Structural revision of periplocosides and periperoxides, natural immunosuppressive agents from the genus Periploca

Article abstract of DOI:10.1016/j.phytochem.2011.07.018

The structures of a series of peroxy function containing pregnane glycosides isolated from Periploca sepium and Periploca forrestii were revised to be orthoester group bearing ones using 2D NMR spectroscopic techniques, as well as chemical transformations and X-ray crystallographic diffraction analysis. The orthoester function appears to be an essential structural feature for immunosuppressive activity.

Full text of DOI:10.1016/j.phytochem.2011.07.018

Phytochemistry 72 (2011) 2230–2236
Contents lists available at ScienceDirect
Phytochemistry
journal homepage: www.elsevier.com/locate/phytochem
Structural revision of periplocosides and periperoxides, natural
immunosuppressive agents from the genus Periploca
⇑
Luo-Yi Wang, Zhen-Hua Chen, Yu Zhou, Wei Tang, Jian-Ping Zuo, Wei-Min Zhao
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 18 May 2011
Received in revised form 5 July 2011
Available online 16 August 2011
The structures of a series of peroxy function containing pregnane glycosides isolated from Periploca sepi-
um and Periploca forrestii were revised to be orthoester group bearing ones using 2D NMR spectroscopic
techniques, as well as chemical transformations and X-ray crystallographic diffraction analysis. The
orthoester function appears to be an essential structural feature for immunosuppressive activity.
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Periploca sepium
Periploca forrestii
Asclepiadaceae
Immunosuppressive
Pregnane glycoside
Structural revision
1. Introduction
suppressing interleukin 12-dependent CCR5 expression and
interferon-c-dependent CXCR3 expression in T lymphocytes (Zhu
Natural products play an important role in the development of
drugs, especially for the treatment of infections and cancer, as well
as immunosuppressive compounds (Tietze et al., 2003). Immuno-
suppressive agents have wide application in organ transplantation
and the treatment of autoimmune diseases, such as rheumatoid
arthritis, systemic lupus erythematosus, and Crohn’s disease, and
almost all the immunosuppressive drugs currently available on
the market are derived from a natural source (Mann, 2001). Some
traditional Chinese medicines (TCM) have been used for centuries
in China to treat various immune system disorders, and represent a
valuable resource to find new immunosuppressive agents (Ramgo-
lam et al., 2000).
The root barks of Periploca sepium Bge. and the roots of Periploca
forrestii Schltr. (Asclepiadaceae) have been used as traditional Chi-
nese medicines for the treatment of autoimmune diseases, espe-
cially for rheumatoid arthritis (Jiangsu New Medical College,
1998). In our recent research, periplocosides A (1a) and E (2a)
(Fig. 1), the main constituents of P. sepium, were found to possess
significant activities against the proliferation of T lymphocyte
in vitro without obvious cytotoxicity (Feng et al., 2008). In vivo,
periplocoside E (i.p., 10 mg/kg) exhibited potent therapeutical
effect in MOG35–55 (myelin oligodendrocyte glycoprotein 35–55)-
induced experimental autoimmune encephalomyelitis (EAE) by
et al., 2006a,b), and periplocoside A (p.o., 25 mg/kg) prevented
EAE by suppressing IL-17 production and inhibits differentiation
of Th17 cells (Zhang et al., 2009). Periplocoside A (i.v., 10 mg/kg)
also showed significantly preventive effect on concanavalin
A-induced mice hepatitis and has now emerged as a promising nat-
ural anti-rheumatoid arthritis agent that shows excellent efficacy
in collagen-induced arthritis in mice (Wan et al., 2008).
