全 文 ：多荚草中的新环肽
丁中涛1 ,2　周　俊1＊　谭宁华1　程永现1　邓世明1
(1.中国科学院昆明植物研究所植物化学开放实验室 , 昆明 650204;2.云南大学化学系 , 昆明 560091)
摘要:　从石竹科植物多荚草(Polycarpon prostratum (Forssk.)Aschers.et Schwein.ex Aschers)中分离得到 2 个新的环
肽化合物 poly carponin B和 C (1 , 2)。它们的结构通过波谱方法分别鉴定为:cyclo(_Gly1_Ile_Val1_Leu1_Val2_Gly2_Leu2_
Pro)和 cyclo(_Pro1_Thr_Leu1_Pro2_Pro3_Val_Leu2_Phe)。
关键词:　多荚草;石竹科;环肽;多荚草环肽
中图分类号:R914　　　文献标识码:A　　　文章编号:0577-7496(2001)05-0541-04
Cyclopeptides from Polycarpon prostratum (Caryophyllaceae)
DING Zhong_Tao1 ,2 , ZHOU Jun1＊ , TAN Ning_Hua1 , CHENG Yong_Xian1 , DENG Shi_Ming1
(1.Laboratory of Phytochemistry , Kunming Institute of Botany , The Chinese Academy of Sciences , Kunming 650204, China;
2.Department of Chemistry , Yunnan University , Kunming 650091 , China)
Abstract:　Two new cyclic peptides , polycarponin B and C (1 , 2), were isolated from the whole plants of
Polycarpon prostratum (Forssk.)Aschers.et Schwein.ex Aschers.By detailed spectroscopic analysis , their
structures were determined as cyclo(_Gly1_Ile_Val1_Leu1_Val2_Gly2_Leu2_Pro)and cyclo(_Pro1_Thr_Leu1_Pro2_
Pro3_Val_Leu2_Phe), respectively.
Key words:　Polycarpon prostratum;Caryophyllaceae;cyclopeptide;polycarponin B and C
　　In a previous study of chemical constituents of Poly-
carpon prostratum (Forssk.)Aschers.et Schwein.ex
Aschers[ 1-4] , we have reported five new triterpenoid
saponins (saikosaponin_like compounds) from n_BuOH
soluble fraction and a new cyclopeptide (named polycar-
ponin A)from EtOAc soluble fraction of this plant.As a
part of our continuous studies on cyclopeptides from
Caryophyllaceae[ 4-11] , a further study on the EtOAc sol-
uble fraction of this plant led to the isolation of two new
cyclopeptides named polycarponin B and C.In this pa-
per , we report the isolation and structure elucidation of
these two compounds.
1　Results and Discussion
Polycarponin B (1)was obtained as colorless nee-
dles , and showed negative reaction to ninhydrin reagent ,
but positive after hydrolysis with 6 mol/L HCl.Its IR ab-
sorption bands at 3 290 and 1 640 cm
-1
were characteris-
tic of amino and amide carbonyl groups.The FABMS gave
an [ M +H] + ion at m/ z 749 which together with the
molecular formula of C37H64N8O8 derived from the HR_
FABMS(found m/ z 749.487 4 [M +H] + , calcd m/ z
749.492 5), indicated the presence of 10 degrees of un-
saturation.The 13 C and 1H_NMR spectra (Table 1)
showed the presence of eight amide carbonyl signals and
seven amide NH signals respectively , suggesting that 1
was a cyclopeptide.
The structure elucidation began with identification of
the amino acid residues.By extensive analysis of the 1H_
1H COSY , HMBC and HMQC spectra , the amino acid
residues were shown to be two valines , two leucines , two
glycines , one isoleucine and one proline , respectively.
These amino acid residues accounted for the molecular
weight observed in the FABMS.The sequence of these
amino acids was elucidated on the basis of HMBC correla-
tions.The HMBC correlations were summarized in Fig.1.
From the information obtained in the FABMS and the cor-
relations between amide CO and NH in the HMBC spec-
trum , the structure of 1was elucidated as cyclo(_Gly1_Ile_
Val1_Leu1_Val2_Gly2_Leu2_Pro).
