See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/51223353
Comparison of Compositions and
Antimicrobial Activities of Essential Oils from
Chemically Stimulated...
Article in Molecules · December 2011
DOI: 10.3390/molecules16064884 · Source: PubMed
CITATIONS
READS
46
108
6 authors, including:
Huaiqiong Chen
Texas Tech University
18 PUBLICATIONS 264 CITATIONS
SEE PROFILE
All content following this page was uploaded by Huaiqiong Chen on 29 August 2014.
The user has requested enhancement of the downloaded file.
Molecules 2011, 16, 4884-4896; doi:10.3390/molecules16064884
OPEN ACCESS
molecules
ISSN 1420-3049
www.mdpi.com/journal/molecules
Article
Comparison of Compositions and Antimicrobial Activities of
Essential Oils from Chemically Stimulated Agarwood, Wild
Agarwood and Healthy Aquilaria sinensis (Lour.) Gilg Trees
Huaiqiong Chen 1, Yun Yang 1,2, Jian Xue 1, Jianhe Wei 1,*, Zheng Zhang 1 and Hongjiang Chen 1,2
1
2
Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine,
Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical
Sciences & Peking Union Medical College, 100193, Beijing, China;
E-Mails: chenhuaiqiong@implad.ac.cn (H.C); jxue@implad.ac.cn (J.X);
zhangzheng@implad.ac.cn (Z.Z.)
Hainan Branch Institute of Medicinal Plant (Hainan Provincial Key Laboratory of Resources
Conservation and Development of Southern Medicine), Chinese Academy of Medical Sciences &
Peking Union Medical College, 571533, Wanning, China; E-Mails: yangyun43@gmail.com (Y.Y.);
hjchen@implad.ac.cn (H.C.)
* Author to whom correspondence should be addressed; E-Mail: wjianh@263.net;
Tel.: +86-010-62818841; Fax: +86-010-62818841.
Received: 17 March 2011; in revised form: 7 June 2011 / Accepted: 8 June 2011 /
Published: 14 June 2011
Abstract: The composition and antimicrobial activity of the essential oils which were
obtained from agarwood originated from Aquilaria sinensis (Lour.) Gilg stimulated by the
chemical method (S1) were characterized, taking wild agarwood (S2) and healthy trees
(S3) respectively as the positive and negative controls. The chemical composition of S1
was investigated by gas chromatography-mass spectrometry (GC-MS). The essential oil of
S1 showed a similar composition to that of S2, being rich in sesquiterpenes and aromatic
constituents. However, the essential oil of S3 was abundant in fatty acids and alkanes.
Essential oils of S1 and S2 had better inhibition activities towards Bacillus subtilis and
Staphyloccus aureus, compared with essential oil of S3. Escherichia coli was not sensitive
to any of them.
Molecules 2011, 16
4885
Keywords: Aquilaria sinensis (Lour.) Gilg; healthy trees; agarwood; essential oil; GC-MS;
antimicrobial activity
1. Introduction
Agarwood, a highly valuable resinous and fragrant heartwood, is used as incense for religious
ceremonies, perfumes in the Arab world, ornamental materials, and medicinal components in oriental
medicine [1,2]. It comes from the damage caused to healthy trunks or branches of the trees of some
Aquilaria species in the family Thymelaeaceae by mold. As a healthy tree Aquilaria is worth next to
nothing, but high-quality agarwood can fetch as much as US$1,000 per kilogram [3]. In a natural
environment, it often takes several years for a wild damaged Aquilaria species plant to form agarwood
[3]. The over-use of agarwood has seriously affected the natural resources of all Aquilaria species
capable of producing agarwood, thus making these endangered species listed in Appendix II of the
Convention on Internal Trade in Endangered Species of Wild Fauna and Flora (CITES) since 2004 [4].
In order to meet the demand for agarwood and protect the wild Aquilaria trees, many countries have
been developing Aquilaria plantationsf [5-7]. A. sinensis, the main plant resource in China for
agarwood, is chiefly distributed in South China [8]. A. sinensis trees are now widely cultivated in
Hainan and Guangzhou provinces, with the planting area estimated to cover more than 700 acres.
