全 文 ：苏铁蕨的化学成分 ?
方云山 , 杨亚滨 , 杨明惠 , 杨雪琼 , 董刘宏 , 丁中涛??
(教育部自然资源药物化学重点实验室 , 云南大学化学科学与工程学院 , 云南 昆明 650091)
摘要 : 从蕨类植物苏铁蕨 ( Brainea insignis) 中分离得到 1 个新的苯乙烯基吡喃酮苷 , 利用波谱技术鉴定了
其结构。此外 , 还得到了 1 个已知的苯乙烯基吡喃酮苷和 4 个其它已知化合物。同时 , 还测定了分离得到
的两个苯乙烯基吡喃酮苷化合物的 DPPH 自由基清除活性。
关键词 : 蕨类植物 ; 苏铁蕨 ; 苯乙烯基吡喃酮苷 ; DPPH 自由基清除活性
中图分类号 : Q 946 文献标识码 : A 文章编号 : 0253 - 2700 (2008) 06 - 725 - 04
Chemical Constituents from the Fern
Brainea insignis (Blechnaceae)
FANG Yun-Shan, YANG Ya-Bing, YANG Ming-Hui , YANG Xue-Qiong,
DONG Liu-Hong, DING Zhong-Tao**
( Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, School of Chemical
Science and Technology, Yunnan University, Kunming 650091 , China)
Abstract: A new styryl-2-pyroneglucoside (1) andaknown styryl-2-pyroneglucoside (2) , together with four other known
compounds (3 - 6) , were isolated fromthe ethanol extract of the fern Brainea insignis . The structures of thesecompounds
were determined by means of spectroscopic analysis including1D and 2D NMR , HR-MS . And the capacities to scavenge
against DPPH radical of two styryl-2-pyrone glucosides were assayed .
Key words: Fern; Brainea insignis; Styryl-2-pyrone glycoside; DPPH radical scavenging activity
Braniea insignis (Hook .) J . Smith is amonotype
genus plant belonging to Blechnaceae . As an ancient
fern species, its early fossils belong to the Mesozoic
era, near 400 million years ago . Now it is mainly dis-
tributed in the South of China, and used as a Chinese
traditional medicinal herb for the treatment of common
cold, suffer burn, trauma bleeding, ascarid disease
etc . (Wu, 1990) . A new flavonoid glycoside and four
lignans have been isolated from Brainea insignis (Mu-
rakami et al. , 1986; Wada et al. , 1992 ) . In the pr-
esent paper, we report the isolation and structural elu-
cidation of a new styryl-2-pyrone glucoside ( 1 ) , a
known styryl-2-pyrone glucoside ( 2 ) , and four other
known compounds (3 - 6) , from Brainea insignis (Fig .
1) . And the activities of twostyryl-2-pyroneglucosides
in scavenging DPPH radical were also reported .
Compound 1 was obtained as a yellow amorphous
powder . The positive-ion HRESI-MS spectrum gave a
[M + H] + ion peak at m?z 393 .1168 ( calcd . m?z
393 .1186 ) , indicating a molecular formula of C19 H20
O9 , with ten degree of unsaturation . In addition, the
ESI-MS gave a [M + H-162 ] + ion at m?z 231 , which
showed that compound 1 might be a glycoside . Its 1 H
NMR and
13
C NMR spectra (Table 1) confirmed that it
云 南 植 物 研 究 2008 , 30 (6) : 725～728
Acta Botanica Yunnanica DOI : 10 .3724?SP. J . 1143 .2008.08160
?
?? ?Author for correspondence; Tel : + 86 - 0871 - 5033726; E-mail : ztding@ ynu. edu. cn
Received date: 2008 - 08 - 19 , Accepted date: 2008 - 10 - 15
作者简介 : 方云山 (1980 - ) 男 , 硕士 , 主要从事天然产物化学研究 , 现在昆明学院工作。 ?
