Cơ cấu HUMULENE-8-HYDROPEROXIDE
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109
Journal of Chemistry, Vol. 41, No. 3, P. 109 - 110, 2003
STRUCTURE OF HUMULENE-8-HYDROPEROXIDE, A NEW
HUMULANE-TYPE SESQUITERPENOID FROM VIETNAMESE
CURCUMA ZEDOARIA
Received 28-6-2002
Phan Minh Giang
Faculty of Chemistry, College of Natural Science, Vietnam National University
Summary
The structure of humulene-8-hydroperoxide, a new oxygenated sesquiterpenoid isolated
from the rhizomes of Curcuma zedoaria (Berg.) Roscoe, Zingiberaceae, grown in the suburbs of
Hanoi, Vietnam, was elucidated on the basis of spectroscopic data (
1
H NMR,
1
3
C NMR, DEPT,
1
H-
1
H COSY, HETCOR) and elemental analysis.
In Vietnamese traditional medicine
rhizomes of Curcuma zedoaria (Berg.) Roscoe,
Zingiberaceae, have been extensively used for
the treatment of cough, gastric and skin
diseases [1, 2]. In our study on chemical
constituents and biological activity of the
rhizomes of Curcuma zedoaria (Berg.) Roscoe,
grown in the suburbs of Hanoi, Vietnam,
several humulane and biogenetically related
caryophyllane sesquiterpenoids -caryophyl-
lene, -humulene, -caryophyllene epoxide,
humulene epoxide I, humulene epoxide II,
humulene epoxide III, zerumbone, zerumbone-
2,3-epoxide and humulene-8-hydroperoxide
were isolated and identified from the n-hexane
soluble fraction of an ethanol extract from the
rhizomes of C. zedoaria [3, 4].
Humulene-8-hydroperoxide (8-hydroperoxy-
humula-2,6,9-triene, 1), colorless needles, mp 100-
107
o
C, is a new natural compound. The molecular
formula C
15
H
24
O
2
was deduced from the elemental
analysis. Thus the compound has four double bond
equivalents. The molecular formula was supported
by the chemical shifts and multiplicities of
1
H
NMR,
13
C NMR and DEPT spectra of 1. The
13
C
NMR and DEPT spectra of 1 indicated the presence
of 15 carbons typical for a sesquiterpene compound
including four methyl groups (4q: 12.7, 15.0, 24.2,
29.4 ppm), three methylene groups (3t: 22.9, 39.1,
41.9), one oxygenated methine group (1d: 78.6),
one quaternary carbon (1s: 37.1) and six olefinic
carbons (2s, 4d) of two trisubstituted [(124.8 (d),
133.0 (s); 124.9 (d), 141.8 (s)] and one 1,2-
disubstituted double bonds (2d: 131.4, 139.3).
The partial structures of 1 was suggested from
the couplings of protons in
1
H NMR and
connectivities based on the two dimensional
1
H-
1
H
COSY and HETCOR spectra. The partial structure
A was deduced from the couplings in
1
H NMR [
4.62, d (7 Hz), 5.24, d (16) and 5.55 dd (7,16)].
The only oxygenated methine group [
H
4.62, d;
C
78.6, d] suggested the presence of a hydroperoxide
group in the structure of 1. A large coupling
constant between H-9 and H-10 indicated trans
configuration of the 9,10-disubstituted double
bond. The partial structure B contained a
trisubstituted double bond [ 5.20, tbr (7.5)]
connected to an ethylene group and a vinylic
methyl group ( 1.66, s), meanwhile the fragment
C contained a three substituted double bond [
4.82, dd (5,10)] connected to a methylene group [
1.80, dd (5,13); 2.0, dd (10,13)] and a vinylic
methyl group ( 1.42, s). The two tertiary methyl
110
groups at 1.06 (s), 1.08 (s) and the quaternary carbon [
C
37.1 (s)] led to the last structural fragment D.
A B C D
All the partial structures were coupled to reveal
the structure of 1 as humulene-8-hydroperoxide. In
comparison of the
1
H and
1
3
C NMR data of 1 and
-humulene isolated from the same source [3, 4],
the differences were observed for the chemical
shifts of H-8 [2.52, d (7) vs 4.62, d (7) and C-8
(40.4 (t) vs 78.6 (d)]. This would also be an
evidence for the supposed structure of 1 and
indicated the trans configuration of all three double
bonds in 1.
1
Table 1:
1
H NMR and
13
C NMR spectral data of
humulene-8-hydroperoxide (1)
(, CDCl
3
, Bruker AM 400, 400 MHz for
1
H NMR and
100 MHz for
13
C NMR)
C/H
1
H NMR
a
[J (Hz)]
13
C NMR
b
1
1.80 dd (5, 13)
2.00 dd (10, 13)
41.9 t
2 4.82 dd (5, 10) 124.8 d
3 133.0 s
4 2.10 m 39.1 t
5 2.10 m 22.9 t
6 5.20 tbr (7.5) 124.9 d
7 141.8 s
8 4.62 d (7) 78.6 d
9 5.55 dd (7, 16) 131.4 d
10 5.24 d (16) 139.3 d
11 37.1 s
CH
3
-12 1.06 s 24.2 q
CH
3
-13 1.08 s 29.4 a
CH
3
-14 1.66 s 12.7 q
CH
3
-15 1.42 s 15.0 q
a
correlated with
1
H-
1
H COSY;
b
correlated with HETCOR.
From biogenetic point of view, humulene-
8-hydroperoxide could be derived from
zerumbone (humula-2,6,9-triene-8-one) [3], the
major constituent of the n-hexane soluble
fraction of the ethanol extract from the
rhizomes of C. zedoaria.
Humulene-8-hydroperoxide (1)
Colorless needles, mp 100 - 107
o
C.
Elemental analysis: C
15
H
24
O
2
(found: C
76.20%; H 10.30% (calculated for C
1
5
H
2
4
O
2
: C
76.27%; H 10.16%).
1
H NMR (CDCl
3
, 400 MHz) and
13
C NMR
(CDCl
3
, 100 MHz) spectral data of 1 are listed
in table 1.
Acknowledgement: The author is grateful to
IFS (International Foundation for Science,
Stockholm, Sweden) and the National Basic
Research Program in Natural Sciences for
financial support for this work.
References
1. Vo Van Chi. Dictionary of Vietnamese
medicinal plants, Publishing House
Medicine (1997).
2. Pham Hoang Ho. Cay co Viet Nam, An
Illustrated Flora of Vietnam, in 3 tomes,
Published by the author, Montreal (1991-
1993).
3. Phan Minh Giang, Van Ngoc Huong, Phan
Tong Son. J. of Chemistry, Vol. 36, No. 4,
P. 70 - 73, 78 (1998).
4. Phan Minh Giang, Van Ngoc Huong, Phan
Tong Son. J. of Chemistry, Vol. 38, No. 1,
P. 91 - 94 (1998).
HOO
1
10 2
3
4
5
6
7
8
9
11
12
13
14
15
HOO
111