The main active compounds in agarwood have been revealed to be sesquiterpenes and
2-(2-phenylethyl) chromone derivatives [9]. In order to improve the planting value of Aquilaria trees,
great efforts have been made to induce healthy trees to produce these sesquiterpenes and 2-(2phenylethyl) chromone derivatives, consequently forming argarwood [5,10]. The common methods
now used in China and other countries include the deliberate wounding of trees with large knives and
the hammering of nails into tree trunks. A chemical treatment method has also been developed recently
[11]. Meanwhile, some studies have been carried out to compare the quality of man-treated and wild
agarwood. Tamuli and Bhuiyan studied the quality of agarwood (A. agallocha Roxb.) formed through
fungal infection by GC-MS [12,13]. Dai Haofu et al. evaluated the quality of three Chinese agarwood
(A. sinensis) samples produced by the methods of nail insetting, holing and trunk breaking,
respectively, through GC-MS [14], but there are no reports about agarwood formed by chemical
methods. In this study, in order to test the quality of the agarwood originated from A. sinensis
stimulated by the chemical method (S1), its chemical composition and relative amount of essential oils
were measured by GC-MS, taking the wild agarwood (S2) and healthy trees (S3) as controls. The
antimicrobial activities of essential oils of the agarwood originating from A. sinensis were also
determined.
2. Results and Discussion
2.1. Chemical Composition of the Essential Oils
The yields of essential oils obtained after hydrodistillation of S1, S2 and S3 were 0.042% (w/w),
0.32% (w/w) and 0.0128% (w/w), respectively. They showed different colors and states (Figure 1). At
Molecules 2011, 16
4886
room temperature, the essential oil of S1 was yellow, aromatic and a liquid, similar to that of S2, but
different from that of S3. The essential oil of S2 was green, aromatic and liquid. The essential oil of S3
had an acidic smell and was a solid at room temperature.
Figure 1. Color and state of the essential oils of three tested samples at room temperature.
A total of sixty-one essential compounds were identified from the three samples (Table 1 and Figure
2). Forty-two components were identified in S1, representing 90.01% of the total volatiles, with the
major constituents being sesquiterpenes and aromatics, such as guaia-1(10),11-dien-9-one (10.89%),
guaiol (9.34%), benzylacetone (7.91%) and hinesol (6.34%). Thirty-six components were identified in
S2, representing 92.16% of the total volatiles. The dominant compounds were baimuxinal (14.78%),
guaiol (10.67%), α-copaen-11-ol (10.22%) and 1,2,5,5,8a-pentamethyl-1,2,3,5,6,7,8,8a-octahydronaphthalen-1-ol (5.82%). Thirty components were identified in the essential oil of S3, representing
95.68% of the total volatiles. N-hexadecanoic acid and oleic acid accounted for 59.65% of the total
essential oil, which explained its smell and state.
The investigation showed that the essential oil of S1 had similar components to those of S2. They
were both rich in sesquiterpenes and aromatics, which reached 80.00% in S1 and 89.01% in S2.
Thirty-one common compounds were identified in S1 and S2. Benzylacetone, cubenol, guaiol,
eudesm-7(11)-en-4α-ol, α-copaen-11-ol, and baimuxinal were found to be the six compounds (in bold
in Table 1) that had high relative amounts both in S1 and S2. They might be used as the reference
compounds in determining the quality of agarwood.
The essential oil of S1 and S2 had significantly different components from that of S3, which had
abundant fatty acid and alkanes. For instance, a trace of n-hexadecanoic acid was found in the oils of
S1 and S2, whereas it reached 49.47% in S3; oleic acid was 10.18% in S3, but it was totally absent in
S1 and S2. As to the alkanes, S1 and S3 were very similar, and most of the alkanes identified in S3
were also identified in S1, whereas no alkanes were detected in S2. This may affect the complex
process of agar accumulation and the prolonged duration of accumulation, as well as the contents of
fatty acid and alkanes [13]. A higher oil yield would require a longer time for resin formation.
It has been reported that different artificial methods used to stimulate agarwood formation in
Aquilaria result in different agarwood qualities. Tamuli and Bhuiyan both showed that the essential
oils obtained from the plants (A. agallocha Roxb.) inoculated with fungus, i.e., Chaetomium globosum,
for 30 days or from plants injected artificial screws showed similar component distributions with that
of healthy trees according to GC-MS [12,13]. Dai et al. found that the essential oils of the agarwood
produced by nail insetting and holing for two years were full of sesquiterpenes and aromatic
constituents, while the essential oil of agarwood formed through trunk breaking for two years was full
of fatty acids [14]. Comparing our results with the above results, we come to the conclusion that the
chemical stimulation method is a simple and efficient way of inducing Aqularia plants to form
resinous material.
Molecules 2011, 16
4887
As to the total of 8.93% sesquiterpene compounds identified in essential oil of healthy trees (S3), it
was probably because the cutting process was sufficient damage to initiate the resinous material
formation process. During the drying period at room temperature, cells might be still alive, and the
sesquiterpene metabolic pathways were thus initiated.
Table 1. Chemical compositions and relative amounts of the essential oils from S1, S2 and S3.
No.
