U.S. patent application number 15/551782 was filed with the patent office on 2018-03-08 for insect repellent.
This patent application is currently assigned to Kao Corporation. The applicant listed for this patent is Kao Corporation. Invention is credited to Takao NAKAGAWA.
Application Number | 20180064109 15/551782 |
Document ID | / |
Family ID | 56788574 |
Filed Date | 2018-03-08 |
United States Patent
Application |
20180064109 |
Kind Code |
A1 |
NAKAGAWA; Takao |
March 8, 2018 |
Insect Repellent
Abstract
Provided is an insect repellent having excellent repellency and
being highly safe. An insect repellent comprising, as an active
ingredient, at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
Inventors: |
NAKAGAWA; Takao; (Sumida-ku,
Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kao Corporation |
Chuo-ku, Tokyo |
|
JP |
|
|
Assignee: |
Kao Corporation
Chuo-ku, Tokyo
JP
|
Family ID: |
56788574 |
Appl. No.: |
15/551782 |
Filed: |
February 23, 2016 |
PCT Filed: |
February 23, 2016 |
PCT NO: |
PCT/JP2016/055255 |
371 Date: |
August 17, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01N 37/10 20130101;
A01N 31/02 20130101; A01N 31/04 20130101; A01N 37/08 20130101; A01N
37/02 20130101; A01N 31/16 20130101; A01N 37/06 20130101 |
International
Class: |
A01N 37/10 20060101
A01N037/10; A01N 31/16 20060101 A01N031/16; A01N 31/04 20060101
A01N031/04; A01N 31/02 20060101 A01N031/02; A01N 37/08 20060101
A01N037/08; A01N 37/02 20060101 A01N037/02; A01N 37/06 20060101
A01N037/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 26, 2015 |
JP |
2015-036217 |
Claims
1. An insect repellent comprising, as an active ingredient, at
least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
2. A carbon dioxide response inhibitor for an insect, comprising,
as an active ingredient, at least one selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
3. The insect repellent according to claim 1, wherein the insect is
at least one selected from the group consisting of mosquitoes,
flies, black flies, and stable flies.
4. The insect repellent according to claim 3, wherein the insect is
a mosquito.
5. A method for repelling an insect, comprising applying at least
one selected from the group consisting of 2-methoxy-4-propylphenol,
ethyl 2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate onto the skin of a mammal.
6. A method for repelling an insect, comprising attaching or
holding at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, and ethyl 2-ethylhexanoate,
trans-2-hexenyl acetate on an apparel article directly or
indirectly contacting the skin.
7. A method for repelling an insect, comprising spreading at least
one selected from the group consisting of 2-methoxy-4-propylphenol,
ethyl 2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate in a defined space.
8.-11. (canceled)
12. The carbon dioxide response inhibitor for an insect according
to claim 2, wherein the insect is at least one selected from the
group consisting of mosquitoes, flies, black flies, and stable
flies.
13. The carbon dioxide response inhibitor for an insect according
to claim 12, wherein the insect is a mosquito.
Description
FILED OF THE INVENTION
[0001] The present invention relates to an insect repellent having
insect repellency.
BACKGROUND OF THE INVENTION
[0002] Most hematophagous insects cause infections among humans and
animals via transmission of a pathogen, or cause skin inflammation.
In particular, mosquitoes carry serious diseases, such as Dengue
fever, Zika fever, yellow fever, encephalitis, and malaria, to
humans, and are thus hygienically very harmful insects.
[0003] Such insects each have a sophisticated chemoreception system
including a heat sensor to sense the body temperature of an animal,
a taste receptor to sense taste, an olfactory receptor to sense
volatile substances such as body odor, and a carbon dioxide
receptor to sense carbon dioxide, which is a highly-volatile
substance, and exhibit a wide variety of behaviors. For example,
female mosquitoes before egg production are known to trace carbon
dioxide expired by an animal and the body odor to approach the
animal for the blood, detect the targeted animal by sensing the
body temperature with the heat sensor, and suck the blood.
