
26.5, CH3
27.5, CH3
27.5, CH3
108.8, CH2
99.7, CH
71.1, CH
71.5, CH
70.6, CH
64.7, CH2
170.1, C
26.5, CH3
26.5, CH3
26.5, CH3
26.5, CH3
21
0.99, d (6.6) 0.99, d (6.6) 1.08, d (6.6)
0.99, d (6.6)
1.06, 1.60, m
22
1.06, 1.60, m 1.52, 1.82, m 5.43, dd (15.2,
8.3)
23
1.35, 1.50, m 1.53, 1.53, m 5.45, ddd (15.2, 1.35, 1.50, m
7.0, 6.9)
99.7, CH
71.1, CH
71.6, CH
70.7, CH
64.8, CH2
170.7, C
99.7, CH
71.1, CH
71.5, CH
70.6, CH
64.7, CH2
170.6, C
96.2, CH
73.6, CH
68.2, CH
70.8, CH
64.5, CH2
170.6, C
2′
3′
4′
5′
24
26
27
28
1.75, 1.90, m
1.53, s
2.60, 2.60, ov
1.52, s
1.75, 1.90, m
1.53, s
1.65, s
1.53, s
1.65, s
1.52, s
1.53, s
5.18, 5.02, s
2.02, s
25-OAc
25-OAc 2.01, s
2.02, s
2.01, s
21.1, CH3
21.1, CH3
21.1, CH3
21.1, CH3
171.4, C
1′
2′
5.55, d (3.6) 5.55, d (3.4) 5.55, d (3.4)
5.71, d (3.6)
2′-OAc
4.65, dd (9.4, 4.62, dd (9.4, 4.62, dd (9.4,
3.6)
5.81, dd (9.4,
3.6)
21.3, CH3
3.4)
3.4)
a
δ in ppm, assignments made by DEPT, COSY, HSQC, HMBC, and
3′
4.55, dd (9.4, 4.52, dd (9.4, 4.52, dd (9.4,
4.62, dd (9.4,
3.4)
b
c
3.4)
3.4)
3.4)
NOESY. At 100 MHz. At 150 MHz.
4′
4.43, brs
4.43 brs
4.43 brs
4.43 brs
5′α
4.10, dd
4.10, dd
4.10, dd (11.9,
2.8)
4.10, dd
carbon atoms at lower field (1 × OC, 1 × CCH) and 31
sp3 carbon atoms at higher field (1 × OC, 4 × OCH, 2 ×
OCH2, 2 × C, 6 × CH, 11 × CH2, 5 × CH3), accounting for
two double-bond equivalents. The O-bearing-methine protons
resonating between δ 4.10 and 5.55 (Table 2) in conjunction
with the presence of related secondary alcohol carbons (δC
71.1, 71.6, 70.7, 64.8) and an acetal carbon (δC 99.7) suggested
the presence of a sugar moiety in the molecule, accounting for
one additional double-bond equivalent. The remaining double-
bond equivalents were due to the presence of four rings in the
(11.9, 2.8)
(11.9, 2.8)
(11.9, 2.8)
5′β
OAc
4.25, d (11.9) 4.25, d (11.9) 4.25, d (11.9)
4.25, d (11.9)
2.02, s
a
δ in ppm, assignments made by DEPT, COSY, HSQC, HMBC, and
b
c
NOESY. At 400 MHz. At 600 MHz.
configuration for both compounds. In particular, a β-
arabinopyranose was clearly indicated by the large coupling
constant between H-2′ and H-3′ (3J = 9.4 Hz) and the small
coupling constant between H-1′ and H-2′ (3J = 3.6 Hz) and
between H-3′ and H-4′ (3J = 3.4 Hz) (in pyridine-d5),
indicating antiaxial protons for H-2′ and H-3′ and equatorial
protons for H-1′and H-4′, respectively. However, the absolute
configuration of the monosaccharide in 1 was determined as L-
1
aglycone of 1. The H and 13C NMR spectra of 1 in CDCl3
(see Table S1 in the Supporting Information) were identical to
those of junceelloside C (5), a 19-hydroxy steroidal glycoside
isolated previously from the gorgonian coral Junceella juncea.8
Detailed 2D NMR analysis revealed the same relative
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Journal of Natural Products
Note
arabinose instead of D-arabinose by comparison of the retention
time of its thiocarbamoyl-thiazolidine derivative of the acid
hydrolysate (20.9 min) with those of standard samples of L-
arabinose (20.8 min) and D-arabinose (23.0 min), respec-
tively.10 Compound 1 was therefore determined as 25-O-acetyl-
3-O-[β-L-arabinopyranosyloxy]cholest-5-ene-3β,19,25-triol.