Previous phytochemical studies on P. sepium have been focused
on its pregnane glycosides, mainly carried out by two Japanese
research groups. Hiroshi Hikino’s research group first reported
the isolation and structural elucidation of periplosides C (1) and
A (2) (Fig. 2), two pregnane glycosides with an orthoester group
(Oshima et al., 1987). Periplocosides A (1a), B (12a), C (13a),
D (3a), E (2a), F (4a), J (5a), and K (6a) (Fig. 3), a series of peroxy
function containing pregnane glycosides, were reported by Hideji
Itokawa’s group from the same plant and a positive color reaction
of peroxides was used to support their structural identification
(Itokawa et al., 1988a–c). Additionally, periperoxides A (7a),
B (8a), C (10a), D (11a) and E (9a) (Fig. 3), further peroxy group
containing pregnane glycosides with immunosuppressive activi-
ties isolated from P. sepium and P. forrestii, were reported in our
preceding paper (Feng et al., 2008).
The completely identical 1H NMR and 13C NMR data of periplo-
coside A (1a) and periploside C (1) suggested that one of two struc-
tures must be incorrect. However, the ambiguous information
obtained from NMR spectra and the lack of more direct structural
evidence kept the puzzle pending for more than two decades. Our
⇑
Corresponding author. Tel./fax: +86 21 50806052.
E-mail address: wmzhao@mail.shcnc.ac.cn (W.-M. Zhao).
0031-9422/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.phytochem.2011.07.018

L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
2231
OMe
OMe
O
OAc
OMe
O
OMe
O
O
OMe
OH
O
O
OH
O
O
O
O
O
O
O
O
H
O
H
H
R =
1a periplocoside A
2a periplocoside E
MeO
RO
O
R = H
Fig. 1. Structures of periplocosides A (1a) and E (2a).
OMe
OMe
O
OAc
O
OMe
O
O
OMe
O
O
OMe
OH
O
OH
O
O
O
O
O
O
O
H
O
H
H
1 periploside C
2 periploside A
R =
R = H
MeO
RO
O
Fig. 2. Structures of periplosides C (1) and A (2).
extensive investigation using 2D NMR spectroscopic techniques, as
well as chemical transformations and X-ray crystallographic dif-
fraction analysis, established that the peroxy function in the sugar
chain of these pregnane glycosides should be revised to an ortho-
ester group.
unambiguously showed the existence of an orthoester rather than
a peroxy functional group in its sugar chain (Fig. 5). Therefore, the
previously proposed structure of periplocoside F (4a) was revised
to 4 and named periploside F. Accordingly, the incorrect structures
of periplocosides A (1a), B (12a), C (13a), D (3a), E (2a), J (5a),
K (6a), and periperoxides A (7a), B (8a), C (10a), D (11a), E (9a) pre-
viously characterized were revised, and with the names periplo-
sides C (1), M (12), N (13), D (3), A (2), J (5), K (6), E (7), G (8),
I (10), L (11), and H (9) assigned, respectively, using 4 as a model
compound (Fig. 6).
The remaining doubt laid in the positive color reaction for per-
oxides of these pregnane glycosides. In our repeated TLC examina-
tions, however, all of these compounds showed negative results
compared with that of 30% hydrogen peroxide, which gave a pur-
ple spot as soon as sprayed with the color developing agent.
Noticeably, each compound, as well as the color agent that em-
ployed as the blank control, turned purple when standing exposed
to the air for a few minutes after they were sprayed with the color
agent. Since no positive control and blank control were mentioned
in H. Itokawa’s reports, the observation might be explained by the
aerial oxidation of N,N-dimethyl-p-phenylenediamine dihydro-
chloride, the color developing agent used in the detection of perox-
ides (Itokawa et al., 1988a–c).
2. Results and discussion
In the course of the reexamination of the HMBC spectrum of
4
periplocoside A (1a), a JCH 1H-13C long-range correlation between
2
H-4 of the canarose and C-20 of the heptulose, and a JCH 1H–13
C
coupling between H-10 and C-20 of the heptulose, were found at
the same time. In the case of periploside C (1), the aforementioned
3
signals could be more reasonably interpreted as JCH 1H–13C long-
range correlations between H-4 of the canarose and C-10 of the ole-
androse, and between the two gem-protons of the dioxymethylene
and C-10 of the oleandrose in 1 (Fig. 4). The two proton resonances
at d 4.74 and 5.14 (each 1H, d, J = 7.6 Hz) in the 1H NMR spectrum
should be more reasonably assigned for the two gem-protons of
dioxymethylene group in periploside C (1) than H-10 of the heptu-
lose in periplocoside A (1a). Structure 1 was therefore thought to
be more reliable.
