A bactericidal composition containing oregano and a method for its preparation

Abstract

The application discloses a oregano-containing bactericidal composition and a preparation method thereof, and belongs to the technical field of bactericidal compositions. The oregano-containing bactericidal composition comprises the following raw materials in parts by weight: oregano extract 0.5-1 parts, plant source bactericide 0.5-1 parts, surfactant 1-2 parts, panthenol 1-3 parts, silk fibroin 1-2 parts, preservative 0.3-0.5 parts, antioxidant 0.5-2 parts and deionized water 100 parts; the oregano-containing bactericidal composition prepared by the application has good bactericidal performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bactericidal composition, and particularly relates to a bactericidal composition containing oregano and a preparation method thereof. BACKGROUND

[0002] Oregano, as a natural plant with broad-spectrum antibacterial activity, has a significant inhibitory effect on various pathogenic bacteria due to its active ingredients such as carvacrol and thymol. Oregano shows great potential in the pet care field. However, the inherent strong hydrophobicity and volatility of these active ingredients result in extremely low solubility and difficulty in uniform dispersion in aqueous systems, which severely restricts their application in liquid formulations and the stable exertion of their efficacy. In addition, the active ingredients of oregano are extremely sensitive to environmental factors such as light, heat and oxygen, and have serious problems such as easy oxidation, easy decomposition and poor anti-aging property. This can cause rapid degradation and failure of the active ingredients during processing, storage and use, not only reducing the bactericidal efficiency of the product, but also shortening the effective shelf life of the preparation.

[0003] Therefore, it is crucial to develop a bactericidal composition that can simultaneously significantly improve the water solubility and antioxidant property of oregano. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application aims to provide a bactericidal composition containing oregano and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0006] A bactericidal composition containing oregano comprises the following raw materials in parts by weight:

[0007] 0.5-1 parts of oregano extract, 0.5-1 parts of plant-derived bactericide, 1-2 parts of surfactant, 1-3 parts of panthenol, 1-2 parts of silk fibroin, 0.3-0.5 parts of preservative, 0.5-2 parts of antioxidant and 100 parts of deionized water;

[0008] The surfactant is prepared by the following method:

[0009] S1: 5,5',5''-(1,3,5-triazine-2,4,6-triazyl)tris(thiophene-2-amine) reacts with N-dodecyl succinic anhydride to form a long-chain alkyl-modified triazine compound,

[0010] S2: The long-chain alkyl-modified triazine compound reacts with aminopolyethylene glycol hydroxyl to form a surfactant.

[0011] The molar ratio of the 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tris(thiophene-2-amine) to N-dodecyl succinic anhydride in step S1 is 1:(3.1-3.3).

[0012] The molar ratio of the long-chain alkyl-modified triazine compound to the amino polyethylene glycol hydroxyl in step S2 is 1:(3.2-3.5).

[0013] The antioxidant is prepared by the following method:

[0014] A1: 12-bromo-1-dodecene reacts under the action of formic acid and H2O2 to form an epoxy compound,

[0015] A2: the epoxy compound reacts with rosemary acid to form an alkyl-modified rosemary,

[0016] A3: the alkyl-modified rosemary reacts with dopamine-polyethylene glycol-carboxyl to form an antioxidant.

[0017] The molar ratio of the 12-bromo-1-dodecene to formic acid in step A1 is 1:1.2.

[0018] The molar ratio of the epoxy compound to rosemary acid in step A2 is 1:1.1.

[0019] The molar ratio of the alkyl-modified rosemary to dopamine-polyethylene glycol-carboxyl in step A3 is 1:1.2.

[0020] The plant-derived fungicide is one of menthol and cnidium.

[0021] The preservative is potassium sorbate.

[0022] A method for preparing a bactericidal composition containing oregano, comprising the following steps:

[0023] (1) weigh by weight parts: oregano extract 0.5-1 part, plant-derived fungicide 0.5-1 part, surfactant 1-2 parts, panthenol 1-3 parts, silk fibroin 1-2 parts, preservative 0.3-0.5 parts, antioxidant 0.5-2 parts, deionized water 100 parts;

[0024] (2) add the surfactant, panthenol, silk fibroin, preservative, and deionized water to the reactor, heat to 70-80°C, stir to completely dissolve, form a mixture A, then cool to 40°C for standby, mix the plant-derived fungicide with the oregano extract to form a mixture B; at 40°C, slowly add the mixture B to the mixture A, emulsify with a high-speed shearing homogenizer to form a stable emulsion, cool to room temperature, adjust the pH to 6.0 to obtain a bactericidal composition containing oregano.

