A new flavonol glycoside from tridaxprocumbens linn

Article abstract of DOI:10.3184/030823409X416929

A new flavonol glycoside which has been isolated from the Tridax procumbens Linn. The present work deals with the isolation and identification of flavonol glycoside, characterised as 8,3'-dihydroxy-3,7,4'-trimethoxy-6-0-[a-L- rhamnopyranosyl-(1->2)]-β-D-g

Full text of DOI:10.3184/030823409X416929

JOURNAL OF CHEMICAL RESEARCH 2009
MARCH, 165-166
RESEARCH PAPER 165
A new flavonol glycoside from Tridax procumbens Linn.
Ke Yuana*, Runsheng XUa,b and Cungui Chenb
aResearch and Development
Certer of Natural Medicine, Zhejiang Forestry University, Linan 311300, P.R. China
bCollege of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, P.R. China
A
new flavonol glycoside which has been isolated from the Tridax procumbens Linn. The present work deals
with the isolation and identification of flavonol glycoside, characterised as 8,3'-dihydroxy-3.7.4'-trimethoxy-6-0-
[u-L-rhamnopyranosyl-(1~2)]-13-D-glucopyranoside flavonol. Its structure elucidated using spectral data.
Keywords: Tridax procumbens Linn., new flavonoid glycoside, aglycone, NMR, HRESIMS
Tridax procumbens Linn. is commonly known as 'Ghamra'
in Hindi.! It has been found to have significant medicinal
properties. Its leaves are used in the treatment of bronchial
catarrh, dysentery and diarrhoea and for preventing hair loss.2,3
The juice of its leaves possesses antiseptic, insecticidal and
parasiticidal properties. It is also used to check haemorrhages
from cuts, bruises and wounds.4 An aqueous extract of this
plant also has marked depressant action on respiration.
proton at Ii 6.86 (s, IH, 5-H). There were signals which were
assigned to two anomeric protons at Ii 5.30 (d, IH, J = 7.6 Hz)
of glucopyranoside and Ii 5.40 (s, IH) of rhanmopyranosyl
sugars together with 15 glycosyl protons between Ii 1.24 and
5.40. Three isolated protons at Ii 1.24 (d, 3H, J = 8.0) were
characteristic signals of a rhamanopyranosyl sugar.
The 13CNMR and DEPT spectra of 1 displayed 30 carbon
signals which consisted of 15 characteristic of the flavonoid
aglycone, three methoxyls and 12 of two glycosyl moieties
(Table 1). The above spectral data revealed that 1 is a flavone
glycoside with 13-sugarunits. The !H and 13CNMR spectral
data were unambignously assigned by HMQC and HMBC
experiments. while the signals assigned to sugar units revealed
the presences of a 6-substituted 13-D-glucopyranosyl units.
After acidic hydrolysis oft, paper chromatography confirmed
the release of glucose and rhanmose from 1. In the HMBC
spectrum long range correlations from H-1" to C-6 uneqivocally
established that a disaccharide 13-D-glucopyranosyl moiety
was located at C-6 aglycone, three methoxyl groups Ii 3.81
(s, 3H) was attached to C-4' of B-ring, Ii 3.88 (s, 3H) was
attached to C-7 of A-ring, Ii 3.94 (s, 3H) was attached to
C-3 of Coring, Ii 3.76(Glu-H2) was attached to Ii 100.0 (Glu-
C!) and Ii 101.9 (Rha-C!) at the same time, showing that
Earlier workers have reported the presence of luteolin,
glucoluteolin,5,6
13-sitosterol,
13-sitosterol-3-0-13-D-
xylopyranoside7 and quercetin8 in this plant. We have now
isolated a novel flavonoid glycoside, named 8,3'-dihydroxy-
3,7,4'- trimethoxy-6-0-[ u- L-rhamnopyranosyl-(1--->2)]-13-D-
glucopyranoside flavone (1). Its structure has been established
by a study of its physical and spectroscopic data (lH NMR,
13CNMR, !H-!H COSY, HSQC, HMBC, HRESIMS, IR).
Its has been hydrolysed to give the aglycone whose structure
has been established as 6,8,3'-trihydroxy-3,7,4'-trimethoxy-
flavone (2).
Air-dried and powdered of Tridax procumbens Linn. were
extracted with 70% ethanol and this ethanolic extract was
successively extracted with petroleum ether, ethyl acetate and
n-butanol. The concentrated ethyl acetate soluble fraction was
subjected to column chromatography over silica. On elution
with ethyl acetate: methanol (7: 3), it gave a compound 1.
This was obtained as yellowish powder, m.p. 302°C (MeOH),
[aHjl-41 ° (c, 0.5 MeOH); which analysed for C30H360!7
(m/z: 691.1846 [M+Na]+. in its HRESIMS). It possessed IR
absorption (KEr, disc): for a hydroxylic group (3394 cm-!),
two benzene rings (1596 cm-!, 1466 cm-!), and a carbonyl
group (1692 cm-!).
OH
~o~
oOH
H
The !H NMR spectrum of 1 in MeOD showed signals
attributed to a 1,3,4-trisubstituted phenyl moiety at Ii 7.65 (dd,
lH, J= 8.4 Hz, 2.2 Hz), Ii7.60 (d, lH, J= 2.2 Hz) and Ii7.03 (d,
IH,J= 8.8 Hz), three methoxyl groups at Ii3.92 (s, 3H, 4'-OMe),
Ii3.87 (s, 3H, 7-0Me), Ii3.80 (s, 3H, 3-0Me), and one isolated
HO~O
CH3
H
OH OH
OH
OH
2
Scheme 1
* Correspondent.E-mail:e-mail:yuan_keOOI@yahoo.com.cn