[0004] In recent years, a means to repel such insects by causing a
change in the chemoreception system and disabling the cognitive
sense of the insect has been devised. Substances acting on the
olfactory receptor, such as N,N-diethyl-3-methylbenzamide (DEET)
and p-menthane-3,8-diol (PMD), have been used as a repellent.
[0005] However, due to uncomfortable odor and high skin
permeability, DEET has problem in that its use by infants and
individuals with sensitive skin is restricted and the duration is
only 2 to 3 hours.
[0006] It is reported that natural essential oils such as lemon
eucalyptus oil, lemongrass oil, orange oil, and cassia oil have
insect-repelling effect (e.g., Patent Literature 1). However, their
repelling effect is not necessarily satisfactory, and thus
insufficient for practical use.
[0007] [Patent Literature 1] JP-A-2002-173407
SUMMARY OF THE INVENTION
[0008] The present invention relates to the following 1) to 9).
[0009] 1) An insect repellent comprising, as an active ingredient,
at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
[0010] 2) A carbon dioxide response inhibitor for an insect,
comprising, as an active ingredient, at least one selected from the
group consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
[0011] 3) A method for repelling an insect, comprising applying at
least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate onto the skin of a mammal.
[0012] 4) A method for repelling an insect, comprising attaching or
holding at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, and ethyl 2-ethylhexanoate,
trans-2-hexenyl acetate on an apparel article directly or
indirectly contacting the skin.
[0013] 5) A method for repelling an insect, comprising spreading at
least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2 ethylhexanoate, and
trans-2-hexenyl acetate in a defined space.
[0014] 6) Use of at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for producing an insect repellent.
[0015] 7) Use of at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
isocyclocitral, 9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl
2-ethylhexanoate, and trans-2-hexenyl acetate for producing a
carbon dioxide response inhibitor for an insect.
[0016] 8) Use of at least one compound selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for repelling an insect.
[0017] 9) Use of at least one compound selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for inhibiting the carbon dioxide response
of an insect.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention relates to providing an insect
repellent having excellent repellency and being highly safe.
[0019] The present inventors searched for a material capable of
inhibiting the nerve response of an insect to a carbon dioxide
stimulus by using an electrophysiological method, and found that
specific fragrance compounds have excellent carbon dioxide
response-inhibiting activity, and are thus useful for an insect
repellent.
[0020] The present invention can provide an insect repellent which
exhibits excellent repelling effect by inhibiting the carbon
dioxide response of an insect, differs in a mechanism from those of
common repellents such as DEET and PMD, and is highly safe.
[0021] Each of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate in the present invention (hereinafter, also
referred to as "the compound according to the present invention")
is a compound known as a fragrance, and commercially available as
follows. [0022] 2-methoxy-4-propylphenol: Sigma-Aldrich Co., LLC.
[0023] 9-decen-1-ol: Sigma-Aldrich Co., LLC. [0024] 1-octen-3-ol:
Sigma-Aldrich Co., LLC. [0025] 1-decanol: Sigma-Aldrich Co., LLC.
[0026] ethyl 2-ethylhexanoate (IROTYL): Kao Corporation [0027]
trans-2-hexenyl acetate: Sigma-Aldrich Co., LLC. [0028] ethyl
2-cyclohexylpropionate (POIRENATE): Kao Corporation [0029] ethyl
phenylacetate: Tokyo Chemical Industry Co., Ltd. [0030]
2,4,6-trimethyl-3-cyclohexene-1-methanol (isocyclogeraniol):
International Flavors & Fragrances (IFF) Inc.
[0031] In the present invention, one of these compounds may be used
singly, or two or more thereof may be used in a mixture.
[0032] The insect intended in the present invention is not limited
and may be any insect having a carbon dioxide reception response
system, and the insect may be hematophagous or non-hematophagous.