Chemical transformations were then carried out for more evi-
dence (Scheme 1). Partial acidic hydrolysis of 1 was undertaken
with 0.001 N H2SO4–MeOH according to H. Itokawa’s report to give
compounds 14, 15, and 16; however, such subacidity seemed
impossible to break the C–C bond between C-10 and C-20 of the
heptulose as in structure 1a (Itokawa et al., 1988b). In contrast,
treatment of 1 with 1 N aqueous HCl in THF led to compound
17 as well as 14 and 16. Basic hydrolysis of 1 with NaOH–MeOH
afforded 4 as the main product. Additionally, the reduction of
4 with diisobutylaluminum hydride (DIBAL-H) in dry toluene
(0 °C, Ar atmosphere) yielded 18. All the chemical transformations
mentioned above belong to the reaction type of orthoesters, and
are in accordance with the fact that orthoesters are highly vulner-
able under acidic conditions and are relatively stable in neutral or
basic aqueous solution (Huang et al., 2007).
As reported in our previous paper, orthoester possessing preg-
nane glycosides showed significant activity against the prolifera-
tion of T lymphocyte in vitro with IC50 values in the range of
0.29–1.97
nane glycosides without orthoester group in their structures exhi-
bit no obvious activity at up to 10 M (Feng et al., 2008). To further
lM without obvious cytotoxicity, whereas those preg-
l
clarify the importance of the orthoester function in these com-
pounds to the immunosuppressive activity, the inhibitory effects
of T cell proliferation of 4 and 14–18 were evaluated. As a result,
the IC50 of compound 4 was found to be 1.13
lM, and compounds
14–18 exhibited no obvious activity at up to 10
lM. More specifi-
cally, removal of the unique spiro orthoester group removes the
activity, suggesting that the orthoester function in the sugar chain
of these pregnane glycosides is critical for immunosuppressive
activity. To the best of our knowledge, the orthoester has been
widely discovered as a structure subunit in natural products of
plant origin, and some of the orthoester containing compounds
have shown important biological activities and have been widely
A single crystal of intermediate 4 was obtained via slow evapo-
ration of a petroleum ether–acetone (1:1) solution and subjected
to X-ray crystallographic diffraction analysis. The result obtained

2232
L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
OMe
OMe
O
OR2
OMe
O
OMe
O
O
OMe
OH
O
O
OH
O
O
O
O
O
O
O
O
O
H
H
H
R1 =
R2 = Ac
R2 = Ac
R2 = H
1a periplocoside A
2a periplocoside E
3a periplocoside D
4a periplocoside F
MeO
R1O
O
O
R1 = H
O
R1
=
MeO
R1 = H
R2 = H
OMe
OH
OR2
OMe
O
OH
O
O
OMe
OH
O
O
OH
O
O
O
O
O
O
O
O
O
H
H
H
R1 = H
R2 = H
R2 = H
5a periplocoside J
6a periplocoside K
R1O
O
O
R1
=
=
MeO
O
O
R1
R2 = Ac
OMe
7a periperoxide A
MeO
OMe
OMe
O
OH
O
O
OMe
OAc
O
O
OH
O
O
O
O
O
O
O
O
O
H
O
R =
8a periperoxide B
9a periperoxide E
H
H
MeO
O
RO
R = H
OMe
OMe
O
OMe
O
OH
O
O
OMe
OH
O
O
OH
O
O
O
O
O
O
O
O
H
O
R =
R = H
10a periperoxide C
11a periperoxide D
H
H
MeO
O
RO
OMe
OMe
O
OMe
OH
O
O
OH
O
O
O
O
O
O
O
H
O
12a periplocoside B
H
H
H
H
OMe
O
MeO
MeO
O
OMe
OH
O
O
O
OH
O
O
O
O
O
H
O
13a periplocoside C
O
O
Fig. 3. Structures of peroxy function containing pregnane glycosides from Periploca sepium and P. forrestii.
