Silyl ether-based essential oil compound as well as preparation method and application thereof

Abstract

The invention provides a silyl ether-based essential oil compound as well as a preparation method and application thereof. The structural general formula of the compound is Si (R) x (-O-EO) 4-x, and-R is any alkyl or aryl with the carbon number not larger than 6; -O-EO is a plant essential oil active group connected with a silicon atom through an oxygen atom, and the structure of the-O-EO is derived from hydroxyl-containing terpenoids, phenylpropanoid compounds and derivatives thereof in plant essential oil; and x is an integer of 0-3. Through ingenious molecular design, essential oil active molecules are combined with environment-sensitive silyl ether bonds, and effective control over the volatilization and release process of the essential oil is achieved. Experiments prove that the compound has excellent environmental stability and intelligent response release characteristics, can meet the dual requirements of long-acting antibiosis and mildew prevention and lasting fragrance slow release at the same time, and can be widely applied to the fields of intelligent antibiosis, cultural relic protection, food preservation, fragrance slow release systems and the like. Moreover, the preparation method of the silyl ether-based essential oil compound is simple, universal, safe and environment-friendly, and has a wide market prospect.

Description

Technical Field

[0001] This invention belongs to the field of organic compound technology, specifically involving the intersection of organic synthesis, functional materials and sustained-release technology, and more specifically involving a new type of compound obtained by chemically modifying the active molecules of plant essential oils through silyl ether bonds, its simple preparation method and its application in the fields of intelligent fragrance sustained release and targeted antibacterial. Background Technology

[0002] Essential oils, as secondary metabolites derived from plants, are rich in various active molecules such as terpenes and aromatic compounds. They are widely used in the fragrance and flavor industry not only for their unique aroma but also for their broad-spectrum antibacterial, antifungal, and antioxidant activities, demonstrating enormous application potential in food preservation, medical and health care, agricultural pest control, and daily chemical products. However, most active ingredients in essential oils (such as monoterpenes and phenols) face common technical challenges in practical applications due to their small molecular weight, high volatility, and unstable chemical properties, including short-lasting fragrance and insufficient antibacterial efficacy leading to ineffectiveness.

[0003] While traditional sustained-release technologies such as physical encapsulation and microencapsulation can delay release to some extent, they are mostly passive diffusion mechanisms, making the release process uncontrollable and unable to intelligently respond to specific application environments (such as microbially contaminated areas or spaces requiring long-lasting fragrance). Moreover, conventional sustained-release product preparation processes are complex, requiring advanced equipment and energy, resulting in high production costs.

[0004] Therefore, developing an essential oil compound with a novel structure, simple process, and the ability to simultaneously achieve both aroma release and / or targeted antibacterial dual intelligent responses is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome many shortcomings of existing technologies in essential oil products, such as rapid evaporation, short-lived efficacy, uncontrollable passive slow-release process, and complex preparation processes for slow-release products. Through synergistic design of structure and function, this invention achieves intelligent and controllable release of the active ingredients in essential oils. The specific design concept is as follows:

[0006] Si-OC bonds, as condition-sensitive chemical bonds, are highly dependent on environmental conditions for stability. They are exceptionally stable in dry, neutral environments, but can undergo controlled hydrolytic cleavage upon exposure to moisture, acidity, or specific enzyme-catalyzed conditions. Currently, there are no reports on using silyl ether bonds to modify small essential oil molecules to construct stimulus-responsive systems. The systematic design of a series of silyl ether-based essential oil compounds with well-defined general formulas, compatibility with various essential oil active skeletons, and the ability to simultaneously achieve aroma sustained release and / or targeted antibacterial dual intelligent responses remains a gap in research.

[0007] This invention combines the properties of essential oil active ingredients with a silyl ether bond response mechanism to provide a novel, versatile, simple, and high-performance silyl ether-based essential oil compound. This type of compound effectively overcomes the inherent volatility and instability of essential oil active ingredients and endows them with intelligent responsiveness to changes in external environmental factors such as humidity and acidity, thereby achieving controllable and long-lasting release of essential oil molecules in both fragrance persistence and targeted antibacterial properties.

[0008] To achieve the above objectives, the present invention provides a silyl ether-based essential oil compound with the general chemical formula SiR. x (-O-EO) 4-x , including The general formula of the structure shown is:

[0009] Mode .

[0010] Wherein, -R is any alkyl or aryl group with no more than 6 carbon atoms; -O-EO is the active group of plant essential oil linked to silicon atoms through an oxygen atom, and its structure is derived from hydroxyl-containing terpenoids, phenylpropanoids and their derivatives in plant essential oils; x is an integer of 0, 1, 2 or 3.

[0011] In this invention, -O-EO represents a plant essential oil compound group linked to a central silicon atom via a silyl ether bond (Si-OC). This group is derived from any active ingredient in plant essential oils containing a free hydroxyl group (-OH), including but not limited to terpenoids, phenylpropanoids, and their derivatives (OH-EO).

