Application of capraldehyde in preparation of blood-sucking midge attractant

Abstract

The invention belongs to the technical field of attractants, and particularly relates to application of capraldehyde in preparation of a blood-sucking midge attractant. The invention provides an application of capraldehyde in preparation of a blood-sucking midge attractant. According to the invention, detection of an EAG reaction and a behavioral reaction of Taiwan Lasiohelea to capraldehyde proves that capraldehyde has a good attracting effect on Taiwan Lasiohelea, and the capraldehyde has an effect of attracting Taiwan Lasiohelea when the concentration of capraldehyde is in a range of 0.000001%-0.01%. As a monomeric compound, capraldehyde has simple components, is environment-friendly, and is expected to be developed into a series of products for preventing and treating blood-sucking midges.

Description

Technical Field

[0001] The invention belongs to the technical field of attractants, and particularly relates to application of decanal in preparing a blood-sucking midge attractant. Background Art

[0002] Blood-sucking midges, also known as blood-sucking midges, belong to the order Diptera, the suborder Longicornis, and the family Ceratidae. They are midges that can spread insect-borne pathogens by sucking the blood of animals. There are 1,671 known species in the world, and 443 known species in China, including the Taiwan midge and the Taiwan scissors midge. Among them, the Taiwan midge is a relatively common type of blood-sucking midge, and it has been reported that it can carry the Japanese encephalitis virus. Midge-borne diseases can cause insect bite hypersensitivity, which is called insectbite hypersensitivity, or IBH for short. Insect bite hypersensitivity is a type I IgE-mediated hypersensitivity reaction caused by the allergens of blood-sucking midges. In addition, blood-sucking midges can cause discomfort to humans and animals after stinging and sucking blood. The harm caused by blood-sucking midges is mainly reflected in the following aspects: (1) Direct harassment. Blood-sucking midges harass humans and animals by sucking blood. Itching, redness, swelling and pain often occur at the bite site, and in severe cases, allergic reactions may occur. In the season when blood-sucking midges appear in large numbers, their repeated bites can make humans and animals feel uneasy and irritable; (2) Triggering allergies and dermatitis. The bites of blood-sucking midges can cause local skin redness, swelling, itching, and even papular urticaria. Scratching may lead to secondary infection, resulting in slow wound healing; (3) Transmission of diseases. Blood-sucking midges are important disease-carrying insects that can transmit a variety of pathogens, including viruses, bacteria and parasites. Among them, Culicoides is the main vector of bluetongue disease, which is extremely harmful to ruminants such as sheep and cattle, and can cause symptoms such as fever, facial edema, and oral and gastrointestinal ulcers. In addition, blood-sucking midges may also spread Japanese encephalitis virus; (4) Impact on animal husbandry: The bites of blood-sucking midges on livestock not only affect their health, but may also lead to reduced production performance. For example, bluetongue disease causes direct and indirect economic losses of up to billions of dollars to the global animal husbandry each year. Therefore, the research and prevention of midges provides a basis for the prevention and control of midge-borne diseases and is of great significance in medical and veterinary research.

[0003] In recent years, with the development and large-scale use of insect attractants, real-time monitoring, large-scale trapping or killing of specific harmful insects have been achieved, reducing insect density and alleviating their harassment and harm to humans. At present, there is no specific attractant for blood-sucking midges, which is extremely unfavorable for the prevention and control of important harassing and blood-sucking midges such as the Taiwan midge. It is urgent to develop attractants for characteristic groups of blood-sucking midges to facilitate large-scale killing of blood-sucking midges, reduce adverse reactions caused by their harassment and blood-sucking, and avoid unnecessary economic losses. Therefore, the development of an attractant for blood-sucking midges has important economic and social benefits for the effective control of blood-sucking midges. Summary of the Invention

[0004] To reduce the density of blood-sucking midges and mitigate the harm they cause, the present invention provides an application of decanal in the preparation of a blood-sucking midge attractant.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides an application of decanal in the preparation of a blood-sucking midge attractant.