used as pharmacological tools in the study of biological processes
or as drug leads. Tremendous efforts aimed at the structure-
activity relationship among the biologically active orthoester con-
taining natural compounds established that the orthoester group

L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
2233
H
orthoester containing pregnane glycosides have complicated struc-
tures compared with small molecular drugs, they have shown ther-
apeutic effects against rheumatoid arthritis, multiple sclerosis, and
autoimmune hepatitis in animal tests, and could represent a new
type of natural therapeutic agent against autoimmune diseases.
OMe
H
3'
O
O
2
5
1'
4'
6'
2'
3
4
1
5'
OH
O
O
O
O O
H
H
heptulos7e'
cana6rose
H
H
1a periplocoside A
O
4. Experimental
H
H
4.1. General experimental procedures
OMe
O
O
2
5
O 2'
3
4
1
3'
5'
OH
ESIMS data were obtained on a Bruker Esquire 3000 plus or
Shimadzu LCMS-2020 instrument, whereas NMR spectra were
run on Bruker AM 400 or INOVA-600 spectrometer with TMS as
internal standard. Column chromatographic (CC) separations were
carried out using silica gel H60 (300–400 mesh) (Qingdao Haiyang
Chemical Group Corporation, Qingdao, People’s Republic of China)
as packing materials. HSGF254 silica gel TLC plates (Yantai Chem-
ical Industrial Institute, Yantai, People’s Republic of China) were
used for analytical TLC. Petroleum ether with boiling range
60-90 °C was used in the experiments.
O
4'
O
1'
O
O
H
H
6
6'
canarose
oleandrose
H
H
1
periploside C
O
Fig. 4. Important HMBC (1H?13C) correlations for 1a and 1.
may function as an essential pharmacophore or serve as a stereo-
chemical constraining element to maintain the desired conforma-
tion for the biological activities (Liao et al., 2009).
4.2. Chemical transformations of periploside C (1) and periploside F (4)
3. Concluding remarks
4.2.1. Partial acid hydrolysis of 1 in H2SO4–MeOH
In summary, the structures of a series of peroxy function con-
taining immunosuppressive pregnane glycosides isolated from
P. sepium and P. forrestii were revised to be orthoester group bear-
ing ones using 2D NMR techniques as well as chemical transforma-
tions and X-ray crystallographic diffraction analysis. The study of
structure-activity relationship indicated that the unique spiro
orthoester group in the sugar chain of these pregnane glycosides
is critical for the immunosuppressive activity. Although these
A solution of 1 (141 mg, 0.10 mmol) in 0.001 N H2SO4–MeOH
(10 mL) was stirred at room temperature until TLC analysis
showed that no starting material remained. The reaction mixture
was diluted with H2O (20 mL) and extracted with EtOAc
(3 ꢀ 30 mL). The organic layer was dried (anhydr. Na2SO4) and
evaporated to dryness. The residue was subjected to silica gel CC
using petroleum ether–acetone (2:1, 1:1) as eluent to give com-
pounds 14 (31 mg), 15 (20 mg) and 16 (26 mg).
OR
OH
O
OMe
O
OMe
O
OAc
OH
O
OMe
O
O
OMe
O
O
OMe
OH
O
a
O
H
O
O
+
O
H
H
14 R = H
15 R = CH2OMe
16
MeO
O
O
OMe
OMe
OAc
OMe
OH
O
O
OMe
O
O
OMe
OH
O
OH
O
O
O
O
O
O
O
HO
H
b
1
O
H
H
+ 14 + 16
17
MeO
O
O
OMe
OMe
O
OH
OMe
O
O
O
O
OMe
O
O
OMe
OH
O
O
O
O
O
OH
O
O
H
c
4
H
H
d
HO
OMe
O
OMe
O
OH
OMe
OH
O
O
O
OMe
O
O
OMe
OH
OH
O
O
O
O
O
H
18
H
H
HO
Scheme 1. Chemical transformations of 1. (a) 0.001 N H2SO4–MeOH, r.t.; (b) 1 N aq. HCl, THF, r.t., 39%; (c) 1% NaOH–MeOH, r.t., 88%; (d) 1 M DIBAL-H, Ar, toluene, 0 °C, 1.5 h,
17%.