[0012] In a preferred embodiment, the hydroxyl-containing terpenoid compound includes one or more of menthol, geraniol, citronellol, terpinen-4-ol, linalool, nerolidol, bisabolol, juniperol, santalol, cedrol, baicaleol, farnesol, dimethyl isoborneol, perillol, juniperol, terpineol, and myrtol; the hydroxyl-containing terpenoid derivative includes one or more of carvacrol and thymol; the hydroxyl-containing phenylpropanoid compound includes one or more of cinnamyl alcohol; and the hydroxyl-containing phenylpropanoid derivative includes one or more of eugenol and isoeugenol.

[0013] In this invention, R represents a non-reactive organic group attached to a silicon atom, selected from C1-C6 alkyl groups (such as methyl, ethyl, isopropyl, n-propyl, tert-butyl, n-butyl, etc.) or aryl groups (such as phenyl), used to adjust the hydrophobicity, steric hindrance, and final hydrolysis kinetics of the compound. The subscript x is an integer from 0 to 3, determining the number of EO groups attached to each silicon atom (4-x), thereby precisely controlling the number of essential oil active units carried by each molecule and the molecular weight of the final product.

[0014] Another object of the present invention is to provide a method for preparing any of the above-mentioned silyl ether-based essential oil compounds, wherein the method uses a hydroxyl-containing essential oil active ingredient (HO-EO) and a silane compound (SiR) containing an alcoholyzable functional group (Y, such as Cl, Br, OMe, OEt, etc.). x Y 4-X Using trimethylamine, triethylamine, ethylenediamine, and diethylenetriamine as raw materials, a nucleophilic substitution condensation reaction is carried out in anhydrous organic solvents (such as ethyl acetate, tetrahydrofuran, dioxane, diethyl ether, dichloromethane, and petroleum ether) in the presence of organic bases (such as trimethylamine, triethylamine, ethylenediamine, and diethylenetriamine). The reaction conditions are mild, the steps are simple, and the target product can be obtained in high yield in a one-pot process. Post-processing is simple and easy to scale up.

[0015] To achieve the above objectives, the present invention provides a method for preparing any one of the aforementioned silyl ether-based essential oil compounds, specifically comprising the following steps:

[0016] S1, under anhydrous conditions, combines the plant essential oil active ingredient HO-EO and the silane precursor SiR. x Y 4-x Dissolve them separately in anhydrous organic solvents, and mix the resulting solutions thoroughly under ice bath and stirring conditions; wherein, Y is a halogen atom or alkoxy group that can be alcoholyzed;

[0017] S2 Add an organic base dropwise to the resulting mixed solution. After the addition is complete, remove the ice bath and bring the temperature to room temperature. Stir the reaction at room temperature for 1-24 hours.

[0018] After the S3 reaction is completed, the mixture is filtered, the filtrate is collected and washed with deionized water until neutral, the deionized water and solvent are removed, and the crude product is obtained. After purification, the silyl ether-based essential oil compound is obtained.

[0019] In a preferred embodiment, in step S1, the active ingredient HO-EO of the plant essential oil is a hydroxyl-containing terpene compound, a phenylpropanoid compound, or its derivatives; more preferably, the mass ratio of the active ingredient HO-EO of the plant essential oil to the anhydrous organic solvent is 1:(2-12).

[0020] In a preferred embodiment, in step S1, the silane precursor includes silicon tetrachloride, methyltrichlorosilane, ethyltrichlorosilane, propyltrichlorosilane, phenyltrichlorosilane, butyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, dipropyldichlorosilane, diisopropyldichlorosilane, dibutyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, triethylchlorosilane, tripropylchlorosilane, triisopropylchlorosilane, tributylchlorosilane, and triphenylchlorosilane. One or more of the following compounds: silane, tetramethoxysilane, tetraethoxysilane, methyltrialkoxysilane, ethyltrialkoxysilane, propyltrialkoxysilane, butyltrialkoxysilane, phenyltrialkoxysilane, dimethyldialkoxysilane, diethyldialkoxysilane, dipropyldialkoxysilane, dibutyldialkoxysilane, and diphenyldialkoxysilane; more preferably, the mass ratio of the silane precursor to the anhydrous organic solvent is 1:(2-12).

[0021] In a preferred embodiment, in step S1, the anhydrous organic solvent includes one or more of acetonitrile, acetone, chloroform, dichloromethane, tetrahydrofuran, dioxane, N,N-dimethylformamide, dimethyl sulfoxide, diethyl ether, petroleum ether, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, dimethylbenzene, chlorobenzene, and N-methylpyrrolidone.

[0022] In a preferred embodiment, in step S1, the ratio of the total molar number of hydroxyl groups in the active ingredient HO-EO of the plant essential oil to the molar number of alcoholyzable groups Y in the silane precursor is (0.8-2):1.

[0023] In a preferred embodiment, in step S1, the ice bath cooling temperature is 0-5°C.

[0024] In a preferred embodiment, in step S1, the stirring speed is 200-3000 rpm.

