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Behavioral Activity of Catnip (Lamiaceae) Essential Oil Components to the German Cockroach (Blattodea: Blattellidae)

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Behavioral Activity of Catnip (Lamiaceae) Essential Oil Components to the German Cockroach (Blattodea: Blattellidae)

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The essential oil of catnip, Nepeta cataria L., contains two isomers of nepetalactone, E,Z-and Z,E-nepetalactone, and was tested for repellent activity to adult male German cockroaches, Blattella germanica (L.), in a choice-test arena. The two isomers of nepetalactone were purified by using preparative thin-layer chromatography and tested for behavioral activity in the choice-test arena. Significant differences due to concentration were detected by analysis of variance, and the responses were compared by least-squared means analysis. The activities of the essential oil and purified isomers were compared with N,NA-diethyl-3-methylbenzamide (DEET) by a paired t-test. E,Z-Nepetalactone was the most active of the compounds tested, being significantly more active to this species than equivalent doses of DEET, the essential oil, or Z,E-nepetalactone. Antennectomized insects showed no response to concentrations that were active against intact insects.
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HOUSEHOLD AND STRUCTURAL INSECTS
Behavioral Activity of Catnip (Lamiaceae) Essential Oil Components
to the German Cockroach (Blattodea: Blattellidae)
CHRIS J. PETERSON, LEAH T. NEMETZ,
1
LEAH M. JONES,
2
AND JOEL R. COATS
3
Pesticide Toxicology Laboratory, Department of Entomology, Iowa State University, Ames, IA 50011
J. Econ. Entomol. 95(2): 377Ð380 (2002)
ABSTRACT The essential oil of catnip, Nepeta cataria L., contains two isomers of nepetalactone, E,Z-
and Z,E-nepetalactone, and was tested for repellent activity to adult male German cockroaches,
Blattella germanica (L.), in a choice-test arena. The two isomers of nepetalactone were puriÞed by
using preparative thin-layer chromatography and tested for behavioral activity in the choice-test
arena. SigniÞcant differences due to concentration were detected by analysis of variance, and the
responses were compared by least-squared means analysis. The activities of the essential oil and
puriÞed isomers were compared with N,N-diethyl-3-methylbenzamide (DEET) by a paired t-test.
E,Z-Nepetalactone was the most active of the compounds tested, being signiÞcantly more active to
this species than equivalent doses of DEET, the essential oil, or Z,E-nepetalactone. Antennectomized
insects showed no response to concentrations that were active against intact insects.
KEY WORDS Blattella germanica, catnip, nepetalactone, repellency
CATNIP,Nepeta cataria L., is well known for its intox-
icating effects on cats. The essential oil of catnip con-
tains the monoterpene-derived iridodial compound
nepetalactone (5,6,7,7a-tetrahydro-4,7-dimethylcy-
clopenta[e]pyran-1-(4aH)-one) (McElvain et al.
1941), which exists in the plant as two isomers, Z,E-
and E,Z-nepetalactone (Fig. 1). The E,Z-isomer is the
more attractive of the two isomers to cats (Bates and
Sigel 1963). Catnip has folk uses as an insect repellent
and some uses have been conÞrmed scientiÞcally.
Nepetalactone vapors were shown to be repellent to
insect species in 13 families (Eisner 1964). Nepeta-
lactone is an important component of the defensive
secretions of the coconut stick insect, Graffea crouani
Le Guillou (Smith et al. 1979), and the lubber grass-
hopper, Romalea guttata (Houttuyn) (Snook et al.
1993). Other essential oils and individual monoterpe-
noids repel German cockroaches, Blattella germanica
(L.) (Inazuka 1982, 1983; Karr and Coats 1988; Coats
et al. 1991), as do various plant extracts (Schefßer and
Dombrowski 1992) and plant products (Appel and
Mack 1989).
In the current study, we describe the isolation and
puriÞcation of the two isomers of nepetalactone and
their behavioral effects against the German cock-
roach. Ethanol and ethyl ether extracts of catnip were
previously reported as being repellent to this species,
but there was no mention of the activity of the isomers
(Bodenstein and Fales 1976). We compared the activity
of the catnip essential oil and the two individual isomers
against N,N-diethyl-3-methylbenzamide (DEET, for-
merly N,N-diethyl-m-toluamide). First synthesized in
the early 1950s (McCabe et al. 1954), worldwide use
of DEET exceeded 200,000,000 persons in 1980 (EPA
1980). DEET can occasionally have severe adverse
effects on mammals (Miller 1982, Roland et al. 1985,
Snyder et al. 1986, Qiu et al. 1998). We tested the effect
of antennectomy on the behavioral response of B.
germanica to doses of extracts and compounds active
to intact B. germanica.