[0007] Preferably, the blood-sucking midges attracted by the blood-sucking midge attractant include at least one of Lasiohelea taiwana and Forcipomyia (Lasiohelea) formosensis.

[0008] The present invention also provides a blood-sucking midge attractant, which is composed of the decanal and pharmaceutically acceptable excipients, and the volume fraction of decanal in the blood-sucking midge attractant is 0.000001% - 0.01%.

[0009] Preferably, the volume fraction of decanal in the blood-sucking midge attractant is 0.00001% - 0.001%.

[0010] Preferably, the volume fraction of decanal in the blood-sucking midge attractant is 0.0001%.

[0011] Preferably, the pharmaceutically acceptable excipients are one or several of diluents, disintegrants, precipitation inhibitors, glidants, binders, dispersants, suspending agents, isotonic agents, thickeners, emulsifiers, preservatives and stabilizers.

[0012] Preferably, the diluent includes any one of starch, lactose, sucrose and mannitol.

[0013] Preferably, the disintegrant includes any one of starch, microcrystalline cellulose and low-substituted hydroxypropyl cellulose.

[0014] Preferably, the precipitation inhibitor includes any one of sodium dodecyl sulfate, Tween-80, polyvinylpyrrolidone and hydroxypropyl methylcellulose.

[0015] Preferably, the glidant includes any one of cationic polyacrylamide, poly(diallyldimethylammonium chloride) and cationic starch.

[0016] Preferably, the binder includes any one of starch paste, hydroxypropyl methylcellulose and polyvinylpyrrolidone.

[0017] Preferably, the dispersant includes any one of sodium dodecyl sulfate, polyvinylpyrrolidone and sodium carboxymethylcellulose.

[0018] Preferably, the suspending agent includes any one of gum arabic, tragacanth, sodium carboxymethyl cellulose, and hydroxypropyl methylcellulose.

[0019] Preferably, the isotonic agent includes any one of sodium chloride, glucose, and mannitol.

[0020] Preferably, the thickening agent includes any one of gum arabic, xanthan gum, and sodium carboxymethyl cellulose.

[0021] Preferably, the emulsifying agent includes any one of sodium dodecyl sulfate, benzalkonium chloride, and sorbitan fatty acid esters.

[0022] Preferably, the preservative includes any one of benzoic acid, sorbic acid, methyl p-hydroxybenzoate, and benzalkonium bromide.

[0023] Preferably, the stabilizer includes any one of sodium sulfite, sodium bisulfite, tocopherol, and disodium ethylenediaminetetraacetate.

[0024] Preferably, the acceptable dosage form of the blood-sucking midge attractant includes one of liquid, tablet, capsule, granule, pill, powder, and ointment.

[0025] Preferably, the auxiliary material used in the liquid is absolute ethanol.

[0026] The beneficial effects of the present invention are as follows:

[0027] The present invention provides an application of decanal in the preparation of a blood-sucking midge attractant. The present invention confirms that decanal has a good attracting effect on Forcipomyia taiwana by detecting the EAG reaction and behavioral reaction of Forcipomyia taiwana to decanal, and it has the effect of attracting Forcipomyia taiwana within the concentration range of 0.000001% to 0.01%. As a monomer compound, decanal has a simple composition and is environmentally friendly, and it is promising to be developed into a series of products for controlling blood-sucking midges.

[0028] Decanal is an organic compound with a special odor, and its chemical formula is C 10 H 20 O, and it is a straight-chain aldehyde compound. It has the following advantages in the preparation of a blood-sucking midge attractant:

[0029] 1. Odor characteristics and attracting effect.

[0030] Decanal has a fresh odor similar to citrus or lemon, and this odor has a significant attracting effect on blood-sucking midges. Blood-sucking midges are very sensitive to certain specific aldehyde compounds, and the odor characteristics of decanal can effectively attract blood-sucking midges. This natural odor advantage enables decanal to efficiently simulate the natural attracting source of blood-sucking midges in the attractant, thereby improving the attractiveness and effectiveness of the attractant.