[0025] As the above technical solutions are adopted, the present application has the following beneficial effects:

[0026] The oregano-containing bactericidal composition prepared by the present application has good bactericidal performance and precipitation inhibition performance. The added amphiphilic surfactant encapsulates the bactericidal molecules by the rigid hydrophobic core, greatly improves the water solubility and stability of the bactericidal molecules, and synergistically destroys the bacterial cell membrane by structural similarity, thereby enhancing the bactericidal efficiency. The added antioxidant removes free radicals through multiple phenolic hydroxyl groups, avoids oxidation of active ingredients, and adheres to the target through the catechol group of dopamine, thereby prolonging the antibacterial time. DETAILED DESCRIPTION

[0027] The present application will be further described below in conjunction with examples, but the present application is not limited to these examples.

[0028] Example 1: Preparation of surfactant

[0029] S1: 600 ml of DMF (N,N-dimethylformamide), 0.1 mol of 5,5',5''-(1,3,5-triazine-2,4,6-triazyl)tris(thiophene-2-amine), 0.31 mol of N-dodecyl succinic anhydride, and 0.02 mol of 4-dimethylaminopyridine were added to a reactor, stirred and mixed, then heated to 60°C, reacted for 8 h, cooled to room temperature, slowly poured into 2000 ml of ice water, stirred, precipitated, and filtered to obtain a crude product, which was dried at 50°C under vacuum for 4 h, dissolved in 300 ml of dichloromethane, purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=1:2), and distilled under reduced pressure at 40°C for 2 h to obtain a long-chain alkyl-modified triazine compound. The reaction equation is as follows:

[0030]

[0031] S2: 1200 ml of DMF / DMSO (dimethyl sulfoxide) mixed solvent (DMF:DMSO (V / V)=1:1), 0.1 mol of long-chain alkyl-modified triazine compound, 0.32 mol of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide (EDC), and 0.32 mol of N-hydroxysuccinimide (NHS) were added to a reactor, stirred and activated at room temperature for 30 min, 0.32 mol of amino polyethylene glycol hydroxyl (NH2-PEG-OH, number average molecular weight 1000) was slowly added, and the reaction was carried out at room temperature for 8 h. The reaction liquid was then transferred to a dialysis bag (MWCO=4000), dialyzed in deionized water for 48 h, the water was changed every 6 hours, 2000 ml of water was added each time, and freeze-dried at -20°C for 24 h to obtain a surfactant. The reaction equation is as follows:

[0032]

[0033] Example 2: Preparation of surfactants:

[0034] S1: Add 600 ml DMF, 0.1 mol 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tris(thiophene-2-amine), 0.32 mol N-dodecylsuccinic anhydride, and 0.02 mol 4-dimethylaminopyridine to the reactor, stir and mix well, then heat to 60 °C and react for 8 h. After cooling to room temperature, slowly pour into 2000 ml ice water, stir, precipitate, filter to obtain crude product, dry under vacuum at 50 °C for 4 h, dissolve the crude product in 300 ml dichloromethane, purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=1:2), and distill under reduced pressure at 40 °C for 2 h to obtain long-chain alkyl-modified triazine compound;

[0035] S2: Add 1200 ml of DMF / DMSO (DMF:DMSO (V / V) = 1:1) mixed solvent, 0.1 mol of long-chain alkyl-modified triazine compound, 0.32 mol of EDC and 0.32 mol of NHS to the reactor, stir and activate at room temperature for 30 min, slowly add 0.33 mol of amino polyethylene glycol hydroxyl (NH2-PEG-OH, number average molecular weight of 1000), react at room temperature for 9 h, transfer the reaction solution to a dialysis bag (MWCO = 4000), dialyze with deionized water for 48 h, change the water every 6 hours, 2000 ml of water each time, freeze dry at -20℃ for 24 h to obtain the surfactant.