Compounds
RI
a
Sesquiterpenes and aromatics
Relative amount (%) c
S1
S2
S3
80.00
89.01
8.93
Identification
1
Benzylacetone *
1257
7.91
2.34
-b
RI,MS,
2
Vanillin
1418
-
-
0.46
RI[15],MS
3
α-Humulene
1464
0.30
-
-
RI,MS,[16,17]
4
α-Selinene
1493
0.45
3.71
-
RI[18],MS
5
α-Agarofuran
1535
-
0.24
-
RI[18],MS
6
Elemol
1556
0.32
0.71
-
RI[19,24],MS
7
2,6-Dimethyl-10-methylene-12-
1576
0.37
0.61
-
MS
oxatricyclo[7.3.1.0(1,6)]tridec-2-ene
8
5 ,7 H,10α-Eudesm-11-en-1α-ol
1583
0.54
0.66
-
MS
9
Caryophyllene oxide
1588
2.22
2.12
-
RI[19,24],MS
10
2H-Benzocyclohepten-2-one, 3,4,4a,5,6,7,8,9-octahydro-4a-
1593
-
0.20
-
MS
1606
0.94
2.77
-
RI[20],MS
1632
1.06
2.84
0.50
RI[21],MS[22]
methyl-, (S)11
12
Isoaromadendrene epoxide
-Eudesmol
13
Hinesol
1638
6.34
0.34
-
RI[23],MS
14
Agarospirol
1643
0.80
4.03
0.85
RI[24],MS
15
Cubenol
1647
2.21
1.97
-
RI[25],MS
16
cis-Z-α-Bisabolene epoxide
1651
0.83
0.78
-
RI[26],MS
17
(-)-Aristolene
1654
0.61
4.70
1.31
MS[22]
18
Guaiol
1661
9.34
10.67
2.18
MS[27-29]
19
Eudesm-7(11)-en-4α-ol
1666
4.35
2.09
-
RI,MS[30]
20
Aromadendrene oxide (1)
1674
1.27
1.41
-
RI[31],MS
21
6-Isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-
1678
1.19
1.33
-
RI[20],MS
naphthalen-2-ol
22
α-Copaen-11-ol
1686
4.06
10.22
-
RI,MS[32]
23
4,4,11,11-tetramethyl-7-tetracyclo-
1690
0.53
1.50
-
MS
[6.2.1.0(3.8)0(3.9)]undecanol
24
Bicyclo[4,4,0]dec-2-ene-4-ol,2-methyl-9-[prop-1-en-3-ol-2-yl]
1697
3.11
0.52
-
MS
25
Diepi-α-cedrene epoxide
1701
6.00
0.38
-
MS
26
Aromadendrene oxide (2)
1705
-
1.88
-
RI[33],MS
Molecules 2011, 16
4888
Table 1. Cont.
27
Baimuxinal
1707
2.44
14.78
1.52
MS[27,28,32]
28
Selina-3,11-dien-14-al
1733
5.50
0.38
-
RI[18], MS
29
5(1H)-Azulenone, 2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-
1736
0.21
1.03
-
RI,MS
(1-methylethylidene)-, (8S-cis)30
Guaia-1(10),11-dien-9-one
1753
10.89
-
-
RI[18],MS
31
1,2,5,5,8a-Pentamethyl-1,2,3,5,6,7,8,8a-
1755
-
5.82
-
RI[34],MS
1769
1.65
0.54
-
RI[34],MS
octahydronaphthalen-1-ol
32
6-Isopropenyl-4,8a-dimethyl-3,5,6,7,8,8a-hexahydro-2(1H)naphthalenone
33
Eremophila-7(11),9-dien-8-one
1811
4.54
5.42
2.11
RI[34],MS
34
Acetic acid, 3-hydroxy-6-isopropenyl-4,8a,dimethyl-
1847
-
3.04
-
RI[34],MS
5.75
0.64
79.31
1,2,3,5,6,7,8,8a-octahydronaphthalen-2-yl ester
Fatty acid and Alkanes
35
Tetradecanoic acid
1772
-
-
2.36
RI[35],MS
36
Nonanoic acid
1278
-
-
1.50
RI[36],MS
37
n-Decanoic acid
1371
-
-
0.52
RI[36],MS
38
cis-5-Dodecenoic acid
1863
0.20
-
-
RI[34],MS
39
Pentadecanoic acid
1878
-
-
4.87
RI[34],MS
40
cis-9-Hexadecenoic acid
1955
-
-
2.87
RI[34],MS
41
n-Hexadecanoic acid
1982
0.30
0.06
49.47
RI[34],MS
42
Hexadecanoic acid, ethyl ester
1996
-
-
1.13
RI[34],MS
43
Eicosane
1999
0.22
0.58
-
RI[34],MS
44
Heptadecanoic acid
2073
-
-
0.37
RI[34],MS
45
Heneicosane
2100
0.51
-
1.09
RI[34],MS
46
Oleic Acid
2153
-
-
10.18
RI[34],MS
47
Docosane
2200
0.80
-
0.53
RI[34],MS
48
Tricosane
2300
0.97
-
0.80
RI[34],MS
49
Tetracosane
2400
0.79
-
0.86
RI[34],MS
50
Pentacosane
2500
0.70
-
0.87
RI[34],MS
51
Hexacosane
2600
0.62
-
0.80
RI[34],MS
52
Heptacosane
2700
0.45
-
0.57
RI[34],MS
53
Octacosane
2800
0.20
-
0.54
RI[34],MS
4.26
2.51
7.44
Others
54