Materials and Methods
Plant Collection and Steam Distillation. The aerial
portions of N. cataria plants were collected from un-
sprayed areas of the Iowa State University campus,
Ames, IA, as needed during the growing season. Plants
not distilled immediately were frozen at Ð80C. Plant
leaves and stems were cut by using scissors, placed into
a 5-liter, three-necked boiling ßask, and steam distilled
according to the method of Pavia et al. (1988). The
collected distillate was washed three times with one
volume each of hexane. The hexane was removed by
using rotary evaporation at 500 mm Hg vacuum at
25C.
Extract Analysis. A portion of the liquid obtained
from rotary evaporation was diluted to 1
l/ml with
hexane and subjected to chromatographic analysis.
Gas chromatographic analyses were conducted on a
Varian 3700 gas chromatograph (Palo Alto, CA) with
a 2-m packed OV-101 column, a nitrogen carrier, an
1
University of WisconsinÐStephens Point, Stephens Point, WI
54481.
2
Millikin University, Decatur, IL 62522.
3
To whom correspondence should be addressed.
0022-0493/02/0377Ð0380$02.00/0 2002 Entomological Society of America
FID detector, an injection temperature of 250C, an
injection volume of 1.5
l, and with an initial column
temperature of 70C ramped at 5C/min to 150Cand
held for 8 min. High-performance liquid chromatog-
raphy (HPLC) was conducted by using a HewlettÐ
Packard 1100 HPLC (Palo Atlo, CA) with a Pirkle
Covalent Phenylglycine hi-chrom preparative column
(25 cm by 10 mm i.d., 5
m S5NH ModiÞed
Shereosorb, Regis Technologies, Morton Grove, IL),
with a mobile phase of 9:1 hexane/ethyl acetate at 2.5
ml/min ßow rate, and detection by using a Spectro-
ßow 757 UV-detector (Chestnut Ridge, NY) at 254 nm.
Separation of Nepetalactone Isomers. The two iso-
mers of nepetalactone were separated by using silica
gel preparative thin-layer chromatography plates (20
by 20 cm, 1,000
m in thickness, Whatman, Hillsboro,
OR) with a solvent system of 19:1 hexane/ethyl ether.
The plates were run seven times and allowed to dry
completely between runs. The products were visual-
ized under 254-nm UV light, and the silica gel was
scraped off the plates and washed with three washings
of ethyl ether. The ether was removed by rotary evap-
oration, and the purity of the isomers was assessed by
using HPLC.
Instrumental Analysis of Isomers. Gas chromatog-
raphy/mass spectroscopy of the nepetalactone iso-
mers was conducted on a Varian 3400 gas chromato-
graph, with a DB-5 ms nonpolar 30-m capillary column
(0.25 mm i.d., J. & W. ScientiÞc, Folsom, CA). The
injector temperature was 250C and the column tem-
perature was held at 150C (isothermal). The gas chro-
matograph was coupled to a Finnigan TSQ 700 triple
quadrupolemass spectrometer (San Jose, CA), with an
electron impact of 70 eV.
Cockroach Bioassay. Adult male B. germanica were
obtained from a colony reared in our laboratory for
several years. Male German cockroaches have been
found by us (data not shown) and others (Schefßer
and Dombrowski 1992) to be more sensitive than
females to olfactory stimuli. The catnip essential oil
and the nepetalactone isomers were dissolved in hex-
ane, and DEET (Aldrich, Milwaukee, WI) was dis-
solved in acetone. A 12.5 cm round Þlter paper was cut
in half. One side was treated with 1 ml of the test
compound solution, and the other side was treated
with either acetone or hexane, depending upon which
solvent was used to dissolve the test material. The
papers were allowed to dry for 2 min before being
placed in a 15 cm petri dish arena. The position of the
treated side (to the right or to the left) was random-
ized by using a random number table. The top of the
petri dish had a hole cut in the center for introduction
of the insect directly into the center of the arena. One
insect at a time was introduced. The hole was stopped
by using a small piece of tape to prevent escape of the
insect. Immediately after the introduction of the in-
sect, the number of seconds it spent on the treated or
untreated side in a total of 300 s (5 min) was timed with
two stopwatches. Filter papers and cockroaches were
used once then discarded. Repellency values were
calculated by subtracting the number of seconds the
insect spent on the treated side from the number of
seconds spent on the untreated side, dividing by the
total number of seconds (300), and then multiplying
that value by 100 to obtain a percentage. Each test was
replicated 10 times. All tests were run between 1000
and 1600 hours (CST) with overhead ßorescent light-
ing at ambient temperature (20Ð25C) and humidity
(50Ð70% RH).
For the tests that used antennectomized cock-
roaches, a razor blade was used to remove the anten-
nae at the scape. The cockroaches were allowed to
recover from the procedure for 24 h before being
exposed to the test compounds by the method out-
lined in the previous paragraph.
SigniÞcance due to concentration was determined
by using ANOVA, and means for each dose were
compared by least-squares means analysis (SAS Insti-
tute 1991) to determine doseÐresponse relationships.
Comparisons between compounds or treatments were
made by using a paired t-test.
