全 文 ：寒莓中三萜成分的研究
邓　烨　彭树林　张晓王容　丁立生　王明奎＊
(中国科学院成都生物研究所 , 成都 610041)
摘要:　从蔷薇科悬钩子属植物寒莓(Rubus buergeri Miq.)中分离鉴定了 12 个三萜类化合物。其中 1 个为新化合
物 ,命名为寒莓酸甲酯(12a),其结构经波谱分析鉴定为 2α, 3α, 19α, 24_四羟基齐墩果_12_烯_28_酸甲酯。
关键词:　寒莓;三萜;寒莓酸甲酯
中图分类号:R914　　　文献标识码:A　　　文章编号:0577-7496(2001)06-0644-03
Triterpenoids from Rubus buergeri
DENG Ye , PENG Shu_Lin , ZHANG Xiao_Rong , DING Li_Sheng , WANG Ming_Kui＊
(Chengdu Institute of Biology , The Chinese Academy of Sciences , Chengdu 610041 , China)
Abstract:　A new triterpenoid , methyl buergericate(12a), which was elucidated as 2α,3α,19α,24_tetrahy-
droxyl olean_12_en_28_oic acid methyl ester by spectroscopic methods , together with eleven known triterpenoids
was isolated from Rubus buergeri Miq.The isolation of the above chemical constituents from this plant was re-
ported for the first time.
Key words:　Rubus buergeri;triterpenoid;methyl buergericate
　　Rubus buergeri Miq., a herb distributed in the
mountainous regions of South China , is used in traditional
Chinese medicine to promote wound healing , ease pain ,
and cure phthisis and jaundice[ 1] .Our investigation on
the MeOH extract of the whole plant has led to the isola-
tion of a new triterpenoid , named methyl buergericate
(12a), and eleven known triterpenoids (Fig.1).The
fractions containing 8-12were treated with diazomethane
in methanol because of the difficulties encountered in sep-
aration of the natural product.We report herein the isola-
tion and structure elucidation of these twelve compounds.
Fig.1.　The chemical structures of compounds 1-7 , 8a , 9a , 10a , 11a and 12a
Received:2000-09-04　Accepted:2000-11-09
Supported by the Sichuan Science and Technology Foundation of Young Scientists.
＊Author for correspondence.Tel.:(028)5223843;E_mail:mkwang@sc.homeway.com.cn;Fax:(028)5222753
植　物　学　报　2001 , 43(6):644-646 　 　 　 　 　 　 　
Acta Botanica Sinica
1　Results and Discussion
The methyl ester (12a)of 12 was obtained as white
needles.Its FABMS gave [M+Li] + at m/ z 525 and [M
+Na] + at m/ z 541 and HREIMS gave a molecular ion
at m/ z 518.359 5 , that is in agreement with the molecu-
lar formula C31H50O6 (calc.for 518.360 7).The IR
spectrum showed absorptions at 3 449 (OH), 1 705
(C O)and 1 638 cm-1 (C C).Positive reaction
with Lieberman_Burchard and Brady s reagents indicated
the presence of a carbonyl_containing triterpenoid.The
1
H_NMR spectrum exhibited the presence of six angular
methyl groups at δ0.87 , 1.03 , 1.06 , 1.15 , 1.49 ,
1.66(each 3H , s)and a hydroxylmethyl atδ3.85 and
4.12(each 1H , d , J =10.8 Hz).One olefinic methine
atδ5.46 (1H , s)and two olefinic carbon signals at
123.7(d)and 144.2(s)were also observed.The above
evidence suggested that 12a was an oleanane_type triter-
penoid.A comparison of 13C-NMR data of 12a with 2α,
3α, 24_trihydoxylolean_12_en_28_oic acid[ 2] and 2α, 3α,
24_trihydoxylurs_12_en_28_oic acid[ 3] indicated that these
three compounds had the identical rings A and B.The
coupling constant of H_2 (δ4.46 , dd , J =2.4 Hz ,
10.0 Hz), HMBC correlation between H_3 and C_2 , H_
24 and C_4 , C_5 , and 1H_1H COSY correlation of H_2
and H_3 further corroborated the above conclusion.The
signal atδC 80.9 indicated that anα_OH was attached to
C_19 and a fragmental ion of FABMS at m/ z 279.3 [ a+
H] + resulting from retro_Diels_Alder cleavage of C_ring
supported the assignment of a hydroxyl group and a
methylcarboxyl group at the D/E rings[ 4] .A comparison
of 13C-NMR data with those of methylsiaresinolate(methyl
3β ,19α_trihydoxyl olean_12_en_28_oate)indicated that the
hydroxyl at C_19 wasα_orientation[ 2] .The 1H_NMR sig-
nals of H_18(δ3.39 , br.s)andH_19(δ3.52 , d , J =
3.6 Hz), HMBC correlation between H_18 and C_13 , C_
17 , between H_19 and C_18 gave further confirmation.
Therefore , the structure of 12 was established as 2α,3α,
19α,24_tetrahydroxyl olean_12_en_28_oic acid.