[0036] Example 3: Preparation of surfactants:

[0037] S1: Add 600 ml DMF, 0.1 mol 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tris(thiophene-2-amine), 0.33 mol N-dodecyl succinic anhydride, and 0.02 mol 4-dimethylaminopyridine to the reactor, stir and mix well, then heat to 60 °C and react for 8 h. After cooling to room temperature, slowly pour into 2000 ml ice water, stir, precipitate, filter to obtain crude product, dry under vacuum at 50 °C for 4 h, dissolve the crude product in 300 ml dichloromethane, purify by silica gel column chromatography (eluent: petroleum ether / ethyl acetate V / V=1:2), and distill under reduced pressure at 40 °C for 2 h to obtain long-chain alkyl-modified triazine compound;

[0038] S2: Add 1200 ml of DMF / DMSO (DMF:DMSO (V / V) = 1:1) mixed solvent, 0.1 mol of long-chain alkyl-modified triazine compound, 0.32 mol of EDC and 0.32 mol of NHS to the reactor, stir and activate at room temperature for 30 min, slowly add 0.35 mol of amino polyethylene glycol hydroxyl (NH2-PEG-OH, number average molecular weight of 1000), react at room temperature for 10 h, transfer the reaction solution to a dialysis bag (MWCO = 4000), dialyze with deionized water for 48 h, change the water every 6 hours, 2000 ml of water each time, freeze dry at -20℃ for 24 h to obtain the surfactant.

[0039] Example 4: Preparation of antioxidants:

[0040] A1: Add 800 ml of dichloromethane, 0.1 mol of 12-bromo-1-dodecene, and 10 g of strong acid cation exchange resin to the reactor, stir to mix, and heat to 35 °C. Then, mix 0.12 mol of formic acid and 14 g of 30 wt% H₂O₂ solution, and slowly add the mixture of formic acid and H₂O₂ solution dropwise over 20 min. After reacting for 8 h, cool to room temperature, filter, transfer the supernatant to a separatory funnel, let stand, discard the lower inorganic layer, and wash three times with deionized water (200 ml each time). Distill under reduced pressure at 30 °C for 3 h, and dry under vacuum at 50 °C for 5 h to obtain the epoxy compound; the reaction equation is shown below:

[0041]

[0042] A2: Under nitrogen protection, 150 ml of anhydrous DMF and 0.11 mol of rosmarinic acid were added to the reactor and stirred until well mixed. Then, 0.5 mol of imidazole and 0.01 mol of DMAP (4-dimethylaminopyridine) were added and stirred until well mixed. The reactor was then placed in an ice-water bath, and 250 ml of anhydrous DMF solution containing 0.45 mol of TBDMS-Cl (tert-butyldimethylchlorosilane) was slowly added dropwise over 20 min. After the addition was complete, the mixture was brought to room temperature and reacted for 12 h. The reaction solution was then quenched in 300 ml of ice water and extracted three times with ethyl acetate (300 ml each time). The combined organic phases were washed three times with deionized water (300 ml each time), dried with 50 g of anhydrous Na2SO4 for 1 h, filtered, and rotary evaporated under reduced pressure at 50 °C for 4 h to obtain hydroxyl-protected rosmarinic acid.

[0043] Under nitrogen protection, 400 ml of xylene and 0.1 mol of epoxide were added to the reactor, stirred and mixed, and the temperature was raised to 100 °C. Then, 0.02 mol of triphenylphosphine and the fully hydroxyl-protected rosmarinic acid prepared in the previous step were added, stirred and dissolved, and reacted for 8 h. After cooling to room temperature, 200 ml of deionized water was added, and the mixture was extracted three times with ethyl acetate (600 ml each time). The organic phase was washed three times with deionized water (200 ml each time), and dried under vacuum at 50 °C for 3 h to obtain alkyl-modified rosemary. The reaction equation is shown below:

[0044]

[0045] A3: Under nitrogen protection, 1000 ml of anhydrous DMF and 0.12 mol of dopamine-polyethylene glycol-carboxyl were added to the reactor and stirred until homogeneous. Then, 0.33 mol of imidazole and 0.01 mol of DMAP were added and stirred until homogeneous. The reactor was then placed in an ice-water bath, and 120 ml of anhydrous DMF solution containing 0.22 mol of TBDMS-Cl was slowly added dropwise over 20 min. After the addition was complete, the mixture was brought to room temperature and reacted for 12 h. The reaction solution was then poured into 500 ml of n-hexane, stirred, and the precipitate was collected. The precipitate was filtered, and the filter cake was washed three times with cold diethyl ether (300 ml each time). The mixture was then dried under vacuum at 70 °C for 10 h to obtain hydroxyl-protected polyethylene glycol-carboxyl.