Results and Discussion
By using gas chromatography, we determined that
the catnip essential oil contained Z,E-nepetalactone
and E,Z-nepetalactone in a 6:1 ratio, or roughly 85:
15%. Bates and Sigel (1963) reported a ratio of 3:1
Z,E-nepetalactone to E,Z-nepetalactone, or 75:25%.
These isomers together comprised 98% of the steam
distillate, and minor components were not identiÞed.
Mass spectral analysis revealed that the two isomers
are indistinguishable. Z,E-Nepetalactone eluted off
the DB-5 ms column at 2.45 min and showed ions at
m/z 166 [M
] (100%), m/z 123 (78.5%), m/z 109
(46.3%), m/z 95 (58.8%), m/z 81 (62.2%), and m/z 69
(46.7%). E,Z-Nepetalactone eluted off the column at
2.65 min and had the following mass spectrum: m/z 166
[M
] (100%), m/z 123 (99.9%), m/z 109 (51.8%), m/z
95 (66.6%), m/z 81 (67.0%), and m/z 69 (50.2%).
SigniÞcance due to concentration was observed by
two-tailed ANOVA for DEET (F4.83; df 5, 54; P
0.001), Z,E-nepetalactone (F20.00; df 4, 45; P
0.0001), and E,Z-nepetalactone (F41.08; df 2, 27;
P0.0001). SigniÞcance due to concentration was not
seen for the catnip essential oil at the 0.05 two-tailed
signiÞcance level, but was seen at the 0.1 signiÞcance
level (F3.44; df 3, 36; P0.0267). Repellency
values (% SEM) were calculated and means were
compared by using least-squares means analysis (Ta-
ble 1). All DEET concentrations tested at 1,600
g/
cm
2
were not signiÞcantly different from the control
by least-squared means analysis (
0.05). The be-
Fig. 1. Nepetalactone isomers from catnip.
378 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 95, no. 2
havioral response to catnip essential oil was signiÞ-
cantly different from the control at a dose of 800
g/cm
2
. The response to Z,E-nepetalactone was sig-
niÞcantly different from the control at doses of 160
g/cm
2
and higher. The response to E,Z-nepetalac-
tone was signiÞcantly different from the control at all
doses tested (down to 16
g/cm
2
).
Paired t-test comparisons (
0.05, df 9) be-
tween the different compounds at equivalent doses
were made. The response of the cockroaches to catnip
essential oil differed signiÞcantly from DEET at 800
g/cm
2
, and did not differ from it at lower doses. The
response to Z,E-nepetalactone differed from equiva-
lent doses of DEET above 80
g/cm
2
and the response
to E,Z-nepetalactone differed signiÞcantly from
DEET at all concentrations tested, down to 16
g/cm
2
.
The response to Z,E-nepetalactone, which comprised
85% of the essential oil, did not differ signiÞcantly
from the response to catnip essential oil at any of the
concentrations tested. E,Z-Nepetalactone was more
active than the catnip essential oil at 80
g/cm
2
. Both
Z,E-andE,Z-nepetalactone were compared at 80 and
16
g/cm
2
,andE,Z-nepetalactone was signiÞcantly
more active than the Z,E- isomer at both concentra-
tions. Catnip essential oil should be more active than
the Z,E-isomer alone because the oil contains 15% of
the more active E,Z-isomer. This was not observed,
perhaps because the variability inherent in behavioral
tests obscures statistical determination of differences.
Visual examination of the results indicates that the
essential oil may be more active than the Z,E-isomer
at the two lowest doses (80 and 16
g/cm
2
), and more
rigorous testing may statistically reveal the expected
differences.
Antennectomy of adult male cockroaches resulted
in a diminished response to the test compounds
(paired t-test,
0.05, df 9) (Table 2). In the three
comparisons, the amount of time the antennecto-
mized insects spent on either the treated or untreated
side did not differ signiÞcantly by the paired t-test.
This indicates that the chemoreceptors involved in
this behavioral response are probably located on the
antennae.
The results presented herein indicate that catnip
essential oil and the isomers of nepetalactone cause
German cockroaches to spend less time in treated
areas. These compounds may be useful in the devel-
opment of exclusion barriers to prevent entry of in-
sects into sensitive areas; e.g., kitchens, childrenÕs
nurseries, and hospital rooms. Using such compounds
in shipping containers may reduce the incidence of
accidental pest introduction to novel areas. That these
compounds are volatile and the response was olfactory
(rather than contact) may be important in providing
protection over a large area, because the insects will
not have contact with the treated surfaces. Volatility,
however, may shorten the effective time. This prob-
lem may be alleviated by special formulations, such as
microincapsulation, to reduce volatile loss. Using
these compounds as part of a push-pullsystem, re-
pelling the insects out of one area and luring into an
attract-and-kill system in another, also may be possi-
ble.