2-Hydroxycyclopentadecanone
1851
0.24
0.30
2.32
RI[37],MS
55
1,2-Benzenedicarboxylic acid, bis(2-methylpropyl) ester
1869
0.69
-
0.85
RI[37],MS
56
Dibutyl phthalate
1962
2.13
1.23
2.47
RI[37],MS
57
1,2,3,4-Tetrahydro-1-nonylnaphthalene
2021
0.64
-
-
MS
58
8,9-Dehydro-9-formyl-cycloisolongifolene
2082
0.56
0.98
-
MS
Molecules 2011, 16
4889
Table 1. Cont.
59
-Palmitolactone
2111
-
-
0.99
RI[34],MS
60
4,8,12,16-Tetramethylheptadecan-4-olide
2357
-
-
0.42
RI[34],MS
61
1,2-Benzenedicarboxylic acid, mono(2-ethylhexyl) ester
2541
-
-
0.39
RI[37],MS
90.01
92.16
95.68
TOTAL
Compounds are listed in the order of elution;
a
RI indicates the retention indices which were
calculated against C8-C40 n-alkanes on the non-polar VF-5MS column;
b
not detected;
c
Relative
amount indicates the relative amount (the peak area relative to the total peak area); * verified by the
authentic compound.
Figure 2. GC chromatograms of the three essential oils. Component numbers in the
chromatogram come from Table 1.
2.2. Antimicrobial Activities
Table 2 shows the antimicrobial activities of the three essential oils. The results indicated that all of
the three essential oils had some activity against almost all the tested bacteria. All the essential oils
were more active against Gram-positive bacterial strains (S. aureus and B. subtilis) than against the
Gram-negative bacterial strain E. coli. Taken together, especially the results of MICs and MBCs, the
essential oils of S1 and S2 had better antimicrobial activities than that of S3. This is probably because
the essential oils of S1 and S2 were full of sesquiterpenes and aromatics, which may include some
active components. It’s known that sesquiterpenes usually possess antimicrobial activity. It is critical
to note that, if active components are isolated and purified, their antimicrobial activities could
become stronger.
Molecules 2011, 16
4890
Table 2. Screening results for antimicrobial activity of the three essential oils.
Essential oil
S1
S2
E. coli
8.14 ± 0.05
S. aureus
10.29 ± 0.20
B. subtilis
11.68 ± 0.26
MIC b
6.25
3.125
0.39
MBC c
25
6.25
12.5
AWD
AWD
Gentamicin
a
a
7.00 ± 0.02
11.25 ± 0.02
11.57 ± 0.02
b
6.25
0.195
0.195
MBC c
12.5
6.25
12.5
MIC
S3
a
AWD
a
7.52 ± 0.26
8.10 ± 0.24
9.39 ± 0.30
MIC
b
12.5
1.56
0.78
MBC
c
>25
12.5
>25
AWD a
23.08 ± 0.88
21.45 ± 1.77
23.73 ± 0.32
MIC
b
0.487
0.487
0.487
MBC
c
0.487
0.487
0.487
DMSO
AWD a
0
0
0
ddH2O
a
0
0
0
AWD
AWD = agar well diffusion method. The diameters of the inhibition zone, including the well
diameters, are 6 mm;
b
MIC = minimum inhibitory concentration. The values of the three oil
samples are given in mg/mL, and the values of gentamicin are given in μg/mLp; c MBC = minimum
bactericidal concentration. The values of the three oil samples are given in mg/ml, and the values of
Gentamicin are given in μg/mL.
The negative-control experiments, including the antimicrobial test for DMSO and ddH2O, indicated
no microbial contamination in the essential oils and media, as shown by the data in Table 2. 5% v/v
DMSO, the maximum concentration used for dissolving essential oil, showed no inhibition on the
microbial growth.