[0046] Add 1000 ml DMF, 0.1 mol alkyl-modified rosemary, and the hydroxyl-protected polyethylene glycol-carboxyl group prepared in the above steps to the reactor, stir and mix well, then add 0.2 mol potassium carbonate in batches (0.05 mol per batch, 5 min interval between batches), stir and mix well, then heat to 60 °C and react for 8 h, cool to room temperature, filter, pour the reaction solution into 2000 ml ice water, extract three times with ethyl acetate (2000 ml each time), wash three times with deionized water (1000 ml each time), add 200 g anhydrous sodium sulfate and dry for 30 min, filter, distill under reduced pressure at 60 °C for 2 h, and vacuum dry at 70 °C for 5 h to obtain crude product;

[0047] Deprotection: The crude product from the previous step was dissolved in 1500 ml of anhydrous tetrahydrofuran. At 0°C, 750 ml of a 1M tetrabutylammonium fluoride tetrahydrofuran solution was slowly added, and the mixture was stirred until homogeneous. After reacting at room temperature for 4 hours, 1000 ml of saturated NH4Cl solution was added to quench the reaction. The mixture was extracted three times with ethyl acetate (2000 ml each time), and the organic phases were combined. The mixture was washed three times with saturated sodium chloride solution (500 ml each time) and dried at 50°C for 12 hours to obtain the antioxidant. The reaction equation is shown below:

[0048]

[0049] Example 5: Preparation of a bactericidal composition containing oregano:

[0050] (1) 5g of oregano extract, 5g of plant-derived bactericide (menthol), 10g of surfactant (prepared in Example 1), 10g of panthenol, 10g of silk fibroin, 3g of preservative (potassium sorbate), 5g of antioxidant (prepared in Example 4), and 1000g of deionized water;

[0051] (2) Add surfactant, panthenol, silk fibroin, preservative and deionized water to the reactor, heat to 70°C, stir at 300 rpm for 30 min to completely dissolve it to form mixture A, and then cool to 40°C for later use; mix the plant-derived bactericide with oregano extract to form mixture B; at 40°C, slowly add mixture B to mixture A, add dropwise for 20 min, emulsify with a high-speed shear homogenizer, emulsify at 3000 rpm for 10 min to form a stable emulsion, cool to room temperature, and adjust the pH to 6.0 with 10 wt% citric acid solution to obtain the bactericidal composition containing oregano.

[0052] Example 6 Preparation of a bactericidal composition containing oregano:

[0053] (1) 8g of oregano extract, 8g of plant-derived bactericide (Cnidium monnieri), 15g of surfactant (prepared in Example 2), 20g of panthenol, 15g of silk fibroin, 4g of preservative (potassium sorbate), 10g of antioxidant (prepared in Example 4), and 1000g of deionized water;

[0054] (2) Add surfactant, panthenol, silk fibroin, preservative and deionized water to the reactor, heat to 75°C, stir at 300 rpm for 30 min to completely dissolve it to form mixture A, and then cool to 40°C for later use; mix the plant-derived bactericide with oregano extract to form mixture B; at 40°C, slowly add mixture B to mixture A dropwise for 20 min, emulsify with a high-speed shear homogenizer, emulsify at 3000 rpm for 10 min to form a stable emulsion, cool to room temperature, and adjust the pH to 6.0 with 10 wt% citric acid solution to obtain the bactericidal composition containing oregano.