Acknowledgments
We thank Erin Schneider and Lindsay Searle for help in
the laboratory. We thank the Program for Women in Science
and Engineering at Iowa State University, Ames, IA, and Iowa
State University Instrument Services, Department of Chem-
istry, Iowa State University, Ames, IA. This is journal paper
J-19112 of the Iowa Agriculture and Home Economics Ex-
Table 1. Percentage repellency (SEM) of DEET and catnip
compounds to male B. germanica in a choice-test assay
Test solution Dose (
g/cm
2
)% repellency
SEM
DEET 1,600 58.3 10.5b
800 25.8 9.5a
160 20.4 9.2a
80 15.5 5.4a
16 15.4 5.9a
0 5.2 7.5a
Catnip essential oil
800 55.6 9.8b
160 27.7 13.1ab
80 33.7 15.7ab
16 31.7 8.1ab
0 2.9 3.7a
Z,E-Nepetalactone
800 68.2 5.7b
160 56.8 7.8b
80 15.4 6.9a
16 16.1 7.4a
0 2.9 3.7a
E,Z-Nepetalactone
80 79.4 3.5c
16 46.4 11.0b
0 2.9 3.7a
For each test solution, repellency values followed by the same letter
are not signiÞcantly different by least-squares means analysis (
0.05). Repellency [(no. of seconds spent on untreated side no.
of seconds spent on treated side)/300] 100.
Table 2. Results of behavioral assay of antennectomized male German cockroaches, and paired ttest comparison with nonanten-
nectomized male cockroaches tested at the same concentration
% repellency
a
SEM
Treatment,
g/cm
2
Antennectomized Nonantennectomized Calculated tvalue
1600 DEET 1.7 11.4 58.3 10.5 3.03*
160 Z,E-Nepetalactone 19.8 7.0 56.8 7.8 3.40*
80 E,Z-Nepetalactone 1.3 10.2 79.4 3.5 7.84*
% Repellency [(no. of seconds spent on untreated side no. of seconds spent on treated side)/300] 100.
*, Difference is signiÞcant by two-tailed paired ttest at
0.05, df 9.
April 2002 PETERSON ET AL.: ACTIVITY OF CATNIP COMPONENTS TO B. germanica 379
periment Station, Iowa State University, Ames, IA, project
number 3187.
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Received for publication 19 March 2001; accepted 22 August
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380 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 95, no. 2
... Nepetalactone has also been found to be the major component in the defensive secretions of lubber grasshopper and the coconut stick insect 18 . Besides these compounds the plant also contains other compounds related to different classes of natural products like flavonoids (luteolin 7-O-glucuronide, 7-O-glucurono-glucoside, apigenin 7-O-glucuronide, etc.); phenolic acid (caffeic, rosmarinic acids, gallic acid, etc.) [26][27][28][29][30] ; steroids (ursolic acid, oleanolic acid, β-sitosterol, stigmasterol, β-amyrin, etc.) 27 and terpenoids (1,8-cineole, α-bisbolene, αcitral, β-caryophyllene, β-farnesene, geraniol, α-humulene, αterpineol, etc.) [28][29][30] 32 . Therefore, in this study, the ethno pharmacological review of N. cataria was carried out aimed at providing a detailed precis of the botany, cultivation, ethnomedicinal uses, pharmacological activities and chemical composition of the species. ...
... Nepetalactone has also been found to be the major component in the defensive secretions of lubber grasshopper and the coconut stick insect 18 . Besides these compounds the plant also contains other compounds related to different classes of natural products like flavonoids (luteolin 7-O-glucuronide, 7-O-glucurono-glucoside, apigenin 7-O-glucuronide, etc.); phenolic acid (caffeic, rosmarinic acids, gallic acid, etc.) [26][27][28][29][30] ; steroids (ursolic acid, oleanolic acid, β-sitosterol, stigmasterol, β-amyrin, etc.) 27 and terpenoids (1,8-cineole, α-bisbolene, αcitral, β-caryophyllene, β-farnesene, geraniol, α-humulene, αterpineol, etc.) [28][29][30] 32 . Therefore, in this study, the ethno pharmacological review of N. cataria was carried out aimed at providing a detailed precis of the botany, cultivation, ethnomedicinal uses, pharmacological activities and chemical composition of the species. ...
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... Wagan et al. (2017) reported 49 and 55% repellency by Piper nigrum L. EO delivered at 31.5 μg cm −2 (Piperaceae) against B. germanica nymphs and adults, respectively after 12 hr. Similar effects against B. germanica nymphs and adults were observed when Lamiaceae EOs were used (Peterson et al. 2002). Interestingly, the most abundant component from the Lamiaceae plant (Z, E-nepetalactone from Nepeta cataria L.) achieved a higher level of repellency (68.2%) than the EO (55%) (Peterson et al. 2002). ...
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... Nepetalactone is usually present in the form of 7S diastereoisomers, which can be found in species-specific amounts and ratios [1,5]. Some studies proved that, even though NL isomers differ only in the orientation of a single chemical bond, they still show differential bioactivities, including attractant effects on cats [6], sex pheromone activity in some aphids [7], as well as repellent activities against a variety of insects [8][9][10]. Antimicrobial activities of pure nepetalactones have only rarely been tested [3,11], and differential activity of the two NL isomers was confirmed against Helicobacter pylori [3]. ...