[0031] 2. Chemical stability and persistence.

[0032] Decanal has relatively stable chemical properties and is not easily decomposed. When preparing a blood-sucking midge attractant, this stability ensures the persistence of the attractant during storage and use. Compared with some volatile or easily decomposed compounds, decanal can maintain its attracting effect for a longer time, reducing the replacement frequency of the attractant and lowering the usage cost.

[0033] 3. Availability and cost-effectiveness.

[0034] Decanal is a common organic compound widely used in the fields of perfumes, pharmaceuticals, and chemical engineering. Its production process is mature, the market supply is sufficient, and the price is relatively low. This gives decanal a significant cost advantage when preparing a blood-sucking midge attractant, enabling an efficient attracting effect without incurring excessive costs.

[0035] 4. Safety and environmental friendliness

[0036] Decanal is a naturally occurring compound widely present in plants and animals in nature. When preparing a blood-sucking midge attractant, using decanal as the main component is not only environmentally friendly but also has less impact on humans and non-target organisms. This safety makes decanal an ideal attractant component, especially suitable for controlling blood-sucking midges in outdoor environments.

[0037] 5. Synergistic effects with other components

[0038] When preparing a blood-sucking midge attractant, decanal can act synergistically with other attracting components such as carbon dioxide and ammonia to further enhance the attracting effect. This synergistic effect not only improves the attractiveness of the attractant but also extends the effective action time of the attractant, enabling it to exhibit more superior performance in complex environments.

[0039] 6. Application prospects and actual effects.

[0040] Due to its high efficiency in attracting and good chemical stability, decanal has broad application prospects in blood-sucking midge attractants. In practical applications, attractants using decanal as the main component can significantly increase the capture rate of blood-sucking midges and reduce the harassment of blood-sucking midges to humans and animals. Such attractants are not only applicable to pest control in the agricultural field but also can be used for mosquito control in the public health field.

[0041] In summary, decanal has significant benefits in preparing blood-sucking midge attractants. Its unique odor characteristics, chemical stability, availability, safety, and synergistic effects with other components make it an ideal attractant component. In practical applications, decanal can effectively increase the capture rate of blood-sucking midges and reduce the harassment of blood-sucking midges to humans and animals, having broad application prospects. Brief Description of the Drawings

[0042] Figure 1 It is the number of Taiwan midge (Forcipomyia taiwana) attracted by 8 volunteers within 20 minutes.

[0043] Figure 2 It is the statistics of volatile substances adsorbed by 8 volunteers.

[0044] Figure 3 It is a schematic diagram of a Y-tube olfactometer.

[0045] Figure 4 It is the test result of the behavioral response of Taiwan midge (Forcipomyia taiwana) to decanal. Detailed Embodiments

[0046] The present invention will be further described below through specific embodiments, but the scope of the present invention is not limited thereby. Without departing from the spirit and scope of the present invention, modifications or substitutions can be made to the details and forms of the technical solutions of the present invention, but such modifications or substitutions all fall within the protection scope of the present invention.

[0047] The inventive concept of the present invention is as follows:

[0048] With the research and development and large-scale use of insect attractants, real-time monitoring, large-scale trapping or killing of specific harmful insects have been achieved, realizing the reduction of insect density and the alleviation of their harassment and harm to humans. Currently, there is no specific attractant for blood-sucking midges, which is extremely disadvantageous for the control of important harassing and blood-sucking midges such as Taiwan midge (Forcipomyia taiwana). There is an urgent need to develop attractants for characteristic groups of blood-sucking midges to facilitate the large-scale killing of blood-sucking midges, reduce adverse reactions caused by their harassment, blood-sucking, etc., and avoid unnecessary economic losses.