[0055] Example 7 Preparation of a bactericidal composition containing oregano:

[0056] (1) 10g of oregano extract, 10g of plant-derived bactericide (Cnidium monnieri), 20g of surfactant (prepared in Example 3), 30g of panthenol, 20g of silk fibroin, 5g of preservative (potassium sorbate), 20g of antioxidant (prepared in Example 4), and 1000g of deionized water;

[0057] (2) Add surfactant, panthenol, silk fibroin, preservative and deionized water to the reactor, heat to 80°C, stir at 300 rpm for 30 min to completely dissolve it to form mixture A, and then cool to 40°C for later use; mix the plant-derived bactericide with oregano extract to form mixture B; at 40°C, slowly add mixture B to mixture A dropwise for 20 min, emulsify with a high-speed shear homogenizer, emulsify at 3000 rpm for 10 min to form a stable emulsion, cool to room temperature, and adjust the pH to 6.0 with 10 wt% citric acid solution to obtain the bactericidal composition containing oregano.

[0058] Comparative Example 1

[0059] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0060] The preparation method of the surfactant is basically the same as that in Example 2, except that 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tri(thiophene-2-amine) in step S1 is replaced with an equimolar amount of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)triphenylamine.

[0061] Comparative Example 2

[0062] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0063] The preparation method of the surfactant is basically the same as that in Example 2, except that the N-dodecyl succinic anhydride in step S1 is replaced with an equimolar amount of butyl succinic anhydride.

[0064] Comparative Example 3

[0065] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the surfactant is replaced with an equal weight of a surfactant prepared by the following method:

[0066] The preparation method of the surfactant is basically the same as that in Example 2, except that the amino polyethylene glycol hydroxyl group in step S2 is replaced with an equimolar amount of amino polyethylene glycol hydroxyl group with a number average molecular weight of 2000.

[0067] Comparative Example 4

[0068] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the surfactant is replaced with an equal weight of an equal weight of a surfactant prepared by the following method:

[0069] The preparation method of the surfactant is basically the same as that in Example 2, except that the amino polyethylene glycol hydroxyl group in step S2 is replaced with an equimolar amount of methoxy polyethylene glycol amino with a number average molecular weight of 1000.

[0070] Comparative Example 5

[0071] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the antioxidant is replaced with an equal weight of an antioxidant prepared by the following method:

[0072] The preparation method of the antioxidant is basically the same as that in Example 4, except that 12-bromo-1-dodecene in step A1 is replaced with an equimolar amount of 4-bromo-1-butene.

[0073] Comparative Example 6

[0074] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the antioxidant is replaced with an equal weight of an antioxidant prepared by the following method:

[0075] The preparation method of the antioxidant is basically the same as that in Example 4, except that the rosmarinic acid in step A2 is replaced with an equimolar amount of caffeic acid.

[0076] Comparative Example 7

[0077] An oregano-containing bactericidal composition, with the same raw material composition and preparation method as in Example 6, except that the antioxidant is replaced with an equal weight of an antioxidant prepared by the following method:

[0078] The preparation method of the antioxidant is basically the same as that in Example 4, except that the dopamine-polyethylene glycol-carboxyl group in step A3 is replaced with an equimolar amount of 3,4-dihydroxybenzoic acid.

[0079] The preparation process of the oregano extract used in the embodiments and comparative examples of this application is as follows:

[0080] Fresh oregano was air-dried at 40℃ for 12 hours. The dried oregano was then pulverized using a pulverizer and passed through a 40-mesh sieve. 2 kg of the pulverized oregano was added to a supercritical CO2 extraction vessel. The extraction conditions were: pressure 30 MPa, temperature 50℃; the desorption conditions were: pressure 6 MPa, temperature 35℃. After extraction for 2.5 hours, oregano extract was collected from the desorption vessel. The extract contained 45.2 wt% carrageenan and 18.7 wt% thymol, for a total content of 63.9 wt%.

[0081] The dopamine-polyethylene glycol-carboxyl group used in the examples and comparative examples of this application has an average molecular weight of 2000 and is produced by Xi'an Kaixin Biotechnology Co., Ltd.; the strong acid cation exchange resin is a polymer of divinylbenzene and sodium vinylbenzene sulfonate, brand name Amberlite® IMACHP1110 resin, purchased from Sinopharm Chemical Reagent Co., Ltd.; the silk fibroin is water-soluble silk fibroin with a molecular weight of 1000 Da, purchased from Ribo (Shanghai) Biochemical Technology Co., Ltd.