Although junceelloside C (5) was reported as a β-D-arabinoside,
the structure of 5 was elucidated from NMR data only, and
there were no data or experiments to support the absolute
respective proton signal at H-2′ from δ 4.65 in 1 to δ 5.81 in 4.
The sugar subunit of 4 was determined as a 2′-monoacetate of
β-D-arabinopyranose by the HPLC analysis as described
above.10 The structure of compound 4 was thus assigned to
be 2′,25-O-diacetyl-3-O-[β-D-arabinopyranosyloxy]cholest-5-
ene-3β,19,25-triol.
The isolates were evaluated in vitro for the tumor growth
inhibitory activity toward the A549 and MG63 cell lines.19
None of the compounds were considered active (IC50 > 10 μM;
see Table S2 in the Supporting Information).
This is the first report of 19-hydroxy steroidal glycosides
from the gorgonian D. gemmacea and the first report of
glycosides with a β-L-arabinopyranose moiety from marine
sources. A series of sterol glycosides have been obtained from
octocorals and a sponge,20 including 4′-O-acetyl-3-O-[β-D-
arabinopyranosyloxy]cholest-5-ene-3β,19-diol7 and junceello-
sides A−D8 from the gorgonian J. juncea, fragiliosides A and
B from the gorgonian Dichotella fragilis,9 and carijoside A from
the octocoral Carijoa sp.15 All of the isolates are simply claimed
to have a β-D-arabinopyranose on the basis of an NMR analysis.
Recently, two steroid glycosides, namely, sokodosides A and B
(6 and 7) (Figure 1), were obtained from the Hachijo sponge
8
configuration of the arabinose. Because the H and 13C NMR
data are identical (see Table S1 in the Supporting Information)
and the specific rotations can be considered the same based on
general variations of these measurements [−116 (c 0.25,
C5H5N) for 1 vs −114.0 (c 0.55, C5H5N) for 58], it is
reasonable to conclude that 1 and junceelloside C are the same
compound, and therefore 1 should be designated as junceello-
side C. The original structure 5 should be revised to structure
1.18
1
Junceelloside E (2) was isolated as an optically active, white,
amorphous solid. Its molecular formula, C35H56O8, was
deduced from the HRESIMS spectrum. The 1H and 13C
NMR spectra of 2 were closely related to those of 1 except for
the appearance of an additional terminal double bond (δH 5.08,
s and 5.12, s; δC 154.2, C and 108.8, CH2). The location of the
double bond at C-24 was clearly indicated by the distinct
HMBC correlations from H2-28 to C-23, C-24, and C-25.
Configurations for the other stereogenic centers in 2 were
proven to be the same as those in 1 by detailed 2D NMR
analysis. The absolute configuration of the sugar moiety was
identified as L-arabinopyranose by HPLC analysis of the
thiocarbamoyl-thiazolidine derivative of the acid hydrolysate of
2 and those of authentic D- and L-arabinoses.10 Compound 2
was thus assigned to be 25-O-acetyl-3-O-[β-L-
arabinopyranosyloxy]cholest-5,24(28)-diene-3β,19,25-triol.
Junceelloside F (3) was isolated as an optically active, white,
amorphous solid. The molecular formula of 3 was established as
C34H54O8 by an HRESIMS experiment. Analysis of the 1H and
13C NMR spectra of 3 revealed a strong similarity to those of 1.
However, an additional disubstituted double bond at lower field
(AB system, δH 5.43, 1H, dd, J = 15.2, 8.3 Hz; 5.45, 1H, ddd, J
= 15.2, 7.0, 6.9 Hz; δC 141.8, CH; 122.8, CH) was assigned as
Δ22 due to the proton connectivity from H3-21 to H2-24 as
established by the COSY experiment and the significant long-
range correlations of H3-21 with C-17, C-20, and C-22
observed in the HMBC spectrum. The E geometry of Δ22
was deduced from the large coupling constant (15.2 Hz)
between the olefinic protons. A β-arabinopyranose was deduced
from the large coupling constant between H-2′ and H-3′ (3J =
9.4 Hz) and the small coupling constant between H-1′ and H-
2′ (3J = 3.4 Hz) and between H-3′ and H-4′ (3J = 3.4 Hz). Its
absolute configuration was identified as D-arabinopyranose in
contrast to L-arabinopyranose by HPLC analysis of the
thiocarbamoyl-thiazolidine derivative of the acid hydrolysate
of 3 and those of authentic D- and L-arabinoses.10 The structure
of 3 was therefore determined as 25-O-acetyl-3-O-[β-D-
arabinopyranosyloxy]-(22E)-cholesta-5,22-diene-3β,19,25-triol.
