全 文 ：Received 23 Jul. 2003 Accepted 1 Dec. 2003
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Acta Botanica Sinica
植 物 学 报 2004, 46 (3): 375-378
A Novel C30 Sterol from Porana racemosa
LI Bo-Gang, CHEN Bin, WANG Ding-Yong, YE Qi, ZHANG Guo-Lin*
(Chengdu Institute of Biology, The Chinese Academy of Sciences, Chengdu 610041, China)
Abstract: A novel C30 sterol, (22E, 24x)-24-n-propylcholest-7, 22-dien-3b-ol (racemosol, 1), along with
scopoletin (2), scopolin (3), umbelliferone (4), methyl b-D-frucopyranoside (5), syringaresinol-4-O-b-D-
glucopyranoside (6), quercetin-3-O-b-D-glucopyranoside (7), quercetin-3-O-a-L-rhamnopyranoside (8),
eupatilin (9), kaempferol-3-O-b-D-glucopyranoside (10) and (E)-N-2-(2,3-dihydroxyphenyl) ethyl cinnamamide
(11), was isolated from the whole plants of Porana racemosa Roxb. Their structures were elucidated
predominantly by spectral evidence.
Key words: Porana racemosa ; Convolvulaceae; C30 sterol; racemosol; flavonol glycoside
Porana racemosa (Convolvulaceae) is widely distrib-
uted in South China (Delectis Florae Reipublicae Popularis
Sinicae Agendae Academiae Sinicae Edita, 1979). Its whole
plants are used in Chinese folk medicine for treatment of
nameless swelling, overworked pain and severe fever
(Jiangsu New Medical College, 2000). Previous study on P.
discifera Schneid led to the isolation of ecdysteroids (Zhu
et al., 2000), coumarins and flavanoids (Yu et al., 2003),
whereas no phytochemical investigation on P. racemosa
has been reported. In this study, eleven compounds were
isolated from the whole plants of P. racemosa and deter-
mined to be (22E, 24x)-24-n-propylcholest-7, 22-dien-3b-ol
(1), scopoletin (2), scopolin (3), umbelliferone (4) (Vilegas
and Pozetti, 1993), methyl b-D-frucopyranoside (5),
syringaresinol-4-O-b-D-glucopyranoside (6) (Zhu et al.,
2001), quercetin-3-O-b-D-glucopyranoside (7) (Bergeron et
al., 1998), quercetin-3-O-a-L-rhamnopyranoside (8)
(Hemandez et al., 1996), eupatilin (9) (Kupchan et al., 1967),
kaempferol-3-O-b-D-glucopyranoside (10) (Markham et al.,
1978) and (E)-N-2-(2,3-dihydroxyphenyl) ethyl cinnamamide
(11) (Tseng et al., 1992) on the basis of spectral data. Com-
pound 1, named as racemosol, is a novel C30 sterol.
1 Results and Discussion
Compound 1, obtained as colorless needles, gave a
quasi-molecular ion peak at m/z 425 [M-H]- in the nega-
tive ESI-MS spectrum. The molecular ion peak at m/z
426.385 2 in the HREI-MS spectrum of compound 1 indi-
cated a molecular formula C30H50O. Thirty signals were
observed in the 13C-NMR spectrum (Table 1). In the 1H-
NMR spectrum, six methyls resonate at d 0.58 (s, 3H), 0.82
(s, 3H), 1.05 (d, 3H, J = 6.4 Hz), 0.84 and 0.88 (each d, 3H, J
= 6.6 Hz), and 0.83 (t, 3H, J = 7.3 Hz). An E-disubstituted
double bond was supported by 1H-NMR signals at d 5.17
(dd, 1H, J = 15.1, 8.8 Hz) and 5.05 (dd, 1H, J = 15.1, 8.7 Hz)
and their corresponding 13C-NMR signals at d 138.4 (d) and
129.6 (d) in HMQC experiment. The HMQC correlation be-
tween d H 5.18 (t, 1H, J = 6.3 Hz) and dC 117.9 (d), combined
with the 13C-NMR signal at d 139.8 (s), indicated the pres-
ence of a trisubstituted double bond.