166 JOURNAL OF CHEMICAL RESEARCH 2009
Table 1 NMR spectral data of compound 1 and 2
Carbon no.
i5c
i5
H(multiplicity, proton in
DEPT
HMBC
tegration, J in Hz)
Aglycone
2
3
4
5
158.3
139.8
180.4
95.5
C
C
C
CH
6.86(s,lH)
108.1; 134.3; 153.2;
157.5; 180.4
6
7
8
157.5
134.3
153.2
151.8
108.1
124.1
116.3
147.6
151.8
112.3
122.4
60.6
C
C
C
C
C
C
CH
C
9
10
l'
2'
3'
4'
5'
6'
7.60(d, 1H, 2.2)
122.4; 147.6; 151.8; 158.3
C
7.03(d, 1H, 8.8)
7.65(dd, 1H, 8.4, 2.2)
3.80(s,3H)
124.1; 147.6; 151.8
116.3; 147.6; 158.3
139.8
CH
7.65
7.03
CH
3-0CH
7-0CH
3
3
CH
3
3.87(s,3H)
61.4
CH
3
134.3
151.8
4'-OCH
D-Glu
1"
2"
3"
4"
5"
6"
3
3.92(s,3H)
56.4
CH
3
5.30(d, 1H, 7.6)
3.76(brs,lH)
3.55(m,lH)
3.41(d, IH, 9.6)
3.71(brs,lH)
157.5;
100.0; 101.9
79.2; 72.1
78.4
62.4
78.4
100.0
79.2
78.3
72.1
78.4
62.4
CH
CH
CH
CH
CH
CH2
5.30
3.71
3.41
3.55
3.65
3.65(s, 1H) 3.90(brs, 1H)
3.903.76
L-Rha
1'"
2'"
3'"
4'"
5'"
6'"
101.9
71.4
72.2
74.1
70.2
18.3
5.40(s,lH)
3.37(d, IH, 9.6)
3.63(m,lH)
3.52(brs,lH)
3.93(s, 1H)
1.25(d, 3H, 6.0)
CH
CH
CH
CH
CH
71.4
101.9
71.4
72.2
74.1
70.2
3.37
3.63
3.52
3.93
1.25
3.93
CH
3
NMR data were measured in MeOD at 400 MHz for proton and at 100 MHz for carbon. The assignments based on DEPT, 1H-1H
COSY,HMQC and HMBC experiments.
1540, 1450, 1240; IH NMR (400 MHz, MeOH): i5 7.58 (dd, lH,
J = 8.0 Hz, 2.0 Hz), 7.55 (d, lH, J = 2.0 Hz), 7.01 (d, lH, J = 8.2 Hz),
6.86 (s, lH, H5), 3.92 (s, 3H, 4'-OMe), 3.87 (s, 3H, 7-0Me), 3.80
(s, 3H, 3-0Me), l3C NMR (100 MHz, MeOH): i5 180.9 (C-4), 159.3
(C-2), 158.2 (C-6), 154.3 (C-8), 152.3 (C-9), 148.2 (C-4'), 142.9
(C-3'), 140.1 (C-3), 133.1 (C-7), 124.8 (C-l'), 122.7 (C-6'), 116.7
(C-2'), 112.9 (C-4'), 106.9 (C-lO), 95.5 (C-5), 61.5 (C-7-0CH3), 61.1
(C-3-0CH3), 56.9 (C-4'-OCH3).
Ii 101.9 (Rha-Cl) was joined to Ii 79.2 (Glu-C2). Consequently
the structure of was determined as 8,3'-dihydroxy-
3,7,4 '-trimethoxy-6-0- [a-L-rhamnopyranosyl-( 1--->2)]-
1
13-D-glucopyranoside flavone (1).
Experimental
Extraction and isolation of compound 1: Tridax procumbens Linn.
(10.0 kg, dry weight) was collected from the city of Sanya ofHainan
province, in October 2007 and identified by Prof. Shiman Huang,
Department of Botany, Hainan University. A voucher specimen has
been deposited in the Herbarium of the department. It was sliced
into small pieces and extracted with 70% ethanol. The concentrated
aqueous ethanol extract was successively extracted with petroleum
ether, ethyl acetate and n-butanol. The concentrated ethyl acetate
soluble fraction (45 g) was subjected to column chromatography on
silica gel (600 g, 200-300 mesh) using a gradient of solvent mixtures
from light petroleum to ethyl acetate. Elution with a mixture of
light petroleum: ethyl acetate (7:3) gave compound 1: 75 mg, m.p.
Thanks are due to Prof. Janxun Kang and Prof. Weiguo Zhu,
Analysis and Testing Centre, Zhengzhou University, China,
for measuring NMR and HRESIMS.
Received 9 November 2008; accepted 19 January 2009
Paper 08/0288 doi: 10.3184/030823409X416929
Published online: 6 April 2009
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