[0049] Based on this, the present invention provides an application of decanal in the preparation of a blood-sucking midge attractant.

[0050] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and the drawings. In the description of the present invention, unless otherwise specified, the reagents used are commercially available, and the methods used are conventional techniques in the art.

[0051] Example 1

[0052] The application of decanal in the preparation of a blood-sucking midge attractant is as follows:

[0053] 1. Attraction experiment.

[0054] A total of 8 volunteers participated in the attraction experiment. Among them, the numbers of attracted *Lasiohelea formosensis* by Volunteer No. 1 to Volunteer No. 8 within 20 minutes were 23.4±2.4, 6.8±3.03, 1.6±1.8, 4.8±1.3, 20.4±3.8, 11±2.24, 5.4±1.67, and 1.2±1.3 respectively. Overall attraction situation: Volunteer No. 1 attracted the most *Lasiohelea formosensis*, and Volunteer No. 8 attracted the least *Lasiohelea formosensis*. It can be seen from Figure 1 that there were statistical differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 1, No. 5 and Volunteer No. 2, No. 3, No. 4, No. 6, No. 7, No. 8. There were statistical differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 2 and Volunteer No. 1, No. 5, No. 3, No. 8; there were differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 3 and Volunteer No. 1, No. 2, No. 5, No. 6; there were differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 4 and Volunteer No. 1, No. 5, No. 6; there were statistical differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 6 and Volunteer No. 1, No. 3, No. 4, No. 5, No. 7, No. 8; there were differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 7 and Volunteer No. 1, No. 5, No. 6; there were differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 8 and Volunteer No. 1, No. 2, No. 5, No. 6; there were no statistical differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 1 and No. 5 with more attracted *Lasiohelea formosensis*; there were no statistical differences in the numbers of attracted *Lasiohelea formosensis* between Volunteer No. 2 and Volunteer No. 4, No. 6, No. 7; there were no statistical differences in the numbers of attracted *Lasiohelea formosensis* between any two of Volunteer No. 3, No. 4, No. 7, No. 8. From Figure 1 the results, it can be obtained that different objects have different attraction forces on *Lasiohelea formosensis*, indicating that *Lasiohelea formosensis* has host preferences for different objects.

[0055] Note: Figure 1 In [[ ]], different letters represent statistical differences between the two with P<0.05, and the same letters or one of the two letters being the same indicates no statistical differences between the two with P>0.05.

[0056] A total of 8 volunteers participated in this invention. By detecting the volatiles adsorbed in the gauze of 8 volunteers, a total of 25 compounds with relatively high contents were identified, including ketones, aldehydes, alcohols, acids, etc. Such as Figure 2As shown, the relative content of volatile substances in the 8th volunteer was relatively high, reaching 54.06%, among which the relative content of 6-methyl-5-hepten-2-one was the highest, reaching 14.62%. In contrast, the relative content of volatile substances in the 3rd volunteer was relatively low, only 12.57%, and the relative content of 6-methyl-5-hepten-2-one was the highest at 2.59%. Generally speaking, the types of volatile substances on the skin surfaces of different people are similar, but only the relative content of each compound is different. Among them, nonanal, 6-methyl-5-hepten-2-one, and decanal exist in the skin volatiles of 8 volunteers, are relatively stable and have relatively high contents. After comparison, decanal, which has a relatively high content in the volatiles and is abundant in the population prone to being bitten, was selected as the alternative compound.

[0057] 2. EAG response of *Lasiohelea taiwana* to decanal.

[0058] The EAG response is the electroantennogram response.

[0059] First, decanal was diluted with absolute ethanol to decanal solutions with volume fractions of 10%, 1%, 0.1%, 0.01%, 0.001%, 0.0001%, 0.00001%, and 0.000001% respectively for standby measurement.

[0060] The EAG response method is as follows:

[0061] (1) Select healthy and active adult *Lasiohelea taiwana*, take 1 antenna, cut it along the base of the single antenna, with a little scalp, to ensure a stable baseline.