[0082] Three groups of the oregano-containing bactericidal compositions prepared in Examples 5-7 and Comparative Examples 1-4 of this application were taken, each group containing 30 mL. The mixtures were placed at room temperature in the dark and allowed to stand still. Every 30 days, one group was taken and filtered. The precipitates were dried with a nitrogen blower and weighed. The test results are shown in Table 1.

[0083] Table 1. Anti-precipitation performance indicators of bactericidal compositions containing oregano.

[0084]

[0085] As can be seen from Table 1, the bactericidal compositions containing oregano prepared in Examples 5, 6, and 7 have good anti-precipitation properties.

[0086] The main antibacterial components of oregano, such as carvacrol and thymol, are hydrophobic small molecules with extremely low solubility in water, easily precipitating and leading to inactivation. Adding the surfactant prepared in this application can effectively inhibit precipitation. This surfactant is an amphiphilic star polymer with a rigid triazine-thiophene core, connecting three hydrophobic dodecyl chains and three hydrophilic polyethylene glycol chains. The planar conjugated structure of the rigid triazine-thiophene can bind to polyphenols or aromatic components in oregano extract through π-π stacking interactions, forming steric hindrance and inhibiting the aggregation and precipitation of extract molecules. The three hydrophobic dodecyl chains bind to hydrophobic components (such as carvacrol and thymol) in oregano extract through hydrophobic interactions, while the three hydrophilic polyethylene glycol chains bind to water molecules through hydrogen bonds, forming a stable micelle structure that effectively prevents the aggregation and precipitation of active ingredients in oregano extract.

[0087] In Comparative Example 3, when the molecular weight of the amino polyethylene glycol hydroxyl group increased from 1000 to 2000, the length of the polyethylene glycol chain increased significantly. However, the excessively long chain segments led to intensified intermolecular entanglement, which reduced the degree of freedom of movement of surfactant molecules in the solution. This made it difficult for surfactants to effectively disperse and stabilize the hydrophobic components in oregano extract, and instead weakened the effect of inhibiting precipitation.

[0088] In Comparative Example 4, when the amino group of methoxy polyethylene glycol was replaced with amino polyethylene glycol, the synthesized surfactant lacked a hydroxyl group, significantly reducing its ability to form hydrogen bonds with water molecules. The hydroxyl group, as a strong hydrophilic group, could normally enhance the stability of the hydration layer of phenolic substances (such as carvacrol) in oregano extract through a hydrogen bond network. However, the methoxy group has a weaker hydrogen bond accepting ability, making the hydrophobic components more prone to aggregation and precipitation due to dehydration.

[0089] The bactericidal properties of the oregano-containing bactericidal compositions prepared in the examples and comparative examples were tested before and after oxidation. Two groups were taken from each group. One group was placed in a 60°C incubator and stored in the dark for 7 days; the other group was placed in a 4°C refrigerator and stored in the dark for 7 days. The activated third-generation bacterial strain was diluted with PBS (0.01M, pH=7.4) to a concentration of 1×10⁻⁶. 8 CFU / mL bacterial suspension: Add 0.1 mL of bacterial suspension to a test tube, then add 0.9 mL of the sample to be tested. The bacterial concentration is 1 × 10⁻⁶. 7 CFU / mL. Place the test tube in a 37℃ water bath and incubate for 30 min. Take 1.0 mL of the mixture from the test tube and add it to a 9.0 mL test tube containing 1.0% (w / v) Tween 80. Vortex mix for 10 s to ensure the sample is completely neutralized and stop the sterilization process. Then, perform a 100-fold dilution. Take 1.0 mL of the diluted liquid and inoculate it onto a plate using the spread plate method. Perform 3 parallel groups. Incubate the bacterial plates upside down in a 37℃ incubator for 48 h. After the incubation, count the plates.

[0090] The formula for calculating the antibacterial rate is as follows: Antibacterial rate (%) = [(N0 - N] t ) / N0]×100%;

[0091] N0: Represents the initial bacterial load before culturing. Take the activated third-generation bacterial strain and dilute it with PBS (0.01M, pH=7.4) to a concentration of 1×10⁻⁶. 7 CFU / mL bacterial suspension: Add 1 mL of bacterial suspension to a test tube, then immediately add 9.0 mL of Tween 80 containing 1.0% (w / v) to neutralize and dilute the bacterial count to obtain the initial bacterial count before culturing.