Foundation item: The Natural Science Foundation of China and Yunnan Province ( 30560178)
Fig . 1 Structures of compounds 1 - 4
Table 1 1 H NMR ( 500 MHz) and 13 C NMR ( 125 MHz)
data of compound 1 in C5 D5 N
No . δC δH
2 w165 . 1
3 w94 e. 0 6 ?. 21 (1H , s)
4 w170 . 3
5 w101 . 8 6 ?. 22 (1H , s)
6 w162 . 0
1 i′ 128 w. 7
2 i′ 131 w. 5 7 ?. 48 (1H , d, 7 f. 8 )
3 i′ 118 w. 4 7 ?. 14 (1H , d, 7 f. 8 )
4 i′ 162 w. 3
5 i′ 118 w. 4 7 ?. 14 (1H , d, 7 f. 8 )
6 i′ 131 w. 5 7 ?. 48 (1H , d, 7 f. 8 )
7 i′ 136 w. 8 7 ?. 53 (1H , d, 16 . 4)
8 i′ 118 w. 1 6 ?. 67 (1H , d, 16 . 4)
1 i″ 102 w. 7 5 ?. 73 (1H , d, 7 f. 4 )
2 i″ 76 e. 1 4 ?. 27 (1H , br d, 6 . 6)
3 i″ 80 e. 0 4 ?. 30 (1H , m)
4 i″ 72 e. 5 4 ?. 32 (1H , m)
5 i″ 80 e. 9 4 ?. 11 (1H , m)
6 i″ 63 e. 7 4 ?. 34 (1H , br d, 11 .2 )
4 ?. 29 (1H , br d, 12 .2 )
was amono-O-β-glucosidewith the anomeric proton atδ
5.73 (1H, d, J = 7.4 Hz, H - 1″) and the anomeric
carbon atδ102.7 (C - 1″) . The 1 H NMR spectrum ex-
hibited an AA′BB′systematδ7 .48 ( 2H, d, J = 7 .8
Hz, H - 2′, 6′) , 7 . 14 ( 2H, d, J = 7 .8 Hz, H - 3′,
5′) , indicating the presence of a p-disubstituted phe-
nyl ring . And the 1 H NMR signals of a trans double
bond was noted atδ6 .67 (1H, d, J = 16 .4 Hz, H -
8′) , 7. 53 (1H, d, J = 16 .4 Hz, H - 7′) . The HM-
BC spectrumshowed the correlations (Fig . 2) between
H - 8′and C - 1′(δ128 .7) suggesting the presenceof
an E-styryl moiety . The 2-pyroneunit was suggested by
a detail comparisonof 13 C NMR and 1 H NMR datawith
the literatures ( Kraut et al. , 1996; Mcglacken and
Fairlamb, 2005 ) , and was identified as a 4 , 6-disub-
stituted 2-pyrone with two proton signals atδ6 .22 ( H
Fig . 2 Key HMBC correlations of compound 1
627 云 南 植 物 研 究 30 卷
- 5 , s) and 6 .21 ( H - 3 , s) in 1 H NMR spectrum .
The HMBC correlations clearly revealed that H - 7′in
theE-styryl moiety was long-range coupled to theC - 6
in 2-pyrone unit, and the anomeric proton ( H - 1″) of
theglucosemoiety was long-range coupled to the C - 4
(δ171 .3) . Therefore, compound 1 was determined to
be bisnoryangonin-4-O-β-D- glucopyranoside .
Compound 2 was also obtained as a yellow amor-
phous powder . It displayed a [M + H] + peak at m?z
409 .1117 ( calcd . m?z 490 .1135) in the positive ion
HRESIMS, indicating a molecular formula of C19 H20
O10 . Compared with 1 , all of the 13 C NMR data were
very similar to that of the compound 1 , except for the
signalsδ149 .2 ( C - 4′) , δ146 .5 ( C - 3′) . This in-
dicated that there are two o-hydroxyls in E-styryl moi-
ety of compound 2 . In 1 H NMR spectrum, the signals
ofδ6 .96 (1H, d, J = 6 .2 Hz, H - 6′) , 6 . 78 ( 1H,
d, J = 6 .2 Hz, H - 5′) , 7 .05 ( 1H, s, H - 2′) also
proved this conclusion . Therefore, the structure of
compound 2 was established as hispidin-4-O-β-D-glu-
copyranoside, which had been isolated fromfern Pteris
ensiformis (Chen et al. , 2007 ) .
Compound 3 was identified as batatasin ( III ) by
analysisof its 1 H, 13 C NMR and MS spectra ( Gao et
al. , 2006) . Compound 4 was identified as ponastero-
side A by comparison of its physicochemical and NMR
data with the reported in the literature ( Zhu et al. ,
2000; Hikino et al. , 1969 ) . Andβ-sitosterol ( 5 ) ,
daucosterol ( 6 ) were identified by comparison with
their authentic samples .
