Fumigant antitermitic activity of plant essential oils and components from ajowan (Trachyspermum ammi), allspice (Pimenta dioica), caraway (Carum carvi), dill (Anethum graveoiens), geranium (Pelargonium graveoiens), and litsea (Litsea cubeba) oils against Japanese termite (Reticulitermes speratus kolbe)

Article abstract of DOI:10.1021/jf9015416

Plant essential oils from 26 plant species were tested for their insecticidal activities against the Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity was observed with the essential oils of ajowan (Trachyspermum ammi), allspice (Pimenta dioica), caraway (Carum carvi), dill (Anethum graveoiens), geranium (Pelargonium graveoiens), and litsea (Litsea cubeba). The composition of six essential oils was identified by using gas chromatographymass spectrometry. The compounds thus identified were tested individually for their insecticidal activities against Japanese termites. Responses varied in a dose-dependent manner for each compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds; furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and compounds described herein merit further study as potential fumigants for termite control. 2009 American Chemical Society.

Full text of DOI:10.1021/jf9015416

6596 J. Agric. Food Chem. 2009, 57, 6596–6602
DOI:10.1021/jf9015416
Fumigant Antitermitic Activity of Plant Essential Oils
and Components from Ajowan (Trachyspermum ammi),
Allspice (Pimenta dioica), Caraway (Carum carvi), Dill
(Anethum graveolens), Geranium (Pelargonium graveolens),
and Litsea (Litsea cubeba) Oils against Japanese Termite
(Reticulitermes speratus Kolbe)
†,
†,
§
SEON-M
I
SEO
,
J
UNHEON
K
S
IM
,
S
ANG-GIL
L
EE,† CHANG-HOON
,†
SHIN
,
†
S
ANG-CHUL
HIN
,
AND
IL
-KWON
P
ARK
*
†Division of Forest Insect Pests and Diseases, Korea Forest Research Institute, Seoul 130-712,
Republic of Korea, and §Institute of Environmental Resource Research, Jeju Special Self-Governing
Province 690-817, Republic of Korea. These authors contributed equally to this work.
Plant essential oils from 26 plant species were tested for their insecticidal activities against the
Japanese termite, Reticulitermes speratus Kolbe, using a fumigation bioassay. Responses varied with
source, exposure time, and concentration. Among the essential oils tested, strong insecticidal activity
was observed with the essential oils of ajowan (Trachyspermum ammi), allspice (Pimenta dioica),
caraway (Carum carvi), dill (Anethum graveolens), geranium (Pelargonium graveolens), and litsea
(Litsea cubeba). The composition of six essential oils was identified by using gas chromatography-
mass spectrometry. The compounds thus identified were tested individually for their insecticidal
activities against Japanese termites. Responses varied in a dose-dependent manner for each
compound. Phenol compounds exhibited the strongest insecticidal activity among the test compounds;
furthermore, alcohol and aldehyde groups were more toxic than hydrocarbons. The essential oils and
compounds described herein merit further study as potential fumigants for termite control.
KEYWORDS: Plant essential oils; Reticulitermes speratus; antitermitic activity; fumigant; ajowan;
allspice; caraway; dill; geranium; litsea; thymol; carvacrol; eugenol
INTRODUCTION
concerns regarding the use of such pesticides leading to environ-
mental pollution and health disorders. To avoid these problems,
there have been efforts to use plant essential oils as potential
alternatives to currently used termite control agents because
they constitute a rich source of bioactive chemicals (4, 5); more-
over, they are known to be safe as they are commonly used as
fragrances and flavoring agents for foods and beverages (6, 7).
Furthermore, plant essential oils are highly volatile and therefore
do not leave toxic residues.
In this study, we selected 26 commercially available plant
essential oils that are widely used as fragrances and flavoring
agents; we assessed their fumigant toxicity against adult Japanese
termites using fumigation bioassays.
Due to their wood-eating habits, several termite species cause
serious damage to houses and wooden structures. Because they
remain well concealed, their presence is often undetected until the
timber is severely damaged from within and shows surface
changes, which typically appear last. Once termites have entered
a building, they damage not only wood but also paper, cloth,
carpets, and other cellulosic materials. The annual damage to
wooden structures and other cellulosic materials by termites has
been estimated to exceed U.S. $3 billion worldwide (1). Among
termite species, subterranean termites from the genera Reticuli-
termes and Coptotermes are the most economically important
species worldwide (2). The Japanese termite, Reticulitermes
speratus Kolbe, is the major termite species distributed through-
out Korea, Japan, and China. Recently, in Korea, this pest has
caused serious damage to important cultural assets such as
temples and palaces.
MATERIALS AND METHODS
Termites. Japanese termites (Reticulitermes speratus Kolbe) were
collected from several damaged pine tree logs at Hongneung arboretum,
Seoul, Republic of Korea, from March to September 2007 and 2008.
Termite-infested wood moistened with distilled water was kept in plastic
cages (60ꢀ40ꢀ40 cm) at 25 ( 1 °C and 80% relative humidity.
Chemicals. Plant essential oils were purchased from Jinarome (USA)
(Table 1). Information regarding the chemicals used in this experiment is
given in Table 3.
Control of the Japanese termite in Korea is primarily depen-
dent upon continued applications of synthetic pesticides or
traditional wood preservatives (3). Although effective, there are
*Author to whom correspondence should be addressed (telephone
þ82-2-961-2672; fax þ82-2-961-2679; e-mail parkik1@forest.go.kr).
pubs.acs.org/JAFC
Published on Web 07/02/2009
© 2009 American Chemical Society

Article
J. Agric. Food Chem., Vol. 57, No. 15, 2009 6597
Table 1. Plant Essential Oils Tested
2,2,2-Trichloro-1-phenylethanol: KOH (1.84 g, 33.0 mmol; Wako) was
added to a solution of benzaldehyde (3.18 g, 30.0 mmol; TCI) and CHCl3
(4 mL) at 0 °C. The solution was stirred for 1 h at 40-50 °C, and 2%
H2SO4 solution was then poured. The solution was diluted with diethyl
ether and washed with NaHCO3, H2O, and brine and dried over MgSO4.