Based on direct comparison with the published spec-
tral data and authentic samples , the known compounds
were identified to be ursolic acid (1), 2α,3α,19α_trihy-
doxyl urs_12_en_28_oic acid (euscaphic acid)(2)[ 5] ,
3β , 19α_dihydroxyl_2_oxo urs_12_en_28_oic acid (2_oxo_
pomolic acid)(3)[ 6] , 2α, 3β , 19α_trihydroxyl urs_12_en_
28_oic acid (tormetic acid)(4)[ 7] , 2α, 3β_dihydroxyl
urs_12_en_28_oic acid (5)[ 8] , 2α, 3α, 19α, 23_tetrahy-
droxyl urs_12_en_28_oic acid (arjungenin)(6)[ 9] , 3β ,
19α_dihydroxyl urs_12_en_28_oic acid_28_O_β_D_glucopy-
ranoside (7), 2α, 3β_dihydroxyl olean_12_en_28_oic acid
(8)[ 2] , 2α, 3β , 19α, 23_tetrahydroxyl olean_12_en_28_oic
acid (9)[ 9] , 2α, 3β ,19α, 23_tetrahydroxyl urs_12_en_28_
oic acid (10)[ 10] and 3_O_β_D_arabinopyranosyl_pomolic
acid(11)[ 11] .By comparison of 8a-12a on TLC with
the original fractions , no methylization products were de-
tected.
Table 1　The 1H and 13C-NMR data of methyl buergericate(12a)
(400 MHz , C5D5N)
C δC 　　　　δH 　　HMBC
1 42.8(t) C_2 , 3 , 5 , 6, 25
2 66.2(d) 4.45(1H , dd , J =2.4 Hz ,
10.0 Hz)
3 74.2(d) 4.58(1H , d , J =2.4 Hz) C_1 , 2 , 4 , 5
4 45.1(s)
5 49.6(d)
6 19.0(t)
7 33.6(t)
8 40.1(s)
9 48.3(d)
10 38.7(s)
11 24.2(t)
12 123.7(d)5.46(1H , br.s) C_9 , 14 , 18
13 144.2(s)
14 41.9(s)
15 28.8(t)
16 28.0(t)
17 46.3(s)
18 44.5(d) 3.39(1H , br.s ,) C_13, 17
19 80.9(d) 3.52(1H , d , J =3.6 Hz) C_18, 21
20 35.5(s)
21 28.7(t)
22 33.2(t)
23 23.8(d) 1.66(3H , s)
24 65.1(t) 3.85(1H , d , J =10.8 Hz)
4.12(1H , d , J =10.8 Hz)
C_3 , 4
25 17.2(q) 1.06(3H , s)
26 16.9(q) 0.87(3H , s)
27 24.6(q) 1.49(3H , s)
28 178.7(s)
29 28.8(q) 1.15(3H , s)
30 24.8(q) 1.03(3H , s)
OCH3 51.7(q) 3.37(3H , s) C_28
6 期 邓　烨等:寒莓中三萜成分的研究(英) 645　
2　Experimental
2.1　General experimental procedures
Melting points were measured with XRC_1 and un-
corrected.Optical rotation was measured with PE_241 po-
larimeter.IR spectra were measured with Nicolet MX_1
spectrometer.NMR spectra were obtained from Bruker
AC_300P and Varian Unity Inova_400 spectrometers.A
VG AutoSpec_3000 and a VG ZAB_HS spectrometer were
used to record HREIMS , FABMS spectrum respectively.
Silica gel(170-200 mesh), Lobar LiChroprep RP_18 ,
Lobar LiChroprep Si_60 and MCI_gel CHP_20P were used
for column chromatography.
2.2　Plant material
The whole plant of Rubus buergeri Miq.was collect-
ed from Nanchuan , Chongqing , China in July 1997 and
identified by Prof.LIU Zheng_Yu.The specimen was de-
posited in the Herbarium of Chengdu Institute of Biology ,
the Chinese Academy of Sciences.
2.3　Extraction , methylization and isolation
The air_dried and powdered whole plant material
(4.5 kg)was extracted with methanol for three times at
room temperature , each time for three days.After removal
of the solvent , the extract(460 g)was suspended in H2O
and extracted with petroleum ether , ethyl acetate , and
n_BuOH successively.The EtOAc extract(92 g)was first
fractionated on a MCI_gel for depigmentation and then
chromatographed on silica gel , RP_18 and Si_60 columns
to give 1(8 mg), 2(160 mg), 3(60 mg), 4(75 mg),
5(30 mg), 6(42 mg)and 7 (110 mg).The n_BuOH
extract(13 g)was chromatographed on silica gel to give
six fractions as A , B , C , D , E and F.Fractions A , C
and D were methylized with CH2N2 and the methylization
derivatives of 8a(23 mg), 9a(30 mg), 10a(50 mg),
11a (35 mg), 12a (40 mg)were isolated by chro-
matographed on silica gel , RP_18 and Si_60 columns.
2.4　Identification
12a , white needles , mp 226 -229 ℃, [ α] 20D
+0.18°(c 2.1 , MeOH), IRνKBrmax cm-1:3 449 , 2 926 ,
1 705 , 1 638 , 1 457 , 1 037;FABMS m/ z:525 [M+
Li] + , 541 [M+Na] + , 279 [ a+H] +;HREIMS m/ z:
518.359 5(C31H50O6 , calc:518.360 7).1H-NMR and
13C_NMR data were shown in Table 1.
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(责任编辑:王　葳)
646　 植　物　学　报　　Acta Botanica Sinica 43 卷