... Further fragmentation of 191 m/z confirmed the presence of quinic acid. Supplementary Figure S4 presents the proposed structural formula and fragmentation pathway of trihydroxy-cinnamoylquinic acid (8). A literature survey revealed that such a compound has not previously been identified in Nepeta species. ...
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Two Balkan Peninsula endemics, Nepeta rtanjensis and N. argolica subsp. argolica, both characterized by specialized metabolite profiles predominated by iridoids and phenolics, are differentiated according to the stereochemistry of major iridoid aglycone nepetalactone (NL). For the first time, the present study provides a comparative analysis of antimicrobial and immunomodulating activities of the two Nepeta species and their major iridoids isolated from natural sources—cis,trans-NL, trans,cis-NL, and 1,5,9-epideoxyloganic acid (1,5,9-eDLA), as well as of phenolic acid rosmarinic acid (RA). Methanol extracts and pure iridoids displayed excellent antimicrobial activity against eight strains of bacteria and seven strains of fungi. They were especially potent against food-borne pathogens such as L. monocytogenes, E. coli, S. aureus, Penicillium sp., and Aspergillus sp. Targeted iridoids were efficient agents in preventing biofilm formation of resistant P. aeruginosa strain, and they displayed additive antimicrobial interaction. Iridoids are, to a great extent, responsible for the prominent antimicrobial activities of the two Nepeta species, although are probably minor contributors to the moderate immunomodulatory effects. The analyzed iridoids and RA, individually or in mixtures, have the potential to be used in the pharmaceutical industry as potent antimicrobials, and in the food industry to increase the shelf life and safety of food products.
... A diversity of biologically active compounds has been isolated from species of Nepeta, such as phenolic acids and their glycosides (rosmarinic acid, gallic acid, caffeic acid), flavonoids and their glycosides (cirsimaritin, salvigenin, luteolin, apigenin), iridoids (nepetalactones), terpenoids (1,8cineole, linalool, β-caryophyllene, germacrene D, parnapimaro, β-amyrin, oleanolic acid, ursolic acid), steroids (β-sitosterol, stigmasterol) etc. (Sharma et al., 2021). Essential oil of the genus also possesses biological activities like insect repellent, cytotoxic activity, antioxidant activity, analgesic, antiinflammatory and CNS depressant activity (Peterson et al., 2002;Suschke et al., 2007;Formisano et al., 2011;Hussain et al., 2012). The project work is aimed at phytochemical investigation and evaluation of biological activities of Nepeta species: Nepeta hindostana (Roth) Haines, Nepeta graciliflora Benth. ...
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Background & Aim: In traditional medicine system, Nepeta species are widely used to reduce chicken pox, tuberculosis, malaria, pneumonia, influenza, measles, stomach disorders, eye complaints, respiratory disorders, asthma, colds, coughs etc. The aim of the present study was to evaluate the chemical composition and biological activities of the essential oils from three species of genus Nepeta viz: Nepeta hindostana (Roth) Haines (NHO), Nepeta graciliflora Benth (NGO) and Nepeta cataria L (NCO). Experimental: The essential oils were analysed by the combination of GC and GC-MS. Antioxidant activity was tested by using reducing power assay, metal chelating of Fe2 +assay, and DPPH radical scavenging assay. In-vitro antinflammatory activity was evaluated using albumin denaturation assay and antidiabetic activity was determined by using α-amylase assay. Results: The major components present in NCO, NHO and NGO were cisnepetalactone (69.78%), β-farnesene (43.41%) and sesquisabinene (28.75%), respectively. NCO showed the highest percentage inhibition of DPPH radical (IC50=5.89 µl/ml) followed by NHO (IC50=8.63 µl/ml) and then NGO (IC50=13.81 µl/ml). In terms of reducing power assay and metal chelating of Fe2+ assay, the highest antioxidant activity was also shown by NCO. Among the tested essential oil, NCO showed highest in-vitro anti-inflammatory potential (IC50 18.463±0.14 µg/ml) followed by NGO and NHO with IC50 22.035±0.11 µg/ml and 26.17±0.14 µg/ml, respectively. NHO showed maximum antidiabetic activity with IC50 8.92±0.10 µg/ml of α-amylase. Recommended applications/industries: On the basis of present research work it is marked that the essential oil of Nepeta hindostana (Roth) Haines, Nepeta graciliflora Benth. and Nepeta cataria L. is a potent antioxidant, anti-inflammatory and anti-diabetic agent indicating their potentiality in the field of food, pharmaceutical and cosmetic industry
... GC/EAG analyses of extracts from the airborne collection of calling oviparae on male antennae of soybean aphids revealed two EAG active peaks (Fig. 1). The GC-MS analyses of the same extract determined the mass spectra of peak A: 168 (81), 135 (Peterson et al. 2002). The mass spectrum of compound A with M r 168 was similar to that of (1R,4aS,7S,7aR)-nepetalactol, which has been reported as a pheromone component used by several aphid species . ...