This is the first report concerning the antimicrobial activities to the three bacterial strains of Chinese
agarwood oil from A. sinensis. In previous studies, Mei [28] showed that the essential oil from Chinese
agarwood had anti-MRSA activity; Wetwitayaklung [18] found that the essential oil of agarwood
(A. crassna) had antimicrobial activities against S. aureus and C. albicans, but it was not active against
E. coli at the maximum study concentration (2 mg/mL). In this study, the MICs and MBCs to E. coli
were more than 6.25 and 12.5 mg/mL, respectively, consistent with the report by Wetwitayaklung.
3. Experimental
3.1. Plant Material
The three types of samples included artificially chemically stimulated plants, wild agarwood and
stems of six-year-old healthy trees (Table 3). A. sinensis trees were cultivated wild in Haikou City,
Hainan Province. The chemical treatment method was used to stimulate the formation of resinous in
A. sinensis trees. A chemical reagent (NaCl) of a certain concentration was injected slowly into the
Molecules 2011, 16
4891
xylem part of a tree. Because of water transport, the chemical reagent was transported to the whole
body of the tree, thus forming an overall injury in the tree. This would stimulate the whole tree to
produce resinous material to defend from the damage. Healthy trees without any treatment were
collected as the negative control. The wild agarwood was purchased from Guangxi Yulin Market and
identified by Dr. Jianhe Wei.
Table 3. Materials used in this study.
Brief Name
S1
S2
S3
Stimulating method
chemical method
unknown natural factor
no damage
Characterization
agarwood
agarwood
healthy trees
Age
6 years
unknown
6 years
Plant origin
A. sinensis
A. sinensis
A. sinensis
3.2. Isolation of Essential Oils
Three samples were powdered, passed through 20 mesh sieves, soaked in water overnight and then
subjected to hydrodistillation for 12 h using a Clevenger apparatus. The distilled oil was dried over
anhydrous sodium sulfate and stored in a freezer at −20 °C until analysis.
3.3. GC-MS Analysis
GC-MS analysis was performed with a Varian 450 gas chromatograph (USA) equipped with a
VF-5MS capillary column (30 m × 0.25 mm i.d., flim thickness 0.25 μm) and a Varian 300 mass
spectrometer with an ion trap detector in full scan mode under election impact ionization (70 eV). The
carrier gas was helium, at a flow rate of 1 mL/min. The injections were performed in splitless mode at
250 °C. 1 μL essential oil solution in hexane (HPLC grade) was injected. The operating parameters
were the temperature program of 50 °C for 1 min, ramp of 10 °C/min up to 155 °C (15 min),
subsequent increase to 280 °C with an 8 °C/min heating ramp, and keeping at 280 °C for 10 min. The
scan range was 50–500 amu under full scan. 1 μL C8-C40 n-alkanes was injected separately and ran in
the same program as the essential oils.
3.4. Identification of Components
Most constituents were identified via gas chromatography by comparing their Kovats retention
indices (RI) with those from the literature, and computer matching against the NIST 08 and NIST
Chemistry WebBook (http://webbook.nist.gov/chemistry/) databases. The Kovats retention indices
were determined in relation to a homologous series of n-alkanes (C8–C40) under the same operating
conditions. AMDIS software was used to calculate Kovats retention indices. Further identification was
made by comparing their mass spectra with these stored in NIST 08 and with mass spectra from the
literature [15-37]. The relative concentrations of the components were obtained by peak areas
normalization without applying correction factors.
Molecules 2011, 16
4892
3.5. Antimicrobial Activity
3.5.1. Test Microorganisms
Three clinical bacteria, Staphylococcus aureus ATCC 25923, Bacillus subtilis ACCC11060 and
Escherichia coli ATCC25922, were used as test organisms in the screening. The microbial strains were
obtained from the College of Life Science, Capital Normal University, Beijing, China.
3.5.2. Determination of Diameters of Inhibition Zone
Simple susceptibility screening test through agar well diffusion method was used [28]. The inocula
of the bacterial strains were adjusted to 0.5 McFarland standard turbidity (approximately 108 CFU/mL)
[38,39]. One hundred μL of a suspension containing approximately 108 CFU/mL of each microorganism
was spread on nutrient agar (NA). Six-millimeter diameter wells were cut from the agar using a sterile
cork-borer, and 50 μL of the oil solution in a concentration of 50 mg/mL (dissolved in DMSO) were
delivered into the wells. Negative controls were prepared using DMSO. Gentamincin (100 μg/mL)
were used as the positive reference standards. The plates were incubated for 18–24 h at 37 °C. The
antimicrobial activity was evaluated by measuring the zone of inhibition against the test organisms.