2234
L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
Fig. 5. Single-crystal X-ray structure of 4.
Compound 14: 1H NMR (CDCl3, 400 MHz) d: 0.70, 0.98 (each 3H,
4.2.3. Basic hydrolysis of 1
s), 1.28 (3H, d, J = 6.2 Hz), 1.31 (3H, d, J = 6.0 Hz), 1.49 (3H, d,
J = 6.9 Hz), 3.61 (3H, s), 3.72 (1H, q, J = 6.1 Hz), 4.58 (1H, dd,
J = 9.4, 1.7 Hz), 4.70 (1H, dq, J = 6.8, 2.8 Hz), 5.03 (1H, s), 5.34 (1H,
br s), 5.77 (1H, d, J = 2.9 Hz); ESIMS m/z 627.5 [M+Na]+. The 1H
NMR and MS data were identical with those of periploside B and
periplocoside M (Oshima et al., 1987; Itokawa et al., 1988b).
Compound 15: 1H NMR (CDCl3, 400 MHz) d: 0.71, 0.98 (each 3H,
s), 1.29, 1.34 (each 3H, d, J = 6.2 Hz), 1.50 (3H, d, J = 6.7 Hz), 3.42,
3.62 (each 3H, s), 3.74 (1H, q, J = 6.5 Hz), 4.56 (1H, dd, J = 9.7,
1.8 Hz), 4.70 (3H, overlapped), 5.04 (1H, s), 5.34 (1H, br s), 5.77
(1H, d, J = 2.9 Hz); ESIMS m/z 671.4 [M+Na]+. The 1H NMR and
MS data were identical with those of periplocoside O (Itokawa
et al., 1988c).
A solution of 1 (284 mg, 0.20 mmol) in 1% methanolic NaOH
(20 mL) was stirred at room temperature until TLC analysis showed
that no starting material remained. The resultant solution was di-
luted with H2O (60 mL) and extracted with EtOAc (3 ꢀ 80 mL). The
organic layer was dried over anhydrous Na2SO4 and evaporated to
dryness to afford compound 4 (216 mg) in 88% yield.
Compound 4: 1H NMR (CDCl3, 400 MHz) d: 0.71, 0.99 (each 3H,
s), 1.19, 1.21, 1.26, 1.28, 1.29 (each 3H, d, J = 6.2 Hz), 1.30 (3H, d,
J = 5.9 Hz), 1.34 (3H, d, J = 6.6 Hz), 3.42 (ꢀ3), 3.43, 3.50 (each 3H,
s), 4.27 (1H, d, J = 7.7 Hz), 4.58 (1H, dd, J = 9.6, 1.5 Hz), 4.73 (1H,
d, J = 7.7 Hz), 4.75, 4.76 (each 1H, dd, J = 9.5, 1.5 Hz), 4.91 (1H, dd,
J = 9.5, 1.2 Hz), 5.12 (1H, d, J = 7.7 Hz), 5.34 (1H, br s); for 13C
NMR (100 MHz, CDCl3) spectrum, see Supplementary data; ESIMS
m/z 1251.8 [M+Na]+. The NMR and MS data were identical with
those of periplocoside F (Itokawa et al., 1988c).