By comparing the 13C-NMR data of compound 1 with
those of spinasterol (12, Table 1) (Raymond and Jose, 1974;
Toshihiro et al., 1981), it could be concluded that com-
pound 1 is a sterol, possessing one more CH2 than
spinasterol. The HMBC correlations of H-19 (d 0.82, s, 3H),
H-3 (d 3.63, m, 1H) and H-7 (d 5.18, t, 1H) with C-5 (d 41.1, d)
confirmed the presence of 7, 8-double bond. The E-disub-
stituted double bond could be assigned to C-22 and C-23 in
view of the HMBC correlations (Fig.1) derived from H-22 (d
5.17, dd, 1H, J = 15.1, 8.7 Hz) and H-21 (d 1.05, d, 3H, J =
6.4 Hz) with C-17 (d 56.1, d). An n-propyl group could be
located at C-24, based on the HMBC correlation H-23
(d 5.05, dd, 1H, J = 15.1, 8.7 Hz) with C-28 (d 25.6, t), and H-
24 (d 2.04, m, 1H) with C-29 (d 21.8, t).
The IR absorption at nmax 3 419 and 1 045 cm-1 displayed
the presence of hydroxyl group. The ion peak at m/z 255
[M+-H2O-C11H21] in its EIMS spectrum showed not only
the presence of a C11H21 side chain with a double bond,
but also a hydroxyl group at sterol nucleus in compound 1.
The 13C-NMR signal at d 71.3 (d) for C-3 suggested that 3-
OH should be b-configurated (Hanne et al., 1976). Thus,
the structure of compound 1 was determined to be (22E,
24x)-24-n-propylcholest-7, 22-dien-3b-ol (racemosol) as
shown in Fig.1.
Acta Botanica Sinica 植物学报 Vol.46 No.3 2004376
2 Experimental
2.1 General experimental procedures
Melting points (uncorrected) were determined on XRC-
1 micro-melting point apparatus. Optical rotation was de-
termined on Perkin-Elmer 341 polarimeter. IR and UV spec-
tra were recorded on PROTEGE 460 spectrometer and
ANTHELIE advanced spectrometer, respectively. NMR
spectra were recorded on a Bruker Avance 600 or Bruker
Avance 500 spectrometer, TMS as internal standard. EI-
MS and HREI-MS spectra were obtained on VG AutoSpec-
3000 mass spectrometer and ESI-MS spectra on LC-QDeca
mass spectrometer. Silica gel (160-200 or 200-300 mesh)
for column chromatography (CC) and silica gel G for TLC
were purchased from Qingdao Ocean Chemical Factory,
Shandong, China.
2.2 Plant material
The whole plants of Porana racemosa Roxb. were col-
lected in December, 1999, in Xishuangbanna, Yunnan
Province, China and identified by Prof. CUI Jing-Yun in
Xishuangbanna Tropical Botanic Garden, The Chinese
Academy of Sciences, where a voucher specimen (No. W-
991021) is deposited.
2.3 Extraction and isolation
The whole plants of P. racemosa (7.5 kg) were soaked
three times with 95% EtOH at room temperature. After
evaporation, 550 g residue was obtained, which was sus-
pended in water (5 L), and then partitionated successively
with petroleum ether, CHCl3, EtOAc and n-BuOH to give
corresponding extracts 75 g, 60 g, 100 g and 110 g. The
petroleum ether extract (75 g) was chromatographied with
petroleum ether (60-90 ℃):acetone (100:1®5:1) to give frac-
tions P1-6. Fraction P5 (10 g) was separated by CC eluted
with petroleum ether:EtOAc (30:1), then recrystallized in
CHCl3 to give compound 1 (755 mg).
The CHCl3 extract (60 g) was separated by CC eluted
with petroleum ether (60-90 ℃):acetone (15:1; 10:1; 5:1,
each 2 L) to give fractions C1-3. Fraction C1 (10 g) was
subjected to CC eluted with petroleum ether (60-90 ℃):
CHCl3:EtOAc (3:2:1) to give compounds 2 (420 mg) and 4
(35 mg). Compound 11 (153 mg) was obtained from fraction
C3 (15 g) by CC eluted with CHCl3: MeOH (40:1).
The EtOAc extract (100 g) was separated by CC eluted
with CHCl3:MeOH (30:1; 20:1; 10:1, each 3 L) to give frac-
tions E1-3. Fraction E1 (15 g) was subjected to CC eluted
with CHCl3:MeOH (30:1) to give compound 9 (380 mg).
Compound 3 (152 mg) was isolated from fraction E2 (35 g)
by CC eluted with CHCl3:MeOH (20:1). The separation of
fraction E3 (12 g) was carried out on CC eluted with CHCl3:
MeOH (15:1) leading to compounds 10 (128 mg) and 8 (370
mg).