After purification by SiO2 column chromatography and distillation, 2.44 g
of the desired alcohol was obtained (yield, 36.3%; purity, 98.4% based on
GC). GC-MS (m/z, %) values were as follows: 224 (Mþ, 0.1), 125 (10.0),
107 (B, 100), 79 (52.7), 77 (32.6), and 51 (9.0). IR (neat, cm-1) values were
as follows: 3600-3100 (br s), 3062 (s), 3032 (s), 2980 (s), 1497 (s), 1454 (s),
820 (s), and 700 (s).
oil
source of plant
part
seeds
origin
India
ajowan
allspice
amyris
Trachyspermum ammi
Pimenta dioica
berries
wood
Jamaica
Caribbean
South Africa
Brazil
Amyris balsamifera
Artemisia afra
Artemisia afra
cabreuva
cajeput
flowering plant
wood
Myrocarpus fastigiatus
Melaleuca cajuputii
Cananga odorata
Elettaria cardamomum
Daucus carota
leaves
blossoms
seeds
Indonesia
Indonesia
Equador
France
cananga
cardamom
carrot seeds
caraway
clementine
copaiva
coriander
davana
Rose acetate: yield, 74.5%; purity, >99% based on GC; GC-MS
(m/z, %) 266 (Mþ, 0.3), 230 (0.6), 209 (0.7), 190 (2.5), 172 (6.0), 149
(40.0), 125 (4.2), 107 (100), 79 (13.6), and 43 (45.9).
seeds
seeds
Carum carvi
Egypt
South Africa
Brazil
Citrus clementina
Copaifera reticulata
Coriandrum sativum
Artemisia pallens
Anethum graveolens
Canarium luzonicum
Fokienia hodgensii
Boswellia carterii
rind
resin
Antitermitic Activity. Antitermitic activity was evaluated using a
fumigation bioassay. A paper disk (8 mm, Advantec) treated with the
essential oil or compound being tested was placed in the bottom lid of a
glass cylinder (5 cm diameterꢀ10 cm) with a wire sieve fitted 3.5 cm above
the bottom; thereafter, the lid was sealed. Ten adult worker termites were
placed on the sieve. This prevented the direct contact of the termites
with the test plant oils and compounds. Filter paper soaked with water
was supplied as food. The insects were maintained at 25 ( 1 °C and 80%
relative humidity. The adult termites were considered to be dead if
appendages did not move when prodded with a brush. Cumulative
mortalities were determined 2 and 7 days after treatment. All treatments
were replicated five times.
fruits
Argenitina
India
leaves
seeds
resin
dill
elemi
Bulgaria
Phillipines
Vietnam
Ethiopia
Iran
fokienia
frankincense
galbanum
geranium
gurjum
wood
resin
Ferula galbaniflua
Pelargonium graveolens
Dipterocarpus turbinatus
Hyssopus officinalis
Larix europea
resin
leaves
resin
Reunion
Indonesia
France
hyssop
larch
flowering plant
resin
Austria
France
lavandin
litsea
patchouli
Lavandula hybrida
Litsea cubeba
Pogostemon patchouli
flowering plant
fruits
whole plant
Statistical Analyses. Mortality of termites was transformed to arcsine
square root values for analysis of variance (ANOVA). Mean values for
Vitenam
Indonesia
treatment data were compared and separated by Scheffe
´
test (9).
Instrumental Analysis. Gas chromatography (GC) analysis was
performed using an Agilent 6890N equipped with a flame ionization
detector. Retention times for comparison with authentic compounds
were measured with a DB-1MS and a HP-INNOWax column (30 mꢀ
0.25 mm i.d., 0.25 μm film thickness; J&W Scientific, Folsom, CA). The
oven temperature was programmed as follows: isothermal at 40 °C for
1 min, raised to 250 °C at 6 °C/min, and maintained at this temperature
for 4 min. Helium was used as the carrier gas at a flow rate of 1.5 mL/
min. To determine the configurations of R-pinene, β-pinene, and
limonene, a chiral column;Beta DEX120 (30 mꢀ0.25 mm i.d., 0.25
μm; Supelco, Bellefonte, PA);was used. The oven temperature was
maintained at 100 °C for 20 min, and the flow rate of the carrier gas was
1.0 mL/min. For the chiral GC separation of carvone, a Beta DEX 225
(30 mꢀ 0.25 mm i.d., 0.25 μm; Supelco) was used. The temperature
program was as follows: 130 °C for 10 min raised to 200 °C at a rate of
10 °C/min. The carrier gas had a flow rate of 1.0 mL/min. GC-mass
spectrometry (GC-MS) analysis was performed on an Agilent 7890A
coupled with a 5975C mass selective detector (MSD). A DB-5MS (30 m
ꢀ0.25 mm i.d., 0.25 μm film thickness; J&W Scientific) was used for the
separation of the analytes. The oven temperatures were identical to
those used for GC. Helium was the carrier gas, at a flow rate of 1.0 mL/
min. Infrared (IR) spectra were recorded on a Nicolet FT-IR (Thermo
Fisher Scientific Inc.) spectrometer.
RESULTS
Antitermitic Activity of Plant Essential Oils. When 26 plant
essential oils were bioassayed, termite mortalities varied according
to the oil type, dose, and exposure time (Table 2). Of these,
6 essential oils, ajowan (Trachyspermum ammi), allspice (Pimenta
dioica), caraway (Carum carvi), dill (Anethum graveolens), gera-
nium (Pelargonium graveolens), and litsea (Litsea cubeba), achieved
>80% mortality 2 days after treatment at 2 mg/filter paper.
Artemisia afra, cajept (Melaleuca cajuputii), cananga (Cananga
odorata), cardamom (Elettaria cardamomum), coriander (Corian-
drum sativum), elemi (Canarium luzonicum), hyssop (Hyssopus
officinalis), larch (Larix europea), and lavindin (Lavandula hybrid)
showed >80% antitermitic activity 7 days after treatment. Plant
essential oils showing >80% mortality at 2 mg/filter paper were
tested at lower concentrations. The insecticidal activity of allspice
essential oil was 88% 7 days after treatment at 0.5 mg/filter paper;
however, this decreased to 0% at 0.25 mg/filter paper. Antitermitic
activities of ajowan, caraway, and litsea were 86, 100, and 96%,
respectively, 7 days after treatment at 1 mg/filter paper; however,
these decreased to 2, 22, and 2%, respectively, at 0.5 mg/filter
paper. Essential oils of dill and geranium produced 92 and 84%
insecticidal activities at 1.5 mg/filter paper but showed 76 and 78%
mortality at 1 mg/filter paper, respectively.