Compound 16: 1H NMR (CDCl3, 300 MHz) d: 1.15, 1.18, 1.29
(each 3H, d, J = 6.1 Hz), 1.35, 1.42 (each 3H, d, J = 6.2 Hz), 2.06
(3H, s), 2.71 (2H, m), 3.36, 3.39, 3.41, 3.42, 3.43 (each 3H, s), 4.37
(1H, d, J = 8.0 Hz), 4.74 (2H, m), 4.87 (1H, dd, J = 9.7, 1.9 Hz), 5.06
(1H, dd, J = 9.9, 8.1 Hz); ESIMS m/z 817.5 [M+Na]+. The 1H NMR
4.2.4. DIBAL-H reduction of 4
To a stirred, cooled (0 °C) solution of compound 4 (190 mg,
0.15 mmol) in dry toluene (5 mL) under Ar was added DIBAL-H
(5 mL, 1.0 M in toluene) dropwisely via a syringe. The reaction
mixture was stirred at 0 °C for 1.5 h and then quenched at 0 °C
by the dropwise addition of MeOH over a period of 10–15 min,
following which iced water (20 mL) was added. The resulting
gelatinous mixture was extracted with EtOAc (3 ꢀ 25 mL). The
combined organic layer was washed with brine, dried with
(anhydr. Na2SO4) and concentrated under reduced pressure. Purifi-
cation of the crude mixture by silica gel CC (CHCl3–MeOH, 21:1)
afforded compound 18 (32 mg, 17% yield).
and MS data were identical with those of 2-O-acetyl-b-
pyranosyl-(1 ? 4)-b- -cymaropyranosyl-(1 ? 4)-b- -cymaropyr-
anosyl-(1 ? 4)-b- -cymaropyranosyl-(1 ? 4)-b- -oleandronic-d-
D-digitalo-
D
D
D
D
lactone (Oshima et al., 1987; Itokawa et al., 1988b).
4.2.2. Hydrolysis of 1 with 1 N aqueous HCl in THF
A solution of 1 N aqueous HCl (0.1 mL) was added to a solution
of compound 1 (71 mg, 0.050 mmol) in THF (3 mL) and the reac-
tion mixture was stirred at room temperature until TLC analysis
showed that no starting material remained. The mixture was then
partitioned between EtOAc (15 mL) and H2O (15 mL). The organic
phase was washed with brine, dried (anhydr. Na2SO4), filtered,
and concentrated. The residue was subjected to silica gel CC to give
compound 17 (27 mg, 39% yield) as the expected product, and
compounds 14 and 16 as the byproducts.
Compound 18: 1H NMR (CDCl3, 400 MHz) d: 0.70, 0.98 (each 3H,
s), 1.18, 1.19, 1.21, 1.24, 1.26, 1.29 (each 3H, d, J = 6.2 Hz), 1.33 (3H,
d, J = 6.6 Hz), 3.40 (ꢀ2), 3.41 (ꢀ2), 3.49 (each 3H, s), 4.26 (1H, d,
J = 8.1 Hz), 4.41 (1H, dd, J = 9.2, 1.5 Hz), 4.56 (1H, dd, J = 9.6,
1.5 Hz), 4.72, 4.74, 4.90 (each 1H, dd, J = 9.5, 1.5 Hz), 5.33 (1H, br
s); for 13C NMR (100 MHz, CDCl3) spectrum, see Supplementary
data; ESIMS m/z 1246.2 [M+COOH]ꢁ.
Compound 17: 1H NMR (CDCl3, 400 MHz) d: 0.71, 0.98 (each 3H,
s), 1.15, 1.17, 1.18, 1.21, 1.22 (each 3H, d, J = 6.2 Hz), 1.28, 1.35
(each 3H, d, J = 6.4 Hz), 1.49 (3H, d, J = 7.0 Hz), 2.06 (3H, s), 2.62
(1H, dd, J = 15.8, 8.0 Hz), 2.84 (1H, dd, J = 15.8, 5.2 Hz), 3.39, 3.40,
3.41, 3.42, 3.43, 3.61 (each 3H, s), 4.17 (1H, m), 4.36 (1H, d,
J = 8.0 Hz), 4.50 (1H, t, J = 9.1 Hz), 4.59 (1H, dd, J = 10.0, 1.5 Hz),
4.72 (3H, overlapped), 4.79 (1H, dd, J = 9.5, 1.0 Hz), 5.03 (1H, s),
5.06 (1H, dd, J = 9.8, 8.0 Hz), 5.34 (1H, br s), 5.76 (1H, d,
J = 3.0 Hz); for 13C NMR (100 MHz, CDCl3) spectrum, see supple-
mentary data; ESIMS m/z 1421.8 [M+Na]+.