3.5.3. Determination of Minimum Inhibitory Concentration (MIC)
The MICs of the samples against the test bacterial strains were determined by the micro-well
dilution method. The inocula of the bacterial strains were adjusted to 0.5 McFarland standard turbidity
(approximately 108 CFU/mL). The essential oils were first dissolved in 10% DMSO, and serial
two-fold dilutions of the oil were prepared in a 96-well plate, ranging from 3.9 mg/mL to 50 mg/mL.
The MIC was defined as the lowest concentration of the essential oil at which the microorganism does
not demonstrate visible growth [38-40]. Microorganism growth was indicated by turbidity. The MICs
of the standard (gentamicin) were also determined in the same experiments.
3.5.4. Determination of Minimum Bactericidal Concentration (MBC)
Referring to the results of the MIC assays, the wells showing complete absence of growth were
identified and 10 μL of each well was transferred to agar plates and incubated at 37 °C for 24 h. The
MBC was defined as the lowest concentration of the juniper essential oil that allows no growth of
microorganisms [40-42]. The MBCs of the standard (gentamicin) were also determined in the
same experiments.
3.5.5. Data Analysis
All experiments were repeated at least twice. The data were recorded as means±standards and were
analyzed with SPSS (version 13.0 for windows, SPSS Inc.).
Molecules 2011, 16
4893
4. Conclusions
The characterization of the essential oil obtained from the agarwood originated from A. sinensis
stimulated by the chemical method has very high similarity with that of the essential oil of wild
agarwood, both in chemical composition and antimicrobial activity. This suggests that agarwood could
be produced by the artificially chemically stimulation method. What chemical agents and duration
would be suitable for inducing better agarwood formation need further studies. This is the first report
concerning the analysis of essential oils from chemically stimulated agarwood.
Acknowledgments
We are very grateful to Pan Ruile and Cao Li (Institute of Medicinal Plant Development, Chinese
Academy of Medical Sciences & Peking Union Medical College, Beijing, China) for technical support
and advice. This work was financially supported by the National Key Project of Scientific and
Technical Supporting Programs funded by the Ministry of Science & Technology of China (No.
2007BAI27B01), the Program for New Century Excellent Talents in University of China (No. 2008),
and the National Natural Science Foundation of China (31000136), both of which were granted to
Jianhe Wei.
References and Notes
1.
Okudera, Y.; Ito, M. Production of agarwood fragrant constituents in Aquilaria calli and cell
suspension cultures. Plant Biotechnol. 2009, 26, 307-315.
2. Kakino, M.; Tazawa, S.; Maruyama, H.; Tsuruma, K.; Araki, Y.; Shimazawa, M.; Hara, H.
Laxative effects of agarwood on low-fiber diet-induced constipation in rats. BMC Comple. Altern.
Med. 2010, 10, 68-75.
3. Gerard. A.P. Agarwood: the life of a wounded tree. Newsletter 2007, 45, 24-25.
4. CITES. Amendments to Appendices I and II of CITES. In Proceedings of Thirteenth Meeting of
the Conference of the Parties, Bangkok, Thailand, 3–14 October 2004. Unpublished.
5. Barden, A.; Anak, N.A.; Mulliken, T.; Song, M. Heart of the matter: Agarwood use and trade and
CITES Implementation for Aquailaria malaccencis. Traffic Network Rep. 2000, 46, 17-18.
6. Mohd, F.M.; Mohd, R.Y.; Lim, H.F.; Alias, R. Costs and benefits analysis of Aquilaria species on
plantation for agarwood production in Malaysia. Int. J. Busi. Soc. Sci. 2010, 1, 162-174.
7. Blanchette, R.A.; Heuveling, V.B.H. Cultivated agarwood. US 7,638,145 B2, 29 December 2009.
8. Qi, S.Y. Aquilaria species: in vitro culture and the production of eaglewood (agarwood)
(Medicinal and Aromatic Plants III). Biotechnology in Agriculture and Forestry; Bajaj, Y.P.S.,
Ed.; Springer Verlag: Berlin, Germany, 1995; Volume 8, pp. 36-44.
9. Chen, H.Q.; Wei, J.H.; Yang, J.S.; Zhang, Z.; Yang, Y. Chemical constituents of agarwood
originating from the endemic genus Aquilaria plants. Chem. Biodiver. 2011,
doi:10.1002/cbdv.201100077.
10. Pojanagaroon, S.; Kaewrak, C. Mechanical methods to stimulate aloes wood formation in
Aquilaria crassna Pierre ex H. Lec. (Kritsana) trees. In Congress on Medicinal and Aromatic
Molecules 2011, 16
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
4894
Plants; Jatisatienr, A., Paratasilpin, T., Elliott, S., Anusarnsunthorn, V., Wedge, D., Craker, L.E.,
Gardner, Z.E., Eds.; Acta Horticulturae: Leuven, Thailand, 2003; Volume 2, pp. 161-166.