[0025] In a preferred embodiment, in step S2, the organic base includes one or more of trimethylamine, triethylamine, ethylenediamine, and diethylenetriamine;

[0026] In a preferred embodiment, the molar ratio of the plant essential oil active ingredient HO-EO in step S1 to the organic base in step S2 is 1:(1-1.5).

[0027] In a preferred embodiment, in step S2, the stirring speed is 200-3000 rpm.

[0028] In a preferred embodiment, in step S3, the removal of deionized water and solvent can be carried out using conventional methods known to those skilled in the art, such as first adding anhydrous magnesium sulfate to dry and remove water, and then removing the solvent by rotary evaporation.

[0029] In a preferred embodiment, in step S3, the purification process includes one or more of filtration, washing, vacuum distillation, and column chromatography. The purification process is a conventional method known to those skilled in the art and will not be described in detail here.

[0030] Another object of the present invention is to provide a pharmaceutical composition or cosmetic composition comprising any one of the above-mentioned silyl ether-based essential oil compounds, and one or more pharmaceutically or cosmetically acceptable excipients; wherein the excipients include one or more of diluents, solvents, excipients, film-forming agents, nanocarriers, and solid support materials.

[0031] In a preferred embodiment, the diluent includes one or more of microcrystalline cellulose, lactose, mannitol, sorbitol, dicalcium phosphate, and pregelatinized starch; the solvent includes one or more of water, ethanol, propylene glycol, glycerol, polyethylene glycol-400, isopropyl myristate, and caprylic / capric triglyceride; the excipient includes one or more of corn starch, dextrin, sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, polyvinylpyrrolidone, and β-cyclodextrin; the film-forming agent includes one or more of polyvinyl alcohol, hydroxypropyl methylcellulose, ethyl cellulose, polyvinylpyrrolidone, acrylic resin, and chitosan; the nanocarrier includes one or more of liposomes and silica nanoparticles; and the solid support material includes one or more of talc, kaolin, magnesium aluminum silicate, titanium dioxide, porous starch, and zeolite.

[0032] In a preferred embodiment, the composition is prepared by loading a silicone ether-based essential oil compound onto a polymer carrier, and the specific preparation method includes:

[0033] Hydroxyethyl acrylate and diisopropyl dichlorosilane were dissolved separately in anhydrous tetrahydrofuran. The resulting solutions were mixed under ice bath and stirring. Triethylamine was added dropwise to the resulting mixed solution. After the addition was complete, the ice bath was removed and the mixture was brought to room temperature. The mixture was stirred at room temperature for 1-24 hours. After the reaction was completed, the mixture was filtered, and the organic solvent was removed by rotary evaporation of the filtrate to obtain hydroxyethyl diacrylate (DHEA).

[0034] The silyl ether-based essential oil compound and DHEA were mixed evenly at a mass ratio of (3-5):1. The resulting mixture was dissolved in dichloromethane (DCM), polymerized under ultraviolet light, and then ground to obtain nanoparticles loaded with DCAR.

[0035] More preferably, the molar ratio of hydroxyethyl acrylate to diisopropyl dichlorosilane is 2:1; the mass ratio of hydroxyethyl acrylate to anhydrous tetrahydrofuran is 1:(2-12); and the mass ratio of diisopropyl dichlorosilane to anhydrous tetrahydrofuran is 1:(2-12).

[0036] More preferably, the stirring speed is 200-3000 rpm;

[0037] More preferably, the mass ratio of the silyl ether-based essential oil compound to DCM is 1:(2-12).

[0038] More preferably, the ultraviolet photopolymerization conditions include: adding 0.5-2% (by mass of DHEA) of a photoinitiator to the system, and using a wavelength of 365 nm and an intensity of 20 mW·cm⁻¹. -2 Irradiate under ultraviolet light for 20-40 min; most preferably, the photoinitiator is photoinitiator 1173, the amount of which is 1% of the mass of DHEA, and the ultraviolet light irradiation time is 30 min.

[0039] Another object of the present invention is to provide the application of any of the above-mentioned silicone ether-based essential oil compounds or compositions in the preparation of products with environmentally responsive release functions, wherein the environmentally responsive release function is triggered by changes in temperature, humidity or pH in the environment, thereby enabling the controlled release of plant essential oil active groups in the silicone ether-based essential oil compound or composition; the product is a fragrance, antibacterial or antifungal product.

[0040] In a preferred embodiment, the application areas include: intelligent antibacterial, cultural relic protection, food preservation, fabric finishing, fragrance slow-release systems, and the preparation of high-end daily chemical products; more preferably, the application areas include: antibacterial and antifungal coatings or coatings, anti-mildew and odor control for cultural relic protection, food packaging preservation and flavor maintenance, fragrance enhancement and antibacterial properties of functional textiles, long-lasting fragrance performance in fragrance products, and slow-release functional additives in daily chemical products.