4.3. X-ray crystallography data of 4
C63H104O23, MW 1229.46, triclinic space 0group P1, a = 11.5609
0
0
(13) ÅA, b = 11.6537(12) AÅ, c = 14.7887(16) ÅA,
a
= 94.035(2)°, b =
= 112.512(2)°, V = 1690.4(3) ÅA3, Z = 1, Dcalcd = 1.208
mg/m3; F(0 0 0) = 666, = 0.091 mmꢁ1, reflection collected 8955,
reflection unique 7498(Rint = 0.0192), final R indices for I > 2 (I),
0
109.436(2)°,
c
l
r

L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
2235
OMe
OMe
O
OR2
OMe
O
O
O
OMe
O
O
OMe
OH
O
OH
O
O
O
O
O
O
O
H
H
H
O
1
2
R1
=
R2 = Ac
R2 = Ac
R2 = H
periploside C
periploside A
R1O
MeO
O
O
R1 = H
O
R1
=
3 periploside D
4 periploside F
MeO
R
1 = H
R2 = H
OMe
OH
OR2
OMe
O
O
O
OH
O
O
OMe
OH
O
OH
O
O
O
O
O
O
O
O
H
H
H
R1 = H
R2 = H
R2 = H
5 periploside J
R1O
O
O
6
R1
R1
=
=
periploside K
MeO
MeO
O
O
7 periploside E
R2 = Ac
OMe
OMe
OMe
O
O
O
OH
O
O
OMe
OAc
O
OH
O
O
O
O
O
O
O
O
H
O
H
H
8
R =
R = H
periploside G
MeO
RO
O
9 periploside H
OMe
OMe
O
OMe
O
O
O
OH
O
OH
O
O
OMe
OH
O
O
O
O
O
O
O
H
O
H
H
10
11
R =
periploside I
periploside L
MeO
RO
O
R = H
OMe
O
OMe
O
O
OMe
O
O
OH
O
O
O
O
OH
O
H
O
12 periploside M
H
H
H
H
MeO
MeO
O
O
OMe
O
OMe
O
O
O
OH
O
OH
O
O
O
O
O
H
O
13
periploside N
Fig. 6. Revised structures of pregnane glycosides from the genus Periploca.
R1 = 0.0508, wR2 = 0.1297, R indices for all data R1 = 0.0687,
wR2 = 0.1468, completeness to (25.50) 98.8%, maximum
transmission 1.00000, minimum transmission 0.71354.
single crystal of dimensions 0.331 ꢀ 0.279 ꢀ 0.156 mm was used
A
h

2236
L.-Y. Wang et al. / Phytochemistry 72 (2011) 2230–2236
for X-ray measurements. The data collection was performed on a
Bruker Smart Apex CCD diffractometer, using graphite monochro-
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Acknowledgments
Wan, J., Zhu, Y.N., Feng, J.Q., Chen, H.J., Zhang, R.J., Ni, J., Chen, Z.H., Hou, L.F., Liu, Q.F.,
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The authors thank Professor Jie Sun of Shanghai Institute of Or-
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Technology Major Project ‘‘Key New Drug Creation and Manufac-
turing Program’’, China (No. 2009ZX09103-413) is gratefully
acknowledged.
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Appendix A. Supplementary data
dependent CCR5 expression and IFN-
lymphocytes. J. Pharmacol. Exp. Ther. 318, 1153–1162.
c-dependent CXCR3 expression in T
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.phytochem.2011.07.018.