Chemical Analyses of Active Essential Oils. The chemical
compositions of the six active essential oils;ajowan (T. ammi),
allspice (P. dioica), caraway (C. carvi), dill (A. graveolens),
geranium (P. graveolens), and litsea (L. cubeba);are shown in
Table 3. Retention indices were obtained using an equation
proposed by van Den Dool and Kratz (12). We determined the
configurations of R-pinene, β-pinene, and limonene by using a
chiral column (Beta DEX120). R-Pinene in litsea essential oil
consisted of (S)-(-)-R-pinene (0.51%) and (R)-(þ)-R-pinene
(0.71%). Only (R)-(þ)-R-pinene was detected in ajowan oil.
Ratios of (þ)-β-pinene and (-)-β-pinene were 0.31 and 0.75%
in litsea oil, respectively. Only (þ)-β-pinene was identified in
ajowan oil. In the case of limonene, two isomers were identified in
ajowan and litsea oils, but only (R)-(þ)-limonene was determined
Synthesis. Citronellyl acetate, neryl acetate, 2-phenylethyl acetate, and
rose acetate (2,2,2-trichloro-1-phenylethyl acetate) were obtained by
acetylation of the corresponding alcohol with acetic acid anhydride and
pyridine by using p-toluenesulfonic acid as catalyst in CH2Cl2. The
corresponding alcohol of rose acetate, 2,2,2-trichloro-1-phenylethanol,
was prepared according to a previously reported method (8). The structure
was confirmed by comparison of its mass spectrum with data from the
NIST mass spectrum library and the IR spectrum.
Neryl acetate: yield, 93.9%; purity, 99.2%; IR (neat, cm-1) 2972 (m),
1743 (s), 1379 (m), 1240 (m), and 1026 (m); GC-MS (m/z, %) 196 (Mþ, 0.1),
154 (2.3), 153 (0.2), 136 (16.9), 121 (22.7), 107 (7.7), 93 (57.7), 80 (21.9),
69 (100), and 53 (10.7).
2-Phenylethyl acetate: yield, 89.6%; purity, >99.0%; GC-MS (m/z, %)
163 (Mþ - H, 0.01), 134 (0.02), 121 (0.2), 105 (11.0), 104 (100), 91 (17.7),
78 (5.5), 77 (5.4), 66 (0.4), and 43 (27.4).
Citronellyl acetate: yield:, 98%; purity, 96.5%; GC-MS (m/z, %) 155
(Mþ -OAc, 0.1), 138 (47.3), 123 (74.0), 109 (36.7), 95 (97.6), 81 (100),
69 (96.1), 67 (65.1), 55 (46.3), and 43 (77.7).

6598 J. Agric. Food Chem., Vol. 57, No. 15, 2009
Seo et al.
Table 2. Fumigant Antitermitic Activity of Essential Oils against Japanese
Termite
17 compounds were identified in geranium oil. Geraniol (10.25%)
was the most abundant followed by citronellol (8.63%),
2-phenylethanol (8.03%), geranyl acetate (7.25%), dihydrocitro-
nellol (3.33%), and rose acetate (3.01). The other compounds
were present in amounts of <2%.
mortality (%, mean ( SEM, N = 5)
concn, mg/filter
paper
essential oil
ajowan
2 days
100.0 aa
7 days
Antitermitic Activity of Essential Oil Components. The anti-
termiticactivity of individualcompounds 2 days after treatment is
shown in Table 4. Fumigant toxicities varied according to
compounds, application dose, and exposure time. The insecticidal
activity of two phenols (thymol and carvacrol) was stronger than
that of the alcohol group. The insecticidal activities of verbenol,
2-phenylethanol, nerol, and geraniol were 100, 100, 90, and 76%
at 0.25 mg/filter paper, but decreased to 96, 0, 4, and 44% at
0.125 mg/filter paper, respectively. The other alcohol compounds
exhibited <70% mortality at 0.25 mg/filter paper. In a test with
phenylpropanoids, the insecticidal activities of eugenol and acetyl-
eugenol was higher than those of methyleugenol, isoeugenol,
and methyl isoeugenol. Ketone compounds showed strong in-
secticidal activity against Japanese termite at 1 mg/filter paper,
except for 6-methyl-5-hepten-2-one. The toxicity of (þ)-carvone
was moderately higher than that of (-)-carvone. 2-Phenylethyl
acetate exhibited the strongest insecticidal activity among the
acetate group. There was a significant difference in the insecticidal
activity of members in the aldehyde group, with neral and
geranial being more toxic than citronellal. Compounds belonging
to the hydrocarbon group exhibited weak insecticidal activity as
compared with the compounds from other functional groups,
with toxicity never higher than 50% at 2 mg/filter paper. The
antitermitic activities of all individual compounds tested at 7 days
after treatment is shown in Table 5. Most compounds showed
higher insecticidal activity at 7 days than at 2 days. The mortality
of some compounds, such as rose acetate, carveol, 6-methyl-
5-hepten-2-one, isoeugenol, and methylisoeugenol, demonstrated
a significant increase in toxicity over the bioassay duration.