[0041] The silyl ether-based essential oil compounds and their compositions provided by this invention, based on their unique sustained-release and responsive properties, are particularly suitable for applications requiring long-lasting and intelligent functions, including but not limited to the following specific scenarios:

[0042] Cultural relic protection: Used for anti-mildew treatment of calligraphy, painting and ancient books. It is stable and non-volatile under normal conditions, but releases antibacterial components in high humidity and moldy environments, and may also be accompanied by a light plant fragrance.

[0043] Food preservation and packaging: As an active packaging coating, when the humidity and acidity of the food surface change due to the growth of microorganisms, it triggers the release of antibacterial ingredients to extend the shelf life and can slowly release natural flavor substances;

[0044] Functional textiles: Finished onto fabrics, providing long-lasting antibacterial properties and a fresh, long-lasting fragrance, and are washable;

[0045] Slow-release system: Used in products such as solid fragrances, gel perfumes, and fragrance beads, it naturally regulates the fragrance release rate by controlling the ambient humidity, achieving a long-lasting and stable fragrance that far exceeds that of traditional formulas;

[0046] Antibacterial coatings and daily chemical products: used in wall coatings and plastic products to provide long-lasting anti-mold properties; used in hand sanitizers and skin care products to achieve slow release of active ingredients and prolong the duration of action.

[0047] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0048] First, this invention introduces the silyl ether bond (Si-O-) as an environmentally responsive switch into the essential oil modification system for the first time, instead of using the conventional methods of stable C-C bonds, Si-C bonds, or physical encapsulation found in existing technologies. This design is not a simple application of known chemical bonds, but an innovative design aimed at meeting the dual requirements of stable retention during the storage period and controllable release during use of essential oil products.

[0049] Specifically, this invention fully utilizes the environmentally responsive hydrolysis characteristics of silyl ether bonds to construct an intelligent regulation mechanism for essential oil compounds: Under normal storage conditions such as dry air and neutral pH, the silyl ether bond structure is stable, and the essential oil compounds are tightly bound together in the form of covalent bonds, with almost no volatilization, achieving long-term stable preservation of the active ingredients of the essential oils; however, when external environmental conditions change, such as increased humidity due to fabric moisture absorption, condensation on food surfaces, or acidification of the local microenvironment caused by bacterial / fungal metabolism, the hydrolysis rate of the silyl ether bonds will significantly accelerate. Through this gradual and controllable hydrolysis process, essential oil molecules (HO-EO) with complete biological activity and aroma can be continuously and gently released. Moreover, the released molecules can immediately exert their inherent antibacterial or fragrance effects, achieving an environmentally responsive release function.

[0050] Secondly, this invention also has a clear design logic in selecting the source of essential oil active groups (-O-EO). The defined hydroxyl-containing terpenoids (such as thymol, carvacrol, etc.) and phenylpropanoids (such as eugenol, cinnamyl alcohol, etc.) not only possess excellent antibacterial, antioxidant, or aromatic activities, but the hydroxyl groups in their molecular structures can also undergo efficient nucleophilic substitution reactions with silane precursors, thereby forming stable silane-ether bonds, ensuring from a structural perspective that the active ingredients will not be released prematurely during storage. At the same time, this invention introduces C1-C6 alkyl or aryl substituents onto the silicon-based skeleton. Through the synergistic regulation of steric hindrance and electronic effects, the cleavage sensitivity of the silane-ether bonds can be precisely optimized: for example, long-chain alkyl substituents can enhance steric hindrance, effectively delaying the hydrolysis rate of silane-ether bonds, suitable for applications requiring long-term sustained release; aryl substituents, due to electronic conjugation effects, can make the silane-ether bonds easier to break under weakly acidic conditions, adapting to the targeted release requirements of microbially contaminated areas. Based on this, the compounds of the present invention can be precisely controlled in terms of their sensitivity to specific environmental stimuli and hydrolysis release rate by flexibly selecting different R groups and EO groups, thereby meeting different long-term application requirements ranging from several days to several months.

[0051] Finally, this invention limits the molar ratio of the plant essential oil active ingredient HO-EO to the silane precursor to (4-x):1, and simultaneously sets the molar ratio of the plant essential oil active ingredient HO-EO to the organic base to 1:(1-1.5). The specific design concept is twofold: firstly, it ensures that each Y group in the silane precursor fully reacts with HO-EO, avoiding raw material waste and reducing the difficulty of subsequent product purification; secondly, it ensures that the organic base fully activates the hydroxyl groups of HO-EO to drive the reaction, without increasing subsequent separation costs due to excessive dosage. Based on this, a simple post-processing purification step effectively removes impurities such as the generated organic base salt and unreacted raw materials, obtaining a high-purity target product, laying a solid foundation for subsequent industrial applications.

[0052] In summary, this invention, through its innovative structural design, mechanism of action, and formulation design, fundamentally solves the technical pain points of traditional essential oil products, such as rapid volatilization, short-lived efficacy, and uncontrollable passive release, successfully filling the technological gap in constructing stimulus-response systems using essential oils modified with silyl ether bonds. Furthermore, the compounds prepared by this invention also possess the following significant effects:

[0053] (1) The essential oil molecules are “locked in” by covalent bonds in the compound, which fundamentally solves the core problems of essential oil’s volatility and instability, and significantly prolongs the effective action time of the active ingredients.

