Proceedinp of the NOST of Vietnam, Vol. 6, No.1 (1994) (29-99)
CONSTITUENTS OF THE AERIAL PARTS OF
EUPATORIUM ODORATUM
L. (SYN. CHROMOLAENA ODORATA (L.)
R. M. KING AND H. ROBINSON),
FAMILY COMPOSITAE-GROWN IN VIETNAM
NGUYEN THI DIEM TRANG, LE VIET NGOC PHUONG,
Faculty of Chemistry, Hanoi University
NGUYEN XUAN DUNG
Centre for Education and Development of Chromatography of Vietnam
PIET A. LECLERCQ
Eindhoven University of Technology, the Netherlands
and
M. J.
WANNER,
G. J.
KOOMEN, AND
R.
FOKKENS
University of Amsterdam, the Netherlands
Summary. Eupatorium odoratum (L.), Family Compositae grows very fast in various places
of the world, especially in tropical countries. This plant belonges to one of the worst plants.
Some applications of this plant used for treatment of diseases such as disrrhoea, dysentery
and scabies have been found in recent years. For detailed studies on Eupatorium odoratum
L. grown in Vietnam we have screened this plant for the most characteristic constituents
such as essential oil and flavonoids by using combinedly chromatographic (EC, TLC, GC,
GCjMS) and spectroscopic (IR, 1H-, 13C-NMR, FAB-MS and UV) methods.
The essential oil of Eupatorium odoratum (L.) from Vietnam obtained by steam distillation of the leaves, has been analysed. More than 40 components were found, with geijerene
(42.5%) and ,B-cubebene (12.5% as major constituents.
Flash chromatographying the crude sample, which was extracted with warm water
obtained from the aerial parts of Vietnamese E. odoratum gave two chalcones and one flavanone, whose structures have been shown to be 2'-hydroxy - 4,4',5',6' - tetramethoxy chalcone (odoratin); 2',4-dihydroxy - 4',5',6'-trimethoxy chalcone and the optically inactive
flavanone.
30
NGUYEN THI DIEM TRANG et al.
I - INTRODUCTION
Eupatorium is one of the endemic genera in Compositae family of Vietnam. Eupatorium odoratum L. (Syn. Chromolaena odorata L.) has been a subject of chemical
examination by N. X. Dung et al. [1-5]. In continuation of our studies on biological actives compounds from Vietnamese Eupatorium species, we isolated from E. ayapana Vent.
the coumarin derivatives and thymoquinol as well as methylthymylether [6], and from E.
stochadosmum Hance also coumarin derivatives, coumarin and some thymol compounds
[7]. This paper present our results of the study on E. odoratum L. from Vietnam.
II - EXPERIMENTAL
The oil was analyzed by using a combination of capillary GC and GC/MS, as described previously [8]. The percentage composition of the oil was calculated from electronic integration measurments, using flame inoization detection without response correction
factors. Mps is uncorr. NMR spectra were measured on a WM-300 instrument. Mass
spectra were recorded on a Varian MAT 711 instrument. Thin Layer Chromatography
(TLC) were performed on Silica gel coated plastic sheets (Merck Silica gel 60 F254) using UV for detection. Chromatographic purification refers to flash chromatography using
Merck silica gel 60 (230-400 mesh).
Following the method to obtain crude sample from E. ayapana and E. stoechadosmum
[6 -7] we receive from 2 kg fresh aerial parts of E. odoratum L. collected from Cau Giay,
Hanoi 877 mg the crude sample, which was chromatographed on Silica gel with CHCbEtOAc as solvents and repeated with Petroleum ether - EtOAc afforded odoratin (2 mg,
0.0022%) orange crystals, mp = 136.5 -137.5°C (EtOAc/p.E) H-NMR (CDCh, 300 MHz)
in ppm: 3.84 (3H, OCH 3 ), 3.86 (3H, OCH 3 ), 3.90 (3H, OCH 3 ), 3.93 (3H, OCH 3 ), 7.85
(H-a and H-.8), 6.30 (H-3'), 6.94 d (J = 8.7 Hz, H-3 and H-5), 7.71 d (J = 8.8 Hz, H2 and H-6) and a br s at 13.78ppm (OH). MS exhibited some prominet peaks at 210
(ClQHlQOs), 195 (C9H 7 0 S), 167 (C S H 7 0 4 ), 91 (C 7 H7 ). Where elution with CHCh EtOAc in different ratio yielded 2',4 - dihydroxy - 4',5',6' - trimethoxy chalcone (2.8 mg,
0.0031%) and 2.9mg flavanone, mp. 193-196°C.