[0062] (2) Cut off a little of the tip of the antenna. Two glass capillaries are filled with physiological saline. One holds the base of the antenna and inserts it into the reference electrode, and the other is inserted into the measuring electrode. Operate to connect the tip of the glass capillary of the measuring electrode to the tip of the antenna, exposing more antennal sensilla.

[0063] (3) The way of attaching the antenna is the glass electrode connection method.

[0064] (4) Close the shielding cabinet and check whether the baseline is stable.

[0065] (5) During the test, take 15 μL of the decanal solution and drop it on a filter paper strip of 4 cm × 0.5 cm, put it into a 1 mL blue pipette tip. Start the test after 20 s. The pipette tip is 1 cm away from the antenna, the air flow rate is 600 mL / min, the stimulating gas flow rate is 500 mL / min, and stimulate once every 1 min, with each stimulation lasting 0.5 s. Each antenna is tested with all concentrations of decanal. The determination order of the decanal solution is: blank group - low-concentration decanal solution - high-concentration decanal solution - blank group. Each concentration of decanal is repeated 10 times with 10 adult *Lasiohelea taiwana*, and only 1 antenna is taken from each adult *Lasiohelea taiwana*. Absolute ethanol is used as the blank group.

[0066] (6) After the baseline is stabilized, place the decanal solution at the small hole on the taste tube and start the test record.

[0067] (7) Calculate the relative value of the EAG response.

[0068] The results are as follows:

[0069] As the concentration of decanal increases, the stimulatory response of decanal to *Lasiohelea taiwana* shows an upward trend. When the concentration of decanal is 0.000001%, the relative value of the electroantennogram response of the antennae of *Lasiohelea taiwana* to decanal is 0.81 ± 0.37; when the concentration of decanal is 0.00001%, the relative value of the electroantennogram response of decanal is 0.97 ± 0.19; when the concentration of the volatile is 0.001%, the relative value of the electroantennogram response of heptanal is 0.99 ± 0.19; when the concentration of the volatile is 0.01%, the relative value of the electroantennogram response to heptanal is 1.12 ± 0.15; when the concentration of the volatile is 0.1%, the relative value of the electroantennogram response to heptanal is 1.13 ± 0.24. When the concentration of the volatile is 1%, the relative value of the electroantennogram response to heptanal is 1.13 ± 0.26. When the concentration of the volatile is 10%, the relative value of the electroantennogram response to heptanal is 1.13 ± 0.16.

[0070] For those skilled in the art, various corresponding changes can be given according to the above technical solutions and concepts, and all these changes should be included within the protection scope of the claims of the present invention.

[0071] 3. Behavioral response of *Lasiohelea taiwana* to decanal.

[0072] Use absolute ethanol to dilute decanal to decanal solutions with volume fractions of 10%, 1%, 0.1%, 0.01%, 0.001%, 0.0001%, 0.00001%, and 0.000001% respectively for standby testing.

[0073] Transfer the *Lasiohelea taiwana* to be tested into the test chamber to adapt to the environment for about 1 h. The experiment uses natural light and conducts behavioral detection on *Lasiohelea taiwana* at a fixed time. Five replicates are made for each concentration of the decanal solution during the determination. The Y-type olfactometer is assembled by an air pump, a washing bottle, a drying tower filled with activated carbon, a sample bottle, a flowmeter, a silica gel tube, a Y-type tube, and an insect collector. The schematic diagram of the Y-type olfactometer is shown in Figure 3 .