[0054] (2) A single compound can simultaneously possess multiple response capabilities to temperature, humidity and pH, and can adapt to environmental changes. When needed (such as when microorganisms breed in an acidic and humid environment, or when the environment needs fragrance supplementation), it can be intelligently triggered to release, thus achieving on-demand supply.

[0055] (3) By selecting different EO groups, materials can be flexibly endowed with antibacterial, antifungal, aromatic or multiple functions, making the application design flexible and suitable for different application scenarios.

[0056] (4) The final hydrolysis products are the original essential oil molecules and non-toxic silicic acid or silicon dioxide, with no harmful residues, and are safe, environmentally friendly and biocompatible.

[0057] (5) The preparation method provided by the present invention is simple, applicable to a variety of essential oil components and has low requirements for equipment and energy consumption, and is especially suitable for large-scale industrial production; it has diverse application forms and can be adapted to various processing methods such as coating, impregnation, blending, and nano-loading. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0059] Figure 1 The silyl ether-based essential oil compound obtained in Example 1 of this invention 1 H NMR spectrum;

[0060] Figure 2 This is a comparison diagram of the volatility of the silyl ether-based essential oil compound prepared in Example 1 of the present invention and the unmodified essential oil compound;

[0061] Figure 3 The silyl ether-based essential oil compound prepared in Example 1 of this invention is hydrolyzed in an acidic environment. 1 H NMR spectrum;

[0062] Figure 4 The image shows the UV-Vis spectrum of the hydrolysis of the silyl ether-based essential oil compound obtained in Example 1 of this invention in fungal culture medium.

[0063] Figure 5 The kinetics of releasing active ingredients from nanoparticles prepared by loading the silyl ether-based essential oil compound obtained in Example 1 of this invention onto a PDHEA polymer are shown.

[0064] Figure 6Images showing the color changes of Müller-Hinton broth culture medium containing fungal spore suspension and sodium resazurin before and after hydrolysis of the silyl ether-based essential oil compound prepared in Example 1 of this invention.

[0065] Figure 7 Images showing the antibacterial zones of the silyl ether-based essential oil compound prepared in Example 1 of this invention before and after hydrolysis, loaded onto PDHEA polymer material;

[0066] Figure 8 The images show the antibacterial effect on the surface of cultural relics before and after using the silyl ether-based essential oil compound prepared in Example 1 of this invention.

[0067] Figure 9 The kinetics of different hydrolysis rates of silyl ether essential oil compounds with different side groups obtained in Examples 1 and 2 of the present invention under acidic conditions. Detailed Implementation

[0068] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] Unless otherwise specified, the technical means used in this invention are conventional means well known to those skilled in the art. All raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Unless otherwise specified, all reagents used in this invention are of analytical grade. In this invention, the ambient temperature is 25±5℃.

[0070] Example 1

[0071] In a dry 100 mL Schlenk flask, carvacrol (CAR) and dimethyldichlorosilane were dissolved separately in anhydrous ethyl acetate at a molar ratio of 2:1 (carvacrol to anhydrous ethyl acetate mass ratio 1:10) and 1:5, respectively. The CAR solution was slowly added dropwise to the dimethyldichlorosilane solution while stirring at 500 rpm in an ice-water bath. Subsequently, an equimolar amount of triethylamine (TEA) was added as an acid-binding agent. The ice bath was removed, and the reaction was allowed to proceed at room temperature with continuous stirring at 500 rpm for 12 hours. After the reaction was complete, the reaction mixture was filtered to remove the generated salts, and the filtrate was washed several times with deionized water until neutral. The organic phase was dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. Further purification by vacuum distillation yielded the target silyl ether compound, DCAR.

[0072] The purified product was subjected to1 ¹H NMR analysis (using deuterated chloroform as solvent). The results are as follows: Figure 1 As shown, the spectrum clearly displays the characteristic peak of the methyl group (Si-CH3) directly bonded to silicon atoms, as well as the characteristic proton peak on the benzene ring of carvacrol. By comparing the infrared spectrum with that of the starting material CAR, it can be confirmed that the hydroxyl (-OH) signal of carvacrol has disappeared, confirming the formation of the silyl ether bond (Si-OC).

[0073] Example 1

[0074] The volatility of the DCAR compound prepared in Example 1 and the carvacrol (CAR) raw material used in step 1 of Example 1 were tested, and the details are as follows:

[0075] Approximately 5 mg of the DCAR synthesized in Example 1 and the unmodified carvacrol bulk (CAR) were placed separately in a platinum dish for thermogravimetric analysis, and the mass loss was measured using a thermogravimetric analyzer at a temperature of 25°C.