Polycarponin C (2)was obtained as colorless nee-
dles , and showed negative reaction to ninhydrin reagent ,
but positive after hydrolysis with 6 mol/L HCl.Its IR
spectrum showed intense NH and CO absorptions at 3 300
Received:2000-07-31　Accepted:2000-10-08
Supported by the grants(9911143 and YP0024)from the Education Commission of Yunnan Province and Young Academic and Technical Leader Raising Founda-
tion of Yunnan Province.
＊Author for correspondence.
植　物　学　报　2001 , 43(5):541-544 　 　 　 　 　 　 　
Acta Botanica Sinica
Table 1　1H and 13C_NMR spectral data of polycarponin B(1)in pyridine_d5
CO Cα Cβ Cγ Cδ HN Hα Hβ Hγ Hδ
Gly1 170.4 45.3 10.20 4.46(dd)
(br.s) J=15.8 , 3.7
3.97(dd)
J=15.5 , 5.7
Gly2 169.5 44.9 9.53(d) 4.79(dd)
J=7.0 J=14.8 , 7.0
3.81(d)
J =14.5
Pro 173.6 59.7 29.7 25.5 48.1 4.74(ca.) 2.08(m) 1.92(m) 3.93(m)
1.74(m) 3.63(m)
Ile 172.5 60.0 36.5 25.7 11.7 8.87(d) 4.62(m) 2.48(m) 1.71(m) 0.861(t)
16.4 J=9.5 1.35(m) J=7.0
1.08(d)
J=6.0
Val1 172.1 62.2 29.7 19.0 8.42(d) 4.46(m) 2.50(m) 1.10(d)
19.9 J=6.0 J=6.0
1.11(d)
J=6.0
Val2 172.9 62.6 31.0 19.2 9.47 4.72(ca.) 2.38(m) 1.12(d)
19.5 (br s) J=6.5
1.14(d)
J=6.5
Leu1 171.6 49.8 41.3 25.2 22.2a 7.73(d) 5.24(ca.) 1.97(m) 1.72(m) 0.97(d)
23.3b J=7.0 1.75(m) J=5.6
1.01c(d)
J=6.3
Leu2 173.3 53.8 42.6 25.2 22.3a 8.69(d) 5.16(ca.) 2.07(m) 1.92(m) 1.13(d)
23.4b J=8.5 1.92(m) J=5.8
1.06c(d)
J=6.0
Assignments wi th the same superscripts(a , b and c)may be interchanged.
Fig.1.　Structure of polycarponin B (1);arrows show selected
HMBC correlations.
and 1 650 cm-1 , respectively.The FABMS gave an [M
+H] + ion at m/z 865 and the molecular formula
C45H68N8O9 derived from the HR_FABMS ([M+H] + at
m/ z 865.525 0 , calcd m/ z 865.518 7), indicated the
presence of 16 degrees of unsaturation.The 13C and 1H_
NMR spectra (Table 2) showed the presence of eight
amide carbonyl signals and five amide NH signals , re-
spectively.From these facts , 2 was deduced to be a cy-
clopeptide.
Amino acid analysis[ 5] of the hydrolysate prepared
from compound 2with 6 mol/L HCl at 110 ℃for 24 h in
a sealed tube revealed the presence of three prolines , two
leucines , one phenylalaine , one threonine and one va-
line , which was confirmed by analysis of the 1H_1H COSY
spectrum.The NOESY and HMBC spectra provided the
evidence for the linkage of amino acid residues(Fig.2).
The HMBC spectrum showed some correlations between
amide CO andNH , indicating the presence of two peptide
fragments (_Pro3_Val_Leu2_Phe_and_Pro1_Thr_Leu1_
Pro2_), and these two peptide fragments had to be linked
in only one sequence.The NOESY spectrum also exhibit-
ed some important NOE correlations , indicating the pres-
ence of the peptide fragments(_Pro3_Val_, Leu2_Phe_Pro1
and _Thr_Leu1_).The combination of the results men-
tioned above gave rise to the structure of 2 as
cyclo (_Pro1_Thr_Leu1_Pro2_Pro3_Val_Leu2_Phe), and
positive FABMS further confirmed the proposed structure.