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The newly invasive soybean aphid, Aphis glycines Matsumura, has seriously threatened soybean production in North America, after having spread to Ͼ20 states in the United States and several southern provinces of Canada. Control of A. glycines has focused on applications of insecticides, which are not a long-term solution to soybean aphid pest management. In autumn, soybean aphids start producing alate females (gynoparae) that search for their overwintering host plants, the common buckthorn, Rhamnus cathartica. The gynoparae then produce pheromone-emitting wingless female offspring (oviparae) that attract male aphids. In this study, we report the chemical identiÞcation of the soybean aphid sex pheromone using gas chromatographyÐ electroantennogram, gas chromatog-raphyÐmass spectrometry, and nuclear magnetic resonance spectroscopy. Behavioral activities of males and gynoparous females in the Þeld were also characterized. The potential applications using formulations containing speciÞc soybean aphid pheromone compositions for reducing overwintering populations are discussed.
... Additional studies showed that N. cataria essential oils containing various nepetalactone stereoisomers where comparable to DEET at repelling mosquitoes, while offering better spatial repellency (Bernier et al. 2005;Peterson and Coats 2011;Schultz et al. 2004). In addition to better spatial repellency, catnip oil has also been shown to be relatively safer when compared to DEET, picaridin and pmenthane-3,8-diol, mosquito repellents approved by the U.S. Environmental Protection Agency (Peterson et al. 2002;Zhu et al. 2009Zhu et al. , 2012. ...
Chapter
Catnip (Nepeta cataria L.), a popular aromatic herb used as a traditional medicine is more widely recognized for its use in the pet toy industry due to the behavioral effects it elicits on cats and other felids. A major interest in catnip is also due to its repellent activity against arthropods. Essential oil of catnip is an effective repellent against several species of mosquitoes, flies, ticks, mites, and other disease vectors, with results comparable to DEET. Both the repellency to arthropods and the characteristic effects on cats are mainly attributed to nepetalactone, a bicyclic oxygenated monoterpene in the essential oil of catnip. While catnip is grown as a garden herb and in the open field for dried biomass and essential oil, the lack of improved genetic materials makes it difficult for North American growers to expand production and ensure adequate product supply. The present chapter provides an overview of the recent advances in breeding, biochemistry, production systems, biological activities and potential new uses of N. cataria and other Nepeta species in North America.
... The catnip essential oil obtained from the leaves is the basis for its long history of use as a cat toy filler and medicinal tea (8,10). Recently, researchers have shown that the nepetalactones found in catnip were 10 times more effective at repelling mosquitoes that diethyl-meta-toluamide (DEET), the compound used in most bug repellents (12). ...
Article
Adventitious rooting and subsequent development of rooted cuttings were evaluated for terminal, single-node, and tip cuttings of catnip (Nepeta cataria L.). During an eight-week production period, cuttings were treated with indole-3-butyric acid (IBA) at 0, 1, 3, and 8 g/kg (0, 1000, 3000, and 8,000 ppm), rooted for one to four weeks, and then grown in the greenhouse for four to seven weeks. At harvest, a first experiment showed that terminal cuttings propagated for four weeks accumulated less shoot dry weight (24 g) than cuttings propagated for two (36 g) or three (31 g) weeks. Terminal cuttings treated with 3 g/kg of IBA and propagated for four weeks had the highest root dry weight, which averaged 12.1 g. In the second experiment, length of the longest shoot and primary root and the number of roots and shoots were greater in single-node cuttings propagated for two or three weeks than those propagated for one week. A third experiment revealed that the development of primary roots in single-node and tip cuttings was similar during a 15-day rooting period.
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Catmint (Nepeta spp., Lamiaceae) contains about 150 species and is largely in the horticultural trade as an ornamental. Catnip (N. cataria L.), a short-lived perennial herbaceous plant, is perhaps the best-known species, long recognized as the plant that induces a state of euphoria and stupor in domesticated cats (Clapperton et al. 1994; Herron 2003). Research has shown that the essential oil of catnip, containing nepetalactones, is largely responsible for the plants biological activities including its application as a cat attractant, insect pheromone, and insect repellent (Peterson and Coats 2001; Peterson et al. 2002; Baranauskiene et al. 2003; Herron 2003; Peterson and Ems-Wilson 2003, Chauhan et al. 2005; Amer and Mehlhorn 2006). Limited commercial crop area of catnip has been centered in the Western US and Canada with most dedicated to the production of essential oils or for seed production; while smaller farms have been focused on the production of dry leaves for catnip toys and herbal uses. Despite the increased interest in this plant as a natural source of insect repellent activity, few studies have documented the horticultural attributes and yield potential. As a source of essential oil, the production of catnip on a large-scale presents numerous challenges in that the available varieties are relatively low biomass producers and produce low yields of essential oil which is difficult to efficiently separate and recover. Catnip is also sensitive to winter injury, handling and cutting and has been observed in many locations to re-grow poorly after the first season. As a result, catnip is also grown horticulturally as an annual rather than a perennial. We report on field studies that were conducted to: (1) evaluate the yield potential of catnip in New Jersey, and (2) ascertain yield differences from available sources or lines of catnip relative to their growth and essential oil yields. We also report on our ongoing selection program that was initiated in 1996 to identify and develop new novel types of catnip and higher yielding lines rich in nepetalactones.