Example of such insects include mosquitoes (female) such as
northern house mosquitoes, Culex tritaeniorhynchus, yellow fever
mosquitoes, Asian tiger mosquitoes, and Chinese malaria mosquitoes;
flies such as houseflies, false stable flies, little house flies,
blow flies, flesh flies, seed-corn flies, onion flies, fruit flies,
vinegar flies, moth flies, and tsetse flies; horseflies; black
flies; stable flies; biting midges; and chironomids. Among them,
mosquitos, flies, black flies, and stable flies are preferred.
[0033] As demonstrated in Examples later, the compound according to
the present invention inhibits the carbon dioxide response of an
Asian tiger mosquito at a neural level to inhibit the seeking
behavior of the mosquito for the human body. Thus, the compound
according to the present invention can serve as an insect repellent
or carbon dioxide response inhibitor for an insect (hereinafter,
simply referred to as "carbon dioxide response inhibitor"), and can
be used for producing an insect repellent or carbon dioxide
response inhibitor. In other words, the compound according to the
present invention can be used for repelling an insect and
inhibiting the carbon dioxide response.
[0034] Here, "repelling an insect" refers to preventing an insect
from approaching to an object or forcing an insect to avoid an
object, and "inhibiting the carbon dioxide response of an insect"
refers to inhibiting the seeking behavior of an insect for a carbon
dioxide source by disabling or reducing the carbon dioxide
reception response of the insect to inhibit the cognitive sense to
the carbon dioxide, and the concept differs from having
insecticidal ability to exterminate an insect.
[0035] The carbon dioxide response of an insect can be measured
through investigation of a nerve firing pattern of the sensory hair
with electrodes inserted therein in response to a carbon dioxide
stimulus by using known single sensillum recording (Nature 461,
277-281 (10 Sep. 2009)).
[0036] The insect repellent or carbon dioxide response inhibitor
according to the present invention can repel an insect, for
example, through applying it onto the skin of a mammal such as a
human, allowing it to attach or be held on an apparel article
directly or indirectly contacting the skin, such as a cloth and an
accessory, or spreading (including evaporating and volatilizing) it
in a defined space such as a room interior and a car interior, and
can be appropriately blended with additional components such as a
solvent and an additive for formulation into a composition to
prepare a formulation. Alternatively, the insect repellent or
carbon dioxide response inhibitor according to the present
invention may be used for a material for imparting insect
repellency to an external preparation for cutaneous administration,
a cleaning agent, a skin cosmetic, a hair cosmetic, a textile
softener, a fabric treatment agent, or the like.
[0037] The quantity of the compound according to the present
invention to be blended in the above composition is preferably
0.001% by mass or more, more preferably 0.01% by mass or more, even
more preferably 0.1% by mass or more and preferably 80% by mass or
less, more preferably 40% by mass or less, even more preferably 10%
by mass or less, or preferably from 0.001 to 80% by mass, more
preferably from 0.01 to 40% by mass, even more preferably from 0.01
to 10% by mass, and further more preferably from 0.1 to 10% by
mass, relative to the total quantity of the composition, although
it varies depending on the dosage form.
[0038] The type of a solvent or additive may be appropriately
selected in accordance with the mode of use or intended use of the
insect repellent or carbon dioxide response inhibitor, and examples
of the solvent include lower alcohols such as methanol, ethanol,
and propanol; and water.
[0039] Examples of the additive include additives commonly used for
various chemical products and cosmetics, specifically, surfactants,
organic solvents, oily components, moisturizing agents, powders,
solubilizers, thickeners, resins, cleaning agents, preservatives,
UV absorbers, inorganic substances, fragrances, pigments,
deodorants, essential oils, pharmaceutical agents, plant extracts,
and other repellents.