Zhang, Z.; Yang, Y.; Meng, H.; Sui, Ch.; Wei, J.H; Chen, H.Q. Advances in studies on
mechanism of agarwood formation in Aquilaria sinensis and its hypothesis of agarwood formation
induced by defense response. Chin. Tradit. Herbal Drugs 2010, 41, 156-160.
Tamuli, P.; Boruah, P.; Nath, S.C.; Leclercq, P. Essential oil of eaglewood tree: a product of
pathogenesis. J. Essent. Oil Res. 2005, 17, 601-604.
Bhuiyan, M.N.I.; Begum, J.; Bhuiyan, M.N.H. Analysis of essential oil of eaglewood tree
(Aquilaria agallocha Roxb.) by gas chromatography mass spectrometry. Bangladesh J. Pharm.
2009, 4, 24-28.
Lin, F.; Mei, W.L.; Wu, J.; Dai, H.F. GC-MS analysis of volatile constituents from Chinese
eaglewood produced by artificial methods. J. Chin. Med. Mater. 2010, 33, 222-225.
Jarunrattanasri, A.; Theerakulkait, C.; Cadwallader, K.R. Aroma components of acid-hydrolyzed
vegetable protein made by partial hydrolysis of rice bran protein. J. Agric. Food Chem. 2007, 55,
3044-3050.
Ito, M.; Okimoto, K.; Yagura, T.; Honda, G. Induction of sesquiterpenoid production by Methyl
Jasmonate in Aquilaria sinensis cell suspension culture. J. Essent. Oil Res. 2005, 17, 175-180.
Kumeta, Y.; Ito, M. Characterization of δ-guaiene synthases from cultured cells of Aquilaria,
responsible for the formation of the sesquiterpenes in agarwood. Plant Physiol. 2010, 154,
1998-2007.
Wetwitayaklung, P.; Thavanapong, N.; Charoenteeraboon, J. Chemical constituents and
antimicrobial activity of essential oil and extracts of heartwood of Aquilaria crassna obtained
from water distillation and supercritical fluid carbon dioxide extraction. Silpakorn Univ. Sci. Tech. J.
2009, 3, 25-33.
Skaltsa, H.D.; Mavrommati, A.; Constantinidis, T. A chemotaxonomic investigation of volatile
constituents in Stachys subsect. Swainsonianeae (Labiatae). Phytochemistry 2001, 57, 235-244.
Vujisic, L.; Vuckovic, I.; Tesevic, V.; Dokovic, D.; Ristic, M.S.; Janackovic, P.; Milosavljevic, S.
Comparative examination of the essential oils of Anthemis ruthenica and A. arvensis wildgrowing in Serbia. Flavour Fragr. J. 2006, 21, 458-461.
Moreira, D.d.L.; Guimaraes, E.F.; Kaplan, M.A.C. Non-polar constituents from leaves of piper
lhotzkyanum. Phytochemistry 1998, 49, 1339-1342.
Yu, F.; Harada, H.; Yamasaki, K.; Okamoto, S.; Hirase, S.; Tanaka, Y.; Misawa, N.; Utsumi, R.
Isolation and functional characterization of a beta-eudesmol synthase, a new sesquiterpene
synthase from Zingiber zerumbet Smith. FEBS Lett. 2008, 582, 565-567.
Lazari, D.M.; Skaltsa, H.D.; Constantinidis, T. Volatile constituents of Centaurea pelia DC., C.
thessala Hausskn. subsp. drakiensis (Freyn & Sint.) Georg. and C. zuccariniana DC. from Greece.
Flavour Fragr. J. 2000, 15, 7-11.
Saroglou, V.; Dorizas, N.; Kypriotakis, Z.; Skaltsa, H.D. Analysis of the essential oil composition
of eight Anthemis species from Greece. J. Chromatogr. A 2006, 1104, 313-322.
Barra, A.; Coroneo, V.; Dessi, S.; Cabras, P.; Angioni, A. Characterization of the volatile
constituents in the essential oil of Pistacia lentiscus L. from different origins and its antifungal
and antioxidant activity. J. Agric. Food Chem. 2007, 55, 7093-7098.
Molecules 2011, 16
4895
26. Zakaria, C.A.; Marcelline, A.; Sylvies, B.; Christian, B.; Timothée, O.; Eewan, P.; Pierre, C.
Composition, and antimicrobial and remarkable antiprotozoal activities of the essential oil of
Rhizomes of Aframomum sceptrum K. SCHUM. (Zingiberaceae). Chem. Biodiver. 2011, 8,
658-667.