[0074] During the measurement process, the gas flow rate was 0.4 L / min. The 2.5 cm × 5 cm filter paper with 100 μL of decanal solution added was designated as the experimental group, and the 2.5 cm × 5 cm filter paper with the same volume of absolute ethanol added was designated as the control group. After the decanal solution and absolute ethanol had evaporated completely, they were placed into the left and right sample bottles respectively. Twenty Taiwan midge flies were placed at the straight opening of the Y-tube, and their first choice within 5 minutes was observed. If there was no choice within 5 minutes, it was recorded as non-responsive. The filter paper was replaced for each experiment, and after repeating the measurement 2 times, the directions of the two arms of the Y-tube were swapped to eliminate the influence of geometric position on the orientation behavior of Taiwan midge flies. After each experiment, it was washed with distilled water and wiped with alcohol, and after drying, the next set of experiments was carried out, and the selection rate was statistically analyzed.

[0075] The results are as Figure 4 shown in Table 1. The ability of decanal solutions with volume fractions of 0.01%, 0.001%, 0.0001%, 0.00001%, and 0.000001% to attract Taiwan midge flies was significantly stronger than that of absolute ethanol, and among them, the 0.0001% decanal solution had the best attracting ability.

[0076] Figure 4 The attracting ability of decanal was tested by chi-square test. Those with "*" indicate that there were differences in the attracting rates between the experimental group and the control group.

[0077] Table 1 Attracting rates of decanal on Taiwan midge flies

[0078] Decanal concentration Decanal attraction rate, % Attraction rate of absolute ethanol, % 0.000001％ 58.8 41.2 0.00001％ 67.5 32.5 0.0001％ 63.6 36.4 0.001％ 70.1 29.9 0.01％ 58.7 41.3 0.1％ 50.5 49.5 1％ 49.4 50.6 10％ 36.9 63.1

[0079] During the process of insects locating hosts, they mainly rely on the odors emitted by the hosts. The differences in the attractiveness of humans to insects mainly stem from the different volatile substances emitted by the body, especially the influence of olfactory signals. By detecting the volatile substances on the human skin surface, it can be found that the compounds present on the human skin are similar, but the relative contents of many compounds are different among different individuals. The present invention discovers that the concentration of volatile substances determines the behavioral responses of insects. Decanal solutions with volume fractions of 0.01%, 0.001%, 0.0001%, 0.00001%, and 0.000001% have strong attracting power to Taiwan midge flies, while higher or lower concentrations have less attracting power or even produce an avoidance effect. Therefore, the results show that the behavioral responses depend on the concentration of the tested volatile substances, and Taiwan midge flies prefer hosts with appropriate volatile substance concentrations.

[0080] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there are no contradictions in the combinations of these technical features, they should all be considered as within the scope described in this specification.

[0081] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. Application of decanal in the preparation of blood-sucking midge attractants.

2. The use according to claim 1, characterized in that The blood-sucking midge attractant is used to attract blood-sucking midges including at least one of Formosan midges and Formosan schizont midges.

3. A blood-sucking midge attractant, characterized in that: The blood-sucking midge attractant is composed of the decanal as claimed in claim 1 and pharmaceutically acceptable excipients, wherein the volume fraction of decanal in the blood-sucking midge attractant is 0.000001% to 0.01%.

4. The blood-sucking midge attractant according to claim 3, characterized in that: The volume fraction of decanal in the blood-sucking midge attractant is 0.00001% to 0.001%.

5. The blood-sucking midge attractant according to claim 4, characterized in that: The volume fraction of decanal in the blood-sucking midge attractant is 0.0001%.

6. The blood-sucking midge attractant according to claim 3, characterized in that: The pharmaceutically acceptable excipient is one or more of a diluent, a disintegrant, a precipitation inhibitor, a glidant, a binder, a dispersant, a suspending agent, an isotonic agent, a thickener, an emulsifier, a preservative and a stabilizer.

7. The blood-sucking midge attractant according to claim 3, characterized in that: The acceptable dosage form of the blood-sucking midge attractant includes one of liquid, tablet, capsule, granule, pill, powder and paste.

8. The blood-sucking midge attractant according to claim 7, characterized in that: The auxiliary material used in the liquid preparation is anhydrous ethanol.

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