542　 植　物　学　报　　Acta Botanica Sinica 43 卷
Table 2　1H and 13C_NMR spectral data of polycarponin C(2)in pyridine_d5
CO Cα Cβ Cγ Cδ HN Hα Hβ Hγ Hδ
Thr 171.2 62.4 67.0 22.3 7.40(d) 4.55(m) 4.64(m) 1.36(d)
J=6.4 J=6.0
Phe 172.2 53.3 38.2 137.3 129.6 11.04(d) 5.06(m) 3.09(m) 7.33(m)
129.2 J=7.6 2.80(m) 7.28(m)
127.5 7.15(d)
J=7.2
Val 171.5 62.6 31.3 19.1 8.30(d) 4.74(m) 2.40(m) 1.05(d)
19.9 J=9.2 J=6.8
1.07(d)
J=7.2
Leu1 171.2 50.1 41.7 25.2 22.8 8.81(d) 5.30(m) 2.16(ca.) 1.74(ca.) 0.782(d)
22.9 J=8.8 J=5.6
0.808(d)
J=5.6
Leu2 173.5 51.4 43.2 25.2 22.8 8.05(d) 5.36(m) 1.74(ca.) 1.90(ca.) 0.925(d)
23.2 J=9.2 J=6.8
0.931(d)
J=6.8
Pro1 173.1 62.3 32.2 22.2 46.7 4.59(d) 2.16(ca.) 1.74(ca.) 3.68(ca.)
J =7.6 1.40(m)
Pro2 171.1 61.6 31.3 22.2 46.7 4.49(d) 1.90(ca.) 1.64(m) 3.68(ca.)
J =7.6 2.72(m) 3.55(m)
Pro3 170.8 59.9 28.8 25.5 47.9 4.35(m) 1.90(ca.) 2.16(ca.) 4.08(m)
1.74(ca.) 1.92(ca.) 3.94(m)
Fig.2.　Structure of polycarponin C(2)
Arrows(※)show selected HMBC correlations;arrows ( )show
selected NOESY correlations.
2　Experimental
2.1　Plant materials
The whole plants of Polycarpon prostratum
(Forssk.)Aschers.et Schwein.ex Aschers were col-
lected in Xishuangbanna , Yunnan Province , China , in
July 1997 , and identified by senior engineer WANG
Hong.A voucher specimen is deposited in the herbarium
of Kunming Institute of Botany , the Chinese Academy of
Sciences.
2.2　Instruments and reagents
Melting points were determined on a Kofler block
and uncorrected.Optical rotations were measured with a
SEPA_300 polarimeter.IR spectra were measured on a
Bio_Rad FTS_135 spectrometer.NMR spectra were ob-
tained on Bruker AM_400 and DRX_500 spectrometers.A
VG Autospec_3000 spectrometer was used to record
FABMS spectra.200-300mesh and 300-400 mesh sil-
ica gel and Diaion HP_20 were used for column chro-
matography.
2.3　Extraction and isolation
Plant material (17.8 kg)was extracted with hot
ethanol four times to afford an EtOH extract that was sus-
pended in water , extracted with EtOAc to afford an EtOAc
residue (168 g), which was subjected to Diaion HP_20
column chromatography using a H2O_MeOH gradient sys-
tem(1∶0-0∶1).The fraction eluted with 70%MeOH
was further subjected to silica gel column chromatography
(CHCl3∶MeOH =9∶1)to afford B(1 , 53 mg)and C
(2 , 180 mg), respectively.
Polycarponin B(1)　Colorless needles(MeOH).
Mp 182-184 ℃;[α] 26D -87.9°(c 0.44 , MeOH);IR
νKBrmax cm-1:3 290 and 1 640.FABMS m/ z:749 [M+
H] +(37), 636(3), 537(3), 424(5), 325(3), 268
(13), 155 (17), 86 (100).HR_FABMS [M +H] + at
m/z 749.487 4 (calcd for C37H64N8O8 , 749.492 5).
5 期 丁中涛等:多荚草中的新环肽(英) 543　
1H , 13C-NMR spectral data see Table 1.
Polycarponin C(2)　Colorless needles(MeOH).
Mp 183-186 ℃;[ α] 25D -124.8°(c 0.57 , MeOH);
IRνKBrmax cm-1:3 300 and 1 650.FABMS m/ z:865 [M
+H] +(20), 554(2), 407 (4), 294(5), 195(4),
120(14), 70 (100);HR_FABMS [ M +H] + at m/ z
865.525 0(calcd for C45H68N8O9 , 865.518 7).1H , 13
C-NMR spectral data see Table 2.
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544　 植　物　学　报　　Acta Botanica Sinica 43 卷