Junceelloside G (4), an optically active, white, amorphous
solid, had a molecular formula of C36H58O9, as established by
Figure 1. Structures of sokodosides A (6) and B (7).
Erylus placenta.21 The structures that were stated to have a β-L-
arabinopyranose based on chiral-phase GC analyses of the
hydrolyzed sugars in fact have an α-L-arabinopyranose moiety
due to the large coupling constant of their anomeric protons (3J
= 6.5 Hz).22 The structures as originally drawn in ref 21 and as
depicted in Figure 1 correctly represent an α-L-arabinose
moiety.
It is extremely interesting to observe that D- and L-arabinose
modifications occur in the same gorgonian specimen. The
isolation of steroids with both D- and L-arabinoses from the
same species indicates it is inappropriate to determine the
absolute configuration of a sugar moiety simply by an NMR
analysis or biogenetic correlation. The use of an HPLC or GC
analysis of a sugar derivative from the acid hydrolysate is
therefore strongly recommended in the absolute structure
determination of the saccharide portion of glycosides.
1
HRESIMS, showing 42 more mass units than 1. The H and
13C NMR spectra of 4 were almost identical to those of 1
(Tables 1 and 2), except for the presence of an additional acetyl
group (δH 2.02, s; δC 21.3, CH3; 171.4, C). The location of the
acetoxy group at C-2′ was shown by the downfield shift of the
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Journal of Natural Products
Note
was performed on an Agilent 1100 HPLC system (Agilent
Technologies Inc.) equipped with a photodiode array detector and a
Diamonsil-C18 column (particle size 5 μm, 250 × 4.6 mm) at 35 °C
with isocratic elution of 25% CH3CN in 50 mmol/L H3PO4 solution
for 40 min and subsequent washing of the column with 90% CH3CN
at a flow rate of 0.8 mL/min. The injection volume was 4 μL, and
peaks were detected at 250 nm. The reaction conditions for authentic
L- and D-arabinose were the same as described above.10 The absolute
configurations of the monosaccharides were determined as L-arabinoae
in 1 (tR 20.9 min) and 2 (tR 21.1 min) and D-arabinoae in 3 (tR 23.2
min) and 4 (tR 23.2 min) by comparison of the retention time of the
thiocarbamoyl-thiazolidine derivative of the acid hydrolysate of
steroidal glycosides (1−4) with those of standard samples of L-
arabinose (20.8 min) and D-arabinose (23.0 min), respectively.
Cytotoxicity Assay. Cytotoxicity was tested against human lung
adenocarcinoma (A549) and human osteosarcoma (MG63) cell lines,
using a modification of the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide] colorimetric method.19 Adriamycin was
used as a positive control; IC50 = 2.8 and 3.4 μM, respectively.
EXPERIMENTAL SECTION
■
General Experimental Procedures. Optical rotations were
measured in CHCl3 on an Anton Paar MCP 500 polarimeter at the
sodium D line (590 nm). Infrared spectra were recorded in thin
polymer films on a Nexus 470 FT-IR spectrophotometer (Nicolet).
The NMR spectra were recorded at 300 K on Bruker DRX 400, DRX
500, and Avance 600 spectrometers. 13C NMR and 1H NMR chemical
shift values were referenced to CDCl3 (δC 77.0 ppm) and the residual
CHCl3 signals (δH 7.26 ppm), and pyridine-d5 (δC 150.3, 135.9, 123.9)
and residual pyridine (δH 8.74, 7.58, 7.22); assignments were
supported by COSY, HSQC, HMBC, and NOESY experiments. The
mass spectra and high-resolution mass spectra were obtained on a Q-
TOF Micro mass spectrometer, resolution 5000. An isopropyl alcohol
solution of sodium iodide (2 mg/mL) was used as a reference
compound. Semipreparative RP-HPLC was performed on an Agilent
1100 system equipped with a refractive index detector using a YMC-
Pack-ODS-A column (particle size 5 μm, 250 × 10 mm). Commercial
silica gel (Yantai, P. R. China, 200−300; 400−500 mesh) was used for
column chromatography. Precoated SiO2 plates (HSGF-254; Yantai,
China) were used for analytical TLC. Spots were detected on TLC
under UV light or by heating after spraying with anisaldehyde−sulfuric
acid reagent.
ASSOCIATED CONTENT
* Supporting Information
■
S
Animal Material. The gorgonian coral Dichotella gemmacea (3.5
kg, wet weight) was collected from the South China Sea in August
2008, at a depth of 16 m, and authenticated by Dr. Xiu-Bao Li (The
South China Sea Institute of Oceanology, Chinese Academy of
Sciences). A voucher specimen (ZS-5) was deposited in the Second
Military Medical University.