[0076] Test results are as follows Figure 2 As shown, after 300 minutes of evaporation, 0.466 mg of unmodified carvacrol evaporated, while only 0.022 mg of DCAR evaporated. This demonstrates that compared to free carvacrol, DCAR significantly improves the stability of the active ingredient and avoids its rapid evaporation loss during storage.

[0077] Example 2

[0078] The hydrolysis kinetics of the DCAR compound prepared in Example 1 were tested, and the details are as follows:

[0079] Take an appropriate amount of the DCAR synthesized in Example 1, dissolve it in a deuterated reagent, and immediately proceed with the reaction. 1 ¹H NMR was performed and recorded as 0 h. The sample was stored at a constant temperature and re-measured every 30 minutes within the 0–2 hour period. 1 1H NMR spectra. By tracking the decrease in the area of ​​DCAR characteristic peaks (such as the Si-CH3 peak) and the increase in the area of ​​free carvacrol (CAR) characteristic peaks (characteristic peaks of hydrogen atoms on the benzene ring) in the spectra, the hydrolysis ratio of DCAR at different time points was quantitatively calculated.

[0080] The results showed that under acidic conditions (pH≈2), DCAR could be completely hydrolyzed to CAR within 12-24 hours, while it was extremely stable under neutral conditions. Figure 3 .

[0081] Example 3

[0082] The DCAR compound prepared in Example 1 can be hydrolyzed and release CAR in the acid produced by fungal metabolism, as detailed below:

[0083] Aspergillus nomiae was cultured in a medium containing triacetin (TAT) as a nutrient source to collect the culture broth containing acidic substances produced by its metabolism. DCAR was added to the above fungal culture and control buffer (pH 7.4), respectively. Samples were taken at different time points, and the absorption spectrum in the 200-300 nm wavelength range was scanned using a UV-Vis spectrophotometer.

[0084] The result is as follows Figure 4 As shown, in the fungal culture medium, a characteristic absorption peak appears and intensifies at a wavelength of 272 nm over time; this is the characteristic absorption peak of released carvacrol (CAR). This phenomenon is not observed in neutral buffer, directly demonstrating that acidification induced by fungal metabolic activity can trigger the hydrolytic release of DCAR.

[0085] Example of effect 4

[0086] The release kinetics of the active ingredient after the DCAR prepared in Example 1 was loaded into a polymer carrier were tested, including the preparation process of the polymer carrier, as detailed below:

[0087] In a dry 100 mL Schlenk flask, hydroxyethyl acrylate (HEA) and diisopropyl dichlorosilane were dissolved separately in anhydrous tetrahydrofuran at a molar ratio of 2:1 (HEA to anhydrous tetrahydrofuran mass ratio 1:10, diisopropyl dichlorosilane to anhydrous tetrahydrofuran mass ratio 1:5). The HEA solution was slowly added dropwise to the dichlorodiisopropyl dichlorosilane solution under stirring in an ice-water bath. Subsequently, triethylamine (TEA) was added dropwise in an equimolar amount as an acid-binding agent. The ice bath was removed, and the reaction was allowed to proceed at room temperature with stirring for 12 hours. After the reaction was complete, the reaction mixture was filtered to remove the formed salts, and the organic phase was subjected to rotary evaporation to remove the solvent, yielding hydroxyethyl diacrylate (DHEA).

[0088] DHEA and DCAR were mixed thoroughly at a mass ratio of 4:1. The resulting mixture was then dissolved in dichloromethane (DCM) at a mass ratio of 1:10. Photoinitiator 1173 was added to the system at 1% of the mass of DHEA. Photoinitiator was then applied at a wavelength of 365 nm and an intensity of 20 mW·cm⁻¹. -2 After irradiation under ultraviolet light for 30 min, DCAR-loaded nanoparticles were obtained by grinding. 0.5 g of DCAR-loaded nanoparticles were placed in acidic buffer solutions with pH values ​​of 3.5, 4.0, and 4.5, respectively. The release of CAR in the solution was measured every 0.5 hours. The sustained-release kinetics of CAR in the nanoparticles were quantitatively calculated by scanning the absorption spectrum in the 200-300 nm wavelength range using a UV-Vis spectrophotometer.

[0089] The result is as follows Figure 5 As shown, the stronger the acidity, the faster the CAR is released.

[0090] Example 5

[0091] The antibacterial activity of the DCAR compound prepared in Example 1 before and after hydrolysis was tested, and the details are as follows:

[0092] In 96-well plates, DCAR and free CAR were serially diluted two-fold using Müller-Hinton broth containing resazurin sodium. A fixed concentration of fungal spore suspension was added to each well, and the plates were incubated at 30°C for 36 hours. The minimum concentration at which the compound completely inhibited fungal growth was determined by observing the color change of the culture medium (red turning blue-purple indicating sterilization).

[0093] Figure 6 Data shows that the minimum inhibitory concentration (MFC) of DCAR is > 4096 μg / mL (almost no direct activity), while the MFC of CAR is 512 μg / mL, proving that DCAR itself has very weak antibacterial activity, but recovers its strong efficacy after hydrolysis.