2',4-dihydroxy - 4',5',6'-trimethoxychalcone - organe crystals, mp = 142 - 144°
(EtOAc/P.E). IH-NMR (CDCh, 300MHz): 3.84 ppm (3H, OCH3 ), 3.90 (3H, OCH 3 ), 3.93
(3H, OCH 3 ), 7.84 (H-a and H-.8), 6.30 (H-3'), 6.87 d (J = 8.6 Hz, H-3 and H-5), 7,57 d
(J = 8.6 Hz, H-2 and H-6) and a br s at 13.76 ppm (OH). MS: caclce for ClsHlS06: MW
330.1102. Found: 330.4 (100%). Other signficant peaks at m/e (comp. %) 210 (ClQHlQOs,
93.46), 195 (C9H 7 0 S, 75.62), 167 (C SH 7 0 4 27.05),91 (C 7 H 7 , 11.21). IR (CHCb): 3300
(br.), 1660,1585 and 1560cm- 1 . NMR (CDCb): 3.83,3.87 and 3.~4 (3-methoxy) 5.32d
(J = 10.5,2.8 Hz, H-2) 2.73 and 2.79 (J 2.9 Hz respectively H-3 clS and H_3trans), 6.34
(H-8), 6.89d (J = 8.6 Hz, H-3' and H-5'), 7.33 d (J = 8.5 Hz, H-2' and H-6'). MS: Calcd
for ClsHlS06: MW 330.1102. Found: 330.1093. Other signficant peaks at m/e (Comp,
%) 210 (ClQHlOOS, 83.5), 195 (C9H 7 0 S, 65.4) and 149 (C 7 H 2 0 4 or C SHS0 3 , 38.7).
=
CONSTITUENTS OF THE AERIAL PARTS OF EATORIUM ODORATUM L ...
31
m - RESULTS AND DISCUSSION
Fresh leaves were harvested in the flowering time, 1989. Steam distillation produced
an oil in 0.22% yield.
The compounds were identified in the Essential Oil of Vietnamese E. odoratum L.
listed in Table 1 in the order of eluation from a OV-1 column [1].
Table 1. Chemical composition of the leaf oil
of E. odoratum L. from Vietnam
a-pinene (2.6%)
6-elemene (0.4%)
sabinene (0.6%)
a-copaene (1.0%)
,B-pinene (2.6%)
,B-bourbonene (0.2%)
myrcene (0.9%)
,B-elemene (1.4%)
a-terpinene (trace)
geijerol* (0.4%)
p-cymene (trace)
,B-caryophylene (7.4%)
limonene (0.5%)
a-humulene (1.9%)
(Z) - ,B- ocimene (0.5%)
(E) - ,B-ocimene (0.5%)
,B-cubebene (12.5%)
-y-elemene of germacrene B (1.3%)
-y-terpinene (0.1%)
a sesquiterpene alcohol (0.5%)
terpinolene (trace)
6-cadinene (2.1%)
linalool (trace)
elemol (2.0%)
(Z) - sabinene hydrate (0.1%)
a-ionone (0.9%)
camphor (trace)
caryophyllene oxide (trace)
geijerene iomer (4.9%)
viridiflorol (0.2%)
geijerene (42.5%)
epi-globulol* (0.3%)
terpinen - 4-01 (0.2%)
6-cadinol (torreyol) (0.2%)
a-terpineol (trace)
a-cadinol (0.6%)
geijerene isomer (0.5%)
isophytol* (trace)
bornyl acetate (3.5%)
unidentified compounds (5.7%)
* : tentative identification trace «
0.1%)
Besides more than 40 components in the essential oil of E. odratum L. from Vietnam
(see Table 1) we have found from the extract of this plant the two compound: 2'-hydroxy4, 4', 5', 6' - trimethoxy chalcone (odorantin) 1 and 2', 4 - dihydroxy - 4', 5', 6' - trimethoxy
chalcone' 2 by comparing their physical properties with those reported in the reference
[9]. They are identical in general respects to the authentic samples (mp, NMR and MS
32
NGUYEN THI DIEM TRANG et a1.