The n-BuOH extract (110 g) was absorbed on
macroporous resin D101 in CC and the resin was eluted with
ethanol after being washed with H2O till no sugar eluted
out. The ethanol eluate was evaporated to dryness under
reduced pressure to give a residue (21 g), which was sub-
jected to CC eluted with CHCl3:MeOH (10:1; 5:1) to give
fractions B1-2. Fraction B1 (8 g) was further separated by
CC eluted with CHCl3:MeOH (10:1) to give compounds 5
(280 mg) and 6 (100 mg). Compound 7 (260 mg) was ob-
tained from fraction B2 (12 g) by CC (polyamide, 80-100
mesh) eluted with MeOH:H2O (1:2).
2.4 Identification
Racemosol (1) Colorless needles (CHCl3), mp 120.0-
121.5 ℃. [a]25D -5.0 ° (c 0.06, CHCl3). IR nmax (KBr) cm-1:
3 419, 2 926, 2 858, 1 657, 1 463, 1 376, 1 159, 1 045, 971.
Negative ESI-MS m/z: 425 [M-H]-. EI-MS m/z (%): 426 (4),
Fig.1. The structures of compounds 1 and 12 (®, HMBC correlation).
LI Bo-Gang et al.: A Novel C30 Sterol from Porana racemosa 377
411 (21), 396 (5), 367 (7), 300 (6), 271 (38), 255 (20), 213 (9),
187 (5), 159 (15), 147 (21), 133 (19), 119 (22), 107 (41), 95 (39),
81 (79), 69 (60), 55 (100). HREI-MS m/z: 426.385 2 ([M]+,
calcd. for C30H50O, 426.386 2). 1H-NMR (600 MHz, CDCl3)
d: 3.63 (1H, m, H-3), 5.18 (1H, t, J = 6.3 Hz, H-7), 5.17 (1H, dd,
J = 15.1, 8.8 Hz, H-22), 5.05 (1H, dd, J = 15.1, 8.7 Hz, H-23),
2.04 (1H, m, H-24), 0.58 (3H, s, H-18), 0.82 (3H, s, H-19), 1.05
(3H, d, J = 6.4 Hz, H-21), 0.84 (3H, d, J = 6.6 Hz, H-26), 0.88
(3H, d, J = 6.6 Hz, H-27), 0.83 (3H, t, J = 7.3 Hz, H-30). 13C-
NMR (150 MHz, CDCl3) data are listed in Table 1.
Scopoletin (2) Light green needles (MeOH), mp 230.5-
232.0 ℃, it was identified by comparison of the mixed melt-
ing point and Rf value (on TLC) with an authentic sample.
Scopolin (3) Light green powder, mp 202.3-204.5 ℃,
it was identified by comparison of the mixed melting point
and Rf value (on TLC) with an authentic sample.
Umbelliferone (4) Yellow powder, mp 225.0-227.5 ℃,
its spectral data are consistent with those reported.
Methyl b-D-frucopyranoside (5) White powder, mp
193.0-195.3 ℃, it was identified by comparing its spectral
data with those reported.
Syringaresinol-4-O-b-D-glucopyranoside (6) White
powder, mp 167.0-168.5 ℃,its spectral data are in agree-
ment with those reported.
Quercetin-3-O-b-D-glucopyranoside (7) Yellow
powder, mp 230-231.5 ℃, it was identified by comparing
its spectral data with those reported.
Quercetin-3-O-a-L-rhamnopyranoside (8) Yellow
needles (MeOH), mp 265.0-267.5 ℃, it was identified by
comparing its spectral data with those reported.
Eupatilin (9) Yellow prisms (MeOH), mp 235.0-237.5
℃,it was identified by comparing its spectral data with
those reported.
Kaempferol-3-O-b-D-glucopyranoside (10) Yellow
powder, mp 192.0-194.5 ℃, it was identified by comparing
its spectral data with those reported.
(E)-N-2-(2, 3-Dihydroxyphenyl)ethyl cinnamic amide
(11) White powder, mp 189.0-191.5 ℃, it was identified
by comparing its spectral data with those reported.
References:
Bergeron C, Marston A, Antus S, Robert G, Kurt H. 1998. Fla-
vonoids from Pyrola elliptica. Phytochemistry, 49:233-236.