2
100.0 a
100.0 a
1.5
1
72.0 ( 4.9 abcde
18.0 ( 5.8 ghi
0.0 i
86.0 ( 2.4 abcd
2.0 ( 2.0 i
100.0 a
0.5
2
allspice
100.0 a
1.5
1
94.0 ( 4.0 a
82.0 ( 3.7 abc
20.0 ( 3.2 fghi
0.0 i
100.0 a
100.0 a
0.5
0.25
2
88.0 ( 5.8 abcd
0.0 i
amyris
Artemisia afra
10.0 ( 5.5 hi
76.0 ( 7.5 abcd
6.0 ( 2.4 hi
10.0 ( 3.2 hi
24.0 ( 7.5 efghi
0.0 i
46.0 ( 7.5 bcdefghi
100.0 a
2
1.5
2
72.0 ( 4.9 abcdef
72.0 ( 6.6 abcdef
100.0 a
cabreuva
cajept extra
2
1.5
2
28.0 ( 8.6 fghi
94.0 ( 4.0 ab
8.0 ( 3.7 hi
cananga
18.0 ( 5.8 ghi
0.0 i
1.5
2
cardamom
52.0 ( 10.2 abcdefgh 100.0 a
1.5
2
2.0 ( 2.0 i
0.0 i
16.0 ( 4.0 ghi
carrot seed
caraway
56.0 ( 4.0 abcdefgh
100.0 a
100.0 a
2
88.0 ( 4.9 ab
64.0 ( 2.4 abcdefg
10.0 ( 6.3 hi
0.0 i
1.5
1
100.0 a
0.5
2
22.0 ( 5.8 ghi
60.0 ( 3.2 abcdefg
76.0 ( 4.0 abcdef
96.0 ( 2.4 a
42.0 ( 5.8 defghi
44.0 ( 2.4 cdefghi
100.0 a
clementine
copaiva
coriander
16.0 ( 5.1 ghi
10.0 ( 3.2 hi
78.0 ( 5.8 abc
4.0 ( 4.0 hi
28.0 ( 3.7 defghi
88.0 ( 4.9 ab
28.0 ( 5.8 defghi
0.0 i
2
2
1.5
2
davana
dill
2
1.5
1
92.0 ( 3.7 abc
76.0 ( 2.4 abcdef
4.0 ( 2.4 i
1.5
2
0.0 i
0.0 i
DISCUSSION
elemi
86.0 ( 6.8 abcd
32.0 ( 3.7 efghi
28.0 ( 6.6 fghi
32.0 ( 3.7 efghi
30.0 ( 5.5 efghi
98.0 ( 2.0 a
84.0 ( 5.1 abcd
78.0 ( 5.8 abcde
8.0 ( 2.0 hi
1.5
2
0.0 i
2.0 ( 2.0 i
0.0 i
Many phytochemicals have been reported to possess antiter-
mitic, antifeedant, or repellent activities against a variety of
insects and pests. Reported antitermitic phytochemicals include
plumbagin, isodiospyrin, and microphyllone from Diospyros
sylvatica (13), 7-methyljuglone from Diopyros virginiana (14),
and chamaecynone from Chamaecyparis pisifera (15). Several
plant essential oils and essential oil components have been also
reported to show antitermitic or repellent activity. Cedrol and
R-cadinol from Taiwania cryptomerioides heartwood oil (3) and
eugenol and sulfide compounds from clove and garlic oils (5) have
exhibited strong insecticidal activity against termites. Other
studies have confirmed that certain essential oils, such as those
extracted from cedarwood (16), L. cubeba (17), and Cinnamomum
spp. (18), are repellent to termites. Inour study, stronginsecticidal
activity against Japanese termite was achieved with essential oils
of ajowan (T. ammi), allspice (P. dioica), caraway (C. carvi), dill
(A. graveolens), geranium (P. graveolens), and litsea (L. cubeba).
Various compounds, including alcohols, aldehydes, fatty acid
derivatives, terpenoids, and phenolics, exist in plant essential oils.
Jointly or independently, they contribute to the insecticidal,
antifungal, and nematicidal activities of these oils (5, 11, 19).
Chemical analysis of ajowan, allspice, and litsea has been re-
ported in a previous study (19). In this study, we determined the
configurations of R-pinene, β-pinene, and limonene by using a
chiral column. Only (R)-(þ)-R-pinene was found in ajowan oil,
but both of the optical isomers were identified in litsea oil. Ratios
of (þ)-β-pinene and (-)-β-pinene were 0.31 and 0.75 in litsea oil,
respectively. However, only (þ)-β-pinene was found in ajowan
fokieniawood
frankincense
galbanum
2
2
2.0 ( 2.0 i
geranium
2
98.0 ( 2.0 a
44.0 ( 6.0 bcdefghi
22.0 ( 3.7 fghi
6.0 ( 2.4 hi
68.0 ( 3.7 abcdef
26.0 ( 6.8 efghi
38.0 ( 7.3 cdefghi
2.0 ( 2.0 i
1.5
1
gurjum
hyssop
2
2
100.0 a
64.0 ( 4.0 abcdefg
100.0 a
1.5
2
larch
1.5
2
72.0 ( 8.0 abcdef
94.0 ( 2.4 ab
30.0 ( 7.1 efghi
100.0 a
lavandin
litsea
34.0 ( 4.0 cdefghi
6.0 ( 2.4 hi
100.0 a
1.5
2
1.5
1
78.0 ( 5.8 abc
42.0 ( 4.9 bcdefghi
0.0 i
100.0 a
96.0 ( 2.4 a
2.0 ( 2.0 i
56.0 ( 4.0 abcdefgh
0.0 i
0.5
2
patchouli
control
2.0 ( 2.0 i
0.0 i
aMeans within a column followed by the same letters are not significantly different
(P = 0.05, Scheffe test).
in allspice oil. The main components of caraway oil were (S)-(þ)-
carvone (48.7%), (R)-(þ)-limonene (24.2%), cis-carveol (0.4%),
and trans-carveol (0.3%). The most abundant compound in dill
oil was (S)-(þ)-carvone (35.56%) followed by (R)-(þ)-limonene
(20.21%), myrcene (4.89%), dill ether (4.58%), and p-cymene
(2.34%). Ratios of the other compounds were <1%. A total of

Article
J. Agric. Food Chem., Vol. 57, No. 15, 2009 6599
Table 3. Chemical Analysis of Active Plant Essential Oils
retention index (std compd)
composition ratio (%, w/w)
no.