Article
Biological tests with Thymus vulgaris against both third and fifth instar larvae of Thaumetopoea pityocampa showed positive correlation between the used doses and mortality after 24 h of application. Treatment against third instars larvae with doses 0.005–0.04 ml L−1 gave 40.97–100% mortalities in vitro condition, and treatment with doses 0.1–0.5 ml L−1 gave 53.85 and 100% mortalities in vivo condition. In addition, similar effect of this natural insecticide is observed against fifth instars larvae with mortality rate varying between 36.11 and 100% at doses of 0.02–0.1 ml in vitro and between 33.96 and 100% mortality with doses of 0.3–1.2 ml in vivo. Bioassay with Lavandula angustifolia against third instar larvae in vitro condition showed between 29.86 and 100% mortality rate, but with high doses between 0.01 and 0.05 ml L−1 compared to T. vulgaris. Furthermore, the mortality recorded in vivo is 73.35% with dose of 1 ml L−1. Whereas the essential oil of L. angustifolia is the least toxic against fifth instar larvae of Thaumetopoea pityocampa with 37.08% at a dose of 1.5 ml L−1 in vivo and 65.97% mortality at a dose of 0.12 ml L−1 in vitro. Histologically, the effect of these essential oils has resulted in a necrosis and degeneration of the intestinal cells, as well as a general destruction of the hair and skin of treated larvae compared to untreated caterpillars. In accordance with these results, it would be possible to use essential oil of T. vulgaris as an effective biological alternative against the larvae of T. pityocampa. The chemical analyses obtained by GC–MS of T. vulgaris essential oil enabled us to identify 35 chemical compounds of which Carvacrol (71%) is the most dominant, whereas for L. angustifolia there are 36 chemical compounds of which we have identified two dominant chemical compounds, Lynalol (37%) and Linalool acetate (25%).
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Cockroaches are important sanitary pests and very difficult to control worldwide. With public concern about traditional insecticides, cockroach control agents should be environmentally friendly, highly efficient, and economical. In this article, 12 essential oils were screened to test their repellent effect against Blattella germanica. To develop essential oils as repellent agents, the oils were further examined in binary synergistic combinations. Ilex chinensis Sims (Sapindales: Aquifoliaceae) oil, Lavandula spp (Tubiflorae: Labiatae) oil, and Elsholtzia ciliata (Thunb.) Hyland (Tubiflorae: Labiatae) oil showed excellent repellent activities with lower RD50 (repellency dose for 50% of treated adults) values of 218.634, 154.590, and 223.989 µg/cm2, respectively, compared to those of other oils and the positive control. The I. chinensis oil and E. ciliata oil (weight ratio of 1:1.41) combination also displayed a remarkable synergistic effect against B. germanica. Their cotoxicity coefficient was 214.4. The major chemical constituents in E. ciliata and I. chinensis oils were respectively 3,7-dimethyl-1, 6-octadien-3-ol and methyl salicylate. The binary oil mixtures were formulated as a sustained release agent with γ-CD. The optimal preparation should be an 8:1 ratio of γ-CD to oils, with a 1 h stirring time, 50°C stirring temperature, and 1:12 ratio of γ-CD to ddH2O. The results of this study suggest that sustained release of binary oil-γ-CD exhibited a prolonged repellent activity (10 h) against B. germanica. This sustained-release agent could be further investigated and developed as a novel repellent preparation.
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: d-Limonene (p-mentha-1,8-diene) is a monocyclic monoterpenoid found in citrus oils. The spectrum of insecticidal activity of d-limonene was examined by using the German cockroach, Blattella germanica (L.), house fly, Musca domestica L., rice weevil, Sitophilus oryzae (L.), and western corn rootworm, Diabrotica virgifera virgifera leconte. bioassays were performed to determine topical, fumigant, oral, repellent, residual, ovicidal, and larvicidal activities. The material was slightly toxic topically to German cockroaches and house flies and was synergized with piperonyl butoxide. High concentrations of vapors caused mortality in German cockroaches and rice weevils. Oral administration did not result in mortality to either adult or nymphal cockroaches but accelerated growth in nymphs. Repellent activity against German cockroaches was noted at high concentrations. No residual activity was observed on any of four surface types exposed to adult German cockroaches. d-Limonene inhibited western corn rootworm egg hatch at high concentrations and showed moderate toxicity in soil against third-instar western corn rootworm larvae. These findings indicate that the insecticidal properties of d-limonene are limited. © 1988, Pesticide Science Society of Japan. All rights reserved.