Delectis Florae Reipublicae Popularis Sinicae Agendae Academiae
Sinicae Edita . 1979. Flora Reipublicae Popularis Sinicae.
Tomus 64. No. 1. Beijing: Science Press. 34-35. (in Chinese)
Hanne E, Craig L V, Norman S B, Carl D. 1976. Carbon-13 nuclear
magnetic resonance spectra of hydroxy steroids. J Org Chem,
41:71-78.
Hemandez P M, Hernandez T, Gomez G, Isabel E, Rosa M R.
1998. Phenolic composition of the “Mocan” (Visuea mocanera
L. f.). J Agric Food Chem, 44:3512-3515.
Jiangsu New Medical College . 2000. Dictionary of Chinese Tra-
ditional Medicine. Vol. 2. Shanghai: Shanghai Publishing House
of Science and Technology. 640. (in Chinese)
Jung J H, Kim C O, Kang S S. 1996. New bioactive cerebrosides
from Arisaema amurense. J Nat Prod, 59:319-322.
Kupchan S M, Sigel C W, Hemingway R T. 1969. Tumor inhibi-
tors-Ⅻ cytotoxic flavones from Eupatorium species.
Tetrahedron, 25:1603-1605.
Markham K R, Ternal B, Stanley R. 1978. 13C-NMR studies of
flavonoids-Ⅲ. Tetrahedron, 34:1389-1398.
Table 1 The 13C-NMR data of compound 1 and spinasterol (12) in CDCl3
1a 12b 1a 12b
C-atom δ C-atom δ
1 37.3 (t) 36.8 16 29.8 (t) 28.5
2 31.7 (t) 31.4 17 56.1 (d) 55.9
3 71.3 (d) 71.0 18 12.3 (q) 12.1
4 38.2 (t) 38.0 19 13.3 (q) 13.0
5 41.1 (d) 40.1 20 40.5 (d) 40.8
6 29.9 (t) 29.5 21 21.3 (q) 21.1
7 117.7 (d) 117.3 22 138.4 (d) 138.1
8 139.8 (s) 139.5 23 129.6 (d) 129.4
9 49.6 (d) 49.3 24 51.5 (d) 51.2
10 34.4 (s) 34.2 25 32.1 (d) 31.9
11 23.2 (t) 21.5 26 21.6 (q) 21.5
12 39.7 (t) 39.4 27 19.2 (q) 19.0
13 43.5 (s) 43.3 28 25.6 (t) 25.4
14 55.3 (d) 55.1 29 21.8 (t) 12.3
15 23.8 (t) 23.0 30 12.5 (q)
a, at 150 MHz, multiplicity determined by DEPT; b, at 25.2 MHz.
Acta Botanica Sinica 植物学报 Vol.46 No.3 2004378
Raymond J A, Jose R M. 1974. 13C nuclear magnetic resonance
spectra of some ergosta-dienes and -trienes. J Chem Soc Perkin
Ⅱ, 6:662-665.
Toshihiro I, Yoshinori K, Toshitake T, Taro M. 1981. Co-occur-
rence of chondrilla- sterol and spinasterol in two Cucurbitaceae
seeds as shown by 13C NMR. Phytochemistry, 20:761-764.
Tseng C F, Iwakami S S, Mikajiri A, Shibuya M, Hanaoka F,
Ebizuka Y, Kosaashi P, Ushio S. 1992. Inhibition of in vitro
prostaglandin and leukotriene biosyntheses by cinnamoyl-
β-phenethylamine and N-acyldopamine derivatives. Chem
Pharm Bull, 40:396-400.
Vilegas W, Pozetti G L. 1993. Coumarins from Brosimum
gaudichaudii. J Nat Prod, 56:416-417.
Yu R ,Xu Q,Li B-G,Zhang G-L . 2003. Chemical study on Porana
discifera. Nat Prod Res Dev , 15:405-407. (in Chinese with
English abstract)
Zhu W-M , Yang X-S , He H-P, Hao X-J . 2000. Phytoecdysones
from Porana discifera. Acta Bot Yunnan , 22:351-357. (in
Chinese with English abstract)
Zhu W-M, Yin C-F, Wang S , Zuo G-Y, Hao X-J . 2001. Chemical
constituents of Porana spectabilis Kurz. Nat Prod Res Dev ,
13:1-4. (in Chinese with English abstract)
(Managing editor: WANG Wei)