compound
R-pinene
(S)-(-)-R-pinene
(R)-(þ)-R-pinene
camphene
sabineneb
purity, companya
1MS
INNOWax
ajowan
0.87
allspice
carvi
dill
geranium
0.08
litsea
1
928 (928)f
1021 (1021)
0.35
1.22
0.51
0.71
0.27
1.51
1.34
1.06
0.31
0.75
0.73
95%, T
99%, A
80%, T
0.87
0.10
0.35
2
3
4
5
940 (940)
963 (-)
964 (964)
1064 (1064)
1128 (-)
1344 (1344)
6-methyl-5-hepten-2-one
β-pinene
(þ)-β-pinene
(-)-β-pinene
myrcene
99%, A
94%, T
967 (967)
1108 (1108)
1.26
1.26
6
95%, A
98%, T
85%, F
95%, F
99%, F
981 (981)
995 (994)
1165 (1167)
1165 (1166)
1181 (1181)
1275 (1275)
1209 (1208)
1200 (1200)
0.48
0.17
4.89
7
R-phellandrene
R-terpinene
p-cymene
8
1007 (1007)
1012 (1012)
1018 (1018)
1020 (1019)
0.13
24.40
0.32
9
2.34g
0.96g
20.48
0.27
10
11
1,8-cineole
limonene
0.10
0.18
1.21
14.64
0.34
0.44
0.08
24.20
24.20
(S)-(-)-limonene
(R)-(þ)-limonene
γ-terpinene
2-phenylethanol
linalool
97%, T
97%, A
97%, F
98%, T
98%, W
95%, A
99%, A
85%, A
97%, A
0.36
27.77
0.18
20.21
14.30
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
1050 (1050)
1082 (1081)
1084 (1084)
1121 (1121)
1127 (1128)
1130 (1130)
1159 (1159)
1165 (-)
1248 (1248)
1929 (1929)
1556 (1557)
1665 (1665)
1533 (1538)
1486 (1486)
1610 (1611)
1484 (-)
8.03
1.14
1.38
0.35
verbenol
isopulegol
0.28
citronellal
terpine-4-ol
dill etherb
0.57
0.32
4.58
0.83
trans-dihydrocarvonec
R-terpineol
98%, A
95%, T
98%, A
1168 (1170)
1170 (1170)
1174 (1175)
1616 (1616)
1707 (1707)
1744 (1744)
0.56
3.33
0.44
cis-dihydrocarvonec
dihydrocitronellolb
cis-carveolc
0.86
97%, A
97%, A
95%, A
97%, A
75%, Se
99%, S
1196 (1196)
1207 (1207)
1209 (1211)
1209 (1211)
1216 (1216)
1223 (1225)
1214 (1213)
1848 (1848)
1878 (1879)
1777 (1776)
1811 (1811)
1690 (1690)
1828 (1828)
1745 (1744)
0.40
0.30
trans-carveolc
citronellol
nerol
8.63g
2.17g
0.27
30.27
neral
2-phenylethyl acetate
carvone
1.57
48.70
48.70
35.56
35.56
(R)-(-)-carvone
(S)-(þ)-carvone
geraniol
96%, A
96%, A
98%, F
95%, T
85%, Se
99%, F
95%, T
96%, S
95%, W
99%, S
97%, F
98%, W
98%, T
90%, T
98%, F
99%, S
31
32
33
34
35
36
37
38
39
40
41
42
43
44
1236 (1236)
1239 (1240)
1245 (1245)
1273 (1273)
1278 (1278)
1333 (1335)
1334 (1334)
1341 (1344)
1360 (1360)
1370 (1370)
1372 (1370)
1414 (1414)
1447 (1447)
1522 (1522)
1858 (1858)
1563 (1563)
1742 (1742)
2207 (2207)
2235 (2236)
1668 (1668)
2186 (2186)
1733 (1734)
1764 (1764)
2025 (2026)
2026 (2026)
1600 (1600)
1673 (1673)
2222 (2223)
10.25
1.03
0.50
linalyl acetate
geranial
thymol
39.23
41.77
0.55
carvacrol
citronellyl acetate
eugenol
0.74
86.44
3.87
neryl acetate
geranyl acetate
methyleugenol
diphenyl ether
β-caryophyllene
R-humulene
rose acetated
1.26
7.25
1.78
0.25
7.70
0.99
0.60
3.01
aA, Aldrich; F, Fluka; S, synthesized in our laboratory; T, TCI; W, Wako. bStructure was tentatively identified by comparison of mas spectrum in the library. cMixture of cis- and trans-,
trans- and cis- isomers were determined from the literature report (10). dIUPAC name of rose acetate is 2,2,2-trichloro-1-phenylethanyl acetate. ePreviously prepared neral and geranial
were used in this experiment (11). fRI of standard compound. gComposition ratio of citronellol and nerol, limonene, and 1,8-cineole were determined on HP-INNOWax column.
oil. The chemical analysis data of caraway, dill, and geranium oils
have been well studied (20, 21). Similar results were observed
therein, albeit with differences in the ratios and the minor
components. Galambosi and Peura (22) have reported that the
composition of essential oil differs widely with production con-
ditions, such as harvesting date or storage time, as well as climate
and soil factors.
in depth. The SAR of monoterpenoids and fumigant activity
against adult Acanthoscelides obtectus (Say) was investigated by
Regnault-Roger and Hamraoui (23). They found that oxygenated
structures, especially carvacrol, linalool, and terpineol, exhibited
the strongest activity. In our study, the antitermitic activities of
verbenol, carvone, thymol, and carvacrol were higher than those
of R-pinene and limonene. Verbenol, carvone, thymol, and
carvacrol are oxygenated compounds of R-pinene, limonene,
and p-cymene, respectively. Choi et al. (24) reported that phenol,
The structure-activity relationships (SAR) of plant com-
pounds against insect pests and nematodes have been studied

6600 J. Agric. Food Chem., Vol. 57, No. 15, 2009
Seo et al.