[0040] The dosage form of the insect repellent or carbon dioxide
response inhibitor according to the present invention can be
appropriately set in accordance with the mode of use, and may be
any of a liquid, a cream, a lotion, an emulsion, a gel, an
ointment, a powder, a granule, a spray, and an aerosol spray,
etc.
[0041] In the case that the insect repellent or carbon dioxide
response inhibitor according to the present invention is spread in
a defined space, it is suitable to employ a method in which the
insect repellent or carbon dioxide response inhibitor supported on
a carrier or dissolved in a solvent is packed in a container with a
liquid-absorbing wick and heated or evaporated through air blow, or
a method in which the insect repellent or carbon dioxide response
inhibitor supported on a carrier is evaporated into the space at
normal temperature. In this case, examples of carriers to support
the insect repellent or carbon dioxide response inhibitor include
natural fibers such as pulp, cotton, wool, linen, and silk;
synthetic fibers such as polypropylene, polyethylene, polyamide,
polyethylene terephthalate, polybutylene terephthalate,
polysulfone, rayon, methacrylic resin, and glass fiber; and porous
materials such as zeolite, talc, white carbon, diatomaceous earth,
lime, silica gel, and activated carbon.
[0042] Examples of the method for allowing the insect repellent or
carbon dioxide response inhibitor according to the present
invention to attach or be held on an apparel article include a
method in which the insect repellent or carbon dioxide response
inhibitor is applied onto an intended article, a method in which
the insect repellent or carbon dioxide response inhibitor is
blended in a textile softener and allowed to attach or be held in
treatment with the softener, and a method in which a fabric base
material which has been treated with the insect repellent or carbon
dioxide response inhibitor in advance to impart insect repellency
is used for production of an intended article.
[0043] In relation to the above-described embodiments, the
following modes are disclosed in the present invention.
[0044] <1> An insect repellent comprising, as an active
ingredient, at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
[0045] <2> A carbon dioxide response inhibitor for an insect,
comprising, as an active ingredient, at least one selected from the
group consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate.
[0046] <3> The insect repellent according to <1> or the
carbon dioxide response inhibitor for an insect according to
<2>, for at least one insect selected from the group
consisting of mosquitoes, flies, black flies, and stable flies.
[0047] <4> The insect repellent or carbon dioxide response
inhibitor for an insect according to <3>, wherein the insect
is a mosquito.
[0048] <5> A method for repelling an insect, comprising
applying at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate onto the skin of a mammal.
[0049] <6> Use of at least one selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for producing an insect repellent.
[0050] <7> Use of at least one selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, isocyclocitral,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for producing a carbon dioxide response
inhibitor for an insect.
[0051] <8> Use of at least one compound selected from the
group consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for repelling an insect.
[0052] <9> Use of at least one compound selected from the
group consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate for inhibiting the carbon dioxide response
of an insect.
[0053] <10> The insect repellent or carbon dioxide response
inhibitor for an insect according to <1> to <4>,
wherein the content of the active ingredient in the composition is
preferably 0.001% by mass or more, more preferably 0.01% by mass or
more, even more preferably 0.1% by mass or more and preferably 80%
by mass or less, more preferably 40% by mass or less, even more
preferably 10% by mass or less, or preferably from 0.001 to 80% by
mass, more preferably from 0.01 to 40% by mass, even more
preferably from 0.01 to 10% by mass, and further more preferably
from 0.1 to 10% by mass.
[0054] <11> A method for repelling an insect, comprising
attaching or holding at least one selected from the group
consisting of 2-methoxy-4-propylphenol, ethyl
2-cyclohexylpropionate, ethyl phenylacetate,
2,4,6-trimethyl-3-cyclohexene-1-methanol, 9-decen-1-ol,
1-octen-3-ol, 1-decanol, and ethyl 2-ethylhexanoate,
trans-2-hexenyl acetate on an apparel article directly or
indirectly contacting the skin.