HRESIMS and NMR spectra for 1−4, NMR data in CDCl3 for
1 and 4, and HPLC spectra for thiocarbamoyl-thiazolidine
derivatives of acid hydrolysates of 1−4 and reference
compounds are available free of charge via the Internet at
http://pubs.acs.org.
Extraction and Isolation. The frozen animals were cut into small
pieces and extracted ultrasonically with acetone (2.0 L × 3) and
MeOH (1.5 L × 3). The combined residue was partitioned between
H2O and EtOAc to afford 16.1 g of an EtOAc extract. The EtOAc
extract was further partitioned between MeOH and hexane, affording
11.2 g of a MeOH-soluble residue. The MeOH extract was subjected
to column chromatography (CC) on silica to give 16 fractions, using
hexane/acetone (from 100:0 to 0:100) as eluent. Fraction 4 was
subjected to Sephadex LH-20 (CHCl3/MeOH, 1:1) to give eight
subfractions. Subfraction 3 was chromatographed on a silica gel
column (gradient n-hexane/acetone, from 10:1 to 1:1) and HPLC
(particle size 5 μm, 250 × 10 mm; 85% MeOH/H2O; 1.5 mL/min) to
yield 1 (10.0 mg, tR 29.3 min), 2 (5.1 mg, tR 27.1 min), 3 (7.8 mg, tR
25.2 min), and 4 (3.5 mg, tR 31.5 min).
AUTHOR INFORMATION
Corresponding Author
*Tel/Fax: 86 21 81871257. E-mail: wenzhang1968@163.com.
Notes
■
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The research work was financially supported by NSFC (Nos.
41076082, 81202453), the National Marine “863” Project (No.
2013AA092902), and the Shanghai Pujiang Program (PJ2008).
Junceelloside C (1): white, amorphous solid; [α]2D5 −82.8 (c 0.27,
CHCl3) and −116 (c 0.25, C5H5N); IR (film) νmax 3370, 2928, 1734,
REFERENCES
■
(1) Bortolotto, M.; Braekman, J. C.; Daloze, D.; Losman, D.; Tursch,
B. Steroids 1976, 28, 461−466.
(2) Aiello, A.; Fattorusso, E.; Menna, M. J. Nat. Prod. 1992, 55, 321−
1
1072, 1014 cm−1; H NMR and 13C NMR data, see Tables 1 and 2;
HRESIMS m/z 615.3870 [M + Na]+ (calcd for C34H56O8Na,
615.3873).
325.
Junceelloside E (2): white, amorphous solid; [α]2D5 −84.3 (c 0.17,
(3) Xu, S. H.; Zeng, L. M. Chin. Chem. Lett. 2000, 11, 531−534.
(4) Van Altena, I. A.; Butler, A. J.; Dunne, S. J. J. Nat. Prod. 1999, 62,
1154−1157.
(5) Zhang, W.; Guo, Y.-W.; Mollo, E.; Fontana, A.; Cimino, G. J. Nat.
Prod. 2004, 67, 2083−2085.
1
CHCl3); IR (film) νmax 3379, 2931, 1735, 1068, 999 cm−1; H NMR
and 13C NMR data, see Tables 1 and 2; HRESIMS m/z 627.3885 [M
+ Na]+ (calcd for C35H56O8Na, 627.3873).
Junceelloside F (3): white, amorphous solid; [α]2D5 −78.6 (c 0.26,
CHCl3); IR (film) νmax 3418, 2933, 1732, 1053, 1015 cm−1; 1H NMR
and 13C NMR data, see Tables 1 and 2; HRESIMS m/z 613.3719 [M
+ Na]+ (calcd for C34H54O8Na, 613.3716).
(6) Sarma, N. S.; Krishna, M. S.; Pasha, S. G.; Rao, T. S. P.;
Venkateswarlu, Y.; Parameswaran, P. Chem. Rev. 2009, 19, 2803−2828.
(7) Qi, S.-H.; Zhang, S.; Xiao, Z.-H.; Huang, J. S.; Wu, J.; Li, Q. X.
Chem. Pharm. Bull. 2004, 52, 1476−1478.
Junceelloside G (4): white, amorphous solid; [α]2D5 −86.5 (c 0.12,
CHCl3); IR (film) νmax 3390, 2928, 1738, 1073, 1003 cm−1; 1H NMR
and 13C NMR data, see Tables 1 and 2; HRESIMS m/z 657.3976 [M
+ Na]+ (calcd for C36H58O9Na, 657.3979).