Table 4. Fumigant Antitermitic Activity of Compounds from Six Active Essential Oils against Japanese Termite at 2 Days after Treatment
mortality of termite at 2 days after treatment with synthetic compound at each concnb (%, mean ( SEM, N = 5)
compound
2
1.5
1
0.5
0.25
0.125
0.062
0.031
hydrocarbons
camphene
d
2.0 ( 42.0 fc
20.0 ( 4.5 def
40.0 ( 4.5 cd
8.0 ( 5.8 ef
6.0 ( 2.4 f
(þ)-R-pinene
(-)-R-pinene
β-pinene
0 e
10.0 ( 3.2 cde
myrcene
R-phellandrene
R-terpinene
p-cymene
0 g
20.0 ( 3.2 def
44.0 ( 2.4 cd
6.0 ( 4.0 f
10.0 ( 4.5 ef
46.0 ( 2.4 c
32.0 ( 5.8 cde
6.0 ( 2.4 cde
4.0 ( 2.4 de
6.0 ( 4.0 cde
(R)-(þ)-limonene
(S)-(-)-limonene
γ-terpinene
R-humulene
β-caryophyllene
4.0 ( 2.4 c
4.0 ( 2.4 c
22.0 ( 4.9 bcd 8.0 ( 3.7 c
24.0 ( 4.0 cdef 18.0 ( 2.0 cde 2.0 ( 2.0 c
aldehydes
citronellal
neral
geranial
100 a
100 a
100 a
100 a
100 a
100 a
82.0 ( 2.0 a
100 a
100 a
2.0 ( 2.0 e
100 a
100 a
80.0 ( 5.5 abc
92.0 ( 4.9 ab
12.0 ( 5.8 cde
38.0 ( 3.7 bc
0 b
acetates
2-phenylethyl acetate
linalyl acetate
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
96.0 ( 4.0 a
24.0 ( 5.1 gh
24.0 ( 5.1 gh
52.0 ( 3.7 cdefg 0 e
60.0 ( 3.2 bcdef 0 e
0 e
58.0 ( 3.7 b
78.0 ( 4.9 ab
100 a
citronellyl acetate
neryl acetate
geranyl acetate
rose acetate
100 a
56.0 ( 6.0 bc
42.0 ( 4.9 defg
32.0 ( 11.0 bcd
0 b
alcohols
2-phenylethanol
linalool
verbenol
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
20.0 ( 7.1 gh
100 a
0 e
56.0 ( 4.0 bc
100 a
100 a
96.0 ( 2.4 a
2.0 ( 2.0 e
6.0 ( 6.0 de
4.0 ( 4.0 de
14.0 ( 4.0 cde
8.0 ( 5.8b
isopulegol
terpinen-4-ol
R-terpineol
carveola
32.0 ( 8.0 efgh
26.0 ( 2.4 fgh
66.0 ( 4 abcde
20.0 ( 5.5 gh
0 h
30.0 ( 3.2 d
94.0 ( 6.0 a
100 a
2.0 ( 2.0 b
2.0 ( 2.0 c
citronellol
nerol
geraniol
0 e
100 a
90.0 ( 4.5 ab
76.0 ( 2.4 abcd
4.0 ( 4.0 de
44.0 ( 6.0 b
100 a
0 b
ketones
6-methyl-5-hepten-2-one 32.0 ( 5.8 cde
24.0 ( 6.8 bc
100 a
100 a
20.0 ( 7.1 b
100 a
100 a
dihydrocarvonea
(R)-(-)-carvone
(S)-(þ)-carvone
100 a
100 a
100 a
66.0 ( 2.4 b
100 a
100 a
50.0 ( 4.5 cdefg 4.0 ( 2.4 de
100 a
100 a
2.0 ( 2.0 e
44.0 ( 2.4 b
0 b
2.0 ( 2.0 b
100 a
100 a
phenols
thymol
carvacrol
eugenol
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
68.0 ( 2.0 a
12.0 ( 4.9 c
48. 0 ( 4.9 b
0 c
100 a
100 a
100 a
100 a
100 a
100 a
100 a
2.0 ( 2.0 b
6.0 ( 4.0 b
methyleugenol
isoeugenol
methylisoeugenol
acetyleugenol
28.0 ( 2.0 d
34.0 ( 5.1 cd 28.0 ( 7.3 fgh
100 a
100 a
0 e
24.0 ( 2.4 gh
20.0 ( 3.2 bcde
22.0 ( 5.8 bcde 10.0 ( 3.2 b 2.0 ( 2.0 c
100 a
100 a
84.0 ( 4.0 a 2.0 ( 2.0 c
others
diphenyl ether
1,8-cineole
100 a
72.0 ( 3.7b
0 f
100 a
38.0 ( 3.7b
0 e
100 a
16.0 ( 6.0c
0 c
98.0 ( 2.0 a
0 h
92.0 ( 5.8 a
0 e
18.0 ( 5.8 b 0 c
control
0 b
0 c
aMixture of cis- and trans-isomers. bMilligrams per filter paper. cMeans within a column followed by the same letters are not significantly different (P = 0.05, Scheffe test).
dNo entry indicates the compound was not tested.
alcohol, and aldehyde compounds were generally more toxic to
the pine wood nematode (Bursaphelenchus xylophilus) than were
compounds from other monoterpenoid groups such as ketones
and hydrocarbons. Inthis study, phenolcompounds exhibited the
strongest insecticidal activity among the compounds tested, and
alcohol and aldehyde groups were more toxic than the hydro-
carbon group.
active than the others at 0.5 mg/filter paper. Lee et al. (11) and
Kim et al. (25) reported that R,β-unsaturated carbonyl com-
pounds were responsible for antifungal and nematicidal activities,
respectively. These results suggested that the double bond at
the R,β position in carbonyl compounds enhanced insecticidal
activity.
Lee at al. (11) and Choi et al. (24) reported that primary
alcohols were more active than secondary and tertiary alcohols in
antifungal and nematicidal activities, respectively. However, such
Among the aldehyde and ketone compounds, R,β-unsaturated
carbonyl compounds (nerol, geranial, and carvones) were more

Article
J. Agric. Food Chem., Vol. 57, No. 15, 2009 6601
Table 5. Fumigant Antitermitic Activity of Compounds from Six Active Essential Oils against Japanese Termite at 7 Days after Treatment
mortality of termite at 2 days after treatment with synthetic compound at each concnb (%, mean ( SEM, N = 5)
compound
2
1.5
1
0.5
0.25
0.125
0.062
0.031
0.015
hydrocarbons
camphene
d
8.0 ( 5.8 efc
(þ)-R-pinene
(-)-R-pinene
β-pinene
80.0 ( 3.2 ab 16.0 ( 5.1 c
100 a
22.0 ( 4.9 c
30.0 ( 3.2 de
30.0 ( 9.5 de
100 a
myrcene
R -phellandrene
R-terpinene
p-cymene
54.0 ( 2.4 b
44.0 ( 2.4 cd
84.0 ( 2.4 ab 10.0 ( 10.0 c
(R)-(þ)-limonene
(S)-(-)-limonene
γ-terpinene
R-humulene
β-caryophyllene
100 a
100 a
76.0 ( 5.1 ab 4.0 ( 2.4 f
92.0 ( 4.9 a
64.0 ( 2.4 b
64.0 ( 2.4 bc
88.0 ( 2.0 a
94.0 ( 4.0 a
84.0 ( 2.4 a
90.0 ( 4.5 a
44.0 ( 6.0 c
10.0 ( 4.5 f
aldehydes
citronellal
neral
geranial
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
14.0 ( 6.0 b
100 a
100 a
82.0 ( 4.9 a 34.0 ( 2.4 cd
100 a
94.0 ( 4.0 a
4.0 ( 2.4 e
acetates
2-phenylethyl acetate 100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
30.0 ( 4.5b
30.0 ( 4.5 b
88.0 ( 4.9 a 4.0 ( 2.4 cd
100 a
100 a
2.0 ( 2.0 cd
linalyl acetate
citronellyl acetate
neryl acetate