Article
62種のモノテルペノイドのチャバネゴキブリに対する忌避性を, 試験管法およびビーカー法を用いて調べた. その結果, 鎖状モノテルペノイドでは (-)-linalool および nerol に, 単環状モノテルペノイドでは (-)-carvone, (+)-pulegone, (+)-isopulegol および (+)-pulegol に強い嗅覚的忌避性を認めた. しかし, 双環状モノテルペノイドおよびイソプロピル基を有していない単環状モノテルペノイドでは弱い忌避性のみを認めた.なお, モノテルペノイドの化学構造と忌避性との関係については, 分子の大きさ, かたち, 蒸気圧との明らかな相関性を認めなかったが, 官能基の種類およびその位置との間に明らかな相関性を認めた. すなわち, 単環状モノテルペノイドにおいてシクロヘキサン環の4位のイソプロピル基および1位のメチル基, C1・C2, C1・C6, C4・C8およびC8・C9の二重結合, 3位および8位の水酸基などの官能基群が, 活性増大に寄与しているとわかった. とくに, 4位のイソプロピル基の立体配置が, 活性増大に大きく寄与していると考えられる. 一方, 水酸基をアセチル化すると, 活性が著しく低下することを認めた.また, 鎖状モノテルペノイドにおいても, 活性に対し官能基に同一傾向を認め, 単環状モノテルペノイドとともに, 触角の化学受容器に対し同一の相互作用をして, 活性が発現していると推定された.
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Two new techniques to evaluate repellency against the German cockroach (Blattella germanica L.) were devised, a test tube method and a beaker method. The former estimates the repellent impact on a roach attracted by roach excrement on a paper filter. The latter, estimating effectiveness by changes in the number of roaches in a beaker, is an excellent method for evaluating olfactory repellency. Among the reference compounds, α-naphthoquinone, 2-hydroxyethyl-n-octylsulfide and naphthalene were effective in the test tube method, however their 2% sublimates were not effective in the beaker method. Those compounds were thus not judged as promising olfactory repellents. The oils of Japanese mint (Mentha arvensis) and spearment (native and Scotch type, Mentha specata) were the most effective among 92 such substances. Strong mosquito repellents such as oils of citronella, lavender, rosemary, and penny royal had little or no effect against the cockroach.
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Adults of the lubber grasshopper (Romalea guttata) secrete increased amounts of catechol from their defensive glands when fed diets containing only catnip leaves (Nepeta cataria). Model compound bioassays showed that these insects were able to sequester and biomagnify simple phenols, such as catechol and hydroquinone, in their defense gland secretions. Excessive catechol secretions from caffeic acid-fortified diets indicated metabolic pathways exist to perform efficiently more complex biochemical conversions. Reverse-phase HPLC of methanol extracts of catnip revealed only one major caffeoyl-polyphenol as a possible precursor for the observed elevated catechol secretions, when this plant is fed to lubbers. The compound was shown to be caffeoyltartronic acid (CTA). During analysis of CTA by probe-MS or gas chromatography (of its silylated derivative), CTA decomposed by loss of carbon dioxide to form caffeoylglycolic acid (CGA), making identification by these methods ambiguous. Only fast atom bombardment mass spectrometry (FAB-MS, negative mode) gave a true molecular weight. Groundivy (Glecoma hederacea), a relative of catnip, was also shown to contain CTA. The mung bean (Phaseolus radiatus=Vigna radiata), a species totally unrelated to catnip, is the only other reported plant source of CTA. Catnip leaves were found to contain about twice as much CTA as mung bean leaves.
Article
Zusammenfassung Die beiden stereoisomeren Nepetalactone wurden durch Gaschromatographie getrennt. Es wurde gezeigt, dass dastrans-cis-Isomere (II) auf Katzen anziehend wirkt. Dascis-trans-Isomere (I), das etwa 75% der Mischung darstellt, ist bedeutend weniger aktiv, möglicherweise völlig inaktiv.
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Thirty-three N,N-diethylamides, chiefly of aromatic acids, were prepared for testing as insect repellents. The most promising mosquito repellents of this series were derived from the ring-substituted benzoic acids. Some structural correlations are discussed.
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Catnip (nepetalactone) is closely related chemically to certain cyclopentanoid monoterpenes recently isolated from insects, and it shares with some of these terpenes an ability to repel insects. It is suggested that the adaptive function of catnip is to protect the plants that produce it against phytophagous insects.
Article
Repellency and toxicity of milled aromatic eastern red cedar, Juniperus virginiana L., flake board were evaluated against the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), the American cockroach, Periplaneta americana (L.) (Dictyoptera: Blattidae), and the smokybrown cockroach, Periplaneta fuliginosa (Serville) (Dictyoptera: Blattidae). Cedar flake board was repellent to B. germanica in Ebeling choice-box tests but was not repellent to either P. americana or P. fuliginosa. The degree of repellency forB. germanica increased linearly (P < 0.05) with surface area of cedar in the choice box, but in no case were >63% of the cockroaches repelled. Cedar boards did not cause cockroach mortality in continuous-exposure tests. Cedar flake boards may be useful as a repellent in indoor cockroach integrated pest management.