The research into natural products as health pro-
tecting factors againstoxidative damage is an interesting
field . DPPH ( 1 , 1-diphenyl-2-picrylhydrazyl) is asta-
ble free radical that loses its purple color when accepts
an electron froman antioxidant compound ( Bao et al. ,
2004; Marino et al. , 2007 ) . In this paper, the radi-
cal scavenging capacitiesof the isolates ( 1 and 2) from
B. insignis were evaluated by investigating them
against theDPPH radical .Thesubstances wereassayed
at three certain concentration of 0 .01 , 0 .03 , 0 .06 mg?
ml , and their activities were compared with rutin, a
known natural antioxidant compound . The results were
reported in Table 2 .
Table 2 Radical DPPH scavenging activity
Concentration
( mg?ml)
Rutin
Scavenging activity ( SC% )
Compound 1 RCompound 2 ?
0 ?. 01 75 .78 6 p. 17 15 .52
0 ?. 03 90 .71 17 .87 42 .95
0 ?. 06 92 .06 29 .07 73 .43
Our previous investigation showed that the extract
of B. insignis exhibited high phenolic content and
strong radical DPPH scavenging activity ( Ding et al. ,
2008) . In this work, all thesubstances showed activity
against the radical DPPH, but rutin was more active
than compound 1 and 2 at the tested contraction . Be-
cause compound 2 bears two phenolic hydroxyl groups
on molecular skeleton, its observed activity was stron-
ger than that of compound 1 which only has one phe-
nolic hydroxyl group in its structure . This indicted that
the phenolic hydroxyl group is the mainly active group
for the activity against the radical DPPH .
Experimental
General Experimental Procedures Optical rotationswere
measured with a Jasco DIP-370 digital polarimeter . 1 H, 13 C
NMR and 2D NMR spectraweremeasuredon aBruker DRX-500
NMR spectrometer ( TMS as internal standard, δ in ppm, J in
Hz) . HRESIMS were obtained on an agilent G3250AA mass
spectrometer . For column chromatography, silica gel ( 200 - 300
mesh, Qingdao Marine Chemical Inc ., China) . Lichroprep RP-
18 ( 40 - 60μm, Merck, Darmstadt, Germany) and Sephadex
LH-20 ( 25 - 100 μm, Amersham Biosciences, Sweden) were
used . A shimazu UV-VIS-PC 2410 spectrometer was used inDP-
PH radical scavenging activity test .
Plant Material The whole plant of Brainea insignis
(Hook .) J . Smith was collected in February 2006 , in Yunnan
province, P . R . China . A voucher specimen (2006D011 ) was
deposited in the school of Chemical Science and Technology of
Yunnan University, and was identified by Prof . Shu-GangLu .
Extraction and Isolation The air-dried plant powder of
Brainea insignis (1 . 4 kg) was extracted with EtOH for 24 h and
filtered . Thefiltrate was evaporated in vacuo to give a residue .
Then the residue (55 g) was subjected to columnchromatography
on silica gel, and was eluted with CHCl3 -MeOH ( 9∶1) to give
four fractions . Fr . III was subjected to Sephadex LH-20 column
chromatography eluting with MeOH to afford compound 1 ( 25
mg) , 2 (12 mg) , 4 (15 mg) , 6 (30 mg) , and were purified by
RP-18 column chromatography elutingwith CH3 OH-H2 O (9∶1) .
7276 期 FANG Yun-Shan et al . : Chemical Constituents from the Fern Brainea insignis (Blechnaceae)
Fr . II was subjected to silica gel column chromatography eluting
with EtOAc-MeOH ( 96∶4 ) to afford compound 3 ( 10 mg) .
Compound5 (50 mg) was fromFr . I .
Bisnoryangonin-4-O-β-D-glucopyranoside ( 1 ) : yellow
amorphous powder . [α] 22. 5D - 44 .13 ( c0 .64 , MeOH) .1 H- and
13 C-NMR data see table 1 . HR-ESI-MS: m?z 393 .1168 [M +
H] + ( calcd . for C19 H21 O9 393 .1186) .
DPPH Radical Scavenging Assay DPPH radical scaveng-
ingactivity was examined by the described method ( Bao et al. ,
2004; Marino et al. , 2007) . In brief , 3 .0 ml each sample in
ethanol was added to 2 .0 ml DPPH (2 . 0×10 - 4 mol?L) solution
and incubated at room temperature for 30 min . Then the absor-
bance of the reaction mixture was determined at 517 nm on a
shimazu UV-VIS-PC 2410 spectrometer .
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