100 a
100 a
100 a
100 a
100 a
geranyl acetate
rose acetate
2.0 ( 2.0 cd
100 a
100 a
92.0 ( 4.9 ab 40.0 ( 4.5 a
alcohols
2-phenylethanol
linalool
verbenol
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100a
100a
100a
10.0 ( 4.4b
100a
4.0 ( 2.4 cd
100a
98.0 ( 2.0a 10.0 ( 6.3 cd
22.0 ( 5.8de
isopulegol
terpinen-4-ol
R-terpineol
carveola
88.0 ( 4.9 a 84.0 ( 2.4a 10.0 ( 7.7 cd
100 a
100 a
100 a
100 a
100 a
82.0 ( 2.0a 22.0 ( 3.7 cd
100a
100a
68.0 ( 4.9 cb 28.0 ( 9.2 de
citronellol
nerol
geraniol
30.0 ( 8.9 b
100 a
100 a
8.0 ( 8.0 cd
80.0 ( 20.0 ab 4.0 ( 4.0 e
ketones
6-methyl-5-hepten-2-one 100 a
100 a
100 a
100 a
100 a
22.0 ( 5.8 de
100 a
100 a
dihydrocarvonea
(R)-(-)-carvone
(S)-(þ)-carvone
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
46.0 ( 4.0 bc
80.0 ( 3.2 ab
100 a
40.0 ( 3.2 d
44.0 ( 4.0 cd
100 a
phenols
thymol
carvacrol
eugenol
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
100 a
98.0 ( 2.0 a
68.0 ( 3.7 bc
96.0 ( 4.0 ab 0 b
20.0 ( 3.1 de
10.0 ( 6.3 b
100 a
100 a
100 a
100 a
methyleugenol
isoeugenol
methylisoeugenol
acetyleugenol
94.0 ( 2.4 a
100 a
100 a
20.0 ( 7.1 de
76.0 ( 2.4 ab 8.0 ( 2.0 e
100 a
84.0 ( 6.8 ab 2.0 ( 2.0 b
others
diphenyl ether
1,8-cineole
100 a
100 a
0 f
100 a
92.0 ( 4.9 a
0 c
100 a
38.0 ( 5.8 cd
100 a
0 c
100 a
0 c
100 a
0 d
72.0 ( 6.6 b
0 e
40.0 ( 3.2 cd
control
0 f
0 e
0 b
aMixture of cis- and trans-isomers. bMilligrams per filter paper. cMeans within a column followed by the same letters are not significantly different (P = 0.05, Scheffe test).
dNo entry indicates that the compound was not tested.
a tendency was not clearly found in this study although alcohol
compounds showed a generally higher activity. This might
indicate that the position of the hydroxy group in alcohol is not
crucial for antitermitic activity.
There was a significant difference in the insecticidal activity
among phenylpropanoid compounds. Park et al. (19) and Kim
et al. (26) reported that the functional group at the C1 position of
the benzene ring or the position of the double bond of the pro-
penyl group was important in nematicidal or antifungal activity.
There was a significant difference in the nematicidal or insecticidal
activity of cis-trans diastereomers such as cis- and trans-asar-
one (25, 27). Nematicidal or insecticidal activities of cis-asarone
were stronger than those of trans-asarone. However, significant
difference in antitermitic activity was not observed in enantiomers
such as (R)-(þ)-limonene, (S)-(-)-limonene, (R)-(þ)-carvone,
and (S)-(-)-carvone.
Although little is known regarding the physiological actions of
essential oils on insects, various oils or their components cause

6602 J. Agric. Food Chem., Vol. 57, No. 15, 2009
Seo et al.
symptoms that suggest a neurotoxic mode of action (28, 29).
Eugenol has been claimed to exert its insecticidal activity by
binding to octopamine receptors (30, 31). Price and Berry (32)
insisted that geraniol and citral showed greater similarities to
octopamine than did eugenol. Elucidating the mode of action of
the lethality of these oils toward insect pests is important for the
safety of humans and other veterbrates (32). Roeder (33) and
Enan (30) have noted the facts that vertebrates possess very few
octopamine receptors and that specific octopamine receptor
binding might not cause any adverse effect in vertebrates exposed
to the oils. However, the exact mode of action of essential oils and
constituents remains unclear.
Our results indicate that ajowan, allspice, caraway, dill,
geranium, and litsea and their components could be developed
as fumigants against Japanese termites. For the practical use of
these oils and their constituents as novel fumigants, the safety of
oils and their constituents in humans and nontarget organisms
needs to be further evaluated; moreover, the development of
formulations with improved efficacy and stability and reduced
costs necessitates further studies.
(16) Adams, R. P. Cedar wood oil;analysis and properties. Mod.
Methods Plant Anal. 1991, 12, 159–173.
(17) Lin, T. S.; Yin, H. W. Effects of Litsea cubeba Pres oils on the control
of termite Coptotermes formosanus Shiraki. Taiwan For. Res. Inst.
New Ser. 1995, 10, 59–63.
(18) Lin, T. S.; Yin, H. W. The effects of Cinnamomum spp. oils on the
control of termite Coptotermes formosanus Shiraki. Taiwan For. Res.
Inst. New Ser. 1995, 10, 459–464.
(19) Park, I. K.; Kim, J.; Lee, S. G.; Shin, S. C. Nematicidal activity of
plant essential oils and components from ajowan (Trachyspermum
ammi), allspice (Pimenta dioica) and litsea (Litsea cubeba) essential
oils against pine wood nematode (Bursaphelenchus xylophilus). J.
Nematol. 2007, 39, 275–279.
(20) Bailer, J.; Aichinger, T.; Hackl, G.; de Hueber, K.; Dachler, M.
Essential oil content and composition in commercially available dill
cultivars in comparison to caraway. Ind. Crop Prod. 2001, 14, 229–
239.
(21) Kulkarni, R. N.; Baskaran, K.; Ramesh, S.; Kumar, S. Intra-clonal
variation for essential oil content and composition in plants derived
from leaf cuttings of rose-scented geranium (Pelargonium sp.). Ind.
Crop Prod. 1997, 6, 107–112.