[0094] DHEA was mixed with CAR and DCAR at different mass ratios and homogenized, and then photopolymerized using the same method to prepare disc-shaped materials with loadings of 0%, 10%, 20%, and 30%, respectively. The discs were placed in the center of PDA plates coated with fungal spores and incubated at 30°C for 48 hours. The diameter of the transparent inhibition zone around the material was then measured.

[0095] Figure 7 It can be seen that the size of the inhibition zone is positively correlated with the loading of CAR and DCAR in the material. Furthermore, under the condition of adding triacetin (simulating fungal metabolism), due to acid-triggered release, the inhibition zone of DCAR is larger than that of the material directly loaded with an equal amount of free CAR.

[0096] Example 6

[0097] The antibacterial properties of the DCAR prepared in Example 1 on simulated cultural relics were tested, and the details are as follows:

[0098] The DCAR-loaded nanoparticles prepared in Example 4 were dispersed in an aqueous solution to prepare a nanoparticle aqueous solution with a solid content of 1%. 100 μL of the nanoparticle aqueous solution and 100 μL of deionized water were sprayed onto two identical simulated artifacts, and then an equal amount of Aspergillus spore solution was sprayed onto each. The two simulated artifacts were then placed under conditions of humidity above 80% and 30°C for incubation, and the growth of mold on the surface of the simulated artifacts was recorded by photographing at different time points.

[0099] Because the organic matter on paper artifacts can serve as a raw material for fungal growth, artifacts without nanoparticles showed a significant increase in mold spots 20 days after fungal infection. Figure 8 The artifacts loaded with drug-eluting nanoparticles successfully inhibited fungal growth because the acid produced by fungal metabolism promoted the release of CAR. This demonstrates that DCAR-loaded nanoparticles possess the ability to prevent fungal growth.

[0100] Example 2

[0101] This embodiment prepares the silyl ether-based essential oil compound DICAR through the condensation reaction of diisopropyl dichlorosilane and carvacrol. The specific steps are as follows:

[0102] In a dry 100 mL Schlenk reaction flask, carvacrol (CAR) and diisopropyldichlorosilane were dissolved separately in anhydrous ethyl acetate at a molar ratio of 2:1 (carvacrol to anhydrous ethyl acetate mass ratio 1:10, diisopropyldichlorosilane to anhydrous ethyl acetate mass ratio 1:5). The CAR solution was slowly added dropwise to the diisopropyldichlorosilane solution under stirring in an ice-water bath. Subsequently, triethylamine (TEA) was added dropwise in an equimolar amount as an acid-binding agent. The ice bath was removed, and the reaction was allowed to proceed at room temperature with stirring for 12 hours. After the reaction was complete, the reaction mixture was filtered to remove the generated salts, and the filtrate was washed sequentially with deionized water until neutral. The organic phase was dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. Further purification by vacuum distillation or column chromatography yielded the target silyl ether compound DICAR.

[0103] Example 3

[0104] This embodiment prepares the silyl ether-based essential oil compound DMEN via the condensation reaction of triisopropylchlorosilane and menthol (MEN). The specific steps are as follows:

[0105] In a dry 100 mL Schlenk reaction flask, menthol (MEN) and triisopropylchlorosilane were dissolved separately in anhydrous tetrahydrofuran at a molar ratio of 1:1 (MEN to anhydrous tetrahydrofuran mass ratio 1:10, triisopropylchlorosilane to anhydrous tetrahydrofuran mass ratio 1:10). The MEN solution was slowly added dropwise to the triisopropylchlorosilane solution under stirring in an ice-water bath. Subsequently, triethylamine (TEA) was added dropwise in an equimolar amount as an acid-binding agent. The ice bath was removed, and the reaction was allowed to proceed at room temperature with stirring for 12 hours. After the reaction was complete, the reaction mixture was filtered to remove the generated salts, and the filtrate was washed sequentially with deionized water until neutral. The organic phase was dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation to obtain the crude product. Further purification by vacuum distillation or column chromatography yielded the target silyl ether compound SMEN.

[0106] As can be seen from the above embodiments and effect examples, this invention successfully designed and synthesized a class of silyl ether-based essential oil compounds with well-defined general formulas and superior performance. Through ingenious molecular design, this compound combines the active molecules of essential oils with environmentally sensitive silyl ether bonds, achieving effective control over the volatilization and release process of essential oils. Experiments have shown that this class of compounds possesses both excellent environmental stability and intelligent responsive release characteristics, simultaneously meeting the dual requirements of long-lasting antibacterial and antifungal effects and sustained fragrance release. Its preparation method is universal, simple, and easy to promote for mass production. This invention provides a novel solution for developing next-generation intelligent, long-lasting, and multifunctional essential oil-derived functional materials, with broad application prospects and extremely high commercial value in numerous industrial fields.