[0055] <12> A method for repelling an insect, comprising
spreading at least one selected from the group consisting of
2-methoxy-4-propylphenol, ethyl 2-cyclohexylpropionate, ethyl
phenylacetate, 2,4,6-trimethyl-3-cyclohexene-1-methanol,
9-decen-1-ol, 1-octen-3-ol, 1-decanol, ethyl 2-ethylhexanoate, and
trans-2-hexenyl acetate in a defined space such as a room interior
and a car interior.
EXAMPLES
Example 1
Reference Example: Evaluation of Carbon Dioxide Response-Inhibiting
Effect
[0056] In accordance with a method described in a literature
(Nature 461, 277-281 (10 Sep. 2009)), evaluation was performed as
follows.
(1) Preparation of Asian Tiger Mosquitoes
[0057] Asian tiger mosquitoes grown from eggs purchased from
Sumitomo Technoservice Corporation were used. A transparent plastic
pan is filled with water to a depth of approximately 1 cm, and a
filter paper on which the eggs had been deposited was put therein.
The larvae were fed with tropical fish feed (TetraMin) every day.
After approximately 1 week, the pupae were collected with a
dropper, and transferred into a 29 mL plastic cup, and the cup was
placed in a netted cage. The adults were fed with 10% by mass of
sucrose contained in a 25 mL plastic tube. The males and females
were kept together in one cage and allowed to mate for 5 days after
eclosion. After 5 days of captivity, the adults were collected with
an insect aspirator and anesthetized on ice for 5 minutes, and
visually sorted into males and females to collect only the females.
The wings and legs were removed from each female mosquito tinder
anesthesia, and the female mosquito was pushed onto a double-sided
adhesive tape pasted on a microscope slide with the back on the
tape and thus fixed thereto, and the antennae and maxillary palpi
were positioned so as to achieve the accessibility of
electrodes.
(2) Preparation of Electrodes for Recording Nerve Response
[0058] A 1 mol/L aqueous solution of potassium hydroxide was
injected into a 50 mL syringe, and the syringe was horizontally
fixed to a magnet stand with a clamp. A tungsten wire fixed to an
electrode holder was horizontally inserted into the syringe, and
polished by electrolysis under microscopic observation. A current
was supplied from an AC power source to the syringe through the
electrode holder via crocodile clips.
(3) Recording of Nerve Response
[0059] The Asian tiger mosquito prepared on a microscope slide was
set under a microscope, and positioned so that the antennae were at
the center of the view through a .times.10 objective lens. A
reference electrode was inserted in the eye of the insect. A
pipette for providing an olfactory stimulus was placed near the
maxillary palpi, and the objective lens was replaced with a
.times.100 objective lens. The recording electrode was brought
close to the sensory hair, and carefully inserted into the sensory
hair with a micromanipulator. The peg-like shape of the carbon
dioxide-sensitive sensory hair of an Asian tiger mosquito can be
confirmed under microscopic observation. After insertion of the
electrode into the sensory hair, the spontaneous nerve firing
pattern was investigated. Carbon dioxide the concentration of which
had been adjusted to 0.1% was fed to an olfactory stimulation
apparatus via a silicone tube to stimulate the maxillary palpi for
1 second, and the carbon dioxide response was investigated.
(4) Evaluation of Carbon Dioxide Response-Inhibiting Effect
[0060] The concentration of each of the fragrances listed in Table
1 was adjusted to 1% with paraffin oil, and the resultant was used
as a sample. On a filter paper (3 mm.times.50 mm) 15 .mu.L of the
sample was dropped, and the filter paper was inserted in a Pasteur
pipette. The Pasteur pipette was connected to a stimulation
apparatus via a plastic tube, and olfactory stimulation was
performed for 1 second while the response to carbon dioxide in the
air was monitored, and the carbon dioxide response-inhibiting
effect was evaluated. The number of nerve firings in 1 second after
stimulation with paraffin oil as a solvent and the number of nerve
firings in 1 second after stimulation with each sample were
counted, and the ratio was used for evaluation of the
response-inhibiting effect (N=1).