spectra). Compound 2 had a UV spectrum characteristic of a chalcone. Since its molecular
formula ClsH1S06 (high resolution MS) was identical with that of flavanone 3 it was
suspected that 2 was derived from 3. This was proved by treating 2 with concentrated
H2 S0 4 then 3 was obtained in 90% yield. The conversion of 3 to 1 with deazomethane
followed by treatment with acetic acid was also reminded (7).
o-~ OH
1(DH
CHjO
OCH3
0
2
OH
The NMR spectra of both compounds showed two trans - olefinic protones (H-a
and H-,B) at about 7.8 ppm as a singlet rather than the usual doublet [10]. One phenolic
proton appeared as a singlet at 13.7 ppm which indicated that the OH group is ortho
to the carbonyl group. The signals in the region of 3.84 to 3.93 ppm were due to the
protons of the methoxy groups whereas the spectrum of 1 showed four and of 2 only three
methoxy groups. Three of these were located in ring A which is confirmed by comparing
the results of electron impact MS on 1 and 2. The double ortho pattern (2x2H's) indicated
a symmetry in the molecule with the presence of 1,4-disubstituted benzenne ring (ring
B).
The H-2 and H-6 protons appeared at 7.5 - 7.6 ppm and H-3 and H-5 protons appeared at 6.8 and 6.8 ppm. The H-3' proton appeared as a singlet at 6.30 ppm. The NMR
spectra were in conformity with those indicated by Ref. [7]. Both 2 and 3 gave a high
intensity peak at mle 210 which could be attributed to cleavage to the carbonyl funcition and some prominent peaks at 195, 167, 91 and 83 commensurate with the indicated
products.
Flavonone 3 white crystal ClsH1S06 (M+330), m.p 193 -196°C, isolated from the
crude sample by flash chromatography with benzene-ethylacetate. The product is shown
as a pure compound in HPLC analysis. The NMR spectrum indicated a doublet of doublets
at 5.33 (J = 10.5, 2.8 Hz, H-2) and two proton signals (AB system) at 2.72 and 2.78 ppm
(J = 2.9Hz respectively) for H-3 cis and H_3trans. In the NMR spectrum there were three
methoxy groups at 3.83, 3.87 and 3.92 ppm; a high intensity peak at mle 210 in the high
resolution MS suggested that all the three exist in ring A. The MS of flavanone exhibited,
bisides the molecular ion peak at mle 330, other prominent peaks at 195, 161 and 149
CONSTITUENTS OF THE AERIAL PARTS OF EATORIUM ODORATUM L ...
33
commensurate with the expected products from the proposed structure 3. Since ring B was
monosubstituted at the 4'-position (A 2 B z system of H-2', H-3', H-5' and H-6' at 6.90 and
7.33 ppm) the remaining oxygen function was placed as hydroxyl which at 4' was revealed
by IR spectrum as abroad band at 3300 cm- 1 . The proposed structure was till confirmed
by 13C-NMR spectrum whereas the carbonly group appeared at 189.67 ppm as a negative
signal. This isolated sample was found to be indentical with reported flavanone in all
respects (NMR, MS and IR spectra) which revealed as and optically inactive compound
[9]. This is the first time that the isolation of the above chalcones and flavanone from
Chromolaena odorata of Vietnam is reported.
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•
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Received
25 April, 1994