[0107] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A silyl ether-based essential oil compound, characterized in that, The general chemical formula of the silyl ether-based essential oil compound is SiR. x (-O-EO) 4-x , including The general formula of the structure shown is: Mode . Wherein, -R is any alkyl or aryl group with no more than 6 carbon atoms; -O-EO is the active group of plant essential oil linked to silicon atoms through an oxygen atom, and its structure is derived from hydroxyl-containing terpenoids, phenylpropanoids and their derivatives in plant essential oils; x is an integer of 0, 1, 2 or 3.

2. The silyl ether-based essential oil compound as described in claim 1, characterized in that, The hydroxyl-containing terpenoids include one or more of the following: menthol, geraniol, citronellol, terpinen-4-ol, linalool, nerolidol, bisabolol, juniperol, santalol, cedrol, baicaleol, farnesol, dimethyl isocamphenol, perillol, juniperol, terpineol, and myrtol. The hydroxyl-containing terpene derivatives include one or more of carvacrol and thymol; The hydroxyl-containing phenylpropanoid compounds include one or more of cinnamyl alcohol; The hydroxyl-containing phenylpropanoid derivatives include one or more of eugenol and isoeugenol.

3. The silyl ether-based essential oil compound as described in claim 1, characterized in that, The -R group includes one or more of methyl, ethyl, isopropyl, n-propyl, tert-butyl, n-butyl, and phenyl.

4. The method for preparing the silyl ether-based essential oil compound according to any one of claims 1-3, characterized in that, Includes the following steps: S1, under anhydrous conditions, combines the plant essential oil active ingredient HO-EO and the silane precursor SiR. x Y 4-x Dissolve them separately in anhydrous organic solvents, and mix the resulting solutions thoroughly under ice bath and stirring conditions; wherein, Y is a halogen atom or alkoxy group that can be alcoholyzed; S2 adds an organic base dropwise to the resulting mixed solution. After the addition is complete, remove the ice bath and bring the temperature to room temperature. Stir the reaction at room temperature for 1-24 hours. After the S3 reaction is completed, the mixture is filtered, the filtrate is collected and washed with deionized water until neutral, the deionized water and solvent are removed, and the crude product is obtained. After purification, the silyl ether-based essential oil compound is obtained.

5. The method for preparing the silyl ether-based essential oil compound as described in claim 4, characterized in that, In step S1, the active ingredient HO-EO of the plant essential oil is a hydroxyl-containing terpene compound, a phenylpropanoid compound, or its derivatives. The silane precursors include one or more of the following compounds: silicon tetrachloride, methyltrichlorosilane, ethyltrichlorosilane, propyltrichlorosilane, phenyltrichlorosilane, butyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, dipropyldichlorosilane, diisopropyldichlorosilane, dibutyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, triethylchlorosilane, tripropylchlorosilane, triisopropylchlorosilane, tributylchlorosilane, triphenylchlorosilane, tetramethoxysilane, tetraethoxysilane, methyltrialkoxysilane, ethyltrialkoxysilane, propyltrialkoxysilane, butyltrialkoxysilane, phenyltrialkoxysilane, dimethyldialkoxysilane, diethyldialkoxysilane, dipropyldialkoxysilane, dibutyldialkoxysilane, and diphenyldialkoxysilane. The anhydrous organic solvent includes one or more of acetonitrile, acetone, chloroform, dichloromethane, tetrahydrofuran, dioxane, N,N-dimethylformamide, dimethyl sulfoxide, diethyl ether, petroleum ether, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, dimethylbenzene, chlorobenzene, and N-methylpyrrolidone.

6. The method for preparing the silyl ether-based essential oil compound as described in claim 4, characterized in that, In step S1, the ratio of the total number of moles of hydroxyl groups in the active ingredient HO-EO of the plant essential oil to the number of moles of alcoholystolytic groups Y in the silane precursor is (0.8-2):

1.

7. The method for preparing the silyl ether-based essential oil compound as described in claim 4, characterized in that, In step S2, the organic base includes one or more of trimethylamine, triethylamine, ethylenediamine, and diethylenetriamine; The molar ratio of the active ingredient HO-EO in the plant essential oil described in step S1 to the organic base described in step S2 is 1:(1-1.5).

8. A pharmaceutical composition or cosmetic composition, characterized in that, The compound comprises a silyl ether-based essential oil compound as described in any one of claims 1-3, and one or more pharmaceutically or cosmetically acceptable excipients; wherein the excipients include one or more of diluents, solvents, excipients, film-forming agents, nanocarriers, and solid support materials.

9. The use of the silyl ether-based essential oil compound according to any one of claims 1-3 or the composition according to claim 8 in the preparation of a product with environmentally responsive release function, characterized in that, The environmentally responsive release function is triggered by changes in temperature, humidity, or pH in the environment, allowing the controlled release of plant essential oil active groups in the silicone ether-based essential oil compound or composition; the product is a fragrance, antibacterial, or antifungal product.

10. The application as described in claim 9, characterized in that, The application areas include: intelligent antibacterial, cultural relic protection, food preservation, fabric finishing, fragrance slow-release systems, and the preparation of high-end daily chemical products.

Images