Inhibitory rate (%)=100.times.([number of firings after stimulation
with paraffin oil-number of firings after stimulation with
sample]/[number of firings after stimulation with paraffin oil])
(Equation 1)
[0061] Table 2 shows the results. The compounds according to the
present invention inhibited the carbon dioxide response of an Asian
tiger mosquito at a neural level.
TABLE-US-00001 TABLE 1 Name Distributor 2-Methoxy-4-propylphenol
SIGMA-ALDRICH CO., LLC. 9-Decen-1-ol SIGMA-ALDRICH CO., LLC.
1-Octen-3-ol SIGMA-ALDRICH CO., LLC. 1-Decanol SIGMA-ALDRICH CO.,
LLC. Ethyl 2-ethylhexanoate ("IROTYL" (R)) Kao Corporation
trans-2-Hexenyl acetate SIGMA-ALDRICH CO., LLC. Ethyl
2-cyclohexylpropionate Kao Corporation ("POIRENATE") (R) Ethyl
phenylacetate Tokyo Chemical Industry Co., Ltd.
2,4,6-Trimethyl-3-cyclohexene-1- IFF INC. methanol
Example 2
Evaluation of Inhibition of Seeking Behavior of Mosquito for Human
Arm
[0062] Mosquitoes were prepared for evaluation in the same manner
as in Example 1. Approximately 150 to 200 female Asian tiger
mosquitoes were transferred in a plastic cage (30.times.30.times.30
cm). The plastic cage had a hole to put the arm inside in only one
side, and the arm was inserted through the hole in an attraction
test. The other three sides were covered with a net, preventing a
smell from remaining in the box. A breathable sheet for disposable
diapers (air permeance (JIS P8117): 2 sec/300 mL32 sheets or
higher, water vapor transmission rate (JIS Z0208): 1 g/100
cm.sup.21 hr or higher) was cut into a size of 6 cm.times.6 cm, and
the resultant was fixed with a tape to the inner side of a Qualatex
glove (AS ONE 8-4053-02) cut in 5 cm.times.5 cm, and 30 mL of an
evaluation sample, the concentration of which had been adjusted to
0.1 vol % with ethanol, was uniformly applied onto the breathable
sheet. After the application, the resultant was left to stand for
approximately 5 minutes, and the attraction test was conducted. The
arm was covered with the Qualatex glove provided with the
breathable sheet, and inserted in the plastic cage. After the
insertion, the number of mosquitoes which landed on the breathable
sheet in 5 minutes was counted. In the case that a mosquito landed
a plurality of times, all of the landings were counted. In view of
the influence of a sample on the mosquitoes, the test was conducted
just four times in one cage, and the cage was then replaced with
another cage and other mosquitoes were used for the subsequent
tests. The inhibitory rate relative to the number of landings with
application of ethanol solvent only was calculated to determine the
inhibitory effect.
Inhibitory rate (%)-100.times.(1-[number of landings with
application of sample]/[number of landings with application of
ethanol]) (Equation 2)
[0063] Table 2 shows the results in combination. The compounds
according to the present invention exhibited excellent inhibitory
effect for an Asian tiger mosquito.
TABLE-US-00002 TABLE 2 Inhibition of carbon dioxide Inhibitory
Sample response (%) rate (%) 2-Methoxy-4-propylphenol 95 100
9-Decen-1-ol 56 93.5 1-Octen-3-ol 55 70.5 1-Decanol 54 97.5 Ethyl
2-ethylhexanoate 51 66 trans-2-Hexenyl acetate 48 54 Ethyl
2-cyclohexylpropionate 48 58 Ethyl phenylacetate 79 38.5
2,4,6-Trimethyl-3- 61 89 cyclohexene-1-methanol
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