27. Mei, W.L.; Zeng, Y.B.; Liu, J.; Dai, H.F. GC-MS analysis of volatile constituents from five
different kinds of Chinese eaglewood. J. Chin. Med. Mater. 2007, 30, 551-555.
28. Mei, W.L.; Zeng, Y.B.; Liu, J.W.; Cui, H.B.; Dai, H.F. Chemical Composition and Anti-MRSA
Activity of the Essential Oil from Chinese Eaglewood. J. Chin. Pharm. Sci. 2008, 17, 225-229.
29. Liang, Z.Y.; Zhang, D.L.; Liu, C.S.; Yang, J.F. Determination of Chemical Composition of the
Essential Oil from Aquilaria sinensis (Lour.) Gilg by CGC-MS. Nat. Sci. J. Hainan Univ. 2005,
23, 228-232.
30. Toyota, M.; Saito, T.; Asakawa, Y. The absolute configuration of eudesmane-type
sesquiterpenoids found in the Japanese liverwort Chiloscyphus polyanthus. Phytochemistry 1999,
51, 913-920.
31. Kristiawan, M.; Sobolik, V.; Al-Haddad, M.; Allaf, K. Effect of pressure-drop rate on the
isolation of cananga oil using instantaneous controlled pressure-drop process. Chem. Eng. Proc.
2008, 47, 66-75.
32. Yang, J.S.; Chen, Y.W. Studies on the constituents of Aquilaria sinensis (Lour.) Gilg. I. Isolation
and structure elucidation of two new sesquiterpenes, baimuxinic acid and baimuxinal. Acta Pharm.
Sinica 1983, 18, 191-198.
33. Raal, A.; Kaur, H.; Orav, A.; Arak, E.; Kailas, T.; Muurisepp, M. Content and composition of
essential oils in some Asteraceae species. Proc. Estonian Acad. Sci. 2011, 60, 55-63.
34. Tret'yakov, K.V. Retention Data. NIST Mass Spectrometry Data Center. NIST Mass
Spectrometry Data Center. 2008. Available online: http://chemdata.nist.gov/mass-spc/pubs/
pittcon-2000/index.htm (accessed on 6 May 2011).
35. Kundakovic, T.; Fokialakis, N.; Kovacevic, N.; Chinou, I. Essential oil composition of Achillea
lingulata and A. umbellata. Flavour Fragr. J. 2007, 22, 184-187.
36. Alissandrakis, E.; Tarantilis, P.A.; Harizanis, P.C.; Polissiou, M. Comparison of the volatile
composition in thyme honeys from several origins in Greece. J. Agric. Food Chem. 2007, 55,
8152-8157.
37. Zeng, Y.X.; Zhao, C.X.; Liang, Y.Z.; Yang, H.; Fang, H.Z.; Yi, L.Z.; Zeng, Z.D. Comparative
analysis of volatile components from Clematis species growing in China. Anal. Chim. Acta 2007,
595, 328-339.
38. Sokmen, A.; Gulluce, M.; Akpulat, H.A.; Daferera, D.; Tepe, B.; Polissiou, M.; Sokmen, M.;
Sahin, F. The in vitro antimicrobial and antioxidant activities of the essential oils and methanol
extracts of endemic Thymus spathulifolius. Food Control 2004, 15, 627-634.
39. Cao, L.; Si, J.Y.; Liu, Y.; Sun, H.; Jin, W.; Li, Z.; Zhao, X.H.; Pan, R.L. Essential oil composition,
antimicrobial and antioxidant properties of Mosla chinensis Maxim. Food Chem. 2009, 115,
801-805.
40. Unlü, M.; Vardar-Unlü, G.; Vural, N.; Dönmez, E.; Ozbaş, Z.Y. Chemical composition,
antibacterial and antifungal activity of the essential oil of Thymbra spicata L. from Turkey. Nat.
Prod. Res. 2009, 23, 572-579.
Molecules 2011, 16
4896
41. Suttiwet, C. Antimicrobial activity of essential oil from Nelumbo Nucifera Gaertn. Pollen. Int. J.
Pharm. 2009, 5, 98-100.
42. Wang, J.H.; Zhao, J.L.; Liu, H.; Zhou, L.G.; Liu, Z.L.; Wang, J.G.; Han, J.G.; Yu, Z.; Yang, F.Y.
Chemical analysis and biological activity of the essential oils of two valerianaceous species from
China: Nardostachys chinensis and Valeriana officinalis. Molecules 2010, 15, 6411-6422.
Sample Availability: Samples of the compounds are available from the authors.
© 2011 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article
distributed under the terms and conditions of the Creative Commons Attribution license
(http://creativecommons.org/licenses/by/3.0/).
View publication stats