(8) Qi, S.; Zhang, S.; Huang, J.; Xiao, Z.; Wu, J.; Li, Q. Magn. Reson.
Chem. 2005, 43, 266−268.
(9) Zhou, Y.; Shao, C.; Wang, C.; Huang, H.; Xu, Y.; Qian, P. Nat.
Prod. Commun. 2011, 6, 1239−1242.
Acid Hydrolysis and Absolute Configuration Determination
of the Monosaccharides for Junceellosides C (1) and E−G (2−
4). The glycosides 1−4 (each 0.8 mg) were dissolved in 2 M
CF3COOH(aq) (1.0 mL) at 120 °C for 2 h. The mixture was
evaporated to dryness, and the residue was partitioned between
CH2Cl2 and H2O. The aqueous phase was concentrated to furnish a
monosaccharide residue. After drying under vacuum, the residue was
dissolved in 0.4 mL of pyridine containing 2 mg of L-cysteine methyl
ester hydrochloride and heated at 60 °C for 1 h. Phenyl isothiocyanate
(2 μL) was then added, and the mixture was heated at 60 °C for 1 h.
The reaction mixture was analyzed by reversed-phase HPLC, which
(10) Sun, P.; Meng, L.-Y.; Tang, H.; Liu, B.-S.; Li, L.; Yi, Y.; Zhang,
W. J. Nat. Prod. 2012, 75, 1656−1659.
(11) Li, C.; La, M.-P.; Tang, H.; Pan, W.-H.; Sun, P.; Krohn, K.; Yi,
Y. H.; Li, L.; Zhang, W. Bioorg. Med. Chem. Lett. 2012, 22, 4368−4372.
(12) Li, C.; La, M.-P.; Sun, P.; Kurtan, T.; Mandi, A.; Tang, H.; Liu,
B.-S.; Yi, Y. H.; Li, L.; Zhang, W. Mar. Drugs 2011, 9, 1403−1418.
(13) Li, C.; La, M.-P.; Li, L.; Li, X.-B.; Tang, H.; Liu, B.-S.; Krohn, K.;
Sun, P.; Yi, Y. H.; Zhang, W. J. Nat. Prod. 2011, 74, 1658−1662.
(14) He, H.; Faulkner, D. J. Tetrahedron 1991, 47, 3271−3280.
767
dx.doi.org/10.1021/np300906b | J. Nat. Prod. 2013, 76, 764−768

Journal of Natural Products
Note
(15) Liu, C.-Y.; Hwang, T.-L.; Lin, M.-R.; Chen, Y.-H.; Chang, Y.-C.;
Fang, L.-S.; Wang, W.-H.; Wu, Y.-C.; Sung, P. J. Mar. Drugs 2010, 8,
2014−2020.
(16) Sun, J.-F.; Han, Z.; Zhou, X.-F.; Yang, B.; Lin, X.; Liu, J.; Peng,
Y.; Yang, X.-W.; Liu, Y. Tetrahedron 2013, 69, 871−880.
(17) Wang, C.-Y.; Zhao, J.; Liu, H.-Y.; Shao, C.-L.; Liu, Q.-A.; Liu, Y.;
Gu, Y.-C. Lipids 2011, 46, 81−85.
1
(18) On the basis of the H NMR chemical shifts of the A-ring
protons for compounds 1−3, it can be seen that there are no major
shift variations when either L-arabinose (1 and 2) or D-arabinose (3) is
present (Table 1). However, there are minor differences for the H-2
protons. Though there are only a few structures in this class that
currently have definitive assignments of L- and D-arabinose, the H-2
shifts originally reported for junceelloside C are consistent with the
presence of the L-arabinose, providing additional support for the
identity of 1 as junceelloside C.
(19) Mosmann, T. J. Immunol. Methods 1983, 65, 55−63.
(20) Ivanchina, N. V.; Kicha, A. A.; Stonik, V. A. Steroids 2011, 76,
425−454.
(21) Okada, Y.; Matsunaga, S.; van Soest, R. W. M.; Fusetani, N. J.
Org. Chem. 2006, 71, 4884−4888.
(22) The designation of a β-L-arabinose in the sokodosides is likely
due to the challenges inherent in using the α/β nomenclature for
various sugars. For the common D-sugar glucose, an equatorial oxygen
at the anomeric center of the pyranose corresponds to the β
configuration. In arabinose, however, an equatorial oxygen at C-1 of
the pyranose corresponds to an α configuration. The arabinose units in
the sokodosides are drawn with the equatorial oxygen linkages and
therefore should be designated as α-L-arabinopyranose moieties.
768
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