[0092] N t The average viable bacterial count (CFU / mL) in the experimental group after 30 min of incubation.

[0093] Indicator standard strains: Staphylococcus aureus CICC10473 and Escherichia coli CICC10305. The test results are shown in Table 2.

[0094] Table 2 Performance Indicators of Bactericidal Compositions Containing Oregano

[0095]

[0096] As can be seen from Table 2, the bactericidal compositions containing oregano prepared in Examples 5, 6, and 7 have good bactericidal effects and antioxidant properties.

[0097] The antioxidant prepared in this application comprises polyether segments, multiple phenolic hydroxyl groups, and dopamine catechol groups. The polyether segments improve the water solubility and dispersibility of the molecule, enabling effective scavenging of free radicals in the aqueous phase and at the interface over a wider spatial range. The multiple phenolic hydroxyl groups act as potent free radical scavengers, protecting the main bactericidal components in oregano from oxidative degradation and maintaining long-term stability of bactericidal activity. The dopamine catechol groups provide strong surface adhesion through their catechol structure, allowing the entire molecule to firmly adhere to bacterial biofilms and prolonging the residence time of the bactericidal components at the target site.

[0098] The long-chain alkyl groups in the surfactant prepared in this application can easily insert into and disrupt the phospholipid bilayer of bacterial cell membranes, and the rigid triazine-thiophene structure of the surfactant synergistically enhances the antibacterial properties with oregano extract.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A bactericidal composition containing oregano, characterized in that, The ingredients include the following parts by weight: Oregano extract 0.5-1 part, plant-derived bactericide 0.5-1 part, surfactant 1-2 parts, panthenol 1-3 parts, silk fibroin 1-2 parts, preservative 0.3-0.5 parts, antioxidant 0.5-2 parts, deionized water 100 parts; The surfactant is prepared by the following method: S1: 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tris(thiophene-2-amine) reacts with N-dodecyl succinic anhydride to generate a long-chain alkyl-modified triazine compound. S2: Long-chain alkyl-modified triazine compounds react with amino polyethylene glycol hydroxyl groups to generate surfactants; In step S2, the number-average molecular weight of the amino polyethylene glycol hydroxyl groups is 1000; The structural formula of the surfactant is as follows: ； The antioxidant is prepared by the following method: A1: 12-Bromo-1-dodecene reacts with formic acid and H2O2 to form an epoxide compound. A2: Epoxides react with rosmarinic acid to produce alkyl-modified rosemary. A3: Alkyl-modified rosemary reacts with dopamine-polyethylene glycol-carboxyl groups to generate antioxidants; In step A3, the dopamine-polyethylene glycol-carboxyl group number-average molecular weight is 2000; The structural formula of the antioxidant is as follows: ； The oregano extract was obtained by supercritical CO2 extraction. The extract contained 45.2 wt% carrageenan, 18.7 wt% thymol, and a total of 63.9 wt%.

2. The bactericidal composition containing oregano according to claim 1, characterized in that, In step S1, the molar ratio of 5,5',5''-(1,3,5-triazine-2,4,6-triyl)tri(thiophene-2-amine) to N-dodecyl succinic anhydride is 1:(3.1-3.3).

3. The bactericidal composition containing oregano according to claim 1, characterized in that, In step S2, the molar ratio of the long-chain alkyl-modified triazine compound to the amino-polyethylene glycol hydroxyl group is 1:(3.2-3.5).

4. The bactericidal composition containing oregano according to claim 1, characterized in that, In step A1, the molar ratio of 12-bromo-1-dodecene to formic acid is 1:1.

2.

5. The bactericidal composition containing oregano according to claim 1, characterized in that, In step A2, the molar ratio of the epoxy compound to rosmarinic acid is 1:1.

1.

6. The bactericidal composition containing oregano according to claim 1, characterized in that, In step A3, the molar ratio of the alkyl-modified rosemary to dopamine-polyethylene glycol-carboxyl is 1:1.

2.

7. The bactericidal composition containing oregano according to claim 1, characterized in that, The plant-derived bactericide is one of menthol and Cnidium monnieri.

8. The bactericidal composition containing oregano according to claim 1, characterized in that, The preservative is potassium sorbate.

Images