(22) Galambosi, B.; Peura, P. Agrobotanical features and oil content of
wild and cultivated forms of caraway (Carum carvi L.). J. Essent. Oil
Res. 1996, 8, 389–397.
LITERATURE CITED
(23) Regnault-Roger, C.; Hamraoui, A. Fumigant toxic activity and
reproductive inhibition induced by monoterpenes on Acanthosce-
lides obtectus (Say) (Coleoptera), a bruchid of kidney bean (Phaseo-
lus vulgaris L.). J. Stored Prod. Res. 1995, 31, 291–299.
(24) Choi, I. H.; Kim, J.; Shin, S. C.; Park, I. K. Nematicidal activity of
monoterpenoids against the pine wood nematode (Bursaphelenchus
xylophilus). Russ. J. Nematol. 2007, 15, 35–40.
(25) Kim, J.; Seo, S. M.; Lee, S. G.; Shin, S. C.; Park, I. K. Nematicidal
activity of plant essential oils and components from coriander
(Coriandrum sativum), oriental sweetgum (Liquidambar orientalis),
and valerian (Valeriana vallichii) essential oils against pine wood
nematode (Bursaphelenchus xylophilus). J. Agric. Food Chem. 2008,
56, 7316–7320.
(26) Kim, J.; Lee, Y. S.; Lee, S. G.; Shin, S. C.; Park, I. K. Fumigant
antifungal activity of plant essential oils and components from west
Indian bay (Pimenta racemosa) and thyme (Thymus vulgaris) oils
against two phytopathogenic fungi. Flavour Fragrance J. 2008, 23,
272–277.
(27) Park, C. Insecticidal activity of β-asarone derived from Acorus
gramineus rhizome against insect pests. M.S. thesis, Seoul National
University, Suwon, Republic of Korea, 2000.
(1) Su, N. Y.; Scheffrahn, R. H. Economically important termites in the
United States and their control. Sociobiology 1990, 17, 77–94.
(2) Zhou, X.; Wheeler, M. M.; Oi, F. M.; Scharf, M. E. Inhibition of
termite cellulases by carbohydrate-based cellulose inhibitors:
evidence from in vitro biochemistry and in vivo feeding studies.
Pestic. Biochem. Physiol. 2008, 90, 31–41.
(3) Lee, D. H.; Ryu, D. P. In Termite Ecology and Their Control; Lee, D.
H., Ed.; Korea Forest Research Institute: Seoul, Republic of Korea, 2003;
pp 321.
(4) Chang, S. T.; Cheng, S. S.; Wang, S. Y. Antitermitic activity of
essential oils and components from Taiwania (Taiwania cryptomer-
ioides). J. Chem. Ecol. 2001, 27, 717–724.
(5) Park, I. K.; Shin, S. C. Fumigant activity of plant essential oils and
components from garlic (Allium sativum) and clove bud (Eugenia
caryophyllata) oils against the Japanese termite (Reticulitermes
speratus). J. Agric. Food Chem. 2005, 53, 4388–4392.
(6) Isman, M. B. Pesticides based on plant essential oils. Pestic. Outlook
1999, 68–72.
(7) Isman, M. B. Plant essential oils for pest and disease management.
Crop Prot. 2000, 19, 603–608.
(8) Galun, A. B.; Kalir, A. p-Bromodiphenylmethane. Org. Synth. Coll.
Vol. V 1973, 130–133.
(9) SAS Institute. SAS/STAT User’s Guide, version 9.1.3; SAS Institute:
Cary, NC, 2002.
(28) Coats, J. R.; Karr, L. L.; Drewes, C. D. Toxicity and neurotoxic
effects of monoterpenoids in insects and earthworms. In Naturally
Occurring Pest Bioregulators; Hedin, P. A., Ed.; ACS Symposium
Series 449; American Chemical Society: Washington, DC, 1991; pp
305-316.
(10) Jirovetz, L.; Buchbauer, G.; Stoyanova, A. S.; Georgiev, E. V.;
Damianova, S. Composition, quality control, and antimicrobial
activity of the essential oil of long-time stored dill (Anethum grave-
olens L.) seeds from Bulgaria. J. Agric. Food Chem. 2003, 51, 3854–
3857.
(11) Lee, Y. S.; Kim, J.; Shin, S. C.; Lee, S. G.; Park, I. K. Antifungal
activity of Myrtaceae essential oils and their components against
three phytopathogenic fungi. Flavour Fragrance J. 2008, 23, 23–28.
(12) van Den Dool, H.; Kratz, P. D. Generalization of the retention index
system including linear temperature programmed gas;liquid parti-
tion chromatography. J. Chromatogr., A 1963, 11, 463–471.
(13) Ganapaty, S.; Thomas, P. S.; Fotso, S.; Laatsch, H. Antitermitic
quinines from Diospyros sylvatica. Phytochemistry 2004, 65, 1265–
1271.
(29) Kostyukovsky, M.; Rafaeli, A.; Gileadi, C.; Demchenko, N.;
Shaaya, E. Activation of octopaminergic receptors by essential oil
constituents isolated from aromatic plants: possible mode of action
against insect pests. Pest Manag. Sci. 2002, 58, 1101–1106.
(30) Enan, E. E. Insecticidal activity of essential oils: octopaminergic sites
of action. Comp. Biochem. Physiol 2001, 130C, 320–325.
(31) Enan, E. E. Molecular and pharmacological analysis of an octopa-
mine receptor from American cockroach and fruit fly in response to
plant essential oils. Arch. Insect Biochem. Physiol. 2005, 59, 161–171.
(32) Price, D. N.; Berry, M. S. Comparison of effects of octopamine and
insecticidal essential oils on activity in the nerve cord, foregut, and
dorsal unpaired median neurons of cockroaches. J. Insect Physiol.
2006, 52, 309–319.
(14) Carter, F. L.; Garlo, A. M.; Stanely, J. B. Termiticidal components
of wood extracts: 7-methyljuglone from Diospyros virginiana. J.
Agric. Food Chem. 1978, 26, 869–873.
(33) Roeder, T. Octopamine in invertebrates. Prog. Neurobiol. 1999, 59,
533–561.
(15) Saeki, I.; Sumimoto, M.; Kondo, T. The termiticidal substances
from the wood Chamaecyparis pisifera D. Don. Holzforschung 1973,
27, 93–96.
Received March 4, 2009. Revised manuscript received June 14, 2009.
Accepted June 17, 2009.